Is Gravitational Shear Limited to Gravitational Lensing?

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SUMMARY

The discussion centers on the concept of "gravitational shear," primarily in the context of gravitational lensing, particularly weak lensing. It highlights the calculation of Earth's orbital velocity variations due to its elliptical orbit around the sun, resulting in a velocity difference of approximately 1.27 meters/second between the sides closest and farthest from the sun. The discussion emphasizes that gravitational shear is typically associated with the distortion of background galaxies caused by foreground mass concentrations, reinforcing its connection to gravitational lensing phenomena.

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  • Understanding of gravitational lensing, particularly weak lensing
  • Basic knowledge of orbital mechanics and velocity calculations
  • Familiarity with the concept of gravitational shear
  • Proficiency in mathematical calculations involving circular motion
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  • Research "weak gravitational lensing" and its implications in astrophysics
  • Study the effects of gravitational shear on galaxy formation and structure
  • Explore advanced orbital mechanics, focusing on elliptical orbits
  • Investigate the mathematical models used in gravitational lensing analysis
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Astronomers, astrophysics students, and researchers interested in gravitational lensing and orbital dynamics will benefit from this discussion.

beech
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Is there more than one meaning for "gravitational shear". It seems to refer to focusing of light beams.

When I calculate the difference in velocity, of Earth's side closest and farthest from the sun: the difference is about one meter/second. Is that gravitational shear?

Calculation

Orbital velocity is 2 times pi times the distance to the sun, divided by time, in this case the number of seconds in a year.

Velocity of Earth
v1 =2 * pi * 1.5 * 10^8 / ( 365.25 * 24 * 60 * 60 )
= 29.8653 km/sec.

v2 =(2 * pi * 1.5 * 10^8 - radiusEarth) / ( 365.25 * 24 * 60 * 60 )


Subrtact v1 - v2

The Radius of Earth is 6378 km.
The orbit is inclined to have a different velocity, at the sides nearest and farthest from the sun. This difference is, 1.27 meters/sec.
 
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Usually, gravitational shear is mentioned in relation to gravitational lensing, mainly weak lensing. The shear causes background galaxies in relation to a foreground cluster to become elongated, and also curved towards the center of the cluster. Look up "weak gravitational lensing". . .
 

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