Universe Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.Anti-spam check. Do not fill this in! === Dark matter === {{Main|Dark matter}} Dark matter is a hypothetical kind of [[matter]] that is invisible to the entire [[electromagnetic spectrum]], but which accounts for most of the matter in the universe. The existence and properties of dark matter are inferred from its gravitational effects on visible matter, radiation, and the [[Observable universe#Large-scale structure|large-scale structure]] of the universe. Other than [[neutrinos]], a form of [[hot dark matter]], dark matter has not been detected directly, making it one of the greatest mysteries in modern [[astrophysics]]. Dark matter neither [[blackbody spectrum|emits]] nor absorbs light or any other [[electromagnetic radiation]] at any significant level. Dark matter is estimated to constitute 26.8% of the total mass–energy and 84.5% <!--26.8/(4.9 + 26.8)--> of the total matter in the universe.<ref name="DarkMatter">Sean Carroll, Ph.D., Caltech, 2007, The Teaching Company, ''Dark Matter, Dark Energy: The Dark Side of the Universe'', Guidebook Part 2. p. 46, Accessed October 7, 2013, "...dark matter: An invisible, essentially collisionless component of matter that makes up about 25 percent of the energy density of the universe... it's a different kind of particle... something not yet observed in the laboratory..."</ref><ref name=planckcam>{{cite web |url=http://www.cam.ac.uk/research/news/planck-captures-portrait-of-the-young-universe-revealing-earliest-light |title=Planck captures portrait of the young universe, revealing earliest light |date=March 21, 2013 |publisher=University of Cambridge |access-date=March 21, 2013 |archive-date=April 17, 2019 |archive-url=https://web.archive.org/web/20190417165900/https://www.cam.ac.uk/research/news/planck-captures-portrait-of-the-young-universe-revealing-earliest-light |url-status=live }}</ref> Summary: Please note that all contributions to Christianpedia may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here. You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see Christianpedia:Copyrights for details). Do not submit copyrighted work without permission! Cancel Editing help (opens in new window) Discuss this page