What Are the Challenges and Proposed Solutions for Terraforming Mars?

[B. Elliott]

I think you are confusing pseudoscience with impractical science.

Due to the fact that nukes in space are outlawed by the order of international space law, it's currently impractical and will remain that way intil those laws are changed.

 

[B. Elliott]

Overly Speculative Posts:
One of the main goals of PF is to help students learn the current status of physics as practiced by the scientific community; accordingly, Physicsforums.com strives to maintain high standards of academic integrity. There are many open questions in physics, and we welcome discussion on those subjects provided the discussion remains intellectually sound. It is against our Posting Guidelines to discuss, in most of the PF forums, new or non-mainstream theories or ideas that have not been published in professional peer-reviewed journals or are not part of current professional mainstream scientific discussion. Posts deleted under this rule will be accompanied by a private message from a Staff member, with an invitation to resubmit the post in accordance with our Independent Research Guidelines. Poorly formulated personal theories, unfounded challenges of mainstream science, and overt crackpottery will not be tolerated anywhere on the site. Linking to obviously "crank" or "crackpot" sites is prohibited.

 

[maze]

Those rules apply to crackpot theories of the laws of physics, not strangely novel applications of correct laws of physics.

I find it hard to believe the level of hatred this thread is generating.

 

[D H]

It is not hatred, it is frustration. The thread started on a bad footing and just got worse.

Thread reported.

 

[B. Elliott]

Those rules apply to crackpot theories of the laws of physics, not strangely novel applications of correct laws of physics.

I find it hard to believe the level of hatred this thread is generating.

It's not hatred as I share the same dreams as you do and have had the exact same thoughts as you're having. It's just that you have to know where to draw the line with practicality.

 

[Astronuc]

The proposals for terraforming, particularly with thermonuclear bombs, were presumptive and didn't address some fundamental issues with respect to feasibility, particularly with respect to atmospheric retention. One must consider what is available to terraform Mars and the goal of such a program.


Mars information from http://en.wikipedia.org/wiki/Mars
The solar day (or sol) on Mars is only slightly longer than an Earth day: 24 hours, 39 minutes, and 35.244 seconds.

Martian year is equal to 1.8809 Earth years, or 1 year, 320 days, and 18.2 hours. Mars's axial tilt is 25.19°, which is similar to the axial tilt of the Earth. So a Martian winter would be nearly twice as long as one on earth, and perhaps much colder.

Surface temp.
min . mean . max
186 K 227 K 268 K
-87°C -46°C -5°C

So for humans to live in an environment similar to that of Earth, the max temperature of Mars would have to be increased by about 30-35°C, and ideally the minimum would increase by about 50°C, otherwise significant thermal differentials would drive extreme weather (i.e. high wind velocities). Given that Mars is 1.52 AU from the sun, it receives less than half the solar energy flux as the Earth (~43%).


But one has to ask, why Mars doesn't have an atmosphere. Well, it simply doesn't have enough gravity to retain the light gases like N₂, O₂, and water vapor H₂O. So, even if the CO₂ on Mars was released and converted to O₂, and the water was released as vapor, the O₂ and H₂O would simply escape to space, especially if the temperature were to be increased to levels experienced by Earth's atmosphere.

http://zebu.uoregon.edu/~soper/Mars/atmosphere.html

So the gravity would have to be increased on Mars by adding mass,
but then from where would the extra mass come. Phobos? Deimos? Asteroids?

Consider the following:

Mars - mass = 6.4185×10²³ kg / 0.107 Earths
Equatorial surface gravity 3.69 m/s² (0.376 g)

Phobos - mass = 1.07×10¹⁶ kg (1.8 nEarths)
Deimos - mass = 1.48×10¹⁵ kg

The masses of Phobos and Deimos are inconsequential, being less than one ten-millionth of the mass of Mars.


Well - what about the asteroids?


More than half the mass within the main belt is contained in the four largest objects: Ceres, 4 Vesta, 2 Pallas, and 10 Hygiea. All of these have mean diameters of more than 400 km, while Ceres has a diameter of about 950 km.

From - http://en.wikipedia.org/wiki/Ceres_(dwarf_planet)#Physical_characteristics
The combined mass of the current asteroid belt is only a small fraction of the mass of the Earth's Moon - mass 7.3477×10²² kg (0.0123 Earths)

The mass of Ceres has been determined by analysis of the influence it exerts on small asteroids. The mass of Ceres comprises about a third of the estimated total 3.0 ± 0.2 ×10²¹ kg mass of the asteroids in the solar system, together totalling about 4% of the mass of the Moon.

Ceres - mass 9.43 ± 0.07×10²⁰ kg, orbit semi-major axis 414,703,838 km
Kovacevic, A.; Kuzmanoski, M. (2007), "A New Determination of the Mass of (1) Ceres". Earth, Moon, and Planets 100: 117–123.
http://adsabs.harvard.edu/abs/2007EM&P..100..117K

Pitjeva, E.V. (2005), "High-Precision Ephemerides of Planets — EPM and Determination of Some Astronomical Constants," Solar System Research 39 (3): 176.
http://iau-comm4.jpl.nasa.gov/EPM2004.pdf

4 Vesta - mass 2.7×10²⁰ kg, orbit semi-major axis 353,268,000 km

2 Pallas - mass 2.2×10²⁰ kg, orbit semi-major axis 414,784,000 km

10 Hygeia - mass 8.6 ± 0.7 ×10¹⁹ kg, orbit semi-major axis 469,345,000 km

http://en.wikipedia.org/wiki/Image:Moon_and_Asteroids_1_to_10.svg


Collecting all the asteroid mass in solar system, would yield about 4% (0.04) of the lunar mass, which is 11.4% (0.114) mass of Mars. So adding all the asteroid mass to Mars would increase its mass 0.04 * 0.114 = 0.00456, and that would still be insufficient to retain an atmosphere with density and temperature similar to earth. Even adding the moon with the asteroids would only increase the mass of Mars by approximately 12%, and it would still be insufficient.


What about the moons of Jupiter and Saturn? Well, they are a long way off, and one would have to lift the moons out of the gravity wells of Jupiter and Saturn.


Jupiter - orbit semi-major axis 778,547,200 km

Saturn - orbit semi-major axis 1,433,449,370 km