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Name: Ankit
Status: student
Grade: 9-12
Country: India
Date: N/A 


Question:
As we know that our sun continuously emits radiation, thus I think from the past billions of years, it must have lost its fraction of mass according to the energy-mass relationship. Hence, the gravitational field should be weaker by some fraction. Has the orbital path of Earth or other planets changed because of this, and if so, what would be their shape?



Replies:
Yes, you are right, the sun is slowly losing mass, but the amount is too small to make any difference in our everyday lives. The National Institute Standards and Testing (NIST) keeps highly accurate track of time, and only very tiny adjustments to the length of days or years must be made (and the Sun's changing mass only accounts for part of that change). The shape of the Earth's orbit is an ellipse - which is a function of gravitation. Although the distance to the sun might change with the Sun's mass, the fact that it is elliptical would not.

Hope this helps,
Burr Zimmerman



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