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Monday, December 25, 2017

Dark Matter and Dark Energy

Dark matter and dark energy universe Image Credit : NASA's Hubble space telescope




     Dark matter and dark energy is a hypothesized theory which was widely accepted around the world. In the field of astronomy and cosmology, dark energy is a unknown form of energy which widely distributed in the universe. This dark matter and dark energy is responsible for the brief expansion and acceleration of the universe. It was mostly accepted hypothesis since 1990. According to the modern concept of cosmology, the total universe constitutes 68.3% percent of dark matter and the remaining are neutrinos and photons. It is very difficult for the scientist in defining and explaining the dark matter by experiments, however it may be proved in upcoming generations.

Discovery:

     Most familiar scientists Alan Guth and Alexei Starobinsky were the one who firstly proposed the dark matter in early 1980 and that could drive the inflation of universe. (Infilation is nothing but , some kind of repulsive force which resulted in expansion of the universe after the great Big-Bang (Giant explosion of dark matter to form universe). It is very interesting that, big-bang took with higher density(sum of dark matter and energy) of universe, it was likely to end within a second.

Hubble Constant:

    During 1980s, when they proposed the theory, they found that 95% of universe consist of cold dark matter and 5% of ordinary matter which is nothing, but the baryons. The discovery led to many difficulties in defining to the value acquired by the Hubble (Hubble constant). This difficulties became very stronger after the COBE Spacecraft of 1992 discovered the anisotropy. The first evidence of dark matter was observed from a supernova explosion in 1998, this was observed by Riess and Perlmutter.

Evidences of dark matter:

     Scientists provided indirect evidences for the existence of dark matter from the independent sources
  1. By measuring the distances and relating it to the redshift
  2. Theoretically, it is not a dark matter to form flattened universe
  3.  By measuring the wave patterns and mass density form various sources of the universe
First Observed Supernova:

     In the year 1998, a team called Hihg-Z Supernova Search Team published their observation on Type-A Supernova. In 1999, Nobel Prize in Physics was awarded to Saul Perlmutter, Brian P.Schmidt and Adam G.Riess for their discovery suggesting the expansion and acceleration of the universe (Supernova Cosmology Project).

Research Papers Published in the high profile referred journals:

      High rated and cited research paper on Dark Matter in google scholar from 1980 to 2000.

1) Smith, P. F., & Lewin, J. D. (1990). Dark matter detection. Physics Reports, 187(5), 203-280.
2) Freese, K., Frieman, J., & Gould, A. (1988). Signal modulation in cold-dark-matter detection. Physical Review D, 37(12), 3388.
3)  Savage, Christopher, et al. "Compatibility of DAMA/LIBRA dark matter detection with other searches." Journal of Cosmology and Astroparticle Physics 2009.04 (2009): 010.
4) Munoz, Carlos. "Dark matter detection in the light of recent experimental results." International Journal of Modern Physics A 19.19 (2004): 3093-3169.
5) Spiro, Michel. "Dark matter." Nuclear Physics B-Proceedings Supplements 43.1-3 (1995): 100-107.

Credits:

Journal credits : Google Scholar 
Image Credit : NASA's Hubble Space Telescope

Tags: dark matter | space facts | universe | relativity 


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