galaxies stars and the solar system Flashcards
what is a star
an object made up of gas it is luminous so it produces light and this is a result of nucleur reaction
what is a nucleur reaction in a star
occurs between tow hydrogen atoms it is the coversion of hydrogen to helium the releases heat and light
what is phase one in the life cycle of a star
formation
there are large gas clouds called nebulae the attractive forges of gravity of the gas particals cause these gases to colapse and come togther
what is phase two of a stars life cycle
the stable period
over billions of years the star becomes stable we call such a star a main sequence star
what is stage 3 of a stars life cycle
the red giant
when a star has used up all its supply of hydrogen it begins burning the helium on its outer parts
what is stage 4 in a stars life cycle
white giant
once the red giant has used up all its supply of hydrogen and helium it condeces , colapses in on itself forming a tiny but very dence star it will produce no more light or heat
what is a galaxy
a collection of millions of stars along with gas and dust all held together by gravitational forces
what is gravity
a force that a planet has that pulls objects towards their centre the closer you a body you get a stronger pull
what is a terrestrial planet
include mercury venus earth and mars
orbit closest to the sun and are known as the inner planets
composed of rock and metal
what is a jovian planet
include jupiter uranus staurn and neptune
mostly composed of helium and gas#
have large rings around them
what are planetoids
objects that are to large to be an asteroid but to small to be a planet
include pluto
how do planets orbit the sun
the suns gravity pulls the planets toward it at the same time the planets are always trying to pull away from the sunand outi nto space but the suns gravity keeps it in orbit
