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Home , Black Eye Galaxy, Dust lane, Sombrero Galaxy, Whirlpool Galaxy

GALAXIES WHAT ARE THE DEEP SKY OBJECTS? •Deep-sky objects are astronomical objects other than individual and solar system objects (, Moon, planets, comets).

TYPES OF DEEP SKY OBJECTS

•Nebulae •Clusters •

CHARLES MESSIER

• Known for the Messier catalogue of galaxies, nebulae and clusters M1 to M110 • He was a French astronomer who lived in the 18th century. • He was a comet hunter and the purpose of the catalogue was to record the sky objects that looked as comets but were not comets because they would not move in the sky. UNITS TO MEASURE DISTANCE

• A Light-year is the distance that light travels in a year with a speed of approximately 300,000 kilometers per second • Closest star to the Sun is Proxima Centauri at 4.37 light years.

• A is the equal to about 3.26 light years GALAXIES • A is an enormous collection of gas, dust and billions of stars held together by gravity. One galaxy can have hundreds of billions of stars and be as large as 200,000 light years across.

• Galaxy is derived from the Greek galaxias meaning "milky", a reference to the .

• Many galaxies are believed to have black holes at their active center. The Milky Way's central , known as Sagittarius A, has a four million times that of our Sun. GALAXIES FACTS • There are potentially more than 170 billion galaxies in the observable universe. Some, called dwarf galaxies, are very small with about 10 million stars, while others are huge containing an estimated 100 trillion stars.

• Supermassive black holes are believed to sit at the center of most galaxies.

TYPES OF GALAXIES ELLIPTICAL GALAXIES

ELLIPTICAL GALAXIES

• Look like enormous globular clusters. • Elliptical galaxies are often bigger than spiral galaxies. • Stars are yellow & red, with very little free dust & gas. • These galaxies are old & no longer forming new stars. • Elliptical galaxies may form from the collision of 2 or more spiral galaxies.

SPIRAL GALAXIES • Like our own Milky Way, all spiral galaxies have a nuclear bulge, and at least 2 spiral or propeller- shaped arms, with a halo of gas, dust, stars, and globular clusters. • Spiral galaxies are classified as Sa, Sb, or Sc depending on the size of the nucleus & how tightly the arms are wrapped. M104 – the , has a large nucleus & very tight spiral arms. THE SOMBRERO GALAXY M104

The Sombrero Galaxy (also known as M104 or NGC 4594) is an unbarred in the . It has a bright nucleus, an unusually large central bulge, and a prominent in its inclined disk. The dark dust lane and the bulge give this galaxy the appearance of a sombrero. The galaxy has an of +9.0, making it easily visible with amateur . The large bulge, the central , and the dust lane all attract the attention of professional astronomers.

• The Andromeda Galaxy (M31) is the closest large galaxy to the Milky Way and is one of only ten galaxies that can be seen with the naked eye from the Earth. • Andromeda is accompanied by at least 10 satellite galaxies the most notable of which is the .

ANDROMEDA GALAXY M31 ANDROMEDA FACTS

• It is 2.2 million light years away from us and • approaching the Milky Way at approximately 100 to 140 kilometers per second… • Five billion years from now it will probably collide with our Milky Way galaxy. • While Andromeda is the largest galaxy in the Local Cluster it is not the most massive as the Milky May is thought to contain more dark matter making it the most massive

HOW TO FIND ANDROMEDA GALAXY - M64

A spiral galaxy in the constellation, Messier 64, the famous "Black Eye" galaxy or the "Sleeping Beauty galaxy," has a spectacular dark band of absorbing dust in front of the galaxy's bright nucleus. It is well known among amateur astronomers because of its appearance in small telescopes.

THE - M51A Also known as Messier 51a, M51a, or NGC 5194, the Whirlpool Galaxy is an interacting grand- design spiral galaxy located at a distance of approximately 23 million light-years in the constellation . It is one of the most famous spiral galaxies in the sky. The galaxy and its companion (NGC 5195) are easily observed by amateur astronomers, and the two galaxies may even be seen with . The Whirlpool Galaxy is also a popular target for professional astronomers, who study it to further understanding of galaxy structure (particularly structure associated with the spiral arms) and galaxy interactions. The Whirlpool Galaxy M51 is one of the largest galaxies visible without using professional . Millions of years ago two galaxies collided to create this colorful and dramatic object. To find it, look about 3.5 degrees southeast of the last star in the ’s handle. M81 URSA MAJOR

The big and beautiful spiral galaxy M81, in the northern constellation Ursa Major, is one of the brightest galaxies visible in the skies of planet Earth. This superbly detailed view reveals its bright nucleus, grand spiral arms and sweeping lanes with a scale comparable to the Milky Way. Hinting at a disorderly past, a remarkable dust lane runs straight through the disk, below and right of the galactic center, contrary to M81's other prominent spiral features. The errant dust lane may be the lingering result of a close encounter between M81 and its smaller companion galaxy, M82. Scrutiny of variable stars in M81 (aka NGC 3031) has yielded one of the best determined distances for an external galaxy -- 11.8 million light-years. THE MILKY WAY

We live in one of the arms of a large spiral galaxy called the Milky Way. The Sun and its planets (including Earth) lie in this quiet part of the galaxy, about half way out from the centre.

Scientists believe that 90% of our galaxy’s mass consists of dark matter, which gives it a mysterious halo. That means that all of the “luminous matter” – i.e. that which we can see with the naked eye or a telescopes – makes up less than 10% of the mass of the Milky Way. MILKY WAY FACTS • The Milky Way galaxy is whirling rapidly, spinning our sun and all its other stars at around 100 million km per hour. • The Sun travels around the galaxy once every 200 million years – a journey of 100,000 light years. • There may be a huge black hole in the very middle of the most of the galaxies.

MILKY WAY FACTS

 The Milky Way is shaped like a huge whirlpool that rotates once every 200 million years.  It is made up of at least 100 billion stars, as well as dust and gas.  It is so big that light takes 100 000 years to cross from one side to the other.  The centre of the Galaxy is very hard to see because clouds of gas and dust block our view.  Scientists think that it contains a supermassive black hole that swallows anything passing too close.

LOCAL GALACTIC GROUP

• The Local Group is the that includes the Milky Way. It comprises more than 54 galaxies, most of them being dwarf galaxies. Its gravitational center is located somewhere between the Milky Way and the Andromeda Galaxy.

• The group is a part of the larger or the Local Supercluster. At least 100 galaxy groups and clusters are located within its diameter of 33 megaparsecs (110 million light-years). It is one of millions of superclusters in the observable universe.

HOW FAST IS THE MILKY WAY GALAXY MOVING?

The speed turns out to be an astounding 1.3 million miles per hour (2.1 million km/hr)! We are moving roughly in the direction on the sky that is defined by the of Leo and Virgo. Astronomers believe that there is a huge concentration of matter in this direction. Some people call it The Great Attractor, although we now know that the pull is probably not due to one group of galaxies but many. Still the extra gravity in this direction pulls the Milky Way (and many neighbor galaxies) in that direction.

RESOURCES

https://www.youtube.com/watch?v=XUbG8jboh4M http://www.skymaps.com/downloads.html https://www.youtube.com/watch?v=ac9Cr6bf-mg https://www.youtube.com/watch?v=UE8yHySiJ4A https://www.youtube.com/watch?v=xwSQVSlccCg http://messier.seds.org/m/m031.html https://en.wikipedia.org/wiki/List_of_Messier_objects