Understanding the Universe
Video Worksheet Answer Key
WHERE ARE WE?
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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
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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
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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