Astrophysics - Motion and the universe - Steller evolution - Cosmology

Question 1

what is m/s squared used for

Answer 1

accelaration

Question 2

What is the universe

Answer 2

A large collection of billions of galaxies

Question 3

What is a galaxy

Answer 3

A collection of billions of stars

Question 4

What galaxy is our solar system in

Answer 4

The milky way

Question 5

Why does the gravitational field strength of things vary

Answer 5

The more mass an object has, the greater its gravitational field will be.

Question 6

Gravitational field strength causes:

Answer 6

1) Moons to orbit planets
2) Artificial satellites to orbit the Earth
3) Causes planets to orbit the sun
4) Causes comets to orbit the sun

Question 7

what is the difference between the orbits of comets moons and planets

Answer 7

A comet orbits a star in an elliptical shape whereas a moon orbits a planet in a circular orbit and a planet orbits in a slightly elliptical shape

Question 8

What is the relationship between orbital speed , orbital radius and time period

Answer 8

Orbital speed =
2 x PIE x orbital radius
———————————
Time period

Question 9

How can stars be classified by colour and what do the colours mean

Answer 9

hot, bright stars are blue, very small, colder or old dying stars are red.

Question 10

What does a stars colour relate to

Answer 10

It’s surface temperature

Question 11

What are the steps of the evolution of the sun and other simillair mass stars

Answer 11

1)Nebula
2) Star (Main Sequence)
3) Red Giant
4) White Dwarf

Question 12

What are the steps of the evolution of stars that have a much larger mass than the sun

Answer 12

Nebula
Protostar
Main Sequence Star
Red Supergiant
Supernova
Neutron Star (or Black Hole)

Question 13

What is absolute magnitude

Answer 13

the magnitude (brightness) of a celestial object as it would be seen at a standard distance of 10 parsecs.

Question 14

Understand and be able to draw the main components on the Hertzsprung-Russel Diagram

Answer 14

http://www.alevelphysicsnotes.com/astrophysics/hr_diagrams.php

Question 15

What are the main arguments in favour of The Big Bang Theory

Answer 15

1) The Universe has expanded from a singular dense point (singularity) and is still expanding

Question 16

What evidence supports the Big Bang Theory

Answer 16

1) Red-Shift - the displacement of spectral lines towards longer wavelengths (the red end of the spectrum) in radiation from distant galaxies and celestial objects
2) Cosmic Microwave Background Radiation (CMBD) - Scientists consider it as an echo or ‘shockwave’ of the Big Bang

Question 17

If a wave source is moving towards an observer, what happens to the frequency and wave length

Answer 17

the frequency increases and the wavelength decreases (It compresses)

Question 18

If a wave source is moving towards an observer, what happens to the frequency and wave length

Answer 18

The frequency increases and the wavelength decreases (It compresses)

Question 19

What is the equation relating to change in wavelength, reference wavelength, velocity of a galaxy and speed

Answer 19

Cange in wavelength
——————————- =
Reference wavelength

velocity of a galaxy / speed

Question 20

How does Red-shift vary

Answer 20

The further away the thing is, the more red-shifted it is

Question 21

Why does Red-shift vary

Answer 21

As a result of the expansion of space: this means that the farther away a galaxy is from us, the more the space has expanded in the time since the light left that galaxy, so the more the light has been stretched, the more redshifted (understand this)