Magnetizing Mars
... sorry, no
Superconductors do not make a stupid idea into a super idea.
Some talk about terraforming Mars, turning this dead ball of rock into a miniature Earth. Mars has no magnetic field, so an artificial atmosphere (somehow) would get stripped away by solar UV and the much weaker gravity. How would a terraformed Mars 2 compared to Earth and Mars 1 today?
|
units |
Earth |
Mars 1 |
Mars 2 |
Semimajor Axis |
AU |
1.0 |
1.52 |
1.52 |
Mass |
kg |
5.972e24 |
6.42e23 |
6.42e23 |
Radius |
km |
6371 |
3389.5 |
3389.5 |
Gravity |
m/s² |
9.81 |
3.71 |
3.71 |
Planet Density |
kg/m³ |
5510 |
3930 |
3930 |
Escape Velocity |
m/s |
11200 |
5030 |
5030 |
Escape Energy |
MJ/kg |
63 |
12.6 |
12.6 |
Dipole moment |
A-m² |
7.94e22 |
~0 |
3.4e22 |
Iron Core radius (est) |
km |
3400 |
1800 |
1800 |
Atmosphere @surface: |
||||
Mass |
kg |
5.15e18 |
2.5e16 |
4e18 |
Temperature |
K |
288 |
210 |
288 |
Density |
kg/m³ |
1.2 |
0.015 |
1.2 |
Pressure |
kPa |
101 |
0.64 |
101 |
Pressure Scale Height |
km |
8.5 |
11.5 |
22.8 |
Temperature Lapse Rate |
K/km |
6.5 |
2.2 |
? |
Primary Components |
|
N₂, O₂ |
CO₂ |
N₂, O₂ |
Molecular Weight |
g/mol |
30.5 |
44.0 |
30.5 |
Molecular Weight |
kg |
1.54e-24 |
2.23e-24 |
1.54e-24 |
Thermal Velocity √3kT/2m |
m/s |
485 |
345 |
485 |
(Vesc/Vthrm)² |
|
533 |
213 |
108 |
CO₂ mass |
kg |
3.2e15 |
2.4e16 |
? |
The most disturbing problem with Mars 2 is that a hotter, lower-mass gas atoms are more likely to escape in the weak Mars gravity field ... (Vesc/Vthrm)² is halved compared to the colder, higher molecular weight current Mars 1 atmosphere. But we'll ignore that, and also ignore how we can create enough greenhouse effect to heat Mars to Earth surface temperature. Terraforming in science fiction novels is done with a few keystrokes.
The shielding effect of the magnetic field is not due to surface field strength, but the dipole of the planetary magnetosphere compared to the solar wind pressure. Presume the solar wind density is inverse-square - (1/1.52)² or 0.433 less dense than at Earth, so the artificial Martian dipole may be 0.433*7.94e22 A-m² or 3.4e22 A-m² .