Cosmological concept · Cosmology
Dark Energy
Cosmology & UniverseStrong Evidence
Definition
The unknown component driving the accelerating expansion of the Universe, making up roughly 68% of it.
Scientific overview
In 1998 two teams found that cosmic expansion is speeding up, not slowing down. The cause — dubbed dark energy — behaves like an energy of empty space with negative pressure. It dominates the present Universe but its nature is a complete mystery.
Evidence
- Type Ia supernovae (1998)
- The CMB combined with large-scale structure
- Baryon acoustic oscillations
Current measurements
| Fraction of the Universe | ≈ 68% | Planck Collaboration |
Open questions
- Is dark energy a cosmological constant, or does it evolve?
- Why is its value so small yet non-zero?
Rests on
Related discoveries & objects
Measured by
Related scientists
Related topics
Knowledge connections
- Required byThe Present Universe
- Related toThe Cosmic Horizon
- Related toBaryon Acoustic Oscillations
- Related toThe Cosmological Constant (Λ)
- Related toThe Expansion of the Universe
- Part of modelThe Lambda-CDM Model
- Depends onGeneral Relativity
- Related toThe Accelerating Universe
- Studied bySaul Perlmutter
- Studied byAdam Riess
- Studied byBrian Schmidt
- Measured byEuclid
- Measured byDESI (Dark Energy Spectroscopic Instrument)
- Measured byDark Energy Survey
- Required byThe Cosmological Constant (Λ)
- Related toThe Lambda-CDM Model
- Related toWhite Dwarf
- Associated withDark Energy Density (ΩΛ)
- Associated withEarly Dark Energy
- Associated withEvidence Chains
- Associated withZero-Point Energy
- Associated withVacuum Energy
- Associated withThe Cosmological Constant Problem
Sources & references
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.
- ESAEuropean Space Agency
European missions, observatories, and space science imagery.
- DESIDark Energy Spectroscopic Instrument
Spectroscopic redshift survey measuring baryon acoustic oscillations and dark energy.