You are here:

Astronomy/lunar mass and revolutions

Advertisement

Expert: - 10/26/2008


Question
if mass or weight is added to the moon,such as astronauts and/or moon bases, overtime will the added mass cause it to crash into earth or speed out of earths orbit one day?

Answer
Hello,

The mass of the Moon is ~ 7.5 x 10^22 kg. Even ten astronauts would not exceed 2000 kg, or a fraction:

2000/ (7.5 x 10^22) =  2.6 x 10^20

or a fraction so minuscule it wouldn't make a dime's worth of difference..

For a lunar base, consider a base even with a mass of 10^12 kg (one billion metric tons), the fraction again is extraordinarily small:

10^12/ (7.5 x 10^22)  =   1.3 x 10^-10

In other words nowhere near enough to alter the Moon's orbit or speed in any significant way.

OTOH, if the Moon were struck by an asteroid moving at over 40,000 m/s and with a mass of ~ 10^18 kg, the outcome would certainly be considerably different!

Astronomy

All Answers

Answers by Expert:

Ask Experts

Volunteer

Philip Stahl

Expertise

I have forty years of experience in Astronomy, specifically solar and space physics. My specialties include the physics of solar flares, sunspots, including their effects on Earth and statistics as applied to astronomical investigations.

Experience

Astronomy: more than forty years experience starting with construction of my own simple telescopes. Worked at university observatory in college, doing astrographic measurements. M.Phil. degree in Physics/Solar Physics and more than ten years as researcher.

Organizations
American Astronomical Society (Solar Physics and Dynamical Astronomy divisions), American Mathematical Society, American Geophysical Union

Publications
Solar Physics (journal), The Journal of the Royal Astronomical Society of Canada, The Proceedings of the Meudon Solar Flare Workshop (1986), The Proceedings of the Caribbean Physics Conference (1985). Books: 'Selected Analyses in Solar Flare Plasma Dynamics', 'Physics Notes for Advanced Level'.

Education/Credentials
B.A. Astronomy, M. Phil. Physics

Awards and Honors
American Astronomical Society Studentship Award (1984), Barbados Government Award for Solar Research

©2012 About.com, a part of The New York Times Company. All rights reserved.