What is dark matter ?
Dark matter is form of matter thought to account for approximately 85% of the matter in the universe and about a quarter of its total energy density. It can refers to any matter that interact with any other known visible matter through gravity, Here the visible matter refers to stars, nebula. It is not necessary is should composed of new form of matter, but also made of standard baryonic matters like neutrons or protons etc.
with the help of Hubble space telescope and its new observing technique, we detected that the dark matter forms a smaller clump then ever before. the result obtained from this confirms the most widely accepted "cold dark matter theory".
(here, within the entire article cold refers to the speed of the dark matter, in a fact that a hot matter has more energy, more energy means more movement, so in this case cold dark matter refers that it has slow movement when compared to speed of light )
what cold dark matter theory says?
According to cold dark matter theory, a small objects that are combining and collapsing under their self gravity first and then starts merging in a continuous hierarchy to form larger and more massive objects.
But the hot dark matter theory is total inverse of cold matter theory structure does not form hierarchically (bottom-up), but forms by fragmentation (top-down), with the largest superclusters forming first in flat pancake-like sheets and subsequently fragmenting into smaller pieces like our galaxy the Milky Way. But this hot dark matter theory is not widely acceptable. Most cosmologist favors cold dark matter theory.
according to this cold dark matter theory, all galaxies form and are embedded within clouds of dark matter. Dark matter itself consists of slow-moving, or “cold,” particles that come together to form structures ranging from hundreds of thousands of times the mass of the Milky Way galaxy But, these dark matter clumps are not more massive then heft of airplane. as of now dark matter concentration has detected near large and medium sized galaxies only through their gravitational effect on visible objects.
The small clump of dark matter is very cold then we think. detection of dark matter through galaxies is very hard process so, Hubble team focus on quasars (regions around active black holes that emit enormous amounts of light) to detect black holes. The astronomers measured how the light emitted by oxygen and neon gas orbiting each of the quasars' black holes is warped by the gravity of a massive foreground galaxy, which is acting as a magnifying lens.
The eight quasars and galaxies were aligned so precisely that the warping effect, called gravitational lensing, produced four distorted images of each quasar. The effect is like looking at a funhouse mirror. Such quadruple images of quasars are rare because of the nearly exact alignment needed between the foreground galaxy and background quasar. However, the researchers needed the multiple images to conduct a more detailed analysis. Researchers used Hubble’s Wide Field Camera 3 to capture the near-infrared light from each quasar and disperse it into its component colors for study with spectroscopy. Unique emissions from the background quasars are best seen in infrared light. However, the type of particle that makes up dark matter is still a mystery. Astronomers will be able to conduct follow-up studies of dark matter using future NASA space telescopes such as the James Webb Space Telescope and the Wide Field Infrared Survey Telescope (WFIRST), both infrared observatories.
Hubble space telescope
comment below if you find something wrong with this article :)
Dark matter is form of matter thought to account for approximately 85% of the matter in the universe and about a quarter of its total energy density. It can refers to any matter that interact with any other known visible matter through gravity, Here the visible matter refers to stars, nebula. It is not necessary is should composed of new form of matter, but also made of standard baryonic matters like neutrons or protons etc.
with the help of Hubble space telescope and its new observing technique, we detected that the dark matter forms a smaller clump then ever before. the result obtained from this confirms the most widely accepted "cold dark matter theory".
(here, within the entire article cold refers to the speed of the dark matter, in a fact that a hot matter has more energy, more energy means more movement, so in this case cold dark matter refers that it has slow movement when compared to speed of light )
what cold dark matter theory says?
According to cold dark matter theory, a small objects that are combining and collapsing under their self gravity first and then starts merging in a continuous hierarchy to form larger and more massive objects.
But the hot dark matter theory is total inverse of cold matter theory structure does not form hierarchically (bottom-up), but forms by fragmentation (top-down), with the largest superclusters forming first in flat pancake-like sheets and subsequently fragmenting into smaller pieces like our galaxy the Milky Way. But this hot dark matter theory is not widely acceptable. Most cosmologist favors cold dark matter theory.
according to this cold dark matter theory, all galaxies form and are embedded within clouds of dark matter. Dark matter itself consists of slow-moving, or “cold,” particles that come together to form structures ranging from hundreds of thousands of times the mass of the Milky Way galaxy But, these dark matter clumps are not more massive then heft of airplane. as of now dark matter concentration has detected near large and medium sized galaxies only through their gravitational effect on visible objects.
The small clump of dark matter is very cold then we think. detection of dark matter through galaxies is very hard process so, Hubble team focus on quasars (regions around active black holes that emit enormous amounts of light) to detect black holes. The astronomers measured how the light emitted by oxygen and neon gas orbiting each of the quasars' black holes is warped by the gravity of a massive foreground galaxy, which is acting as a magnifying lens.
The eight quasars and galaxies were aligned so precisely that the warping effect, called gravitational lensing, produced four distorted images of each quasar. The effect is like looking at a funhouse mirror. Such quadruple images of quasars are rare because of the nearly exact alignment needed between the foreground galaxy and background quasar. However, the researchers needed the multiple images to conduct a more detailed analysis. Researchers used Hubble’s Wide Field Camera 3 to capture the near-infrared light from each quasar and disperse it into its component colors for study with spectroscopy. Unique emissions from the background quasars are best seen in infrared light. However, the type of particle that makes up dark matter is still a mystery. Astronomers will be able to conduct follow-up studies of dark matter using future NASA space telescopes such as the James Webb Space Telescope and the Wide Field Infrared Survey Telescope (WFIRST), both infrared observatories.
Hubble space telescope
comment below if you find something wrong with this article :)
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