sign in sign up
<<
Home , 3 Geminorum, 81 Geminorum, Analemma, Coma Supercluster, Draco Dwarf, Draco Supercluster

08-06-2015

Atoms to

How can we say so much about small twinkling specks of in the ?

Mayank N Vahia Tata Institute of Fundamental Research Homi Bhabha Road, Mumbai 400 005

Atoms to Astronomy 1 Atoms to Astronomy 2 [email protected]

We study the light from the distant objects with increasing accuracy and correlate it to our knowledge of material on

We measure and compare size, shape, distance and variability. We look at how the intensity light is divided between various Part 1:Technology of observation . We look at how light intensity changes with time. We try and do this from the smallest possible region of the sky. We correlate it to our understanding of how matter behaves in our laboratories to what we see from the heavens.

Atoms to Astronomy 3 Atoms to Astronomy 4

Measuring angle in sky

Distances in the sky are given in angular measure. Angular measure can be approximated using ones hand as show above.

5

1 08-06-2015

Local Sky – Finding Sky Charts

The limiting from a dark site is between 5 and 6.

The changing sky

As the Earth the , the Sun appears to move eastward along the . At midnight, the on our meridian are opposite the Sun in the sky.

Using to magnify the images of objects

10

Main Types of optical telescopes

• Refracting

1: Primary 2:Secondary lens 3: Eye 4: Object 5: first inverted image 6: Final inverted image 7: Telescope tube • In , the secondary lens is replaced by a reflecting that focuses the beam. This significantly shortens the telescope size and is more tolerant of manufacturing problems. They can be of a variety of types. 11

2 08-06-2015

Stereoscopic Telescope

• are actually two refracting telescopes hinged together.

• 7 X 50mm means the binocular magnifies the object 7 and 50mm is the size of the lens.

16

Properties of a telescope Resolution • : Point where the is focused? Longer the focal length, the narrower the . Thinner the • θ: better. sin(θ) = 1.22 λ/D • Angular : Decides how big the object will θ is in radians be. The thicker the lens the better. λ the in meters • Field of View: Decides how much of the sky you can D the diameter of the lens in m. observe at a time. The bigger the lens the better. Note that this is the theoretical limit. • Resolving Power: Decides how close by objects can • Spatial resolution, Δℓ: be resolved. The thicker the lens the better. Δℓ = 1.22 f λ/D • Limiting Magnitude: Decides what is the faintest object where f is the focal length of the objective you can see. 17 18

3 08-06-2015

Chromatic Aberrations

19 Atoms to Astronomy 20

Spherical Aberration

21 22

Astigmatism Distortion

• problem arising from a non-constant magnification of a lens is called distortion.

Astigmatism is caused because the focal length along one diameter differs from that along another. When the object is on the axis, the two planes are identical, so there is no astigmatism. When the object is not focused, it is seen like an . 23 24

4 08-06-2015

Focal plane instrumentation

The capabilities of a telescope are critically dependent on the type of detectors put at the . These can be: – Photographic films – CCD Camera – Spectroscopic devices like gratings – Any other light to electricity converting device

They then have the appropriate ‘read out’ electronics which feed the signal to a computer for analysis.

25

Telescopes mounts Types of Mounts for Optical Telescopes

– Alt- Mount: mounts allow telescopes to be moved in altitude, up and down, or azimuth, side to side, as separate motions.

– Equatorial Mount: A mount for instruments that follows the rotation of the sky () by having one rotational axis parallel to the Earth's axis of rotation.

– Dobsonian Mount: Simplest and easy to use mount for quick observations with large amateur 27 Atoms to Astronomy 28 telescopes,

The Seasons

Part 2: Quantifying the sky

29 30

5 08-06-2015

Rising Point of Sun Over the

21/7 21/8 21/9 21/10 21/11 21/6 21/5 21/4 21/3 21/2 21/1 21/12

Angle depends on E SS WS

Rise Points A Gnomon Astronomy in stones 32

Sunrise on:

Direction of Sun

Summer on:

Solstice tml http://www.jaloxa.eu/resources/daylighting/sunpath.sh Summer Solstice Equinox

Winter Solstice Summer Solstice Winter

Solstice Direction of Shadow Movement of Sun over 6 6 MONTHSover ofMovement Sun

Direction of shadow during the 34

Two Circles Motion of the stars

The Celestial Stars near the north celestial pole are circumpolar and never set. – Projection of the Earth‚equator on We cannot see stars near the celestial pole. the sky The Ecliptic – Relative path of the Sun in the sky for a terrestrial observer This never sets Their Crossing Point Vernal (Spring) Equinox (ascending node) ♈ Autumnal Equinox (descending node) This star Inclination of Ecliptic w.r.t. : 23.5° never rises

35

6 08-06-2015

Geometry of the Sphere Geometry of the Sphere

 Great Circle: Any circle on the surface of sphere. Its centre coincides with centre of the sphere.  Cosine Rule

 Small circle: All other circles on the surface  cos(c) = cos(a) cos(c) of the sphere. + sin(a) sin(b) cos(C)  Spherical angle: Angle between the planes  Sine Rule of any two great circles.  Sin(A) / sin(a) = sin(B) / sin(b) = sin(C) / sin(c)  Properties of Spherical triangle:  Analogue of Cosine Rule  All three sides are arcs of great circles.  sin(a) cos(B) = cos(b) sin(c) – sin(b) cos(c) cos(A)  Any two sides are together greater than the third side. o  The sum of the three angles is greater than 180 .  Four Parts Formula o,  Each spherical angle is less than 180  cos(a) cos(C) = sin(a) cot(b) – sin(C) cot(B)

37 38

Lines of

Lines of

Spring Equinox

39

Equatorial Coordinates (absolute) The extraterrestrial solar illuminance (Eext): Declination:  푑푛−3 퐸푒푥푡 = 퐸푠푐 1 + 0.033412. cos 2휋 365 Right Ascension (RA): Angle from VE in : • dn=1 on January 1 and so on.  = t - H (Eastwards) • dn-3 is used, because in modern times Earth's perihelion, the Both coordinates are closest approach to the Sun and the maximum E occurs ext time and place independent around January 3 each year. Vernel Equinox (VE) changes • The value of 0.033412 is determined knowing that the ratio between the perihelion (0.98328989AU) squared and the its position slowly aphelion (1.01671033 AU) squared is approximately 0.935338.  Another parameter is needed  Stardate Earth's axis is not fixed in space (Precession, Nutation)  Reference to star date of VE, e.g. 1950.0 or 2000.0

Atoms to Astronomy 41 42

7 08-06-2015

Ecliptic Coordinates Transformations

of the Earth, e = 23.439281°  Ecliptic Latitude b: North or south of the Ecliptic to Equatorial Ecliptic -90o to +90o  sin  = sin e sin l cos b + cos e sin b  cos  cos  = cos l cos b  Ecliptic l:  sin  cos  = cos e sin l cos b - sin e sin b 0o to 360o from VE eastwards Equatorial to Ecliptic  Best system for  sin b = cos ε sin  - sin  cos  sin e objects.  cos l cos b = cos  cos   sin l cos b = sin e sin  + sin  cos  cos e

43 44

Galactic Coordinates Time &

 True Sun:

angle of the Sun + 12h

 Time shown by a  Mean Sun:

 Hour angle of the Sun assuming it moves with the constant agular velocity  Difference between true and mean Sun can be up to 16 min: • of the Earth is elliptical • Obliquity of the ecliptic . (= true – mean) Effect: sunrise in early January to a nearly fixed time, although day length is increasing.

Analemma

Shape created by plotting Analamma arises in the from the projection of sky as observed from the celestial plane on the Equatorial plane. same place at same time In this projection, the on different days. sun moves fastest midway of the curve.

The shape depends on

Latitude of the place (lp), inclination of orbit (e) and accentricity of orbit (e)

47 Atoms to Astronomy 48

8 08-06-2015

Equation of Time 푀 − θ + λ − α Δ푡 = λ = θ + λ ω 푝

Spring Eq Summer S Autumn Eq Winter SS

49 Atoms to Astronomy 50

Solar and Sidereal Times

 (Solar) Day: Time between two successive culminations of the Sun

 Sidereal Day: Time between two successive culminations of given distant star

 The Earth moves 1° per day around the Sun  Solar day is longer by 4 min than the sidereal day

 1Sidereal day ≈ 23h56m4s.091.

52

The Year Duration of a : Time between two successive passages of the Sun d h m s through the Vernal Equinox = 365 05 48 46 = 365.242199 d. Month type Length in days  : One revolution around the Sun w.r.t. the distant Anomalistic 27.554549878 - 0.000000010390 × Y stars 365d06h09m10s = 365.2564 d (Longer due to the Earth's precession). Sidereal 27.321661547 + 0.000000001857 × Y

 Anomalistic Year: Time between two successive passages of earth Tropical 27.321582241 + 0.000000001506 × Y through its perihelion (or aphelion) point 365d06h13m53s = 365.2596 d (Differs from sidereal year due to precession of Draconic 27.212220817 + 0.000000003833 × Y perihelion). Synodic 29.530588853 + 0.000000002162 × Y  Synodic Period: Time between two successive (same type) conjunctions of the solar system object. Y is the year since 2000  Draconic Period: Time between two successive passages through ascending node. 54 55

9 08-06-2015

The Calendar The (46 BC)

Lunar (e.g. Roman/ Jewish / Islamic / Vedic): Jewish and add an intercalary month The year has 365 days every 2.5 • 12 from Full to Full Moon or New Moon to New Moon: An extra leap day every 4th year (years divisible by 4) totalling (29.5x12=) 355 Days • Intercalary Months once in 2.5 years Average yearlength 365.25 days, •Differs by 11m14s per year ≈ 1 day every 128 years.  Modern calendar is . It is entirely a solar calendar, and the year 1 is 2013 years ago. (Many lunar calendars are much older.)

56 57

The Julian Dates

Till 1582, the Julian Calendar accumulated 10 days (VE on 11 March) Continuous day counting •Days skipped from 4 Oct. 1582 to 15 Oct. 1582 •Reference Point: 1.1.4713 BC • are only when divisible by 400  Correction by 3/400 Days, from 1/128  Accuracy: 1 day in 3300 years •Day change at noon in UT ('s night!) •Years divisible by 4000 are not leap years  Accuracy: 1 day in 20,000 years •Simple subtraction used to find # days between two events months or even year apart.  16-18 Centuries: Change implemented in Catholic countries, but •It was chosen when the Julian Calendar was being reformed for a mix of not in protestant or orthodox countries convenience and religious reason. •Prussia: 1700 Abbrevation: JD •England, American Colonies and British India: 1752 (11 Days) • Till that time the year in England began on 25th March Examples: • Fun Trivia: Washington's Birthday as per current norms is 22.2.1732, but in his time it was recorded as 11.2.1731. Similarly Shivaji‘s birthday, recorded in Julian Calendar •1 Jan 1980, 00:00 UT: JD 2,444,239.5000 is celebrated 11 days after the true date! •12 Jan 2011, 13:30 IST: JD 2,455,936.8337

 Russia: 1918 (13 Days) 58 59

Part 3:Telescopes at other wavelengths

60 61

10 08-06-2015

Types of Telescopes Atmospheric transmission • (λ: cm to meters) • Microwave telescope (λ: mm to cm) • IR () Telescope (λ: 7000 – 10,000 A0) • Optical Telescope (λ: 4000 – 7000 A0) • UV Telescope (λ: 100 – 4000 A0) • X- Telescope (λ: 0.1 – 100 A0) • Gamma Ray Telescope (λ: <0.1 A0) • Cosmic Ray Telescopes (charged particles) (1 A0 = 10-10 meters)

62 63

Ooty Radio AtacamaWilkinson Large Microwave Millimeter/Submillimeter Anisotropy Probe Telescope COBE Cosmic Background Explorer Array(ALMA) (WMAP)

Giant Meterwave 64 65 Radio Telescope

Spitzer

66 67

11 08-06-2015

Hopkins Ultraviolet Telescope Optical Telescope

The ‘Keck Telescope’ in Hawaii is the world's largest optical telescope. It doesn't have just one big mirror, it has 36 little that fit together like bathroom tiles. With the help of a computer, these little mirrors work together like one big 10 meter mirror. 68 69

Chandra X-Ray Telescope HESS(HighCompton Energy Gamma Stereoscopic Ray System ) GammaObservatory-Ray Telescope

70 71

Multi-wavelength Crab

Chandra image: 33 73 Rotations/sec

12 08-06-2015

LIGHT APPEARS WHEN Part 4: of astronomy CHARGED PARTICLES CHANGE THEIR VELOCITY

Atoms to Astronomy 74 Atoms to Astronomy 75

Atoms to Astronomy 76 Atoms to Astronomy 77

NOT TO SCALE

Atoms to Astronomy 78 Atoms to Astronomy 79

13 08-06-2015

Energy Level Diagram for a

NOT TO SCALE E is Energy  1 1  h is the Plank’s Constant E  hv  Rhc    2 2   is the frequency of light  n1 n2  R is Rydberg Constant

n1 and n2 are the energy levels

Atoms to Astronomy 80 Atoms to Astronomy 81

• Atomic lines are decided by the structure of the Nucleus. • Molecular lines depend on the nature of chemical bonding

Atoms to Astronomy 82 Atoms to Astronomy 83

102 Black body radiation

1

Light as electromagnetic radiation 10-2

)

1 -

10-4 rad -6

1 10 - 1,000,0000 K

Hz 10-6 100,000 K 2 - 10,000 K -8 10 6,000 K 1,000 K 10-10 100 K 10-12

-14 Power (Wm Power 10

10-16

10-18

10-20

1022

10-9 10-8 10-6 10-4 10-2 1 102 104 λ (m)

γ-rays X-rays UV Opt IR Microwave and radio wave Atoms to Astronomy 84 AtomsWavelength to Astronomy (m) 85

14 08-06-2015

Light Polarisation Maxwell or Newton

• Maxwell’s theory of electromagnetism suggests that the light arises from oscillating electric and magnetic field and the speed of propagation of this disturbance in vacuum has a fixed velocity and velocity of light in a medium cannot be changed. • Newton insisted that velocities can be co-added. • Maxwell was correct. • So Newtonian physics had to be modified in a manner first suggested by Einstein in his Special .

Atoms to Astronomy 87 Atoms to Astronomy 88

Special theory of Relativity

It is a basic property of Nature that:

Velocity of Light in vacuum is constant and is the fastest any signal can travel. If an object appears to move with a constant velocity with respect to another, it is impossible to say which is moving and which is not. This has significant consequences.

Atoms to Astronomy 89 Atoms to Astronomy 90

Consequences

• Because velocity of light is constant: – space and time must contract. – Acceleration must change momentum and not just velocity of an object and hence objects become heavier as they move faster – No object with finite can move at velocity of light and no object of zero mass can move at a slower velocity! – It also gives the famous equation E = m c2.

Atoms to Astronomy 91 Atoms to Astronomy 92

15 08-06-2015

Gravity - 1 Gravity - 2 • Gravity is the attractive force that attracts two bodies of mass M • It also defines “Keplerian Velocity”: In order for 퐺푀푚 and m with a force which is given by 퐹 = 푖 where i is the an object to remain in stable revolution around 푟2 unit vector in the line joining the centre of mass of the two another, it must have a velocity so that gravity objects. and centrifugal force are balanced. • The inverse square law implies that in general, the orbit of an object experiencing the • From this, one can derive Kepler’s 3 laws: gravitational attraction of another body will – Each goes around the sun in an elliptical orbit with the Sun at one focus of the ellipse. undergo motion best explained by conic curves – cover equal in equal times. (ellipse, parabola or hyperbola) defined by initial – The square of the period of the revolution (T) of the planet is proportional conditions. to the cube of the semi-major access (a) of the orbit. • Also, the centre of mass of the two objects going around each other will be the stable point around which both the objects will revolve.

Atoms to Astronomy 93 Atoms to Astronomy 94

Lagrangian points ROCHE LOBE Problems

The Lagrangian points libration points • However, this is not fully satisfactory and cannot are five positions between 2 gravitating bodies, where a small explain precession of orbits etc. object affected only by gravity can theoretically be stationary relative to two larger objects (such as a • This led Einstein to expand it into a larger with respect to the Earth and Moon). formulation called General Theory of Relativity. The Lagrange points mark positions where the combined gravitational pull of the two large provides precisely the centripetal force • Newton’s laws are a special case of General required to rotate with them. Theory of relativity when the masses and

Balanced potential point: speeds are small. • Object will be balanced Equipotential surfaces • Mass transfer occurs from here Atoms to Astronomy 95 Atoms to Astronomy 96

General theory of Relativity General Theory of relativity states that:

Influence of Gravity is identical to that of sitting in an accelerated frame. Identifying the curvature of space-time with Gravity. It becomes important in the presence of Strong gravitational fields such as those existing near compact objects. Atoms to Astronomy 97 Atoms to Astronomy 98

16 08-06-2015

Quantum Mechanics

• Complications arise the observer and the observed are intermixed!

• Since energy and mass are equivalent, one can imagine mass as a packet of energy and wavelength.

• Light which is a packet of energy can be considered as if it was a solid object.

• The wavelength of a matter object is in fact the probability of finding the object somewhere etc.

• It also produces some interesting effects such as: – stable electron orbits. – Tunnelling. Atoms to Astronomy 99 Atoms to Astronomy 100

Three Generations of Matter Other concepts I II III Forces

Mass Charge • Pressure balance and Spin gravity. Name Protons, neutrons etc.

• Supersonic motion and compression of matter.

Electrons etc.

Atoms to Astronomy 101 Atoms to Astronomy 102

This page was copied from Nick Strobel's Astronomy Notes. Go to his site at www.astronomynotes.com for the updated and corrected version. 300 400 500 600 700 1000 nm Atoms to Astronomy 103 Atoms to Astronomy 104

17 08-06-2015

H2 (absorption) For normal incidence: n l = d sin() Hydrogen

11Na doublet 0.6 nm apart

He Noble gas

10Ne Noble gas

Fe(absorption)

Atoms to Astronomy 105 Luminiscent lamp Atoms to Astronomy 106

Atoms to Astronomy 107 Atoms to Astronomy 108

 v  v  n' n o  Hot Dense (Opaque) Hot, thin (transparent) Cool in front of hot black body    v  vs  THERMAL EMISSION LINE ABSORPTION LINE

Atoms to Astronomy 109 Atoms to Astronomy 110

18 08-06-2015

red Doppler Shift Broadening of spectral lines yellow Light from1 stationaryv c v' v star 1 v c blue red yellow Light from star moving away from us (red shift)

blue red Light from object yellow moving towards us

blue (blue shift)

Atoms to Astronomy 111 Atoms to Astronomy 112

Southern Sky

Part 5: Measuring Distances

Northern Sky

Atoms to Astronomy 113 Atoms to Astronomy 114

Difference in brightness can arise because a) The stars are at different distances b) Stars are of different intrinsic brightness

Atoms to Astronomy 115

19 08-06-2015

Magnitudes

(m)

푓표푏푗푒푐푡 푚 = −2.512 퐱 log 푓푟푒푓.

2.5125 ≈ 100 푓1 푚1 − 푚2 = −2.512 퐱 log 푓2

푚푐표푚푏푖푛푒푑 ≠ 푚1 + 푚2

푓푐표푚푏푖푛푒푑 = 푓1 + 푓2

f is the flux received from the source

 Finding combined magnitudes of binary stars / star clusters

Magnitudes

(S)

 Magnitude of extended object of area A 2  Mag / arcsec 푆 = 푚 + 2.512log 퐴 

 All stars at 10pc 푀 = 푚 + 5 − 5log 퐷

 All planets at 1AU from the Earth and the Sun

1 Dpc  parcsec

For stars at an angle, an additional cos() factor has to be considered Atoms to Astronomy 121 Atoms to Astronomy 122

20 08-06-2015

Measuring distances to involves using some selected objects

These are objects of known intrinsic brightness. Hence a ratio of their apparent brightness to their intrinsic (absolute) brightness gives their distance.

For objects inside our an additional parameter comes from extinction where distance is measured by and ISM by extinction.

Atoms to Astronomy 123 Atoms to Astronomy 124

Measuring distances to galaxies Variable Stars as distance indicators involves using some selected objects STANDARD CANDLES

These are objects of known intrinsic brightness.

Hence a ratio: How bright a star appears How bright it really is

gives its distance.

©Terrence Tao, UCLA Atoms to astronomy 125 Atoms to Astronomy 126

©Terrence Tao, UCLA

Atoms to Astronomy 127 Atoms to Astronomy 128

21 08-06-2015

Additional complications

• When distance measured by two different methods gives different answers, a wealth of new data emerges on: – The matter that is in between us and the object: • close to it or • in the general space in between – Manner in which the object itself is behaving

Atoms to Astronomy 129 Atoms to Astronomy 130

Great Wall Super Cluster: Galaxies up to 250 million light years away. It measures 200 million by 600 million light years in area with a thickness of only 20 million light years. At 1016 solar masses the Coma- make up the bulk this wall. In the schematic is only part of the great wall--the Coma --is visible. The is not pictured in the schematic but it would be up above and adjacent to the . Atoms to Astronomy 131 Atoms to Astronomy 132

Spectroscopic Binaries

Part 6: Moving objects

Atoms to Astronomy 133

22 08-06-2015

Molecules in clouds and their movement

Atoms to Astronomy 135 Atoms to Astronomy 136

Super massive black hole in the Iron line in galaxy NGC4258 compact objects

Quasi periodic oscillations of 0.01 to 500 Hz and direct evidence of BH

MCG-6-30-16 - 400 ks long XMM observation

Atoms to Astronomy 137 Atoms to Astronomy 138

Part 7: Multicolour

Atoms to Astronomy 139 Atoms to Astronomy 140

23 08-06-2015

Astrophysical Processes and energy

Physical Process Atomic and molecular transitions; Reprocessing of star Plasma - Magnetic field interaction light by cool objects RADIO MICROWAVE FAR IR IR

Energy: 10-10 10-9 10-8 10-7 10-6 10-5 10-4 10 -3 10-2 10-1 100 eV Temp: (K) 3 300

Sites: Large scale magnetic fields, jets, shocks, dust clouds, Dust, protostar , Star forming regions Phys. Thermal, Middle Inner atomic Nuclear Exotic > Extreme shocks Proc.: outer atomic atomic transitions process Processes Strong fields transitions transitions Gal size accn Opt UV EUV X-ray Gamma Rays

Energy: 100 101 102 103 104 105 106 10 7 108 109 1010 upto 1021 eV Temp (K): 3000 30,000 106

Sites: Atmospheric Active magnetic regions Collision of energetic particles, Magnetospheres of Phenomena Stellar atmosphere SN explosions Pulsars, SN Shock SN Remnants and exotic Exotic particles Galactic jets, BH Objects Radio loud Galaxies, Atoms to Astronomy 141 GRB, Strings?

Andromeda, IR, Wide field Andromeda, Optical IR Surveyor

Andromeda, IR, Spitzer 24 micron Andromeda, UV

Atoms to Astronomy 143 144

Crab in: Optical, near UV, Far UV and X-rays Crab in Optical and X-rays

Atoms to Astronomy 146

24 08-06-2015

Problems in observing region multicolour universe Visual Far Infrared • Different radiation has different wavelength. Hence – Different objects have different brightness in different radiation. – Radiation reacts differently with material and the detectors of radiation are highly wavelength dependant. – The atmosphere has different permeability to different radiation. Orion

Atoms to Astronomy 147 Atoms to Astronomy 148

Part 8:Solar System

Atoms to Astronomy 149 Atoms to Astronomy 150

Spectrum of the Sun

Atoms to Astronomy 151 http://www.cfa.harvard.edu/ssp/stars_planets/solarspectrum.htmlAtoms to Astronomy 152

25 08-06-2015

Heating: Nano flares or wave heating?

Atoms to Astronomy 153 Atoms to Astronomy 154

Atoms to Astronomy 155 Atoms to Astronomy 156

Giant plasma cell flow paths on the sun for June 8, 2010. The underlying cell pattern shows westerly winds in red and easterly Granulation and super granulation Images winds in blue. © David Hathaway/NASA from Science 6 December 2013: Vol. 342 no. 6163 pp. 1217-1219 , GiantOur Convection solar system 157 Atoms to Astronomy 159 Cells Found on the Sun. David H. Hathaway, Lisa Upton, Owen Colegrove http://www.see.murdoch.edu.au/resources/info/Res/sun/

26 08-06-2015

The Multi wavelength Sun Looking at the Sun in different wavelengths of light reveals different parts of the Sun with different temperatures.

2 dark spots 2 bright spots

Visible light Fe XII Extreme (white light): Ultraviolet light: Wavelength = Wavelength = 400-700 nm 19.5 nm T = 5,800 K T = 1.5 million K

2 bright spots 2 bright spots

He II Extreme Fe IX, X Ultraviolet light: Extreme Wavelength = Ultraviolet light: 30.4 nm Wavelength = T = 60,000- 17.1 nm 80,000 KOur solar system T = 1 million160 K Atoms to Astronomy 161

Atoms to Astronomy 162 Atoms to Astronomy 163

11,000 year variability of Solar activity

Atoms to Astronomy 164 Atoms to Astronomy 165

27 08-06-2015

Movement of plasma

Solar magnetic field

The unusual minimum of cycle 23 caused by meridional plasma flow variations, Dibyendu Nandy, Andrés Muñoz-Jaramillo, & Petrus C. H. Nature Volume: 471, Pages: 80–82 03 March 2011

As each cycle progresses, the movement of this plasma (black loop) shifts the solar magnetic fields (gold strands)—from which erupt—from the sun's midlatitudes to its equator. An extended minimum occurs whenever the plasma moves quickly at the beginning of a cycle—preventing a large buildup of magnetic fields—but then slows down toward the end, delaying the onset of the next cycle.

Atoms to Astronomy 166 Atoms to Astronomy 167

Atoms to Astronomy 168 Atoms to Astronomy 169

Atoms to Astronomy 170 Atoms to Astronomy 171

28 08-06-2015

Dense molten metal particles pool together Dust and grains begin to clump together. The growing body heats up and and sink towards the center of the body. Collisions between larger and larger Lighter silicate liquid, or magma, rises begins to melt. towards the surface, leaving denser solid objects produce an -sized minerals in the mantle.

Meteorites are the main The result: a layered, or evidence we have for the Atoms to Astronomy 172 differentiated, body with evolution of the Solar System. 173 core, mantle, and crust

Solar System visible to unaided eye

Our solar system 174 Atoms to Astronomy 175 Nature, 511, 222 2014

Solar System at the beginning of 20th Solar System of my text book (40 years ago)

Atoms to Astronomy 176 Atoms to Astronomy 177

29 08-06-2015

Solar System

11 DEarth

109 DEarth

Venus

Atoms to Astronomy 178 Atoms to Astronomy 179

Mercury

Atoms to Astronomy 180 Atoms to Astronomy 181

Inside . Recent measurements suggest a rather unusual interior structure for Mercury. The rocky mantle is comparatively thin and is sandwiched between a surface volcanic crust and an underplated iron-sulfide “anticrust.” The size of Mercury’s likely inner core of solid iron (plus dissolved metallic silicon) is poorly constrained, as are possible immiscible zones in the molten outer core. How http://www.collectspace.com/ubb/Forum33/HTML/000008.html much of Mercury’s crust is volcanic, and how much (if any) may be a primitive fl otation crust, is also unknown. William B. McKinnon, Science, 336 162, April 2012 Atoms to Astronomy 182 Atoms to Astronomy 183

30 08-06-2015

Planet Mercury

• Mercury is the smallest and closest to the Sun of about 88 Earth days. • Greatest temperature variation of all the planets, – 100 K at night to 700 K during the day at some equatorial regions. – The poles are constantly below 180 K (−93 °C). 1 • Has the smallest tilt (about ⁄30 of a degree), but largest . At aphelion, Mercury is about 1.5 times as far from the Sun as it is at perihelion. • Its rotation axis is perpendicular to its plane of rotation so it has no seasons. • As seen relative to the fixed stars, it rotates exactly three times for every two revolutions it makes around its orbit. • As seen from the Sun, it appears to rotate only once every two Mercurian years. An observer on Mercury would therefore see only one day every two years. • Permanently shadowed craters near Mercury’s poles have temperatures less than - 280F (-173C), and water ice is stable on their dark inner surfaces. Some of the polar ice is covered by a mysterious dark organic material that researchers still do not understand.

Atoms to Astronomy 184 Atoms to Astronomy 185

Atoms to Astronomy 186 Atoms to Astronomy 187

Planet • Venus Length of a year 224.7 Earth days, length of a day is 243 Earth days. • It can reach an apparent magnitude of −4.6, bright enough to cast shadows. • Its elongation reaches a maximum of 47.8°. • It differs from Earth because: – has the densest atmosphere of the four terrestrial planets, consisting of more than 96% carbon dioxide – The atmospheric pressure at the planet's surface is 92 times that of Earth's. – With a mean surface temperature of 735 K (462 °C), Venus is by far the hottest planet in the Solar System • Venus is shrouded by an opaque layer of highly reflective clouds of sulfuric acid.

Atoms to Astronomy 188 Atoms to Astronomy 189

31 08-06-2015

Atoms to Astronomy 190 Our solar system 191

Planet Earth • It the densest and fifth-largest of the eight planets in the Solar System. • It will be able to continue to support life range from 500 million years (myr), to as long as 2.3 . • Surface is divided into several rigid segments, or tectonic plates, that migrate across the surface over periods of many millions of years. • About 71% of the surface is covered oceans. • The planet's interior remains active, with a solid iron inner core, a liquid outer core that generates the magnetic field (0.3 gauss at poles), and a thick layer of relatively solid mantle. • During one orbit around the Sun, the Earth rotates about its own axis 366.26 times, creating 365.26 solar days, or one sidereal year. • The Earth's axis of rotation is tilted 23.4° away from the perpendicular of its orbital plane, producing seasons with a period of one tropical year (365.24 solar days). • The Moon is Earth's only . It began orbiting the Earth about 4.53 billion years ago. • The Moon's gravitational interaction with Earth stimulates ocean tides, stabilizes the http://astronomy.nmsu.edu/tharriso/ast105/Ast105week08.ht axial tilt, and gradually slows the planet's rotation. ml Our solar system 192 Atoms to Astronomy 193

Earth and life • Earth is able to support evolving life because: – It is at correct distance from the Sun – It is large enough to have a good inert atmosphere – It is warm enough to have liquid water – It has a good inclination ensuring seasons – It is in a nearly circular orbit which means seasonal changes are few – It has a magnetic field strong enough to prevent damage from radiation – It has an Ozone layer to protect from UV light – It has an active geology to keep churning material. – It has moon to stabilise it – Outer planets protect against meteors. Atoms to Astronomy 194 Atoms to Astronomy 195

32 08-06-2015

Atoms to Astronomy 196 Atoms to Astronomy 197

Moon formed from Earth within the first 100 million years since the formation of the Solar System about 4.5 billion years ago. Science 17 APRIL 2015 • VOL 348 ISSUE 6232 Atoms to Astronomy 198 Atoms to Astronomy 199

Blue: water and hydroxyl molecules at three micrometers.

Green brightness of the surface in infrared radiation at 2.4 micrometers

Red: Iron-bearing mineral (pyroxene) detected at 2.0- micrometer infrared light.

Photo Credit: NASA

08/06/2015 India in Space 200 08/06/2015 India in Space 201

33 08-06-2015

Above: A surface temperature map of the lunar made by LRO's Diviner Lunar Radiometer Experiment . The map contains several intensely cold impact craters that could trap water ice and other icy compounds commonly observed in . The approximateAtoms maximum to Astronomy temperatures at which these compounds would202 be 08/06/2015 India in Space 203 frozen in place for more than a billion years are noted at right. http://news.sciencemag.org/space/2015/03/lopsided-ice-moon-points-past-shift-poles?utm_campaign=email-news-weekly&utm_src=email

Water on Moon • Water on the Moon comes from 3 distinct sources: Sun – Comets – Solar wind reaction Dust Tail – Primordial Earth • Apparently water moves at a subterranean level depending on porosity and pressure gradients. A computer simulation of Earth's dust tail/ring seen from a vantage • Evaporating water has also been seen. point outside our solar system. Colours indicate density; purple is lowest, red is highest. Credit: Christopher Stark, GSFC Atoms to Astronomy 204 Atoms to Astronomy 205

Atoms to Astronomy 206 Atoms to Astronomy 207

34 08-06-2015

A map of MAVEN's Imaging Ultraviolet Spectrograph (IUVS) auroral detections in December 2014 overlaid on ’ surface. The map shows that the aurora was widespread in the northern hemisphere, not tied to any geographic location. The aurora was detected in all observations during a 5-day period. Credits: University of Colorado

Atoms to Astronomy 208 Atoms to Astronomy 209

November 2013

Credit: NASA/JPL-Caltech/SAM-GSFC/Univ. of Michigan

This graphic shows tenfold spiking in the abundance of methane in the Martian atmosphere surrounding NASA's Curiosity Mars rover, as detected by a series of measurements made with the Tunable Laser Spectrometer instrument in the rover's 210 Sample Analysis at Mars laboratory suite. Image Credit: NASA/JPL-Caltech 211

Atoms to Astronomy 212 Atoms to Astronomy 213

35 08-06-2015

Planet Mars

• It is smallest planet in the Solar System. • It has impact craters, volcanoes, valleys, deserts, and polar ice caps. • The tilt that produces the seasons. Mount Olympus Mons on Mars, the second highest known mountain within the Solar System (the tallest on a planet), and of Valles Marineris, one of the largest canyons. • Mars has two known , and , which are small and irregularly shaped. • Mars once had large-scale water coverage on its surface with large quantities of water ice at the poles and at mid- and chemical compounds containing water molecules. • Mars has scattered magnetic field • Mars also seems to emit Methane.

Atoms to Astronomy 214 Atoms to Astronomy 215

Atoms to Astronomy 216 Atoms to Astronomy 217

Thermal images of Great Red Spot: Part of the Changing waist line of dynamo that drives the 35,000-kilometer- wide storm.

Brightest orange- red zone in the central part of the spot runs up to 4°C warmer than the rest of the storm.

Its average surface temperature is about -160°C,

From large telescopes in Chile and Hawaii

Atoms to Astronomy 218 Atoms to Astronomy 219

36 08-06-2015

Planet Jupiter

• Jupiter: largest planet in the Solar System with mass 1/1000 of that of the Sun 2.5Xmass of all other planes combined. • Its apparent magnitude can be −2.94 – bright enough to cast shadows. • It is composed of hydrogen with a quarter of its mass being helium, although helium only comprises about a tenth of the number of molecules. • It may also have a rocky core of heavier elements, but like the other gas giants, Jupiter lacks a well-defined solid surface. • The outer atmosphere is segregated into several bands at different latitudes, resulting in turbulence and storms along their interacting boundaries. • A prominent result is the Great Red Spot, a giant storm that is known since the 17th century • Surrounding Jupiter is a faint planetary and a powerful magnetosphere. • There are also at least 67 moons, including the four large moons called the that were first discovered by in 1610. Ganymede, the largest of these moons, has a diameter greater than that of the planet Mercury.

Atoms to Astronomy 220 Atoms to Astronomy 221

Atoms to Astronomy 222 Atoms to Astronomy 223

Atoms to Astronomy 224 Atoms to Astronomy 225

37 08-06-2015

The Galilean moons, compared to Earth's Moon Diameter Mass Orbital radius Orbital period Name km % kg % km % days %

Io 3643 105 8.9×1022 120 421,700 110 1.77 7

Europa 3122 90 4.8×1022 65 671,034 175 3.55 13

Ganymede 5262 150 14.8×1022 200 1,070,412 280 7.15 26

Callisto 4821 140 10.8×1022 150 1,882,709 490 16.69 61

Atoms to Astronomy 226 Atoms to Astronomy 227

Cyclone on the ScienceShot: Mysterious Hexagon May Reveal north Length of 's Day 7 May 2014 2:15 pm pole of NASA/JPL-Caltech/SSI/Hampton University Fixed above Saturn’s is something as Saturn beguiling as Jupiter’s Great Red Spot: a hexagonal storm kept in place by a peculiar jet stream. Now, planetary scientists say that the rotation of the hexagon could most accurately reflect the length of Saturn’s Size of the eye short-lived day: 10 hours, 39 , and 23 . Like the other gas giants, Saturn lacks a solid surface 2000 km that can be used to measure its rotation period; surficial atmospheric features at the equator move faster than at the poles. Many planetary scientists use magnetic-field radio emissions as a way to calculate the rotation period, because those emissions are assumed to originate from deep within the planet’s interior, where the rotation period is more constant. At Saturn, however, this technique has proved to be problematic: Those emissions differ by about 15 minutes between the northern and southern hemisphere. The hexagon could be the key to a more constant rotation rate. Publishing in Geophysical Research Letters, researchers combined images from the Cassini spacecraft spanning 5.5 years and found that the hexagon’s rotation period barely changed. They suggest that the storm, which could Via NASA: “Image taken with the Cassini spacecraft narrow-angle camera on Nov. 27, 2012, using a combination extend hundreds of kilometers below the surface, is of spectral filters sensitive to wavelengths of near-infrared light. The images filtered at 890 nanometers are intimately coupled with the interior, and therefore a good projected as blue. The images filtered at 728 nanometers are projected as green, and images filtered at 752 marker for the planet’s true rotation period. nanometers are projected as red. In this scheme, red indicates low clouds and green indicates high ones. The Atoms to Astronomy 228 he long-term steady motion of Saturn's hexagon and the stability of its enclosed jet stream under seasonal changes view was acquired at a distance of approximately 261,000 miles (419,000 kilometers) from Saturn and at a sun- 1.A. Sánchez-Lavega1,2,*, et al;. Geophysical Research Letters Volume 41, Issue 5, pages 1425–1431, 16 March 2014 Saturn-spacecraft, or phase, angle of 94 degrees. Image scale is 1 mile (2 kilometers) per pixel.”

Atoms to Astronomy 229

Planet Saturn • Saturn's interior is composed of a core of iron, nickel and rock (silicon and oxygen compounds), surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium and an outer gaseous layer. • The planet exhibits a pale yellow hue due to ammonia crystals in its upper atmosphere. Electrical current within the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is slightly weaker than Earth's and around one-twentieth the strength of Jupiter's. • The outer atmosphere is bland and lacking in contrast, although long-lived features can appear. Wind speeds on Saturn can reach 1,800 km/h, faster than on Jupiter, but not as fast as those on . • Saturn has a prominent ring system that consists of nine continuous main rings and three discontinuous arcs, composed mostly of ice particles with a smaller amount of rocky debris and dust. Sixty-two known moons orbit the planet; fifty-three are officially named. • This does not include the hundreds of "moonlets" within the rings.

About once every Saturn year—29.5 of our years—a mysterious great white spot erupts in the planet's atmosphere that can outshine the planet’s brilliant rings. • Titan, Saturn's largest and the Solar System's second largest moon, is larger than This image shows the last outbreak, which began as a spot in the north in late 2010 that then spread into a band bigger than Earth. Now, planetary scientists writing online today in Nature Geoscience propose that these periodic superstorms arise from water. Water vapor is heavier than Saturn's dominant gases, the planet Mercury and is the only moon in the Solar System to retain a substantial hydrogen and helium, so as rain or snow ferries water from the upper atmosphere to the lower, the lower layer becomes denser than the air above it, a stable atmosphere configuration that the scientists calculate keeps a lid on rising warm air for . During that time, however, the upper atmosphere gradually cools by radiating warmth into space and gets so cold that it becomes denserAtoms than the to air Astronomy below. Then, the warm moist air below finally rushes upward to trigger230 a rash of Atoms to Astronomy 231 thunderstorms so enormous that observers marvel at them through backyard telescopes. Science| DOI: 10.1126/science.aab2475 (2015)

38 08-06-2015

Evolution of a corrugation pattern after the entire toy ring has been tilted along a constant line by 0.5°.

A leading one-armed spiral pattern forms due to the winding of orbital planes.

After ∼30 years the pattern would appear as tight as observed in Saturn's rings. However, the vertical amplitude is exaggerated by a factor of ∼100,000.

Parts of the ring are in its own shadow (alternating darker zones lit by multiple reflections). In Saturn's rings, very subtle brightness variations discernible only when the Sun is shining near the ring plane.

Atoms to Astronomy 232 Atoms to Astronomy 233

Atoms to Astronomy 234 Atoms to Astronomy 235

Atoms to Astronomy 236 Atoms to Astronomy 237

39 08-06-2015

Enceladus

In its latest flyby of Enceladus, the Cassini spacecraft has captured a veritable array of fountains spraying ice crystals and water above the moon's southern pole—a phenomenon unique in the solar system. Tidal forces created by gravity from the giant ringed planet and its other moons open fissures called "tiger stripes" in the deeply frozen surface of Saturn's moon Enceladus harbors a large underground ocean, furthering scientific interest in the moon as a potential home to Enceladus. The gravity also warps the moon's ice and creates enough heat to force the ice and water out of the extraterrestrial microbes. New data on the moon's gravity field reported in the April 4, 2014, edition of the journal Science strengthen fissures and into space. This image, taken 21 November, will be the last of the geysers for a long time. Soon that region the case for an ocean hidden inside Enceladus. The gravity measurements suggest a large, possibly regional, ocean about 10 will be shaded from the sun for 15 years, hiding the fountains from Cassini's cameras. kilometers deep, beneath an ice shell about 30 to 40 kilometers thick. The subsurface ocean evidence supports the Atoms to Astronomy 238 inclusion of Enceladus among the most likely places in Atomsour solar to system Astronomy to host microbial life. Before Cassini reached Saturn239 in July 2004, no version of that short list included this icy moon, barely 300 miles (500 kilometers) in diameter. Nasa http://science.nasa.gov/science-news/science-at-nasa/2014/03apr_deepocean/

Saturn's major , compared to Earth's Moon Name Diameter Mass Orbital radius Orbital period (km) (kg) (km) (days)

396 0.4×1020 185,000 0.9 Mimas (12% Moon) (0.05% Moon) (50% Moon) (3% Moon)

504 1.1×1020 238,000 1.4 Enceladus (14% Moon) (0.2% Moon) (60% Moon) (5% Moon)

1,062 6.2×1020 295,000 1.9 Tethys (30% Moon) (0.8% Moon) (80% Moon) (7% Moon)

1,123 11×1020 377,000 2.7 Dione (32% Moon) (1.5% Moon) (100% Moon) (10% Moon)

1,527 23×1020 527,000 4.5 Rhea (44% Moon) (3% Moon) (140% Moon) (20% Moon)

5,150 1,350×1020 1,222,000 16 Titan (148% Moon) (180% Moon) (320% Moon) (60% Moon) (75% Mars)

1,470 18×1020 3,560,000 79 Iapetus (42% Moon) (2.5% Moon) (930% Moon) (290% Moon)

Atoms to Astronomy 240 Atoms to Astronomy 241

Planet • Uranus is similar in composition to Neptune, and both are of different chemical composition than the larger gas giants Jupiter and Saturn. • Uranus's atmosphere, although similar to Jupiter's and Saturn's in its primary composition of hydrogen and helium, contains more "ices" such as water, ammonia, and methane, along with traces of hydrocarbons. • It is the coldest planetary atmosphere in the Solar System, with a minimum temperature of 49 K (−224.2 °C), and has a complex, layered cloud structure, with water lower down, and methane in uppermost layer of clouds. • The interior of Uranus is mainly composed of ices and rock. • Uranus has a ring system, a magnetosphere, and numerous moons. • Uranus’s axis of rotation is tilted sideways, nearly into the plane of its revolution about the Sun. • Its north and south poles therefore lie where most other planets have their . • Uranus as a virtually featureless planet in visible light without the cloud bands or storms associated with the other giants. • Terrestrial observers have seen signs of seasonal change and increased weather activity in recent years as Uranus approached its equinox. The wind speeds on Uranus can reach 250 meters per second (900 km/h, 560 mph) Atoms to Astronomy 242 Atoms to Astronomy 243

40 08-06-2015

Neptune Atoms to Astronomy 244 Atoms to Astronomy 245

Atoms to Astronomy 246 Atoms to Astronomy 247

Planet Neptune Comparison of inner and outer • Neptune was the first planet found by mathematical prediction by its influence on Uranus planets • Its largest moon, Triton, was discovered shortly thereafter, though none of the planet's remaining 13 moons were located telescopically until the 20th century. • Inner planets (Mercury and Venus) show: • Neptune's atmosphere, is composed primarily of hydrogen and helium, along with – Phases. traces of hydrocarbons and possibly nitrogen, contains a higher proportion of "ices" – Remain close to the Sun in the sky. such as water, ammonia, and methane. – Show inferior conjunction and opposition. • The interior of Neptune, is primarily composed of ices and rock. It is possible that the core has a solid surface, but the temperature would be thousands of degrees and the – Have period < 1 Earth year. atmospheric pressure crushing. Traces of methane in the outermost regions in part • Outer planets (Mars, Jupiter, Saturn, Uranus and Neptune) account for the planet's blue appearance. show: • Neptune's atmosphere is notable for its active and visible weather patterns. – Retrograde motion • The planet's southern hemisphere has a Great Dark Spot comparable to the Great Red Spot on Jupiter with recorded wind speeds as high as 2,100 k. per hour – Superior conjunction and opposition • Neptune's outer atmosphere is one of the coldest places in the Solar System, with – Can be seen anywhere on the ecliptic temperatures at its cloud tops approaching 55 K (−218 °C). – Have period > 1 Earth year. • Temperatures at the planet's centre are approximately 5,400 K (5,000 °C).

Atoms to Astronomy 248 Atoms to Astronomy 249

41 08-06-2015

Phases of inner planets

Our solar system 250

Structure of planets

Atoms to Astronomy 252 Atoms to Astronomy 253

Atoms to Astronomy 254 Atoms to Astronomy 255

42 08-06-2015

Jovian Magnetic Fields A comparison of the magnetic field strengths, orientations, and offsets in the four jovian planets: (a) Jupiter, (b) Saturn, (c) Uranus, (d) Neptune. The planets are drawn to scale, and in each case the magnetic field is represented as though it came from a simple bar magnet. The size and location of each magnet represent the strength and orientation of the planetary field. Notice that the fields of Uranus and Neptune are significantly offset from the center of the planet and are significantly inclined to the planet’s rotation axis. Earth’s magnetic field is shown for comparison. One end of each magnet is marked N to indicate the polarity of Earth’s field. 256 Our solar system 257 http://astronomy.nju.edu.cn/~lixd/GA/AT4/AT413/HTML/AT41305.h tm

Planet Mass Dia. Rotn. Dist. Rev. Eccn. Inclin.

(km) (A.U.) (* ME)

Mercury 0.0553 4880 58.81 d 0.39 87.97 d 0.211 7.0

Venus 0.815 12,104 -243.69 d 0.72 224.70 d 0.007 3.4

Earth 1.000 12,742 23.93 h 1.00 365.26 d 0.017 0.00

Mars 0.107 6780 24.62 h 1.52 686.98 d 0.093 1.85 Jupiter 317.83 139,822 9.93 h 5.20 11.86 y 0.048 1.305 Minor Bodies in Solar System Saturn 95.162 116,464 10.50 h 9.54 29.46 y 0.056 2.489

Uranus 14.536 50,724 17.24 h 19.18 84.01 y 0.047 0.773

Neptune 17.147 49,248 16.11 h 30.06 164.79 y 0.009 1.773

Pluto 0.0021 2274 6.41 d 39.53 247.68 y 0.2482 17.15

Moon 0.0123 1738 27.32* d 1.000 365.26 0.0554 5.145*

* Around Earth Atoms to Astronomy 258 Atoms to Astronomy 259

Dwarf Planets

Atoms to Astronomy 260 Irrelevance of being 261

43 08-06-2015

Pluto

Pluto (bottom right) compared in size to the largest moons in the solar system: Ganymede (Jupiter), Titan (Saturn),Irrelevance of being(Jupiter), Pluto (Jupiter), Moon (Earth),262 Irrelevance of being Pluto 263 (Jupiter) and Triton.

NASA New Mission

NASA New Horizons Images of Pluto May 2015 Atoms to Astronomy 264 Our solar system 265

Our solar system 266 Irrelevance of being Pluto 267

44 08-06-2015

Atoms to Astronomy 268 Atoms to Astronomy 269

Kuiper Belt Objects

• By late 2005 at least a dozen objects KB objects needed to be accommodated in solar system.

• They were of size comparable to Pluto.

• More were being discovered at an increasing rate.

Irrelevance of being Pluto 270 Irrelevance of being Pluto 271

Irrelevance of being Pluto 272 Irrelevance of being Pluto 273

45 08-06-2015

Irrelevance of being Pluto 274 Irrelevance of being Pluto 275

Semimajor Designation Diameter (km) axis (AU) Date found Pluto 2320 39.4 1930 2003 UB313 2400 ± 100 67.7 2003 136472 1800 ± 200 45.7 2005 136108 ~1500 43.3 2005 Charon 1205 39.4 1978 (90482) Orcus ~1500 39.4 2004 (50000) Quaoar 1260 ± 190 43.5 2002 (28978) Ixion 400 – 550 39.6 2001 55636 < 709 43.1 2002 55565 650 – 750 47.4 2002 55637 ~910 42.5 2002 (20000) Varuna 450 – 750 43 2000

Irrelevance of being Pluto 276 Irrelevance of being Pluto 277

Asteroid Belt

Asteroids

Atoms to Astronomy 278 Atoms to Astronomy 279

46 08-06-2015

Atoms to Astronomy 280 Atoms to Astronomy 281

Positions of known outer Solar System objects. The Centaurs are those objects (in orange) that lie generally inwards of the (in green) and outside the Jupiter Trojans (pink).

Atoms to Astronomy 282 Atoms to Astronomy 283

Atoms to Astronomy 284 Atoms to Astronomy 285

47 08-06-2015

Comets

Atoms to Astronomy 286 Atoms to Astronomy 287

Fig. 1. Comparison of a small part of (left) Tempel 1 with (right) Hartley 2 at approximately the same image scale and with nearly identical instruments.

Sun is to the right.

Michael F. A’Hearn (SCIENCE VOL 332 17 NE 2011 1396

This contrast-enhanced image obtained during Deep Impact's Nov. 4th flyby of Hartley 2 reveals a cloud of icy particles surrounding the comet's active nucleus.

An artist's concept of Comet Hartley 2

shows how CO2 jets drag water ice out of nucleus, producing a 'comet Atoms to Astronomy 288 snowstorm.' Atoms to Astronomy 289

Trans Neptunian Objects and Oort’s Cloud extending beyond 1 light year from the Sun. Constituents of Solar System

• Planet: A planet must meet the following conditions: – (a) It has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly spherical) shape, – (b) It is in orbit around a star, and is neither a star nor a satellite of a planet. – (c) it should be the dominant object in their region – There are 2 kinds: Gas Giants (Jupiter, Saturn, Uranus, Neptune) and Classical (Mercury, Venus, Earth, Mars) Only 8 objects belong to this class.

• Dwarfs or Pluton: Dwarf planets are all medium size objects. – They satisfy the necessary conditions (a and b) to be planets. – Those beyond Neptune, near Pluto are called Plutons.

– Plutons includes Pluto and “Xena” (2003 UB313) now renamed and its moon is called . 3 dwarf planets are now known, probably another 12 or 13 need to be added.

• Satellite: Anything orbiting a planet. Centre of gravity does not fall outside the planet. Includes several bodies much larger than many planets, such as Jupiter's moon Ganymede (diameter: 5262 kilometres). More than 150 are known.

• : Anything orbiting the Sun that's not a planet or a satellite. Atoms to Astronomy 290 Most and comets wouldIrrelevance be SSSBs of being. More Pluto than 130,000 are known. 291

48 08-06-2015

History of Solar System

Part 9: Local Neighbourhood

Atoms to Astronomy 292 Atoms to Astronomy 293

Manoharan, 2012, Ap J

Atoms to Astronomy 294 Atoms to Astronomy 295

Ooty IPS Solar Minimum Results Interplanetary Medium Solar wind Density Solar wind Speed

Atoms to Astronomy 296 Ecliptic view of 3-AU heliosphere

49 08-06-2015

Transition region

Interstellar region

Region of Solar dominance

Atoms to Astronomy 298 Atoms to Astronomy 299

Schematic of the very local Interplanetary medium

Atoms to Astronomy 300 Atoms to Astronomy 301

Atoms to Astronomy 302 Atoms to Astronomy 303

50 08-06-2015

Atoms to Astronomy 304 Atoms to Astronomy 305

Time (yBP) dT Region Den. (cm-3) Comments(b) Start End (y) &(Temp (K))

0 1.0 104 1.0 104 Fluff 0.08 Size 5 pc, From SCA, ~(7000) moving in orthogonal direction to Sun @ 20 km/s B= 1-5 G. Highly Inhomogeneous

1.0 105 3.1 105 6.0 103 SN(?) 4 (104) ?

1.0 104 1.0 105 (0.1-1)105 bubble 0.04 ~(106 ) Expanding bubble from SCA. Age 15 My 4 104 km s-1 orthogonal to Sun, B~ 1.5 muG Crossed the Sun 250,000 to 400,000 y ago

1.0 105 1.0 107 (0.01-1) Inter-arm 0.0005 107 (~100)

1.0 107 2.50 107 3.00 106 HI shock 4 (104 ) From Gould belt. Duration is taken as that for The earlier SN.

2.5 107 4.0 107 5.0 105 Orion 104 (~10) Size ~ 5pc, Sun must have belt taken 5 105 yrs to cross at current velocity

4.0 107 5.0 107 (2.5-4)107 inter-arm 0.005 (10)

5.0 107 6.0 107 (4-5)107 Persius 1 (1000) Duration uncertain arm 7 < 6 10 Atoms to Astronomy 306 Atoms to Astronomy 307

Part 10: Life History of a Star

Atoms to Astronomy 308 Atoms to Astronomy 309

51 08-06-2015

8hc 1 ul)dl  dl l5 ehc/ lkT 1)

FOR NORMALISED AREA

lmaxT  0.29 cm K

Atoms to Astronomy 310 Atoms to Astronomy 311

Atoms to Astronomy 312 Atoms to Astronomy 313

Eagle head Nebula using NASA's Hubble Space Telescope have assembled a bigger and sharper of the iconic 's "Pillars of Creation". Credit: NASA/ESA/Hubble Heritage Team (STScI/AURA)/J. Hester, P. Scowen (Arizona State U.) Atoms to Astronomy 314 Atoms to Astronomy 315

52 08-06-2015

Atoms to Astronomy 316 Atoms to Astronomy 317

Atoms to Astronomy 318 Atoms to Astronomy 319

T Tauri stars

Atoms to Astronomy 320 Atoms to Astronomy 321

53 08-06-2015

dMr) 1. Equation of Continuity  4r2r) dr dPr) GM r)r) 2. Equation of Hydrostatic Equilibrium   Some important time scales dr r 2

dLr) 2 M L 3. Equation of Thermal Equilibrium  4r r)e r) • Nuclear time scale – time   1010 SUN years dr for star to evolve N M L 4. Equation of Energy Transfer SUN

dT 3r)Lr)r) • Thermal Time scale – 2 If there is radiative equilibrium    M  R L 2 3 time for star to restore 7   SUN sun dr 16acr T r)  T  310   years equilibrium from  M SUN  R L perturbation dT  1 T r) GM r)r) If there is convective equilibrium   2 dr  Pr) r • Dynamical Time scale – 1 3 2 2 e  amount of energy released per unit mass time scale to restore  M SUN   RSUN   D  0.04    days   Opacity,   ratio of specific heats at constant pressure and constant volume hydrostatic equilibrium  M   R  a  4  / c where  is the Stephen Boltzmann constant  5.67 x 10-8 W m-2 K -4

Atoms to Astronomy 322 Atoms to Astronomy 323

Atoms to Astronomy 324 Atoms to Astronomy 325

Synthesis of elements

Atoms to Astronomy 326 Atoms to Astronomy 327

54 08-06-2015

Atoms to Astronomy 328 Atoms to Astronomy 329

Depending on the mass and stage of nuclear burning the stars appear different due to:

1) Difference in surface temperature 2) Difference in size

16 Dsun

Atoms to Astronomy 330 Atoms to Astronomy 331

1 AU

700 Dsun

Atoms to Astronomy 332

55 08-06-2015

Atoms to Astronomy 334 Atoms to Astronomy 335

Spectral class

Mass Radius Fraction Temp Apparent Hydrogen Class (solar (solar (bolometric) of all (Kelvin) colour lines masses) radii) L☉ MS stars < O ≥ 30,000 blue ≥ 16 ≥ 6.6 ≥ 30,000 Weak 0.003% 10,000– blue 25– B 2.1–16 1.8–6.6 Medium 0.13% 30,000 white 30,000 white to 7,500– A blue 1.4–2.1 1.4–1.8 5–25 Strong 0.6% 10,000 white 6,000– F white 1.04–1.4 1.15–1.4 1.5–5 Medium 3% 7,500 5,200– yellowish 0.96– G 0.8–1.04 0.6–1.5 Weak 7.6% 6,000 white 1.15 3,700– yellow Very K 0.45–0.8 0.7–0.96 0.08–0.6 12.1% 5,200 orange weak orange Very M ≤ 3,700 ≤ 0.45 ≤ 0.7 ≤ 0.08 76.45% red weak Atoms to Astronomy 337

Atoms to Astronomy 338 Atoms to Astronomy 339

56 08-06-2015

Limits to production of heavy elements in the Universe: The Binding energy curve

Atoms to Astronomy 340 Atoms to Astronomy 341

Credit: ESO/VISTA/J. Emerson/Cambridge Unit; (Inset) ESO/Digitized Sky Survey 2/D. De Martin A new infrared image of the in the constellation Aquarius. It reveals solar-system-sized clumps and strands of hydrogen gas. These Type II features, dubbed cometary knots because they typically point directly away from the star at the center of the nebula, can't be easily seen in visible light (inset). The main ring of the Helix Nebula is aboutAtoms 2 light -toyears Astronomy across. Material in the nebula, which lies about 700 light-years342 from Atoms to Astronomy 343 Earth, was shed from a sun-type star during the final stages of its life. Eventually that star, which now shines fiercely in ultraviolet wavelengths, will evolve to become a , a dense star about as massive as our sun yet only slightly larger than Earth.

Cassiopeia A

Cassiopeia A Chandra image of remnant Cas A. Red colour temp below 20 million degrees Kelvin. Blue colour temp above 30 million degrees Kelvin.

57 08-06-2015

Cassiopeia A composite image

We reproduce the spatial distributions shown in Fig. 2 and add the 4–6-keV continuum emission (white) and the spatial distribution of X-ray-bright Fe (red) seen by Chandra (Fe distribution courtesy of U. Hwang). We find that the 44Ti does not follow the distribution of Fe K-shell X-ray emission, suggesting either that a significant amount of Fe remains unshocked and therefore does not radiate in the X-ray, or that the Fe/Ti ratio in the ejecta deviates from the expectation of standard nucleosynthesis models.

Nature, 506, 339–342 (20 February 2014) doi:10.1038/nature12997

Atoms to Astronomy 346 Atoms to Astronomy 347

Cassiopeia A Titanium image Supernova 1987a

The data have been smoothed with a 20′′-radius top-hat function (dashed circle) and are shown with 3σ and 4σ significance contours (green). In addition to the features shown in Fig. 1, here we also show locations of the forward (R ≈ 150′′) and reverse (R ≈ 100′′) shocks17 (white dashed circles), for context. The 44Ti clearly resolves into several significantly identified clumps that are non-uniformly distributed around the centre of expansion.

Atoms to Astronomy 348 Atoms to Astronomy 349

TIFR Colloquium March 19, 2003 350 Atoms to Astronomy 351

58 08-06-2015

Hubble image of Butterfly Nebula 3800 light years away.

Atoms to Astronomy 352 Atoms to Astronomy 353

Atoms to Astronomy 354 Atoms to Astronomy 355

Atoms to Astronomy 356 Atoms to Astronomy 357

59 08-06-2015

Atoms to Astronomy 358 Atoms to Astronomy 359

Atoms to Astronomy 360 Atoms to Astronomy 361

Most accurate simulation of what a black hole looks like. Created by Kip Thorne for the movie Interstellar Atoms to Astronomy 362 Atoms to Astronomy 363

60 08-06-2015

Quasars and Microquasars

Atoms to Astronomy 364 Atoms to Astronomy 365

Science, Feb 17, 2010 Atoms to Astronomy 366 Atoms to Astronomy 367

Variable stars

Stars vary in intensity for the following reasons: 1) They may be being eclipsed. 2) They may be unstable, where the external pressure and internal outward forces are not balanced. This results in pulsations. 3) The magnetic fields may produce bursts. 4) The surface star may be readjusting producing star quakes. 5) The environment around the star may be disrupting the star. 6) The star may be in the last stages of existence.

Atoms to Astronomy 368 Atoms to Astronomy 369

61 08-06-2015

Variable Stars

• Pulsating Stars - • Cepheid Variables- Period of 1-70 days. Late type stars. Strict period-luminosity relation. • RR Lyrae – Period of 30-100 days. Yellow Super-giants. • Long-period Variables (LPVs) Time – Mira type - Giant red variables. Periods ranging from 80 to 1000 days – Semiregular - Periods of 30-1000 days. – Irregular variables - Red giants, are pulsating variables. – Rotating variables - Rotating stars with to dark spots.

• Supernovae - Sudden, dramatic, final magnitude increase as result of stellar explosion • Novae - Thermonuclear fusion explosion • Recurrent Novae • Dwarf Novae - Close binary system made up of a Sun-like star, white dwarf, and surrounding the white dwarf INTENSITY • - Erupt for 5 to 20 days with long quiescence – Z - Similar to U Gem except no well-defined quiescence and has “standstills” of brightness – SU Ursae Majoris - Similar to U Gem except have short orbital periods of less than two hours and 2 bursts • Symbiotic Stars - Semiperiodic -like outbursts • R Coronae Borealis - Go into outburst by fading and then return to maximum brightness • Flare stars- Faint, cool, red, main-sequence stars that undergo intense outbursts from localized of the surface. The result is an increase in brightness of two or more magnitudes in several seconds, followed by a decrease to its normal minimum in about 10 to 20 minutes. Atoms to Astronomy 370 Atoms to Astronomy 371

Time

Part 11: Stars as a group

INTENSITY

Atoms to Astronomy 372 Atoms to Astronomy 373

Binary Stars Are most stars born in binaries? • About 50% of stars are in binaries • By observation – Eclipsing binaries Binary stars are more common amongst older generation and in – spectroscopic binaries larger stars. Sun like stars are mostly single. – visual binaries Overall about 1/3 of all stars are in binaries.

• By process – Detached binaries – Semidetached binaries – Interacting binaries – Cataclysmic Variables - One giant, and one white dwarf star that leads to “outbursts” of activity – LMXB – compact objects with low mass companion – HMXB – compact objects with high mass companion

Atoms to Astronomy 374 Atoms to Astronomy 375

62 08-06-2015

Atoms to Astronomy 376 Atoms to Astronomy 377

“Great Eruption” occurred in 1843 with luminosity of 30 million : High opacity implies a convective shell explosion with multiple cycles (of 4 year period) ejection.

“Little Eruption” occurred in 1890s

TIFR Colloquium March 19, 2003 378 Atoms to Astronomy 379

Atoms to Astronomy 380 Atoms to Astronomy 381

63 08-06-2015

Clusters of stars

Possibility of Type 1a Supernova • Clusters of stars are of two type: – Open Clusters: They are not gravitationally bound and invariably consists of young stars.

– Globular (bound) Clusters: They are typically found in the Halo regions of galaxies where they can exist undisturbed. They tend to be lage.

Atoms to Astronomy 382 Atoms to Astronomy 383

Open Clusters

• The Hertzprung-Russell diagram of an shows a wide variety of main sequence stars.

• Open clusters in molecular clouds in the disks of spiral and barred-spiral galaxies encounter spiral arms or bars, where they are compressed, thus triggering the birth of new clusters of stars.

• As these newly-born clusters mature, they will continue their orbits around the , they will disassociate and scatter along the galactic disk.

Globular Clusters

• The H-R diagram of a globular has a prominent centered at around magnitude 0.

• Globular clusters are found outside of the galactic disk. Part 12: Diffused Matter in Space • Their stars will frequently remain bound together for long periods of time, but suffer from of orbital perturbations and tidal forces.

• This will cause a slow attrition pattern that will lead to their eventual disruption or "evaporation".

• It is estimated that half of our Milky Way's globular clusters will disappear during the next 10,000 million years. Atoms to Astronomy 387

64 08-06-2015

Components of diffuse matter in Diffuse Matter in Space space • Less than 10% of normal matter in space is bound in stars. • Rest is in the form of diffuse matter. This includes: • Inter planetary medium – H and H2 regions in galaxies – Nova and supernova remnants • Inter stellar medium – Material thrown out by jets and stellar winds • Inter galactic medium – Matter in intergalactic matter • It consists of everything from large chunks of rock to very low • Large scale diffuse matter density diffuse gas. In the galaxy its average density is about – in the Universe 50 atoms/m3 intergalactic region average density is about 1 atom/m3

Atoms to Astronomy 388 Atoms to Astronomy 389

Interstellar Medium

Atoms to Astronomy 390 Atoms to Astronomy 391

NGC 6946

Atoms to Astronomy 392 Atoms to Astronomy 393

65 08-06-2015

Dark is more important than bright

Atoms to Astronomy 394 Atoms to Astronomy 395

Atoms to Astronomy 396 Atoms to Astronomy 397

Detecting diffuse matter in space • It can be detected by the following means: – Scattering light of distant stars – Enveloping stars into a cocoon – Producing diffuse radiation in interstellar and intergalactic matter – Affecting the rotation of objects by exerting gravitational pull. – Producing ‘lensing effect’ – By measuring the composition By following how it is channelled, it can provide important clues to interstellar and intergalactic magnetic fields.

Atoms to Astronomy 398 Atoms to Astronomy 399

66 08-06-2015

Atoms to Astronomy 400 Atoms to Astronomy 401

Component Fractional Scale Temperatur Density State of hydrogen Primary Volume Height (pc) e (K) (atoms/cm³) observational techniques Molecular < 1% 70 10—20 102—106 molecular Radio and infrared clouds molecular emission and absorption lines Cold Neutral 1—5% 100—300 50—100 20—50 neutral atomic H I 21 cm line Medium absorption (CNM) Warm Neutral 10—20% 300—400 6000— 0.2—0.5 Neutral atomic H I 21 cm line Medium 10000 emission (WNM) Warm Ionized 20—50% 1000 8000 0.2—0.5 ionized Hα emission and Medium pulsar dispersion (WIM) H II regions < 1% 70 8000 102—104 ionized Hα emission and pulsar dispersion Coronal gas Hot Ionized 30—70% 1000—3000 106—107 10−4—10−2 ionized (metals X-ray emission; Medium (HIM) also highly absorption lines of ionized) highly ionized metals, primarily in the ultraviolet Based on Microlensing data for 10 million galaxies over 6 billion light years Credit: L. Van Waerbeke, C. Heymans,Atoms to Astronomy and CFHT Lens collaboration 402 Atoms to Astronomy 403

What effects diffuse matter Affects of Diffuse matter in space • It can significantly affect the dynamics of • Cosmic Rays the universe in the following manner: • Photoelectric heating in grains – By changing the composition of cosmic rays • Gravitational acceleration – By changing the rotation curves of galaxies • Photo-ionisation – By providing matter for creating stars • X-rays from compact objects – By providing a binding the luminous matter – By reprocessing starlight to lower • Chemical reactions wavelengths especially in IR • Grain-gas interaction – By producing high energy radiation when accelerated especially in intergalactic region Atoms to Astronomy 405

67 08-06-2015

Nature of dark matter

• It is becoming more and more clear that the dark matter in the universe is not just ordinary matter not emitting light. • For every bit of ordinary matter not emitting light there is 6 times as much matter that seems to consist of particles that do little more than exert gravity. • It does not seem to be in large chunks and seems to consist of exotic particles.

Atoms to Astronomy 406 Atoms to Astronomy 407

Atoms to Astronomy 408 Atoms to Astronomy 409

Part 13: Heavy Elements in the Universe

Atoms to Astronomy 410 Atoms to Astronomy 411

68 08-06-2015

Proton formation: 1 sec

Inflation 10-35 s

Atoms to Astronomy 412 Atoms to Astronomy 413

Synthesis of elements Limits to production of heavy elements in the Universe: The Binding energy curve

Atoms to Astronomy 415 Atoms to Astronomy 416

Atoms to Astronomy 417 Atoms to Astronomy 419

69 08-06-2015

Abundance of matter in the Universe Accelerated of matter in the Universe: Cosmic rays

Atoms to Astronomy 420 Atoms to Astronomy 421

Sources of cosmic rays

Atoms to Astronomy 422 Atoms to Astronomy 423

A UV image of the Sun along with Gamma rays (blue) and X-rays (red)

Atoms to Astronomy 424 Atoms to Astronomy 425

70 08-06-2015

Atoms to Astronomy 426 Atoms to Astronomy 427

Atoms to Astronomy 428 Atoms to Astronomy 429

Part 14: and Life in the Universe

Image shows a face-on millimetre-wave view of the protoplanetary disk around the young star HL Tau (located at the bright central blob but not detected in this image). The dotted circles represent the locations of emission dips (dark regions) where water ice, frozen ammonia hydrates and clathrate hydrates are expected to condense. Combining such images, which can directly probe the disk's dust and ice content, with spectral-line observations such as those presented by Öberg et al.1 for the disk around the young star MWC 480, which selectively probe the gas and ice reservoirs of the disk, will provide Atoms to Astronomy 430 insights into the evolution of water and organic chemistry during planet formation. Atoms1 AU is the distanceto Astronomy from Earth to the Sun. (Image created by K. Zhang in G. A. Blake's research group,431 from public-domain commissioning and science verification data from the ALMA observatory8.) : Prebiotic chemistry on the rocks Geoffrey A. Blake & Edwin A. Bergin Nature 520, 161–162 (09 April 2015)

71 08-06-2015

Search for planets Kepler Mission (kepler.nasa.gov) (1) Doppler Method • Kepler Mission of NASA launched 5 years ago has completely revolutionised the subject. • It worked from March 2009 to May 2013. (2) Transit • The mission was designed to find transiting planets for 145,000 stars by monitoring their light for 3 years. • It was sensitive to light fluctuation of 1 part in 100,000

(3) Micro-lensing • The Kepler found 1,790 host stars with a total of 2,321 planet candidates as of 2012 Feb 27.

72 08-06-2015

What is life? Carbon of life • It seems that where ever the life is found, it will be carbon based. This is because: We find it easier to define life by what it is not! – Carbon is best suited for living molecules which are: We assume life does the following: • Capable of accepting all types of atoms (both acidic and basic) in reactions 1) It consumes food • Capable of forming really long chains of chemicals 2) It reacts to its environment in a complex manner • Can make very flexible chains with reversible reactions 3) It grows and self-replicates • Can form both, close chained and open chained molecules which are very versatile • It is easily available in the Universe 4) It produces a large number of chemical reactions At the core of life is a-periodic complexity and not order. – It has a companion of water, a unique liquid that has: • Wide temperature where it remains liquid A more accurate definition would be: A living objects are a region of • It is an excellent solvent order which use energy to maintain their organization against the • It is chemically a simple molecule disruptive force of entropy! • It has the ‘triple point’ advantage • It has high specific heat and high vapour pressure

LIFE CONSISTS OF MOLECULES THAT KNOW – Si, the other element of periodic table that can form long molecules has none of • WHAT THEY LOOK LIKE these advantages. • HOW TO MAKE A COPY OF THEMSELVES • However, such a life form need not be oxygen breathing or biped. 438 439

General aspects of life Habitable zones around planets

• Wherever we find life it will almost certainly be based on Carbon and will need liquid water.

• For life to arise, the minimum requirements are: – Availability of carbon and other heavy elements. – Correct temperature in which C and water are not frozen.

• It will also need a whole host of other conditions.

Atoms to Astronomy 440 Atoms to Astronomy 441

HZ Candidates 48 with Teq between 185 and 303 K Jun 2010 Feb 2011 Dec 2011

Planetary scientists agree that a planet's distance from its parent star is of paramount importance for creating conditions where liquid water might spur life. A greater abundance of carbon, sodium, magnesium, and silicon should be a plus for an inner solar system's long-term habitability because the abundance of these elements make the star cooler and cause it to evolve more slowly, thereby giving planets in its habitable zone more time to develop life as we know it. The stellar abundance of oxygen, in particular, seems crucial in determining how long newly formed planets

stay in the habitable zone around their host star, the researchers report. If our own Size Relative to Earth sun had a lower abundance of oxygen, for example, Earth would have left the habitable zone a billion years ago,Atoms well tobefore Astronomy complex organisms evolved. 442 Equilibrium Temperature [K]

73 08-06-2015

Other conditions • Being in habitable zone alone is not enough. • In addition you need: – Correct mix of elements – isolation of the star. – stability of the star. www.sciencemag.org SCIENCE – correct temperature range. VOL 344 18 APRIL 2014 279 – Planet size and structure and something to stabilize the planet. – Protection from residual dust from making of planets. – Atmosphere. – circular orbit and its tilt of the axis of rotation. – magnetic field and UV shield to protect from radiation. – Complex geological upheavals to circulate material on planet.

Atoms to Astronomy 445 Atoms to Astronomy 446 www.sciencemag.org SCIENCE VOL 344 18 APRIL 2014 249

Life on moons of planets? Euceladus (Saturn)

Titan (Saturn) Io (Jupiter)

447 448

Habitability of

• Several moons of Jupiter (Europa, Ganymede etc.) have attracted attention of people. • They seem to have a lot of possibilities because: – They lie in the region beyond the ‘ice line’ of solar system and have a rocky core. – Their top layers are protected from vagaries of space by a layer of ice. – They seem to harbour liquid ocean probably of water. – They seem to have active geological activity. – The heat and light coming from Jupiter can provide an energy source.

• Even if they harbour life, it will be primitive. 449 High-energy chemistry of formamide: A unified mechanism of nucleobase formation Martin Ferusa et al. 2015, PNAS www.pnas.org/cgi/doi/10.1073/pnas.1412072111A

74 08-06-2015

Heat flux across an open pore enables the continuous replication and selection of oligonucleotides towards increasing length Moritz Kreysing†‡, Lorenz Keil‡, Simon Lanzmich‡ and Dieter Braun*, Nature Genetics, Jan 2015

Search for Intelligent life on Habitable Planets • Drake’s Equation: The probability of finding intelligent life is:

P = Pt Ps Pp Ph Pg PI Pe Pc Pi Pr Pd Where P = Total probability given by:

11 Pt = total number of stars in the galaxy (~10 ) P = percentage of stars that can have planets (~20% late type only) Part 15: Galaxy s Pp = percentage of star that actually have planets (~80%) Ph = percentage of stars with habitable zones (~10%) Pg = percentage of planets with stable circular orbits PI = percentage of planets where life has evolved Pe = percentage of planets where life has moved beyond simple molecules Pc= percentage of planets where life has moved to multi-cellular structure Pi = percentage of planets that have intelligent life Pr = percentage of life that avoided self destruction Pd = duration before which they emit detectable signals to earth

455 Atoms to Astronomy 456

Our galaxy

Centre galaxy Bar

Sun

Scorpios Centourus arm

Atoms to Astronomy 457 Atoms to Astronomy 458

75 08-06-2015

Vital statistics diameter 100,000 light-years thickness of disk 2,300 to 2,600 light-years thickness of bulge 16,000 light-years 12 mass 1–2 × 10 Msun proportion of gas and dust 5–10% of

mean density 0.1 Msun per cubic total luminosity ~ 1044 erg/s magnetic field 3–5 × 10-6 gauss age (oldest star) 13.2 billion years

Atoms to Astronomy 459 Atoms to Astronomy 461

Atoms to Astronomy 462 Atoms to Astronomy 463

Centre of our Galaxy with 4 million black hole disrupting the region

Centre of Milky Way

Atoms to Astronomy 466

76 08-06-2015

The Milky Way's central black hole suddenly increased in brightness early last year due to a mysterious x-ray flare

NASA release Jan 2015.

STAR TRACKER, BY ANN FINKBEINER NEWS, FEATURE, 2 9 6 | N AT U R E | VO L 4 9 5 | 2 Atoms1 M A R to C AstronomyH 2 0 1 3 468 Atoms to Astronomy 470

Satellite galaxies of the Milky Way distance absolute diameter galaxy discovered (light-years) magnitude (light-years) 1 Dwarf 25,000 2003 - - Sagittarius Dwarf 2 78,000 1994 -13.4 >10,000 ? Elliptical 3 160,000 prehistoric -18.1 20,000 4 180,000 prehistoric -16.2 15,000 5 II 200,000 2006 - - 6 220,000 1954 -8.9 1,000 7 Dwarf 270,000 1954 -8.8 500 8 Sculptor Dwarf 285,000 1938 -11.1 1,000 9 Sextans Dwarf 290,000 1990 -9.5 3,000 10 Dwarf 330,000 1977 -9.3 500 11 450,000 1938 -13.2 3,000 12 I 670,000 1950 -9.6 500

Atoms to Astronomy 471 13 Leo II 830,000Atoms to Astronomy1950 -11.9 1,000472

Formation of Galaxies

Atoms to Astronomy 474 Atoms to Astronomy 475

77 08-06-2015

Atoms to Astronomy 476 Atoms to Astronomy 477

Hubble’s ‘tuning fork’ diagram of galactic classes, including normal Fig. 4. Proposed sketch of the evolution of massive galaxies. Our results suggest a picture in which the total stellar mass and bulge mass grow synchronously in z ~ 2 main sequence galaxies, and quenching is concurrent with their total masses and central densities approaching the highest values observed in massive spheroids in today’s universe Science, 17 APRIL 2015 • VOL 348 and barred counterparts ISSUE 6232. p316,

Atoms to Astronomy 478 Atoms to Astronomy 479

Less likely

More likely

Nature May 14, 2015

Atoms to Astronomy 480 Atoms to Astronomy 481

78 08-06-2015

Centre of A

Size of Milky Way Galaxy

Atoms to Astronomy 482 2,000,000 LIGHT YEARS

All galaxies are formed by Active Galactic Nuclei Central Black holes

Atoms to Astronomy 484 Atoms to Astronomy 485

Atoms to Astronomy 486 Atoms to Astronomy 487

79 08-06-2015

Quasar/Seyfert 1 Galaxy - / Seyfert 2 Galaxy

Blazar /Seyfert 1 Galaxy

Atoms to Astronomy 488 Atoms to Astronomy 489

Persus Skull Most massive black hole in the 10 The bright spot at the centre of Galaxy: 2 x 10 the image is thought to signal the presence of a super- Solar masses massive black hole at the core of A, the largest galaxy Z = 0.307 in the cluster.

Binary companion a black The "eyes" are thought to be 8 hole just 10 solar masses! buoyant magnetized bubbles of energetic particles produced near the black hole - each is nearly as big as the Milky Way.

The "nose" is thought to be a dark spot produced by cool gas in a galaxy being swallowed by the central black hole in Perseus A.

Atoms to Astronomy 490

NGC 1265

3C465

M87

NVSS 2146+82

Atoms to Astronomy 492 Atoms to Astronomy 493

80 08-06-2015

• The problem of origin of magnetic fields is one of the great, unsolved problem of astronomy.

Part 16: Magnetic fields in the • You cannot start with a zero magnetic field and Universe hope to generate magnetic field. • Yet, magnetic fields are very common in the Universe.

• So magnetic fields must have originated in the Big Bang itself.

Atoms to Astronomy 494 Atoms to Astronomy 495

Magnetic fields in our Magnetic field in our galaxy neighbourhood

Atoms to Astronomy 496 Atoms to Astronomy 497

Galactic Magnetic fields

Magnetic field derived from galaxy Optical image of the M simulation overlaid 51 obtained with the Hubble Space on the galaxy NGC Telescope (from Hubble Heritage), 4151. The blue overlaid by contours of the total radio 'ribbons' are intensity and vectors at components of a 6cm wavelength, combined from radio vertical magnetic observations with the Effelsberg and VLA radio telescopes. The magnetic field while the green field follows well the optical spiral arrows depict both structure, but the regions between the the axisymmetric spiral arms also contain strong and and bisymmetric ordered fields. The bar in the top right magnetic fields corner indicates a scale of 1 observed in galaxies arcminute or about 9000 light years of this (about 3 kiloparsecs) at the distance morphological type. of the galaxy. Copyright: MPIfR Bonn

Atoms to Astronomy 498 Atoms to Astronomy 499

81 08-06-2015

Part 17: Groups of Galaxies

Atoms to Astronomy 500 Atoms to Astronomy 501

Atoms to Astronomy 502 Atoms to Astronomy 503

2 Billion years

Today

3 billion 4 Billion

This series of photo illustrations shows the predicted merger between the Milky Way and Andromeda as seen from Earth. The first frame is the 4.1 4.3 present day; the last frame is 7 billion years from now.

5 7

Atoms to Astronomy 504 Atoms to Astronomy 505

82 08-06-2015

Superposed galaxies (NGC 1334)

Credit: NASA/ESA, Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration/W. Keel/U. Alabama Atoms to Astronomy 506 Atoms to Astronomy 507

In the vastness of the universe, collisions between galaxies are AGN and merging galaxies surprisingly common. In this particular cosmic train wreck between two galaxies located (Ap J, June 20, 2010) about 38 million light-years away, the result apparently was the creation of a gigantic circle of gas. For nearly 30 years, astronomers have wondered what formed the so- called Leo ring—named because the galaxies are located within the constellation Leo. Observations in infrared light had suggested the ring was composed of cold primordial gas left over from the big bang. But a new study, to be reported in The Astrophysical Journal Letters (July 2010), used visible light. In the images astronomers found evidence of star making within the ring—something not possible in primordial gas clouds. Then a computer simulation based on the new observations solved the mystery: about 1 billion years ago, a violent encounter between the two galaxies ripped out their star making gas and spread it as a ring Atoms to Astronomy some 650,000 light-508years wide. Atoms to Astronomy 509

Quasar SDSS J0123+00

July 2010

Humbling as it seems, even whole galaxies can be ripped apart—as is the one in the red area near the center of this image. The culprit? A quasar (yellow), a galaxy with a at its center that creates so much radiation it outshines everything else in the universe. Until now, astronomers have had a hard time getting much of a look at these cosmic beacons, because their light obscures everything around them. But this quasar, known as SDSS J0123+00, is obscured by a thick doughnut of dust called a torus (inset). That's allowed astronomers to sneak a peak at the beast as it rips away giant clouds of gas (green) from a nearby galaxy. The finding, reported in an upcoming issue of the Monthly Notices of the Royal Astronomy Society, confirms a long-held theory about : They power their intense luminescence by dining on the gas of other galaxies. 510 Atoms to Astronomy 511

83 08-06-2015

Atoms to Astronomy 512 Atoms to Astronomy 513

Cosmic crash. El Gordo consists of two clusters in collision, as revealed by the two separate swarms of individual Atoms to Astronomy 514 galaxies (red) and the asymmetric cloud of hot, Atomsx-ray emitting to Astronomy gas (blue) in between. 515 Credit: ESO/SOAR/NASA

A significant fraction of stars seem to reside in the Intergalactic space

Atoms to Astronomy 516 Atoms to Astronomy 517

84 08-06-2015

Part 18: Large scale structure of the Universe

Atoms to Astronomy 518

Dark Matter in IGM

X-ray Optical

http://www.nature.com/news/missing-galaxy-mass-Atomsfound- 1.14731?WT.ec_id=NATUREto Astronomy -20140220 521

A simulated Black Hole of ten solar masses as seen from a distance of 600km with the Milky Way in the background

Atoms to Astronomy 522 Atoms to Astronomy 523

85 08-06-2015

Part 19: Story of the Universe

Atoms to Astronomy 524 Atoms to Astronomy 525

Redshift (z) is defined as z = l /l 1/2 z = 1+[(c+vrec)/(c-vrec)]

Depth of Universe Visible (a) is a = (1+ z)-1 Atoms to Astronomy 526 Atoms to Astronomy 527

v  H D v  recessional velocity H  Hubble Constant (73 km/s/Mpc) D  Distance

Planck Value: 67.3 km/s/Mpc

Atoms to Astronomy 528 Atoms to Astronomy 529

86 08-06-2015

3000 K

Atoms to Astronomy 530 Atoms to Astronomy 531

Rogue stars between galaxies 13+ billion years of galaxy collisions could make up to 50% of all stars and mergers

Inflation fraction of a trillionth of a second

Cosmic microwave background 380,00 years Gravity dominated Initial galaxy formation ~400 million years Present nearby universe ~13.8 billion years Expansion dominated

SCIENCE 7 NOVEMBER 2014 • VOL 346 ISSUE 6210 Atoms to Astronomy 532 Atoms to Astronomy 533

Wonders of the Universe 534 Atoms to Astronomy 535

87 08-06-2015

Gamma

Dense clouds of gas collapse into the first (Pop III) massive stars and probably produce the first GRBs. GRBs can then precede the formation of the first galaxies, which in turn precede that of active galactic nuclei (AGN) powered by supermassive black holes. Thus, GRBs could probe the first structures and galaxies to emerge after the 'dark ages' of the Universe. The narrow beaming of GRBs, best defined by GRB 080319B (not shown to scale), makes them the most luminous back- for mapping the far-distant visible Universe.

Atoms to Astronomy 536 Atoms to Astronomy 537

WMAP

Planck (2.725 + 0.0003

Atoms to Astronomy 538 Atoms to Astronomy 539

Proton formation: Entropy 1 sec

A conspiracy of Gravity and Nuclear forces

The earliest galaxies we have seen are at z ~ 9, i.e. about 1.5 billion years 3 min since the birth of the Time 380,000 years Present Universe. The earliest stars were Inflation born 200 million years 10-35 s after the Universe was 541 born!

Atoms to Astronomy 540

88 08-06-2015

Atoms to Astronomy 542 Atoms to Astronomy 543

Inflation • Nascent universe passed through a phase of exponential expansion driven by a negative-pressure vacuum energy density.

• Inflation explains of the big bang cosmology:

– why the universe is flat, homogeneous and isotropic. – Origin of the large-scale structure of the cosmos – quantum fluctuations in the microscopic inflationary region, magnified to cosmic size, become the seeds for the growth of structure in the universe. Atoms to Astronomy 544 Atoms to Astronomy 545

String Theory? Maxwell’s Electromagnetic Theory of Abdul Theory Salam’s Vacuum Standard Model Electroweak Atoms to Astronomy 546 fluctuations??? Theory 547

89 08-06-2015

Atoms to Astronomy 548 Atoms to Astronomy 549

Star formationCosmic through time time

Atoms to Astronomy 550 Madau plot (Cole etAtoms al. 2001)to Astronomy 551

This is an artist's view of night sky from a hypothetical planet within a young Milky Way-like galaxy 10 billion years ago, the sky ablaze with star birth. Pink clouds of gas harbor newborn stars, and bluish-white, young star clusters litter the landscape. Credit: NASA/ESA/Z. Levay (STScI), April 2015) http://www.eurekalert.org/pub_releases/2015-04/nsfc-osc040915.php page 5 5 4 | N AT U R E | VO L 4 9 7 | 3 0 M AY 2 0 1 3 Atoms to Astronomy 552 Atoms to Astronomy 553

90 08-06-2015

Cosmic

Event time H and He formation 3 min. 109 Recombination 400,000 yr 1,500 The first stars 400 Myr 10

Z8-GND-5296 is forming stars extremely rapidly – producing each year about Reionization 400 Myr 9 300 times the mass of our Sun. By comparison, our Milky Way Galaxy forms only 2 – 3 stars per year. Even galaxies observed at a time when the Universe had reached only 5% of its current age may already be chemically enriched with dust and heavy The first galaxies 0.8 Gyr 6.5 elements, which must have been produced by an earlier generation of stars. Finkelstein, S. L. et al. Nature 502, 524–527 (2013); see also Riecher 24 October 2013, Nature, 502, 459 Today 13.7 Gyr 0

This is an artist’s impression of the galaxy Z8-GND-5296. Atoms to Astronomy 554 Atoms to Astronomy 555 Image credit: V. Tilvi / S.L. Finkelstein / C. Papovich / the Hubble Heritage Team

Part 20: Dark Energy

Atoms to Astronomy 556 Atoms to Astronomy 557

~ 6 billion years ago

Atoms to Astronomy 558 Atoms to Astronomy 559

91 08-06-2015

Matter Strength of the repulsive force in the Universe

68.3% 4.9% 26.8 %

Atoms to Astronomy 560 Atoms to Astronomy 561

End

Atoms to Astronomy 562 Atoms to Astronomy 563

I should have stopped long back 

Atoms to Astronomy 564

92