Space Physics

Question 1

I The life cycle for smaller stars?

Answer 1

1. Cloud of dust and gas
2. Protostar
3. Main sequence star
4. Red giant
5. White dwarf
6. Black dwarf

Question 2

The life cycle for larger stars?

Answer 2

1. Cloud of dust and gas
2. Protostar
3. Main sequence star
4. Red super giant
5. Supernova
6. Neutron star or black hole

Question 3

What is the cloud of dust and gas that stars form from called?

Answer 3

1. A nebula

Question 4

How does a protostar form?

Answer 4

1. The force of gravity pulls the dust and gas together to form a protostar.
2. The temperature rises as the star gets denser and more particles collide with each other.
3. When the temperature gets high enough, hydrogen nuclei undergo nuclear fission to form helium nuclei.
4. This gives out large amounts of energy, which keeps the core of the star hot.
5. A star is born.

Question 5

How does a main sequence star form?

Answer 5

1. The star enters a long stable period where the outward pressure caused by the nuclear fusion that tries to expand the star balances the force of gravity pulling everything inwards.
2. In this stable period it is called a main sequence star and it typically lasts several billion years.

Question 6

How do red giants and red super giants form?

Answer 6

1. Eventually the hydrogen begins to run out. The star then swells into a red giant if it is a small star, or a red super giant if it is a large star.
2. It becomes red because the surface cools.
3. Fusion of helium occurs. Heavier elements are created in the core of the star.

Question 7

How does a small sized star become a white dwarf, and then a black dwarf?

Answer 7

1. It becomes unstable and ejects the outer layer of dust and gas. This leaves behind a hot, dense solid core - a white dwarf.
2. As a white dwarf cools down, it emits less and less energy. When it no longer emits a significant amount, it is called a black dwarf.

Question 8

How does a supernova form?

Answer 8

1. Big stars start to glow brightly again as they undergo more fusion and expand and contract several times, forming elements as heavy as iron in various nuclear reactions.
2. Eventually they will explode in a supernova, forming elements heavier than iron and ejecting them into the universe to form new planets and stars.
3. Stars and their life cycles produce and distribute all naturally occurring elements.

Question 9

How do neutron stars and black holes form?

Answer 9

1. The exploding supernova throws the outer layers of dust and gas into space, leaving a very dense core called a neutron star.
2. If the star becomes is massive enough, it will become a black hole - a super dense point in space that not even light can escape from.

Question 10

What is red shift?

Answer 10

1. When we look at light from most distant galaxies, we find that the wavelength has increased.
2. The wavelengths are all longer than they should be - they’re shifted toward the red end of the spectrum.
3. This is called red shift.

Question 11

What does red shift prove?

Answer 11

1. It suggests that the source of light is moving away from us. Measurements of the red shift indicate that these distant galaxies are moving away from us very quickly.
2. More distant galaxies have greater redshifts