The Universe Flashcards
What are distances in the solar system measured in?
Astronomical Units (AU)
What are very large distances in space measured in?
Light Years
How big is the universe?
About 100 billion light years
What are space probes used for?
They are sent out to detect the presence of water and minerals on other planets
What are robotic landers used for?
They collect soil samples and search for microscopic life forms, such as bacteria
What is the SETI used for?
It is used for looking for radio broadcasts from alien civilisations which may exist on other planets orbiting distant stars
What can photographs taken using xrays provide?
They reveal different information about the structure of space bodies, such as their magnetic fields
When and how was the sun formed?
About 4.6 billion years ago from a thin cloud of dust, ice and gas, called a nebula. The material was pulled together by gravity and it began to spin and increase in temperature. At a few million degrees C, a nuclear fusion reaction ocurred and the star began to emit its own light
What is the cycle for stars similar to the sun?
nebula - sun - red giant - white dwarf - black dwarf
What is the cycle for massive stars?
large nebula - star - super red giant - supernova - black hole/neutron star
What does the steady state theory show?
That the model of the universe is:
- expanding
- has unchanging density
- spontaneously created matter
- had no beginning and will never end
What does the big bang theory show?
That the model of the universe is:
- expanding
- is finite and ever-changing
- was created 14 billion years ago by big bang
- may never end, depending on density
What is CMB and how can it be detected?
It is radiation that is left over from the big bang and can be detected using radio telescopes
What does red-shift indicate?
Red-shift from distant galaxies shows that they are moving away from each other. This is evidence that the universe is expanding
What is the strong evidence supporting the big bang theory?
- all galaxies show red-shift
- the temp. of universe was predicted and then confirmed to be -270
