# Thread: Weighing the planet earth.

1. Kind of a foolish little question, but who was the first person to weigh the earth and how did they get their result?

2.

3. The Earth is in free fall so it has no weight. So, "Who was the first person to determine the mass of the Earth?"

I always thought that it was Newton but maybe it wasn't till 1798: the British scientist Henry Cavendish.

Cavendish experiment - Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Cavendish_experiment#Derivation_of_G_and_the_Earth .27s_mass

After converting to SI units, Cavendish's value for the Earth's density, 5.448 g cm−3, gives

G = 6.74 × 10−11 m3 kg−1 s−2, which differs by only 1% from the currently accepted value: 6.67428 × 10−11 m3 kg−1 s−2.

 Bookmarks
##### Bookmarks
 Posting Permissions
 You may not post new threads You may not post replies You may not post attachments You may not edit your posts   BB code is On Smilies are On [IMG] code is On [VIDEO] code is On HTML code is Off Trackbacks are Off Pingbacks are Off Refbacks are On Terms of Use Agreement