Gravitational lensing

An image of gravitational lensing, compiled from images by NASA and ESA

Gravitational lensing is a gravitational-optical effect whereby a background object like a distant quasar is magnified, distorted and brightened by a foreground galaxies. An intervening concentration of matter is declared to bring 'focusing' effect attributed to general relativity so that even objects normally beyond observational distance can be seen by astronomers at the Earth. It is alleged that, for example, the galaxy cluster Abell 2218, distorts and magnifies light from galaxies behind it.[1]

## Contents

* 1 Gravitational lensing and Cosmic microwave background
* 2 See also
* 3 External links
* 4 References

## Gravitational lensing and Cosmic microwave background[edit]

Galactic groups and clusters are the largest foreground concentration of matter in the universe that are accountable for the gravitational lensing. However, Lieu and Mitaz have shown that WMAP (Wilkinson Microwave Anisotropy Probe) high resolution observational data of the Cosmic microwave background (CMB) could reveal no evidence whatsoever for such effect.[2] Consequently, a conclusion was drawn by authors of the paper that important elements of physics are missing from the standard cosmological Big Bang model.[2] Other suggested that this is a major blow to the Big Bang theory where the existence of CMB is regarded for being the main evidence for its occurrence and cosmic inflation as an ad-hoc idea to support it falls apart. If the CMB is not of cosmological origin (i.e. remnant of Big Bang) but rather local phenomenon, it has been suggested it could be a rather homogeneous expulsion of a nearby supernova.[1] The latest research and consequent analysis has highlighted even more problems for the inflationary big bang theory.[3]

## See also[edit]

General theory of relativity: Gravitational Lensing

## External links[edit]

* Gravitational lensing

## References[edit]

1. ↑ 1.0 1.1 Ron Samec. No sign of gravitational lensing in the cosmic microwave background. Creation Ministries International. Retrieved on 2012-10-25.
2. ↑ 2.0 2.1 Lieu, R. and Mitaz, J (2005). On the Absence of Gravitational Lensing of the Cosmic Microwave Background. The Astrophysical Journal. DOI:10.1086/429793.
3. ↑ John Hartnett. CMB Conundrums. Retrieved on August 4, 2013.