P6 space physics

Question 1

what does the solar system contain

Answer 1

one star: the sun
8 planets:
- mercury, venus, earth, mars, jupiter, saturn, uranus, neptune
minor planets that orbit the sun
- dwarf planets eg pluto
- asteroids in asteroid belt
moons that orbit planets

Question 2

how to memorise order of planets in solar system

Answer 2

My Very Early Morning Jam Sandwich, Unbelievably Nice

Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune

Question 3

what is the closest star to the earth

Answer 3

the sun

Question 4

how can astronomical distances be measured

Answer 4

light-years

Question 5

what is a light-year

Answer 5

• distance travelled in (the vacuum of) space
• in one year

Question 6

why do the planets orbit the sun

Answer 6

contains most of mass of solar system

Question 7

orbital speed equation

Answer 7

Question 8

what is the cause of the force that keeps an object in orbit around the sun

Answer 8

gravitational attraction of the sun

Question 9

how does suns gravitational field change as distance from sun increases

Answer 9

decreases

Question 10

describe the sun

Answer 10

• star of medium size
• consists mostly of hydrogen and helium
• radiates most of its energy in IR, visible, UV regions of EM spectrum

Question 11

how are stars powered

Answer 11

• nuclear reactions that release energy
• involve fusion of hydrogen into helium

Question 12

how are stable stars formed

Answer 12

• formed as protostars
• from interstellar clouds of gas and dust
• due to gravitational attraction

Question 13

stages of life cycle of small mass star

Answer 13

• interstellar clouds of gas and dust
• protostar
• red giant
• white dwarf + planetary nebula

Question 14

stages of life cycle of large mass star

Answer 14

• interstellar clouds of gas and dust
• protostar
• red supergiant
• supernova
• neutron star

Question 15

stages of life cycle of very large mass star

Answer 15

• interstellar clouds of gas and dust
• protostar
• red supergiant
• supernova
• black hole

Question 16

what are galaxies made up of

Answer 16

billions of stars

Question 17

which galaxy is the sun in

Answer 17

milky way

Question 18

approx diameter of milky way

Answer 18

100 000 light-years approx

Question 19

how is the big bang theory supported

Answer 19

by many astronomical observations

Question 20

explain the big bang theory

Answer 20

• universe expanding from single point of high density and temperature
• universe is still expanding
• universe is approx 13.8 bn years old