TOPIC 8 - SPACE PHYSICS

Give other types of object that form our solar system

stars; planets; dwarf planets; moons; natural satellites

What name is given to objects that orbit a planet?

satellite

Explain the effect of the Earth’s gravitational force on the motion of the Hubble Space Telescope

• gravitational force causes the Hubble Space Telescope to accelerate towards the Earth

• this changes the direction of motion

• so changes the velocity of the Telescope

Compare the formation and life cycles of stars with a similar mass to the Sun to stars with a much greater mass than the Sun

ALL STARS

• form in a cloud of gas + dust (nebula) by gravity - mostly hydrogen

• forms a protostar

• fusion begins

• fusion of small nuclei into larger nuclei (hydrogen into helium)

• main sequence star - stable period where gravitational forces balance forces due to fusion processes

COMPARISONS

• stars about the same size as the Sun expand to become a red giant; stars much bigger than the Sun expand to become a red super giant

• stars about the same size as the Sun contract (+ temp inc) to become a white dwarf, stars much bigger than Sun explode in a supernovae

• stars about the same size as Sun cool to become a black dwarf, stars much bigger become neutron or black hole

If a galaxy shows red-shift, what does that mean about the movement?

it is moving away from us

If the wavelength of the absorption lines from a galaxy has increased, what does that mean about the movement?

it is moving away from us

Describe what is meant by red-shift

the observed increase in wavelength of light from galaxies; as they move away from us

Explain how above diagram provides evidence for the Big Bang theory

• the furthest galaxies are moving away the fastest

• which suggests that at some time all matter started at the same point

Sometimes scientists have to change theories about the universe - why?

there are new observations/ evidence that does not fit into current theory/ models

Explain why a star remains stable

expansion due to fusion; is in equilibrium with gravitational collapse acting inwards

Describe what will happen to the Sun between it leaving the main sequence group and becoming a white dwarf

• sun goes from main sequence to red giant

• when changes, the surface temperature will decrease + relative luminosity iwll increases

• then to white dwarf

• the surface temp will increase

• and relative luminosity decreases

Describe what will happen to the star between the main sequence stage and the end of the star’s life cycle

• expand to become a red giant

• collapse to become a white dwarf

• cool to become a blaxk dwarf

What do the new observations suggest is happening to the universe?

it is epxanding at an ever greater rate

Give one reason why peer review is an important process

detects false calims; detects inaccurate data; detects bias; verifies new data; provides a consensus of opinion

Describe how the wavelength and frequency of the light from Andromeda seem to have changed when viewed from the Earth (it is moving towards us)

wavelength decreased; frequency increased

Explain why the velocity of the satellite changes as it orbits the Earth

• gravity causes the satellite to accelerate

• the acceleration causes a change in direction

• velocity changes because direction changes

What provides the force needed to keep a satellite in orbit around the Earth?

gravity