Dark Matter, Dark Energy, Dark Matter, Dark Energy, and the Expansion of the and the Expansion of the

UniverseUniverse

By Michael HowardBy Michael Howard

10-3-201210-3-2012

Is the Universe StaticIs the Universe Static

Einstein’s General Theory of Relativity predicts Einstein’s General Theory of Relativity predicts that the Universe must not be static, but Einstein that the Universe must not be static, but Einstein refused to believe itrefused to believe it

Edwin Hubble began studying the distances of Edwin Hubble began studying the distances of galaxies and compared them to the speed at galaxies and compared them to the speed at which they were moving away from Earth.which they were moving away from Earth.

Then he compared it to the work of a man who Then he compared it to the work of a man who had been making similar observations years had been making similar observations years earlier. He found that the galaxies that were earlier. He found that the galaxies that were farther away were moving at a higher speed.farther away were moving at a higher speed.

The Expansion of the UniverseThe Expansion of the Universe

Hubble decided that since the Earth must Hubble decided that since the Earth must not be the center of the universe, this must not be the center of the universe, this must be true for any galaxy, not just our own.be true for any galaxy, not just our own.

This is what led Hubble to the conclusion This is what led Hubble to the conclusion that the universe is expanding.that the universe is expanding.

Einstein’s Biggest BlunderEinstein’s Biggest Blunder

Had Einstein not created the cosmological Had Einstein not created the cosmological constant he most likely would have constant he most likely would have discovered the expansion of the universe discovered the expansion of the universe before Hubble.before Hubble.

The Big CrunchThe Big Crunch

The Big Bang gives the universe the force The Big Bang gives the universe the force to continue to expand, but it would stand to continue to expand, but it would stand to reason that gravity would eventually to reason that gravity would eventually slow this force down.slow this force down.

When gravity begins to overpower this When gravity begins to overpower this force the universe would begin to contractforce the universe would begin to contract

The Expansion/Contraction of the UniverseThe Expansion/Contraction of the UniverseBottom to Top- The Big BangBottom to Top- The Big Bang

Top to Bottom- The Big CrunchTop to Bottom- The Big Crunch

The Problem with the Big CrunchThe Problem with the Big Crunch

1998 Announcement that not only was the 1998 Announcement that not only was the Universe expanding, but it was doing it at an Universe expanding, but it was doing it at an accelerating rateaccelerating rate

The 2011 Nobel Prize in The 2011 Nobel Prize in PhysicsPhysics

From Left to Right- Saul Perlmutter, From Left to Right- Saul Perlmutter, Brian Schmidt and Adam RiessBrian Schmidt and Adam Riess

Type Ia Supernovae

It was discovered that these supernovae had a smaller redshift than would be expected.

Because these telescopes are looking back in time the fact that the redshift was smaller than expected means that they were moving slower in the past.

Why is the Universe Why is the Universe Accelerating?Accelerating?

We don’t knowWe don’t know

One would expect the force the caused One would expect the force the caused the expansion to eventually be the expansion to eventually be overpowered by gravityoverpowered by gravity

Because this is not the case something Because this is not the case something must be overpowering the force of gravity must be overpowering the force of gravity or the general theory of relativity has a or the general theory of relativity has a major flaw.major flaw.

So if the explanation is that there is a force So if the explanation is that there is a force that is overpowering gravity then that that is overpowering gravity then that would mean that Einstein was correct in would mean that Einstein was correct in adding the cosmological constant adding the cosmological constant

The Cosmological ConstantThe Cosmological Constant

Maybe Einstein wasn’t wrongMaybe Einstein wasn’t wrong

Dark EnergyDark Energy

Quantum Vacuum Energy- particles which Quantum Vacuum Energy- particles which are constantly coming in and out of are constantly coming in and out of existence generate energyexistence generate energy

The problem is that the calculation of this The problem is that the calculation of this energy is a problem in quantum energy is a problem in quantum mechanics and the expansion of the mechanics and the expansion of the universe is in terms of general relativityuniverse is in terms of general relativity

Accounts for about 70% of the universe.Accounts for about 70% of the universe.

Dark MatterDark Matter

Can not absorb or emit lightCan not absorb or emit light

Thought to exist because of its effect on Thought to exist because of its effect on gravitygravity

If there was no dark matter the galaxies If there was no dark matter the galaxies would fly apartwould fly apart

Could be MACHOs or WIMPsCould be MACHOs or WIMPs

Referenceshttp://scienceblogs.com/startswithabang/2012/07/19/one-does-not-simply-believe-in-dark-energy/http://skyserver.sdss.org/dr1/en/proj/basic/universe/http://scienceblogs.com/startswithabang/2009/11/04/dark-energy-hard-to-kill-part/http://scienceblogs.com/startswithabang/2009/07/15/the-last-100-years-1998-and-th/http://en.wikipedia.org/wiki/Big_Crunchhttp://en.wikipedia.org/wiki/Standard_candlehttp://answers.yahoo.com/question/index?qid=20110410171536AAllTHphttp://curious.astro.cornell.edu/question.php?number=634http://www.atlasoftheuniverse.com/redshift.htmlhttp://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/http://www.popsci.com/science/article/2011-10/dark-energy-discovery-wins-physics-nobelhttp://www.mpa-garching.mpg.de/mpa/institute/news_archives/news0702_wfh/news0702_wfh-en.htmlhttp://www.time.com/time/magazine/article/0,9171,996611,00.htmlhttp://www.sciencemag.org/content/282/5397.cover-expansionhttp://www.sciencedaily.com/releases/2007/11/071127142128.htmhttp://www.astronomycorner.net/notes/accelerate.htmlhttp://news.nationalgeographic.com/news/2011/10/111004-nobel-prize-physics-universe-expansion-what-is-dark-energy-science/http://answers.yahoo.com/question/index?qid=20091104130421AASlWSuhttp://www.astro.umd.edu/~miller/teaching/astr422/lecture12.pdfhttp://news.nationalgeographic.com/news/2010/03/100310-einstein-theory-general-relativity-gravity-dark-matter-proof/http://science.nasa.gov/missions/jdem/http://science.nationalgeographic.com/science/space/solar-system/mercury-article.htmlhttp://news.nationalgeographic.com/news/2006/08/060822-dark-matter.htmlhttp://en.wikipedia.org/wiki/Einstein_field_equationshttp://www.astronomy.ohio-state.edu/~ryden/ast162_10/fig28-17.jpghttp://www.astronomy.ohio-state.edu/~ryden/ast162_10/notes41.htmlhttp://math.ucr.edu/home/baez/physics/Relativity/GR/dark_matter.html