What is the Big Bang cosmology?
Q: What is the Big Bang cosmology?
A: Big Bang cosmology is a scientific theory that explains how the universe began and has evolved over time. It states that the universe began from an extremely hot and dense state, known as the "Big Bang," about 13.8 billion years ago.
Q: What is an observable universe?
A: An observable universe is what, in theory, can be seen from Earth. This includes light or other signals which have had time to reach Earth since the beginning of the cosmological expansion. Every place in the universe has its own observable universe, which may or may not overlap with one centered on Earth.
Q: How far back can we see light?
A: We can see light only from as far back as when particles were first able to emit photons that were not quickly re-absorbed by other particles. Before then, the universe was filled with a plasma that was opaque to photons.
Q: What is the difference between visible and observable universes?
A: The visible universe includes only signals emitted since recombination while the observable universe includes signals since the beginning of cosmological expansion (the end of inflationary epoch).
Q: How big is radius of visible Universe?
A: The radius of visible Universe is about 14 billion parsecs (45.7 billion light years).
Q: How old is estimated age of Universe?
A: The best estimate of age of Universe as of 2013 is 13.798 ± 0.037 billion years old.
Q: How far away is edge of observable Universe? A:The edge of observable Universe is about 46–47 billion light-years away
