Space (8) - Pt1

Question 1

How is a Neutron star formed?

Answer 1

Cloud of dust and gas > protostar > main sequence star > red super giant > supernova > neutron star

Question 2

How is a black hole formed?

Answer 2

Cloud of dust and gas > protostar > main sequence star > red super giant > supernova > black hole

Question 3

How is a black dwarf formed?

Answer 3

Cloud of dust and gas > protostar > main sequence star > red giant > white dwarf > black dwarf

Question 4

Explain in how a protostar in formed?

Answer 4

1. They’re formed from a cloud of dust and gas called a nebula
2. Gravity pulls the nebula together forming a protostar.
   The temp. rises as the star gets denser & more particles collide. When the temp is high enough, hydrogen nuclei undergo nuclear fission to form helium nuclei.
   Giving out tons of energy keeping the core of the star hot

Question 5

Explain how a main sequence star is formed?

Answer 5

3. The star enters a stable period where the outward pressure of nuclear fission tries to expand the star equals the force of gravity pulling everything inwards.
   This is when it’s a main sequence star (usually lasts billions of years)

Question 6

Explain how a main sequence star turns into either a red super giant or a red giant?

Answer 6

4. Eventually hydrogen begins to run out
   Then star then swells into a red giant (if it’s a smaller star like our sun) or a red super giant (if it’s a bigger star)
   It becomes red because it’s surface cools
   Fusion of helium (& other element) occur.
   Heavier elements (up to iron) are created in the core of the star

Question 7

What stage in our sun in at the moment?

Answer 7

It’s a main sequence star

Question 8

Explain how a red giant becomes a black dwarf?

Answer 8

5. a small medium star (eg. Our sun) becomes unstable and ejects its outer layer of dust and gas.
   Leaving a hot, dense solid core -a white dwarf
6. As the white dwarf cools down, it emits less energy.
   when it no longer emits a significant amount it’s called a black dwarf

Question 9

A red super giant turns into a supernova?

Answer 9

7. Big stars start glowing brightly again undergoing more fusion and expand and contract several times, forming elements as heavy as iron
   Eventually they’ll explode in a supernova ejecting elements heavier then iron to form new planets and stars

Question 10

Explain how a super move becomes either a neutron star or a black hole?

Answer 10

8. an exploding supernova throws the outer layer of dust and gas into space, leaving a very dense core called a neutron star
   If the star is massive enough it becomes a black hole-a very dense point in space that not even light can espace from

Question 11

What is the solar system?

Answer 11

• the things that orbit the sun
• our solar system is a tiny part of the Milky Way galaxy- which is a collection of billions of stars that are held together by gravity

Question 12

What’s a planet?

Answer 12

• They’re large objects that orbit a star
• there’s 8 in our solar system
• they have to be large enough that they’re gravity is strong enough to have pulled in nearby objects apart from their natural satellites (eg. A moon)

Question 13

What’s an artificial satellite?

Answer 13

• Human built satellites

- they generally orbit the earth

Question 14

How are obits created and how do they work?

Answer 14

Gravity provides the force that allows planets and satellites (both natural and artificial) to maintain their circular orbits.

• as it’s a circular orbits, the force of gravity leads to a changing velocity but unchanged speed
• for a stable orbit, the radius must change if the speed changes.

Question 15

Explain the theory of the Big Bang?

Answer 15

• at the start the universe occupied a very small space, which was very dense and hot
• then it ‘exploded’ and space started expanding, this expansion is still continuing

Question 16

What’s proof of the bang big and that the universe is expanding?

Answer 16

There’s an increase in the wavelength of light from distant galaxies

• the wavelengths are longer than they should be they’ve shifted to the red end of the spectrum.This effect is called red-shift. Suggesting light is moving away from us.
• further galaxies have greater red-shifts then closer ones suggesting that distant galaxies are move faster than nearer ones
• red-shift provides evidence that the universe is expanding supporting the Big Bang theory.
• this theory has been intact since 1998

Question 17

What’s dark matter?

Answer 17

It’s an unknown substance which holds galaxies together but doesn’t emit any electromagnetic radiation
(Just a theory)

Question 18

What’s dark energy?

Answer 18

-is thought be responsible for the accelerated expansion of the universe
(Just a theory)