Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Sun Mass Loss, Gravitation, Planetary Orbits
Name: Ankit
Status: student
Grade: 9-12
Country: India
Date: N/A 

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?

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

Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory