03 January 2014

Earth at Perihelion:


Earth will be at Perihelion on 4th of January; this is the closest distance from earth to Sun. At perihelion the distance between earth and sun is close to 147.09 million km. Since Earth’s orbit eccentricity is very low at 0.016 which is very close to circle the distance between perihelion and aphelion (furthest point from Sun) does not differ much. The Aphelion distance of earth and Sun is 152.10 million km, making the difference just 5.01 million kilometres. This is not much to cause any problem to us, but due to proximity to sun earth receives 7% more sunlight.
The angular size of the Sun seen from earth does not differ much during perihelion and aphelion due to low eccentricity for earth’s orbit. The sun subtends an angle of 0.54183 degrees during perihelion, and at aphelion (furthest distance from sun) the angle subtended is 0.52398 degrees the difference is very small at 0.01785 degrees.
When compared with Mercury which has highest eccentricity of 0.2056 the difference in angular size is apparent during perihelion and aphelion.

 

Sun
Sun
Max.Angular Dia
Min.Angular Dia
Perihelion
Aphelion
Earth
0.54183
0.52398
Mercury
1.7324
1.1414

 

Say Hi to Sun when you go out on January 4th!

1 comment:

  1. Excellent read, I just passed this onto a colleague who was doing a little research on this topic. And he actually bought me lunch because I found it for him. So I should thank you for the free lunch I got.

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