Skip to main content

Dark matter

Dark matter is an unidentified type of matter distinct from dark energy, baryonic matter (ordinary matter), and neutrinos. It comprises approximately 27% of the mass and energy in the  observable universe. The name refers to the fact that it does not emit or interact with electromagnetic radiation, such as light, and is thus invisible to the entire electromagnetic spectrum. Although dark matter has not been directly observed, its existence and properties are inferred from its gravitational effects such as the motions of visible matter, gravitational lensing, its influence on the universe's large-scale structure, and its effects in the cosmic microwave background. Dark matter is transparent to  electromagnetic radiation and/or is so dense and small that it fails to absorb or emit enough radiation to be detectable with current imaging technology.   
                             



Estimates of masses for galaxies and larger structures via dynamical and general relativistic means are much greater than those based on the mass of the visible "luminous" matter.
The standard model of cosmology indicates that the total mass-energy of the universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy.Thus, dark matter constitutes 84.5% of total mass, while dark energy plus dark matter constitute 95.1% of total mass–energy content.The great majority of ordinary matter in the universe is also unseen, since visible stars and gas inside galaxies and clusters account for less than 10% of the ordinary matter contribution to the mass-energy density of the universe.                      

Comments

Post a Comment

Popular posts from this blog

Collide Of Continents

The concept of supercontinent was first proposed by the Alfred Wegener (His full name is Alfred-Lothar-Wegener) in the year of 1912. He was born on 1 November 1880. He is a German polar researcher, Geophysicist, and Meteorologist. The reason behind he proposed this concept is he found some fossil's which lived on the earth. In all the continents but the distance between the continents are so long. That is the reason he proposed his concept of continental drift.  This continental drift was controversial and not widely accepted because he did not prove that how the continents are moved due to this reason every not accepted until the 1950's. After tectonic plates was discovered based on this tectonic plates the continents are moved. now we assume that how the modern continents was placed. Alfred-Lothar-Wegener FOSSIL Every 300-500 Million years the supercontinent was formed. In 300 Million years ago one supercontinent was formed it was named as PANGAEA. The word P...
Post a Comment
Read more

Red rain

The Kerala red rain phenomenon was a blood rain event that occurred from 25 July to 23 September 2001, when heavy downpours of red-colored rain fell sporadically on the southern Indian state of Kerala, staining clothes pink. Yellow, green, and black rain was also reported. Coloured rain was also reported in Kerala in 1896 and several times since, most recently in June 2012, and from 15 November 2012 to 27 December 2012 in eastern and north-central provinces of Sri Lanka.                   Following a light microscopy examination in 2001, it was initially thought that the rains were colored by fallout from a hypothetical meteor burst, but a study commissioned by the Government of India concluded that the rains had been colored by airborne spores from a locally prolific terrestrial green alga from the genus Trentepohlia. an international team later identified the exact species as T.annulata...
Post a Comment
Read more

Tectonic Plates

Tectonic plates are pieces of earth's crust and uppermost mantle,together referred to as the lithosphere.The plates are around 100 km (62 mi)thick and consist of two principal material:ocean -crust(also called sima from silicon magnesium) and continental crust (sial from silicon and aluminium).The composition of the two types of crust differs markedly,with basaltic rocks ("mafic") dominating oceanic crust,while continental crust consists principally of lower density granitic rocks. Geologists generally agree that the following tectonic plates exist on the earth's surface with roughly definable boundaries.Tectonic plates are sometimes subdivided into three fairly arbitrary categories: major (or primary) plates,minor (or secondary) plates, and micro (or tertiary) plates. Major plates : These plates comprise the bulk of  the continents and the pacific ocean .A major plate is any plate with an area greater than 20 million km. Minor plates : These smaller ...
Post a Comment
Read more