Chapter 1 Flashcards
An astronomical unit:
Earth’s average distance from the Sun
The star Betelgeuse is about 600 light years away. If it explodes tonight…
We won’t know about it until 600 years from now
Could we see a galaxy that is 50 billion light years away?
No, because it would be beyond the bounds of our observable universe
Which of the following correctly lists our “cosmic address” from smallest to largest?
Earth, solar system, milky way galaxy, local group, local supercluster, universe
If we represent the solar system on a scale that allows us to walk from the sun to pluto in a few minutes then:
The planets would be all be marble size or smaller and the nearest stars would be thousands of miles away
The total number of stars in the observable universe is roughly equivalent to:
The number of grains of sand on all the beaches on Earth
Light travels at a speed of
3×10^5 km/s
If stars existed but galaxies did not
We would not exist because we are made of material that required recycling in galaxies
The age of our solar system is about
One third of the age of the universe
The fact that nearly all galaxies are moving away from us, with more distant ones moving faster, helped us to conclude that:
The universe is expanding
Dark matter can be detected only by
its gravity, that affects other objects we can see
Why can’t you see dark matter in a telescope?
Dark matter does not emit light
Where does dark matter reside in our galaxy?
Most dark matter resides in the halo of the galaxy
What makes dark matter and dark energy mysterious?
Because we do not know what they exactly are
What makes dark matter and dark energy important?
Dark matter and dark energy make up the majority of the total energy within the universe
