Dark Matter

1
Dark Matter In the 1970s, using spectral
analysis, it was discovered that spiral galaxies
were not rotating like they looked like they
should be. If you have a system where most of the
mass is in the center, like the solar system with
the Sun having 99.8 of the mass, the closer a
planet is, the faster it moves.
2
Spiral galaxies look like most of the mass is
near the center in the nucleus, so nearer stars
to the center should rotate faster.
3
Astronomers found that stars near the center of
spiral galaxies were rotating slower than stars
farther out, implying that most of the mass was
not in the bright center.
4
There had to be some other invisible mass
changing the rotation speed of stars. This got
the name Dark Matter. Several explanations for
this Dark Matter have come forward. Neutrinos MA
CHOs WIMPs/Sparticles Dark Energy
5
Neutrinos are subatomic particles given off
during nuclear fusion. They dont react with much
of anything, and thus are nearly impossible to
detect. Right now buzillions of them are
traveling through you, and the Earth from the
Sun. If they weigh something, they could account
for the missing mass.
6
MACHOs are massive compact halo objects, implying
they are objects with mass that dont give off
light (in the halo or outskirts of a galaxy).
These things could be planets, black holes, or
neutron stars.
7
WIMPS are weakly interacting massive particles,
meaning they are massive subatomic particles that
dont react with other matter. They have yet to
be discovered. String theory predicts a similar
particle called a sparticle.
8
Dark Energy is an undefined source of
matter/energy that is causing the entire Universe
to expand faster than it should be. There are no
explanations of what it is or what causes it.