START's reply

===> How many people live on Earth?

As of Saturday, July 23, 2016; 12:55:42pm, the total population of the world is 7,250,104,514.

Source: U.S. Census Bureau


Earth

Atmosphere

Surface pressure: 1014 mb
Surface density: 1.217 kg/m3
Scale height: 8.5 km
Total mass of atmosphere:	5.1 x 1018 kg
Total mass of hydrosphere:	1.4 x 1021 kg
Average temperature:	288 K (15 C)
Diurnal temperature range: 283 K to 293 K (10 to 20 C)
Wind speeds: 0 to 100 m/s
Mean molecular weight: 28.97 
Atmospheric composition (by volume, dry air): 
	Major	: 78.08% Nitrogen (N2), 20.95% Oxygen (O2), 
	Minor (ppm): Argon (Ar) - 9340; Carbon Dioxide (CO2) - 400
	Neon (Ne) - 18.18; Helium (He) - 5.24; CH4 - 1.7
	Krypton (Kr) - 1.14; Hydrogen (H2) - 0.55 
	Numbers do not add up to exactly 100% due to roundoff and uncertainty
	Water is highly variable, typically makes up about 1%
Magnetosphere

Model GSFC-1283

Dipole field strength: 0.306 Gauss-Re3
Dipole tilt to rotational axis: 11.2
Longitude of tilt: 70.8 degrees
Dipole offset: 0.076 Re
Surface (1 Re) field strength: 0.24 - 0.66 Gauss

Re denotes Earth model radius, here defined to be 6,378 km

Source: Planetary Sciences at the National Space Science Data Center