THE HITAVADA,NAGPUR ON 1ST MAY 2012
Here is a view of the latest article titled as " Spectacles in the Universe" which was published in the 1st May 2012 edition of The Hitavada newspaper. The article is on the very basics of gravitational lensing and its analogy to a person wearing specs on the Earth. The article has been co-authored by myself ( Akshay Deoras) and Prof.Shashikumar Chitre ( Dr S.M Chitre) who is Professor Emeritus at the Centre for Excellence in Basic Sciences at Mumbai.
Prof.Chitre has many years experience in the field of Gravitational Lensing and known for his joint work with Prof.Jayant V Narlikar ( IUCAA) of proposing "The apparent Superluminal Motion in Quasars through Gravitational Lensing" in 1978.
The idea of writing this article generated in my mind a few days ago ignited by the Public Lecture by Prof.Jayant V Narlikar a few days ago in Nagpur. The article is purposively titled as Spectacles in the Universe as a comparison is made between the gravitational lens and the spectacles of a person which is a convex lens basically.
Following Keywords shall assist the readers to understand the topic-
General Theory of Relativity- Proposed by Albert Einstein in 1916 explains the relation between the Space and Time referred as Space Time with Gravitation. The theory explains how a gravitational mass influence the space-time in the universe consisting of Space-Time Fabrics causing curvatures in the Space-Time called as Space Time Curvature. The theory also proposed that a ray of light will be influenced by this bending of space time causing the light to travel a geodesic path.
Quasar- Quasar stands for Quasi-Stellar Radio Source is a very compact form of the Galactic Nuclei ( roughly the center of galaxy) known as an AGN ( Active Galactic Nuclei). Quasars are being studied and are known to be powered by the accretion ( falling in) of material such as interstellar gas etc. in a black hole ( Supermassive BlackHole) at the centers of Galaxy. Thus mechanism produces a source which generates tremendous emissions especially across the Radio and Visible Spectrum. A single quasar can outshine an entire galaxy.
Einstein Cross,Einstein Ring,Einstein Arc- These are the names given to a specific shaped images of a distant quasar mostly influenced by a gravitational lens like high mass galaxies.
Extra-solar planet- known as exoplanets which are orbiting distant stars in their respective star-planet system. Its a classical case of Gravitational Microlensing where as mentioned below images ( virtual or real) of the sources aren't produced by there are changes in the intensity of light coming from the source ( similar to astronomical transit). A major difference between astronomical transit and a result of Gravitational Microlensing is that in the case of a transit, an object ( say any heavenly body appearing smaller than the source star) passes infront of the source and hence an observer viewing in the same plane and same axis notices a dim in the light from the source. In the case of Gravitational Microlensing, a star can even pass infront of the source and due to the lensing, the light of the source instead of dimming magnifies...
Credits-
Prof.S M Chitre
Prof. Jayant V Narlikar
Vikas Vaidya ( The Hitavada)
Here is a view of the latest article titled as " Spectacles in the Universe" which was published in the 1st May 2012 edition of The Hitavada newspaper. The article is on the very basics of gravitational lensing and its analogy to a person wearing specs on the Earth. The article has been co-authored by myself ( Akshay Deoras) and Prof.Shashikumar Chitre ( Dr S.M Chitre) who is Professor Emeritus at the Centre for Excellence in Basic Sciences at Mumbai.
Prof.Chitre has many years experience in the field of Gravitational Lensing and known for his joint work with Prof.Jayant V Narlikar ( IUCAA) of proposing "The apparent Superluminal Motion in Quasars through Gravitational Lensing" in 1978.
The idea of writing this article generated in my mind a few days ago ignited by the Public Lecture by Prof.Jayant V Narlikar a few days ago in Nagpur. The article is purposively titled as Spectacles in the Universe as a comparison is made between the gravitational lens and the spectacles of a person which is a convex lens basically.
Following Keywords shall assist the readers to understand the topic-
General Theory of Relativity- Proposed by Albert Einstein in 1916 explains the relation between the Space and Time referred as Space Time with Gravitation. The theory explains how a gravitational mass influence the space-time in the universe consisting of Space-Time Fabrics causing curvatures in the Space-Time called as Space Time Curvature. The theory also proposed that a ray of light will be influenced by this bending of space time causing the light to travel a geodesic path.
Quasar- Quasar stands for Quasi-Stellar Radio Source is a very compact form of the Galactic Nuclei ( roughly the center of galaxy) known as an AGN ( Active Galactic Nuclei). Quasars are being studied and are known to be powered by the accretion ( falling in) of material such as interstellar gas etc. in a black hole ( Supermassive BlackHole) at the centers of Galaxy. Thus mechanism produces a source which generates tremendous emissions especially across the Radio and Visible Spectrum. A single quasar can outshine an entire galaxy.
Einstein Cross,Einstein Ring,Einstein Arc- These are the names given to a specific shaped images of a distant quasar mostly influenced by a gravitational lens like high mass galaxies.
Extra-solar planet- known as exoplanets which are orbiting distant stars in their respective star-planet system. Its a classical case of Gravitational Microlensing where as mentioned below images ( virtual or real) of the sources aren't produced by there are changes in the intensity of light coming from the source ( similar to astronomical transit). A major difference between astronomical transit and a result of Gravitational Microlensing is that in the case of a transit, an object ( say any heavenly body appearing smaller than the source star) passes infront of the source and hence an observer viewing in the same plane and same axis notices a dim in the light from the source. In the case of Gravitational Microlensing, a star can even pass infront of the source and due to the lensing, the light of the source instead of dimming magnifies...
Credits-
Prof.S M Chitre
Prof. Jayant V Narlikar
Vikas Vaidya ( The Hitavada)
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