Space 1 Flashcards
how is a protostar formed
gravitational forces pull clouds of dust and gas together
why do protostar become denser
the nuclei of hydrogen atoms and other light elements fuse together and energy is released making the protostar hotter and brighter
why do stars radiate energy
because of hydrogen fusion in the core
why is a star stable
the inward force of gravity is balanced by the outward force of the core
what is a star called when it is stable
main-sequence star
what happens when a main-sequence star runs out of hydrogen
it will swell, cool down and turn red
what will stars similar to the sun eventually become
a red giant
what happens when a main-sequence star becomes a red giant
helium and other light elements in the core fuse to become heavier elements.
fusion then eventually stops and the star contacts forming a white dwarf
what will a star much larger than the sun swell to
a red super giant
what will eventually happen to a red supergiant
it will collapse and explode in a supernova
why are elements bigger than iron only formed in the final stages of a stars life
because the process requires the input of so much energy
what happens in a supernova
the outer layers of a star are thrown into space and the core is left as a neutron star
what will a neutron star form if it is big enough
a black hole
what angle is the direction of the velocity of an object orbiting a planet at
at right angle to the direction of gravity
what is the force needed to keep an object moving in a circular motion called
centripetal force
where does centripetal force always act
towards the centre of the circle
what is the centripetal force for a a planet or satellite in orbit around a bigger object
the centripetal force is the gravitational force from the bigger object and acts towards its centre
what happens if the distance of an orbit decreases
the speed will increase
what must an object be to orbit at a particular distance
must go at a particular speed
what is a galaxy
large collection of stars
