Please enable JavaScript.
Coggle requires JavaScript to display documents.
SPACE PHYSICS: STARS AND THE SOLAR SYSTEM (THE FORMATION OF OUR SOLAR…
SPACE PHYSICS: STARS AND THE SOLAR SYSTEM
OUR SOLAR SYSTEM
universe is made up of billions of galaxies
each galaxy contains hundreds of millions of stars
our solar system is a tiny part of the Milky Way Galaxy
our solar system
one star (the Sun)
planets and dwarf planets that orbit the sun
asteroids and comets that orbit the sun
moons that orbit planets
THE FORMATION OF OUR SOLAR SYSTEM
the Sun was formed from a nebula (cloud of dust and gas) pulled together by gravitational attraction
as the dust and gas were drawn together, they collided, increasing the temperature and creating a protostar
as more and more material was drawn together by gravity, these collisions increase until the temperature and pressure was high enough for hydrogen nuclei to fuse together forming helium and a main sequence star
energy released by nuclear fusion keeps the core of the Sun hot
material that was not drawn into the Sun remained in orbit around the new star and formed the planets and other objects in our solar system
the Sun is still in the main sequence period of its lifecycle and is stable
stability is the result of the balance between
the fusion energy trying to expand the Sun
gravity acting inwards trying to collapse the Sun
LIFECYCLE OF A STAR
all stars go through a lifecycle that is determined by the size of the star
small stars, like the Sun, end up as black dwarf stars
larger stars become neutron stars
largest stars become black holes
all stars begin in the same way as the Sun did, clouds of dust and gas are pulled together by gravity to form a protostar and eventually a main sequence star
during the main sequence, hydrogen fuses together to create helium and, in large stars, lithium
fusion processes are how new elements are formed
star ages
more and more of its mass is converted into energy by nuclear fusion
as the mass decreases, the outward forces become larger than the force of gravity
the star expands and cools becoming a red giant or red super giant
as the star cools and the hydrogen fuel is used up, the outward forces are reduced
the star collapses inwards due to gravity and this causes an increase in temperature once more
the star begins to fuse helium and lithium
the largest stars explode as a supernova, releasing tremendous amounts of energy and scattering the material of the star into space
CREATING NEW ELEMENTS
before stars, the only element in the universe was hydrogen
it is fusion processes in stars that have created all of the elements in the periodic table
all stars, even the smallest, will fuse hydrogen into helium
bigger stars then fuse helium into lithium and other lightweight elements, up to and including iron
during a supernova, the amount of energy released is so great that the temperature and pressure is high enough to force nuclei together to create elements heavier than iron
KEY WORDS