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## Main Question or Discussion Point

Ok, so I am tryting to calcualte the mass of an orbiting body.

I am using M = 4 * PI^2 * r^3 / ( G * T^2 )

Lets use the Earth as an example.

However I am not getting what Nasa has for answers of 5.9 E24 kg.

http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html

Using this calculator: http://www.ajdesigner.com/phpgravity/keplers_law_equation_mass.php

I am using a Radius of 149,600,000,000 meters

Ref: Semimajor axis (106 km) 149.60

Period of 365.25 or 365.25*24*24 = 31,557,600 seconds

G = 6.67E-11 N-m^2 / kg^2

That calculator gets 1.98 E+21 kg. Not even close to 5.9E+24

I get 1.98E+30 because I am using meters. But still not matching 5.9E+24

Can someone help with my math - not sure what is wrong.

Thanks

I am using M = 4 * PI^2 * r^3 / ( G * T^2 )

Lets use the Earth as an example.

However I am not getting what Nasa has for answers of 5.9 E24 kg.

http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html

Using this calculator: http://www.ajdesigner.com/phpgravity/keplers_law_equation_mass.php

I am using a Radius of 149,600,000,000 meters

Ref: Semimajor axis (106 km) 149.60

Period of 365.25 or 365.25*24*24 = 31,557,600 seconds

G = 6.67E-11 N-m^2 / kg^2

That calculator gets 1.98 E+21 kg. Not even close to 5.9E+24

I get 1.98E+30 because I am using meters. But still not matching 5.9E+24

Can someone help with my math - not sure what is wrong.

Thanks