Understanding the Universe

Understanding the Universe

Video Worksheet Answer Key

WHERE ARE WE?

·  The universe may be billions of years too young

·  The universe contains, dark stars, dwarf stars, stars that eat each other, stars clumped in galaxies, and galaxies clumped in larger stranger structures

·  The smallest scale used to talk about time is 10-42

·  The largest scale used to talk about the universe expanding is 1030

·  Largest number used to talk about degrees is 1032

·  Mercury is the closest planet to the sun

·  The sun is 93 000 000 miles away from earth

·  Stars are suns but further away, the nearest star is

25 000 000 000 000 miles away, it is the Proxima Centauri

·  Light is the fastest thing in the universe and it takes 4 years and 4 months to get to earth

·  That is the same are 4 1/3 light years away

·  The sun is one of billions of stars in the galaxy, the Milky Way

·  The Milky Way is one hundred thousand light years across

·  There are 50 billion galaxies, it is a million light years to the nearest galaxy

·  It takes hundreds of millions of light years to cross the galactic neighbourhood

·  The grouping of stars in the southern sky is known as Orion

·  Prehistoric astronomers used elaborate monuments to mark the sunrise and sunset

·  In 300 B.C., Aristotle taught that there were transparent globes around the earth on which were mounted the sun, moon, planets and furthest out a sphere studded with little stars

·  As late as the 16th century, most still believed the earth was the centre of the universe

·  Copernicus was one of the first to think the earth circled the sun

·  In 1608, the Italian, Galileo, created the telescope

·  They found the Milky Way was just stars

·  Venus has phases like the moon

·  The Sun has spots on it

·  The Moon had mountains

·  Jupiter had 4 moons

·  The fuzzy blotches in the sky are nebulas

·  In 1924, telescopes had a mirror and lenses to concentrate light

·  Images were captured on photographic plates in slow careful time exposures

·  Edwin Hubble, first invented the use of the Cepheid Variable, using distinctive stars to measure the distance

·  This meant the dimmer the star the further away it was

·  Hubble also discovered Andromeda 2 million light years away

·  They realized the light from the galaxies looked redder than expected

·  This meant the galaxies were moving away from each other at great speeds

·  This meant the universe was growing

·  Researchers wanted to believe in a universe that “Always was, and always will be”

·  Once long ago, galaxies were clumped together

·  The Big Bang Theory was created, the universe was a bright hot point, then a huge explosion occurred and it started expanding

·  The hydrogen gas in space cooled down and formed stars and galaxies of stars

·  If you take the speed and distance, you can get the time

·  Red Shift tells us the speed of the stars

·  Milestone Cepheid stars tell us how far they have travelled

·  The Big Bang happened 15-20 billion years ago

·  The 3 major philosophical questions are:

-  How old is the universe we live in?

-  How did it begin?

-  What’s it evolution?

TOO MANY CANDLES ON THE CAKE?

·  Robert Kirshner works 85 hundred feet up

·  Light pollution has chased astronomers out of cities

·  He watches for supernova, which is, a sudden flare up, a star exploding

·  A smaller version of a supernova is a Nova

·  A supernova out shines their entire galaxy for a few weeks

·  They may be better distance measurers than Cepheids

·  Gas and dust mark where stars have blown up

·  Supernova are rare, a galaxy of 100 million stars may have one exploding star every 100 years

·  Telescopes are in orbit to get better pictures of the stars, they are used to get rid of the twinkle of the stars

·  Wendy Freedman has calculated the age of the universe to be in range of 8-12 billion years old

·  To find the age of a star you look at the brightness of the brightest star, that is still burning hydrogen in its core. This star will burn out first, this showing the age of the cluster

·  Stars are 6 billion years older than Freedman’s universe

THE DARK SIDE OF THE UNIVERSE

·  Visible light is the rainbow from red to violet

·  People are now using x-rays, info red, and radio waves to look at things

·  Nuclear reactions are boiling beneath the suns surface

·  The sun is a self-contained thermal nuclear explosion

·  Stars forming regions of the universe are often hidden from view by dust clouds

·  Info red astronomy can now allow us to see through the dust clouds

·  Most of the understanding of the universe comes from radio static, “a whisper fro the sky”

·  In 1939, a satellite called the Cosmic Background Explorer found subtle variations in the energy left over from the moment of creation

·  In 1992, the discovery was announced and was the momentous discovery of the century

·  Stars on the fringes of the galaxies should be moving slower than the stars at the centre

·  But defying the laws of physics the stars at the edge were moving just as fast as the stars in the middle

·  Earth orbits at half a million miles per hour

·  All the things we have observed in the universe, the sun, stars, galaxies, etc. make up 10% or less of all matter

·  90% that is not visible is called dark matter

·  David Snowden-Ifft, theorizes that dark matter is made up of what physicists call wimps, interacting mass of particles

·  Wimps bump into Mica which causes a recoiling change in the mica

·  Unfortunately, David Snowden-Ifft has yet to find any wimps

·  In 1996, a group of researchers announced they have found the dark matter

·  They picked up ripples star light caused by dwarf stars too dim to be seen directly

·  A halo of these objects around galaxies would account for the missing part of the universe

·  MACHO stands for MAssive Compact Halo Object

·  If there is enough dark matter the expansion of the universe stops and reverses, with everything falling back together, till the Big Bang ends in a ‘Big Crunch’

STRANGE ATTRACTIONS

·  Everything in the large scale depends on gravity

·  Gravity is a property of matter and space

·  The moon goes around the earth because it is trapped in a dimple in space

·  When enough matter collects, gravity is strong enough to squish hydrogen atoms into helium atoms, this fusion releases enough energy to turn on a star

·  Gravity is always trying to crunch stars into small points

·  Stars burn away and produce radiation

·  A teaspoon of stuff from a neutron star would weigh one hundred million tonnes

·  A star 50 times the size of the sun blows up as a supernova leaving a neutron star but keeps shrinking to infinity with gravity so powerful not even light can escape, this is called a Black Hole

·  VLA stand for Very Large Array of antennas

·  James Moran is one of the world’s foremost radio astronomers

·  Black holes create radio waves in the form of a of beam micro waves, a micro wave laser or maser

·  A theory is that white holes are regurgitating black hole matter called Worm Holes

INFINITY AND BEYOND

·  Nothing can go faster than the speed of light

·  Star trek, is a television show that features life in space

·  Earth is the only star in the universe that has life on it

·  If there were no stars, the universe would be all hydrogen

·  Theoretically, human beings can be made out of stardust