Space Physics Flashcards
What is a nebula
A cloud of dust and gas
What causes the rise in temperature that leads to nuclear fusion in a protostar
As the star gets denser and more particles collide with each other temperature rises.
What causes a main sequence star to remain stable for a long time
The nuclear fusion that tries to expand the star balances the force of gravity pulling it inwards.
What happens to a star about the same size as our Sun when it begins to run out of hydrogen
It turns into a red giant which turns red because the surface cools and expands as the fusion of elements up iron are created.
What is a black dwarf and how is it made
When a red giant becomes unstable and ejects it’s outer layer this leaves behind a hot dense solid core called a white dwarf. As the white dwarf cools town it emits less energy and turns into a black dward
At what stage in a star’s life cycle are elements heavier than iron formed
In a supernova and eject theses into the universe to form new planets and stars
What type of satellite is the moon
A natural satellite (not man made)
What galaxy is our solar system part of
Milky Way galaxy
What is the approximate shape of the planets orbit around the Sun
almost circular orbits
Does an object in a stable orbit have a continually changing speed
No it only changes velocity as it constantly changes direction
What is the name of the force that pulls an orbiting object towards Earth
The gravitational force
State the direction of the orbiting object’s instantaneous velocity in relation to this force
At a right angle to the acceleration which keeps it travelling in a circle
How does the strength of a planet’s gravitational force change as you get closer to its surface
The closer you get to the surface the stronger the gravitational force is.
What happens to the speed of an orbiting object if its orbital radius increases.
It decreases as if the speed of the object changes the size of its orbit must too
What is red shift
When we look at light from distant galaxies we find the wavelength has increased and they are longer than they should be this is called redshift and tells us they are moving away from us.
