Atronomy 8 (for my love)

You observe a galaxy moving away from you at 0.1 light-years per year, and it is now 1.4 billion light-years away from you. How long has it taken to get there?

• 1 million years

• 14 million years

• 10 billion years

• 14 billion years

Your friend leaves your house. She later calls you on her cell phone, saying that she's been driving at 60 miles an hour directly away from you the whole time and is now 60 miles away. How long has she been gone?

• 1 minute

• 30 minutes

• 60 minutes

• 120 minutes

Why does ongoing star formation lead to a blue-white appearance?

• There aren't any red or yellow stars

• Short-lived blue stars outshine the others

• Gas in the disk scatters blue light

When the Sun dies, it will leave behind

• a planetary nebula

• a white dwarf.

• a supernova

A white dwarf

• is the core of the star from which it formed, and contains most of the mass

• is about the size of Earth

• is supported by electron degeneracy

• is so dense that one teaspoonful would weigh about as much as an elephant

• all of the above

What keeps a white dwarf from collapsing further?

• electrical forces

• chemical forces

• nuclear forces

• degeneracy pressure

If a white dwarf in a binary has a companion close enough that some material begins to spill onto it, it can

• cool off

• be hidden from view behind the material

• have new nuclear reactions and experience a nova

• become much larger

• all of the above

What happens if a white dwarf has a nearby binary companion that tries to expand as it evolves?

• Hydrogen may be pulled into an accretion disk around the white dwarf, then onto it

• The hydrogen may begin to fuse and create a nova, as bright as 100,000 Suns

• The white dwarf may then collapse into a black hole

• all of the above

If the mass transferred to a white dwarf causes it to exceed the 1.4 solar mass limit, what happens?

• Carbon can begin to fuse rapidly in the white dwarf.

• The star can emit 100 billion times as much light as the Sun for several days

• The star can explode in a supernova

• all of the above

A supernova may leave behind as a remnant

• a white dwarf

• a neutron star

• a black hole

• any of the above