Question

1. scientists are always looking for answers and creating theories, including the big bang theory. (20 points)

a. what happens in the big bang theory? (4 points)
b. what are two forms of evidence used to support this theory? (6 points)
c. how do these forms of evidence support the theory? (10 point)

1. a stars stellar mass will influence its life cycle. (10 points)

a. what happens during the life cycle of a star with one stellar mass? (4 points)
b. what happens during the life cycle of a star with two to three stellar masses? (4 points)
c. what is left behind after a star with four or more stellar masses has died? (2 points)

Explanation:

A.

The Big Bang Theory posits that the universe originated from a singularity. It then underwent a rapid expansion, creating matter, energy, space, and time. Temperatures were extremely high initially and have been cooling ever since as the universe expands.

B.

1. Cosmic Microwave Background Radiation (CMBR): It is a faint glow of electromagnetic radiation filling the universe. It is considered the "after - glow" of the Big Bang, with a nearly uniform temperature across the sky, which is consistent with the early universe being in a hot, dense state.
2. Hubble's Law and the Expansion of the Universe: Galaxies are moving away from each other, and the farther a galaxy is, the faster it is receding. This expansion is a key prediction of the Big Bang Theory, as the initial explosion would have sent matter flying outward.

C.

1. For CMBR: The uniformity of CMBR across the sky supports the idea that the early universe was in a highly homogeneous and isotropic state, which is a prediction of the Big Bang. The tiny temperature fluctuations in CMBR also provide evidence for the seeds of structure formation in the universe.
2. For Hubble's Law: The observed expansion of the universe implies that in the past, all matter was closer together. Tracing this expansion backward leads to the concept of a single, dense starting point, which is the essence of the Big Bang Theory.

4.A

A star with one solar mass (one stellar mass) begins as a main - sequence star, fusing hydrogen into helium in its core. After billions of years, the hydrogen in the core is exhausted, and the star expands into a red giant. Eventually, the outer layers are shed, forming a planetary nebula, and the core remains as a white dwarf, which cools over time.

4.B

A star with two to three solar masses also starts as a main - sequence star. When hydrogen fusion in the core stops, it expands into a red super - giant. It then undergoes a series of nuclear fusion reactions in its core, creating heavier elements. Eventually, it explodes in a supernova, and the core can collapse to form a neutron star.

4.C

After a star with four or more solar masses has died, it undergoes a supernova explosion. The core collapses under its own gravity, and if the mass of the core is high enough, it can form a black hole.

Answer:

A.

The universe originated from a singularity, underwent rapid expansion, with high initial temperatures that have been cooling as the universe expands.

B.

1. Cosmic Microwave Background Radiation (CMBR)
2. Hubble's Law and the Expansion of the Universe

C.

1. CMBR's uniformity and temperature fluctuations support the early universe's homogeneous state and structure - formation seeds.
2. Hubble's Law implies a past dense starting point for the universe.

4.A

Starts as main - sequence, becomes red giant, sheds outer layers as planetary nebula, leaves white dwarf core.

4.B

Starts as main - sequence, becomes red super - giant, explodes as supernova, core forms neutron star.

4.C

A black hole.