Black Hole - a theoretical massive object, formed at the beginning of the universe or by the gravitational collapse

of a star exploding as a supernova, whose

gravitational field is so intense that no

electromagnetic radiation can escape.

Galaxies - a large system of stars held together by mutual gravitation and isolated from

similar systems by vast regions of space.

Dark Matter - matter known to make up perhaps 90% of

the mass of the universe, but not detectable by its

absorption or emission of electromagnetic radiation

•There are many galaxies in the

universe, and our galaxy, the Milky Way galaxy, has

many solar systems and planets in it.

•The nearest spiral galaxy,

the Andromeda galaxy, is

many of the thousands in our universe;

they all expand to the outer reaches

of space.

Another galaxy , The Canis Major

Dwarf, was found by German

Astronomers on November 10, 2010. This is currently the

closest galaxy to our own.

•Spiral Galaxy- A spiral galaxy

has a revolution every 250

million years. Our own

galaxy is 175 million more years to have

another revolution.

•Elliptical Galaxy- In an

Elliptical Galaxy, the

stars have no current

rotation, so it cannot have a

revolution.

•Irregular Galaxy- This Galaxy take just as long

as a spiral galaxy to have a revolution due to it being a type of

spiral galaxy.

• Black holes are formed when a

supergiant star’s life ends.

•These pull everything into it with its enormous

amount of gravitational pull.

http://science.discovery.com/videos/supermassive-black-holes-the-black-hole.html

Black holes were fist found in the late 1790s

by two astronomers from Germany and

France.

•If you look at a picture of our

universe, you will see a big bright circle. That is called a super massive black

hole

• A black hole will use its gravity to pull and shrink

any mass towards itself down to a

marble

•Dark Matter is impossible to see with the naked eye and even a

telescope, but it is there.

This is what dark matter would look like if it was blue.

Dark matter was found on January of

1937.

http://www.pbs.org/wgbh/nova/physics/dark-matter.html

It is theoretical that dark

matter is just in space, but they

are debating whether it is on earth and other

planets too.