Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics > Astrophysics > Flashcards

Astrophysics Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

What is the Universe?

A

Large collection of billions of galaxies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a Galaxy?

A

Large collection of stars

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q 
What are Planets?
Many
Vampires
Eat
Mothers 
Joyfully
So 
Undress 
Now
A 
•Large objects that orbit the Sun in circular orbits 
•There are 8 planets :
Mercury 
Venus 
Earth
Mars
Jupiter 
Saturn
Uranus 
Neptune
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are Dwarf Planets and give an example?

A
  • Plant like objects that aren’t big enough to be planets

* E.g. Pluto

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are Moons?

A
  • Orbit planets with circular orbits

* Type of Natural satellite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are Artificial Satellite?

A
  • Ones humans have built

* Orbit Earth in circular orbits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are Asteroids?

A
  • Lumps of rock and metal that orbit the Sun

* Found in asteroid belt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are Comets?

A
  • Lumps of ice and dust that orbit the Sun
  • Orbits are highly elliptical
  • Some travel from near to Sun to outskirts of our solar system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does Gravity provide the Force that creates Orbits?

A
  • Object travelling in circle = changes direction = accelerating = there’s a force acting on it
  • Centripetal force causing it - causes object to change direction because it’s moving
  • Object keeps accelerating towards what its orbiting but velocity travelling in circle
  • Gravitational force - gravitational attraction of Sun keeps planets + comets in their orbits
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens the Closer you get to a Star or Plant?

A
  • Stronger the gravitational force is

* The faster you need to go to remain in orbit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the different types of Orbit?

A
  • Moons + planets are slightly elliptical

* Comets have very elliptical elongated orbits with the Sun at one focus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

When do Comets travel faster?

A
  • Nearer the sun

* Because increased pull of gravity makes it sped up the closer it gets to the sun

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are Geostationary Satellites and what are they Useful for?

A
  • Artificial Earth satellites have orbital period of one day
  • Useful in communications because they’re always over same part of plant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a Nebula?

A

Stars initially form from a cloud of dust and gas called nebula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a Protostar?

A

Force of gravity pulls gas/dust together to form a protostar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is a Star Born from a Protostar?

A
  • Temp rises as star gets denser and more particles collide
  • High enough temp = hydrogen nuclei undergo nuclear fusion to form helium nuclei
  • Give our a lot of energy, keeping core of star hot
  • Star is born
17
Q

What is a Main Sequence Star?

A
  • Star enters long stable period - outward pressure caused by thermal expansion balances the force of gravity pulling everything inwards = main sequence star
  • Heavier star = shorter its time on main sequence
18
Q

What is a Red Giant and Red SuperGiant?

A
  • Hydrogen in core runs out + force is larger than pressure of thermal expansion
  • Stars compressed, until it’s dense + hot so energy makes outer layers of Star expand
  • Red giant = smaller star
  • Red supergiant = larger star
  • Red because surface cools
19
Q

What is a White Dwarf?

A
  • Small star becomes unstable + ejects outer layers of dust + gas
  • Leaves behind hot, dense solid core = a white dwarf
20
Q

What is a SuperNova?

A
  • Big stars glow brightly again as undergo more fusion to make heavier elements
  • They expand + contract several times
  • Balance shifts between gravity + thermal expansion
  • They explode in supernova
21
Q

What is a Neutron Star and a Black Hole?

A
  • Exploding supernova throws outer layers of dust + gas
  • Leaves dense core = neutron Star
  • If Star is massive enough, it will collapse and become a black hole - super dense
22
Q

What is Sequence of Star that has a Low Mass?

A
  • Nebula
  • Protostar
  • Main sequence star
  • Red giant
  • White dwarf
23
Q

What is Sequence of Star that has a High Mass?

A
  • Nebula
  • Protostar
  • Main sequence star
  • Red supergiant
  • Supernova
  • Neutron Star or black hole
24
Q

What does a Stars Brightness depend on?

A
  • It’s size + temperature + distance from Earth + absolute magnitude
  • Bigger star + hotter star + closer to Earth + lower absolute magnitude = brighter
25
Q

What is Absolute Magnitude?

A
  • Measure of how bright a star would appear if it was a fixed distance from Earth
  • Used to compare brightness of stars
26
Q

What is the Hertzsprung-Russel Diagram?

A
  • Graph of absolute magnitude against temperature for stars

* Groups that correspond to different periods in stars life cycle

27
Q

Where are Red Giants or Red SuperGiants on the Hertzsprung-Russel Diagram?

A
  • Top right

* They’re cool, Large, bright

28
Q

Where are White Dwarfs on the Hertzsprung-Russel Diagram?

A
  • Bottom left

* They’re hot, small, dim

29
Q

Where are Main Sequence Stars on the Hertzsprung-Russel Diagram?

A
  • Whole of graph diagonally from top left to bottom right

* Brighter Star = higher temp

30
Q

What is the Red-Shift?

A

If light source moving away from you, light it emits will appear to be shifted towards the red end of EM spectrum

31
Q

What is the evidence that light from galaxies are Red-Shifted?

A
  • Different elements absorb different frequencies of light
  • Light passed through sample of element, pattern of dark lines produced
  • When look at light from distant galaxies we see same patterns at lower frequencies than they should be
  • Patterns shifted towards red end of spectrum = red-shift
32
Q

What does measurements of the red-shift suggest?

A
  • All distant galaxies are moving away from us quickly
  • More distant = greater red shift = show bigger observed increase in wavelength = moving away faster
  • Whole universe is expanding
33
Q

What is the Cosmic Microwave Background (CMB) Radiation and what is it Evidence of?

A
  • Scientists detect low frequency microwave radiation coming from all directions + all parts of the universe
  • Background radiation is evidence for initial Big Bang
  • As universe expands + cools - background radiation cools + drops in frequency
34
Q

What is the theory of a Big Bang?

A
  • All matter in universe occupied at single point
  • This tiny space was dense + hot
  • This single point ‘exploded’ = Big Bang
  • Space started expanding, and explosion is still going on
  • CMB radiation is leftover energy of initial explosion

Physics (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions