Dark Matter, Dark Energy,
and the Expansion of the
Universe
By Michael Howard
10-3-2012
Is the Universe Static
Einstein’s General Theory of Relativity predicts
that the Universe must not be static, but Einstein
refused to believe it
Edwin Hubble began studying the distances of
galaxies and compared them to the speed at
which they were moving away from Earth.
Then he compared it to the work of a man who
had been making similar observations years
earlier. He found that the galaxies that were
farther away were moving at a higher speed.
The Expansion of the Universe
Hubble decided that since the Earth must
not be the center of the universe, this must
be true for any galaxy, not just our own.
This is what led Hubble to the conclusion
that the universe is expanding.
Einstein’s Biggest Blunder
Had Einstein not created the cosmological
constant he most likely would have
discovered the expansion of the universe
before Hubble.
The Big Crunch
The Big Bang gives the universe the force
to continue to expand, but it would stand
to reason that gravity would eventually
slow this force down.
When gravity begins to overpower this
force the universe would begin to contract
The Expansion/Contraction of the Universe
Bottom to Top- The Big Bang
Top to Bottom- The Big Crunch
The Problem with the Big Crunch
1998 Announcement that not only was the
Universe expanding, but it was doing it at an
accelerating rate
The 2011 Nobel Prize in
Physics
From Left to Right- Saul Perlmutter,
Brian 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
Accelerating?
We don’t know
One would expect the force the caused
the expansion to eventually be
overpowered by gravity
Because this is not the case something
must be overpowering the force of gravity
or the general theory of relativity has a
major flaw.
So if the explanation is that there is a force
that is overpowering gravity then that
would mean that Einstein was correct in
adding the cosmological constant
The Cosmological Constant
Maybe Einstein wasn’t wrong
Dark Energy
Quantum Vacuum Energy- particles which
are constantly coming in and out of
existence generate energy
The problem is that the calculation of this
energy is a problem in quantum
mechanics and the expansion of the
universe is in terms of general relativity
Accounts for about 70% of the universe.
Dark Matter
Can not absorb or emit light
Thought to exist because of its effect on
gravity
If there was no dark matter the galaxies
would fly apart
Could be MACHOs or WIMPs
References
http://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_Crunch
http://en.wikipedia.org/wiki/Standard_candle
http://answers.yahoo.com/question/index?qid=20110410171536AAllTHp
http://curious.astro.cornell.edu/question.php?number=634
http://www.atlasoftheuniverse.com/redshift.html
http://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/
http://www.popsci.com/science/article/2011-10/dark-energy-discovery-wins-physics-nobel
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http://answers.yahoo.com/question/index?qid=20091104130421AASlWSu
http://www.astro.umd.edu/~miller/teaching/astr422/lecture12.pdf
http://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.html
http://news.nationalgeographic.com/news/2006/08/060822-dark-matter.html
http://en.wikipedia.org/wiki/Einstein_field_equations
http://www.astronomy.ohio-state.edu/~ryden/ast162_10/fig28-17.jpg
http://www.astronomy.ohio-state.edu/~ryden/ast162_10/notes41.html
http://math.ucr.edu/home/baez/physics/Relativity/GR/dark_matter.html