Was our sun/planets formed at the beginning of the universe? How can we tell?

No - heavy elements are present that can only be formed in very old stars

What happens to a planetary nebula?

It eventually reforms into a new star (with some other material)

What's a planetary nebula?

The outer layers of a star that are shed as the start collapses

What causes a main sequence star to become a red giant?

It runs out of hydrogen and begins fusing helium.

What happens to the least massive stars?

They never become a red giant and just shrink to form a brown dwarf

Black holes form after massive stars go supernova. Why are they called black holes?

They're so dense that gravity is so strong that light cannot escape.

Why are red giant stars bigger than main sequence stars?

The outward pressure from fusion is greater when fusing helium

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Stellar Evolution

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Questions 19

Answers

1
After the red giant stage, multiple things could happen. What determines the next stage of a star?
The brightness
The mass
The weight
The density
2
Was our sun/planets formed at the beginning of the universe? How can we tell?
No - Stars didn't start forming until a billion years after the big bang
Yes - we can measure the age of both and compare
Yes - it's impossible for stars to be formed after the universe
No - heavy elements are present that can only be formed in very old stars
3
A massive, blue star will age slower than a smaller, red star.
True
False
4
Why don't black dwarfs exist?
They break the laws of physics.
They're just a made up thing that scientists thought of to look cool
Our universe is just too young
There's only a 0.01% chance of them forming after a supernova
5
What happens to a planetary nebula?
It disappears
It just sits in space for forever
It spreads out, covering nearby stars and planets
It eventually reforms into a new star (with some other material)
6
What's a planetary nebula?
A superhero from the 1960s.
The outer layers of a star that are shed as the start collapses
The remains of an exploded star
The cloud of dust where stars are born
7
The first stage of a star's life cycle is a
Red giant
Planetary nebula
Main sequence
Stellar nebula
8
Our sun will form a
Black hole
Neutron star
White dwarf
Brown dwarf
9
As protostars spin, they lose some material that begins orbiting the protostar in a disk. What might this disk become?
None of the above
More stars
Planets, asteroids, moons, etc
Nothing - it always gets pulled back to the star
10
What pulls the gas and dust in a nebula together to begin star formation?
Gravity
Nuclear fusion
Random chance
Static electricity
11
When does a protostar become a star?
Protostars are already stars
When nuclear fission begins
When they play a major role in a movie
When nuclear fusion begins
12
Most of the stellar life cycle is spent in this phase (where our sun currently is)
White dwarf
Red giant
Black hole
Main sequence
13
What causes a main sequence star to become a red giant?
It runs out of hydrogen and begins fusing helium.
They don't - main sequence stars become white dwarfs
It pulls in more mass from the solar system around it.
It makes more helium, which is bigger and takes up more space than hydrogen
14
In a red giant, the core of the star is ________ than the core of a main sequence
Smaller
Bigger
15
What happens to the least massive stars?
They go supernova and form a neutron star
They go supernova and form a black hole
They expand to a red giant before shrinking to a white dwarf
They never become a red giant and just shrink to form a brown dwarf
16
Black dwarfs exist in our universe right now.
False
True
17
In the main sequence, a star is doing this
Just sitting there, looking good
Splitting helium to make hydrogen
Fusing hydrogen into helium
Fusing helium into larger elements
18
Black holes form after massive stars go supernova. Why are they called black holes?
They're so dense that gravity is so strong that light cannot escape.
It sounds cool
After collapse, the remains of the star no longer emit light.
It's a misnomer - they're actually blue
19
Why are red giant stars bigger than main sequence stars?
They have more mass
It's just the way it is
Stars are continuously growing through their life - older star = bigger
The outward pressure from fusion is greater when fusing helium

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