Question

gravitational waves are ripples in the fabric of space - time caused by some of the most violent and energetic processes in the universe.
true
false
which of the following provides evidence that the big bang occurred? (choose all that apply)
gravitational waves
distance and movement of galaxies
abundance of elements
cosmic background radiation
the farther away a galaxy is, the faster it is moving away from us.
true
false
the big bang was a huge explosion.
true
false

Explanation:

• First Question: Gravitational waves are indeed ripples in spacetime caused by violent and energetic cosmic events like merging black holes or neutron stars.
• Second Question:
• Distance and Movement of Galaxies: Hubble's law (recession velocity \(v = H_0d\), where \(H_0\) is the Hubble constant and \(d\) is distance) shows galaxies are moving apart, supporting expansion from the Big Bang.
• Abundance of Elements: The Big Bang nucleosynthesis predicts the abundance of light elements (H, He, Li), which matches observations.
• Cosmic Background Radiation: It is the after - glow of the hot early universe, a key evidence. Gravitational waves from the Big Bang (primordial) are still being searched for more conclusively, but current evidence for the Big Bang mainly comes from the other three.
• Third Question: Hubble's law describes that the velocity of a galaxy's recession (\(v\)) is proportional to its distance (\(d\)) from us (\(v\propto d\)), so the farther, the faster.
• Fourth Question: The Big Bang was not an explosion in the traditional sense (like in space with a center). It was the expansion of space - time itself.

Answer:

• First Question: True
• Second Question: Distance and Movement of Galaxies, Abundance of Elements, Cosmic Background Radiation
• Third Question: True
• Fourth Question: False