Dark Matter and Dark Energy

By: Matt TanakaAnd Bryent Kaneshiro

Dark matter is matter that is inferred to exist from gravitational effects on visible matter and background radiationIts existence was hypothesized because of the discrepancies between measurements of the mass of galaxies and clusters of galaxies

http://www.youtube.com/watch?v=nJN2X3NrQAE

It turns out there is about 5 times more material in clusters of galaxies than what we would expect from the galaxies and hot gas we can see.It is undetectable by emitted or scattered electromagnetic radiation or in other words “invisible”

Dark matter was discovered in 1933 from astronomer Fritz Zwicky for evidence of missing mass.

Dark matter plays a role on the universes fate

The universe is expanding everyday.

Gravity is dependent upon the mass of the universe.

If actual mass density is greater then critical mass density, the universe will expand, slow, stop and collapse back on itself

If actual mass density equals critical mass, the universe will continue to expand forever, but rate of expansion will slow more over time.

If actual mass density is less than critical mass density, the universe will continue to expand with no change in its rate of expansion

Dark energy is a hypothetical form of energy that permeates all of space and tends to increase the rate of expansion of the universe.

Dark energy accounts for 70 % of the total mass – energy of the universe.http://www.youtube.com/watch?v=LPoV_v7xL2w

2 forms of dark energy. cosmological

constant - a constant energy density filling space homogeneously.

scalar fields-energy density can vary in time and space

Albert Einstein was the first person to realize that empty space is not nothing. The 1st to Proposed the theory of cosmological constant.

"Dark Matter." Wikipedia, the Free Encyclopedia. Web. 11 Jan. 2011. <http://en.wikipedia.org/wiki/Dark_matter>.

"Dark Energy, Dark Matter." NASA Science. 19 Aug. 2010. Web. 11 Jan. 2011. <http://science.nasa.gov/astrophysics/focus-areas/what-

is-dark-energy/>.

"Dark Energy." Wikipedia, the Free Encyclopedia. Web. 11 Jan. 2011. <http://en.wikipedia.org/wiki/Dark_energy>.

"What Is Dark Energy? | Space.com." Space, NASA Information & News | Outer Space Flight Videos & Pictures | Astronomy, Solar

System Images | Space.com. Web. 11 Jan. 2011. <http://www.space.com/6619-dark-energy.html>.