Space

Question 1

Explain how a main sequence star can form.

Answer 1

A cloud of dust and gas (a nebula) pulled together by gravity can cause fusion reactions, potentially leading to an equilibrium between the gravitational collapse and the outward pressure from energy resultant from fusion.

Question 2

Explain the life cycle of less massive main sequence stars.

Answer 2

Less massive main sequence stars grow into red giants, then eventually develop into white dwarfs which degrade into black dwarfs.

Question 3

Explain the life cycle of more massive main sequence stars.

Answer 3

More massive main sequence stars grow into red supergiants, which eventually explode in supernovae, most becoming ultra-dense neutron stars. The most massive become theoretically infinitely dense black holes.

Question 4

How are heavier natural elements formed and distributed?

Answer 4

Fusion processes in stars produce the heaviest natural elements in their dying stages, after which a supernova occurs, distributing the elements throughout the universe.

Question 5

Which centripetal force keeps planets and satellites in orbit?

Answer 5

Gravity

Question 6

Describe red shift.

Answer 6

There is an observed increase in the wavelength of light from most distant galaxies. The further away the galaxies, the faster they are moving and the bigger the observed increase in wavelength.

Question 7

What does red shift suggest about the origin and nature of the universe?

Answer 7

Red shift provides evidence that the universe is expanding, supporting the Big Bang theory.