Tamna energija
U astronomiji je tamna energija naziv za vrstu nepoznate energije koja prožima ceo svemir i ubrzava njegovo širenje. 
Teorija tamne energije je najšire prihvaćena hipoteza kojom se objašnjavaja uočeno ubrzano širenje svemira. U okviru trenutno dominantne lambda CDM paradigme, a na osnovu prikupljenih podataka Plank letelice, vidljivi deo svemira se sastoji od:
 26.8% tamne materije
 68.3% tamne energije
 4.9% materije
Iako po toj teoriji tamna energija ima vrlu malu gustinu, 6.91 × 10−27 kg/m3, ona je dominantna zbog svoje rasprostranjenosti po celom svemiru.

Dokazi postojanja

Supernove 
U toku 1998. i 1999. godine su objavljena posmatranja supernovih  koja sugerišu da se širenje svemira ubrzava. Za ovo otkriće je 2011. godine astrofizičarima Saulu Perlmuteru, Brajanu Šmitu i Adamu G. Reisu dodeljena Nobelova nagrada za fiziku.
Od tada su ovi nalazi potvrđeni iz više izvora. Merenja svemirskog mikrotalasnog pozadinskog zračenja, efekat gravitacionog sočiva, svemirska struktura velikih razmera, kao i poboljšana merenja supernovih su u skladu sa Lambda-CDM modelom
.

Reference

Literatura 

 Gerhard Börner, Matthias Bartelmann: Astronomen entziffern das Buch der Schöpfung. in: Physik in unserer Zeit. Weinheim 33.2002,3, S.114–120. 
 Harald Lesch, Jörn Müller: Kosmologie für helle Köpfe – Die dunklen Seiten des Universums. Wilhelm Goldmann, München 2006. 
 Welt der Wunder. Stuttgart 2008, 2, S.24.  
 Sidney C. Wolff, Tod R. Lauer: Observing dark energy. Astronomical Soc. of the Pacific conference series. Bd 339. San Francisco Calif. 2005. 
 Luca Amendola, et al.: Dark energy - theory and observations. Cambridge Univ. Pr., Cambridge 2010, .

Vanjske veze 
Dark energy: how the paradigm shifted Physicsworld.com

"Mysterious force's long presence" BBC News online (2006) More evidence for dark energy being the cosmological constant
"Astronomy Picture of the Day" one of the images of the Cosmic Microwave Background which confirmed the presence of dark energy and dark matter
SuperNova Legacy Survey home page The Canada-France-Hawaii Telescope Legacy Survey Supernova Program aims primarily at measuring the equation of state of Dark Energy. It is designed to precisely measure several hundred high-redshift supernovae.
"Report of the Dark Energy Task Force"
"HubbleSite.org – Dark Energy Website" Multimedia presentation explores the science of dark energy and Hubble's role in its discovery.
"Surveying the dark side"
"Dark energy and 3-manifold topology" Acta Physica Polonica 38 (2007), p. 3633–3639
The Dark Energy Survey
The Joint Dark Energy Mission 
Harvard: Dark Energy Found Stifling Growth in Universe, primary source
April 2010 Smithsonian Magazine Article 
HETDEX Dark energy experiment
Dark Energy FAQ 
"The Hunt for Dark Energy" George FR Ellis, Peter Cameron and David Tong discuss the presence of dark energy in the Universe
April 2010 Smithsonian Magazine Article]
Euclid ESA Satellite, a mission to map the geometry of the dark universe

Kosmologija