|How are stars, planets, moons, and nebula made?|
|Question Date: 2017-08-28|
Objects in space, including stars and planets,
are formed by a process called accretion.
Accretion occurs when small particles in space
attract each other due to gravity, and begin
colliding and clumping into larger particles.
After a long, long time, enough particles merge
together to become the size of a planet or star.
Moons can either form from accretion and then
become trapped in the orbit of larger planets, or
they can form when a body collides with a
planet with enough force to eject material into
the orbit of the planet. It has been proposed
that the earth’s moon formed after a body
approximately the size of mars collided with the
earth (although scientists still don’t all agree
on how our moon was formed).
Good question. Nebulae are diffuse clouds of
gas and dust in space that are drawn together
by gravity. If a clump of matter gets dense
enough, then the gravity can pull it together
where it becomes a star. Other clumps of gas
and dust tend to coalesce around forming stars,
too, which makes the planets, moons, etc. That
tend to orbit stars. Exactly how this happens is
still up to some debate, however.
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