Space Physics

Question 1

Galaxies

Answer 1

Collections of billions of stars orbiting around a galactic centre (black hole)

Question 2

Star

Answer 2

Ball of gas (hydrogen and helium) which radiate energy in the form of electromagnetic wave

Question 3

The sun

Answer 3

An average star in the Milky Way, halfway through its lifespan, which emits infrared, ultraviolet and visible light

Question 4

Nuclear fusion in a stable star

Answer 4

Hydrogen atoms join together with enough force to fuse into helium atoms. This reaction produces a lot of energy which is released in the form of electromagnetic waves

Question 5

Nuclear fusion in older stars

Answer 5

Old stars run out of hydrogen, so start fusing other things together and becomes unstable

Question 6

From where a star is born

Answer 6

Interstellar clouds of gas and dust of which hydrogen must b present in

Question 7

When is a star considered a protostar

Answer 7

When, due to gravity, the interstellar clouds start to collapse upon themselves causing all the elements to clump together. Hydrogen nuclei start fusing together and gravity pulls in more materials causing the temperature to increase

Question 8

How can astronomical distances be measured

Answer 8

In light years where one light year is the distance travelled in the vacuum of space by light in one year.

9.5 x 10^5

Question 9

Life cycle of a star (8)b

Answer 9

-Star formed from interstellar clouds of gas and dust containing hydrogen
-protostar forms due to the cloud collapsing and increasing in temperature due to its internal gravitational attraction
-Stable star forms when the inward force of gravity is balanced by an outward force due to the high temperatures
-

Question 10

Describe what the solar system contains (5)

Answer 10

One star, the sun
8 planets mvemjsun
Minor planets, dwarf planets (Pluto) and asteroids in the asteroid belt
Moons that orbit the planets
Smaller solar system bodies (comets + natural satellites)

Question 11

What are seasons caused by

Answer 11

Solar rays are more concentrated over a smaller area in the summer than in the winter

Question 12

Comets

Answer 12

Clumps of loosely bound rock and ice moving in highly elliptical orbits around the sun

Question 13

Orbits of the planets and comets etc.

Answer 13

They have elliptical orbits, of which the sun is not the centre unless when the orbit is approximately circular. When an object is closer to the sun it is faster as gravitational potential energy is converted to kinetic

Question 14

What does the gravitational field strength of a planet depend on

Answer 14

It’s mass

Question 15

Compare the first 4 planets to the last 4, why are they different

Answer 15

First 4 are rocky and small, last 4 are gaseous and large

The accretion model for solar system formation

Question 16

Accretion model

Answer 16

4.5 billion years ago:
-Interstellar clouds of gas pulled together by gravity
-Planets formed in the accretion disk formed, through the rotation of material in the cloud, as the dust and gas comprised of many elements came together
When there was enough mass in the sun:
- Huge amount of energy produced that blew lighter particles from the planets to the outer parts of the solar system, resulting in the inner planets having a higher density than the outer

Question 17

Why planets orbit the sun

Answer 17

As the sun contains most of the mass in the solar system. This means that the sun has a very strong gravitational attraction which keeps the planets in orbit

Question 18

Describe the sun referring to size, composition and energy radiation

Answer 18

Star in the galaxy called the milky way
Medium size
Hydrogen and helium
Infrared, visible and ultraviolet regions of the electromagnetic spectrum

Question 19

What are stars powered by

Answer 19

Nuclear reactions that release energy

Question 20

What Nuclear reactions in stable stars involve

Answer 20

The fusion of hydrogen into helium

Question 21

Galaxies

Answer 21

Consist of billions of stars

Question 22

Describe the distance between the earth and the sun and other stars in the Milky Way

Answer 22

The earth is closer to the sun than the other stars

Question 23

How can astronomical distances be measured

Answer 23

In light years (distance traveled in the vacuum of space by light in one year)
9.5x10*15

Question 24

Light year

Answer 24

Distance travelled in the vacuum of space by light in one year
9.5x10*15

Question 25

Redshift

Answer 25

Increase in the observed wavelength of the electromagnetic radiation emitted from receding stars and galaxies

Question 26

Diameter of the Milky Way

Answer 26

100 000 light years

Question 27

The universe

Answer 27

Made up of billions of galaxies

Question 28

Describe Light emitted from distance galaxies

Answer 28

Appears redshift in comparison to light on earth, is evidence of the universe expanding and supports the Big Bang theory

Question 29

CMBR

Answer 29

Cosmic Microwave Background Radiation
Microwave radiation of a specific frequency observed at all points in space, produced shortly after the universe was formed and expanded into the microwave region of the electromagnetic spectrum as the universe expanded

Question 30

How can the speed at which a galaxy is moving away from the earth be found

Answer 30

The change in wavelength of the galaxy’s starlight due to red shift

Question 31

How can the distance of a galaxy be determined

Answer 31

From the brightness of a supernova in that galaxy

Question 32

How can the distance of a galaxy be found

Answer 32

Using the brightness of a supernova in that galaxy

Question 33

Hubble constant

Answer 33

Ratio of the speed at which the galaxy is moving away from the earth due to its distance from the earth
H0=v/d

Question 34

Current estimate for bubbles constant

Answer 34

2.2x10*-18 per second

Question 35

What does
d/v=1/H
Represent

Answer 35

An estimate for the age of the universe
Evidence for the idea that all matter in the universe was present at a single point