Dark Energy, Dark Matter - NASA Science

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Home >Astrophysics >Focus Areas >Dark Energy, Dark Matter

- Dark Energy, Dark Matter -

In the early 1990's, one thing was fairly certain about the expansion of
the Universe. It might have enough energy density to stop its expansion and
recollapse, it might have so little energy density that it would never stop
expanding, but gravity was certain to slow the expansion as time went on.
Granted, the slowing had not been observed, but, theoretically, the
Universe had to slow. The Universe is full of matter and the attractive
force of gravity pulls all matter together. Then came 1998 and the Hubble
Space Telescope (HST) observations of very distant supernovae that showed
that, a long time ago, the Universe was actually expanding more slowly than
it is today. So the expansion of the Universe has not been slowing due to
gravity, as everyone thought, it has been accelerating. No one expected
this, no one knew how to explain it. But something was causing it.

Eventually theorists came up with three sorts of explanations. Maybe it was
a result of a long-discarded version of Einstein's theory of gravity, one
that contained what was called a "cosmological constant." Maybe there was
some strange kind of energy-fluid that filled

Source: science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/

what is dark matter

Dark matter - Wikipedia, the free encyclopedia


** Dark matter **

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Not to be confused with antimatter, dark energy, dark fluid, or dark flow.
For other uses, see Dark Matter (disambiguation)

Beyond the Standard Model
CMS Higgs-event.jpgSimulated Large Hadron Collider CMS particle detector
data depicting a Higgs boson produced by colliding protons decaying into
hadron jets and electrons
Standard Model

· Hierarchy problem
· *Dark matter*
· Cosmological constant problem
· Strong CP problem
· Neutrino oscillation


· Technicolor
· Kaluza–Klein theory
· Grand Unified Theory
· Theory of everything
· String theory
· Superfluid vacuum theory


· Superstring theory
· Supergravity

Quantum gravity

· String theory
· Loop quantum gravity
· Causal dynamical triangulation
· Canonical quantum gravity
· Superfluid vacuum theory
· Structural quantum gravity


· Gran Sasso
· Super-K
· Tevatron
· NOνA

· v
· t
· e

Part of a series on
Physical cosmology
Ilc 9yr moll4096.png
· Universe
· Big Bang
· Age of the universe
· Chronology of the universe

Early universe

· Inflation
· Nucleosynthesis
· Neutrino background
· Cosmic microwave background

Expanding universe

· Redshift
· Hubble's law
· Metric expansion of space
· Friedmann equations
· FLRW metric

Structure formation

· Shape of the universe
· Structure formation
· Reionization
· Galaxy formation
· Large quasar group
· Large-scale structure
· Galaxy filament

Future of universe

· Ultimate fate of the universe
· Future of an expanding universe


· Lambda-CDM model
· Dark energy
· *Dark matter*


· Timeline of cosmological theories
· History of the Big Bang theory
· Discovery of cosmic microwave
background radiation


· Observational cosmology
· 2dF

Source: en.wikipedia.org/wiki/Dark_matter

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