Dark Energy: “The Anti-Gravity”
Joseph C. Brossett
Consequences of Dark Matter
• Consider the ratio presented before:
omega = actual density / critical density
• If omega is < 1, we live in an open
universe with constant expansion.
• If omega is > 1, we live in a closed
universe that ends in a “big crunch.”
• If omega is = 1, we live in a flat universe
that eventually becomes static.
Explaining “Anti-Gravity”
• In contrast with dark matter, dark energy hopes
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to explain the motion of galaxies.
Galaxies, according to gravity, should move
toward one another but do not.
This effect is observed through contrasting red
shifts with the brightness of supernovas.
Dark energy is not necessarily energy in the
conventional sense.
Dark Energy Candidates
• Physicists ultimately do not know what causes
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the repulsion of galaxies.
One candidate is a cosmological constant
corresponding to some “vacuum” energy.
Another is a proposed “quintessential” repulsive
field pushing the galaxies apart.
In the end, plans to look at more distant
supernovae will hopefully give better estimates.
Summary
• Dark energy plays a large role in the ending fate
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of our universe.
Dark energy, unlike dark matter, is a phenomena
to explain the motion between galaxies (“antigravity”).
Essentially, dark matter and dark energy
dominate the universe on large scales.
Unfortunately, scientists really are not sure what
dark energy is since it violates current laws.