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#1 2003-11-25 12:57:31

Earthfirst
Member
From: Phoenix Arizona
Registered: 2002-09-25
Posts: 343

Re: Solar wind! - Mars is not protected like earth.

One of the bigest problems that I see in terraforming Mars is that Mars is not protected from the solar wind and cosmic rays. Although people could protect them selfs from the radiation any biosphere on Mars would have to with stand an high radiation envirnoment. Solar flares would be a constant danger like it was on the moon. But besides the changles to life any atmosphere you make would help to protect you but would be lost in the long run as did before on mars.
The solution is mars needs an magnetsphere like the Earth does to protect it from the solar wind from blowing it all away.
How to do this it is hard to say, it would take all of energy to generate one like the earth. One possible way is too have many small local magnet fields that protect a settlements or farms. Also the many small fields of magnetism would protect the atmosphere from the solar wind. Not as good as a gobal field but better then nothing.
On way to get a gobal magnete field would be to coil power lines around mars many times, and let current flow through them. the power line could link up to citys to, a dual use.
In effect you would make a magnete field as along as the wire have current in them. Mars is smaller than the earth and we all ready have power grids that span all the coninates.
So it possible to do it on mars, How many times the wir must go around mars, I guess it depends on how storng a field you want.


I love plants!

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#2 2003-11-25 13:31:35

dickbill
Member
Registered: 2002-09-28
Posts: 749

Re: Solar wind! - Mars is not protected like earth.

. One possible way is too have many small local magnet fields that protect a settlements or farms.

There are small magnetic field areas on Mars, mostly in the southern highlands if I remember well the MGS picture.

Maybe one of these small areas would povide good shelter, it's a matter of finding the good one, because they might as well concentrate the radiations rather than diverting them, as Shaun pointed one day, so not all these areas are "good" probably.

In the best of the world, that magnetically protected area should be better in the northen lowlands, or Hellas, where atmosphere is thicker, but there are no magnet there. bad luck.

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#3 2003-11-25 13:50:39

kippy
Banned
From: Chicago area
Registered: 2003-11-06
Posts: 70

Re: Solar wind! - Mars is not protected like earth.

I've been giving this some thought lately but I'm not a true physics buff so I might be off my rocker on some of this.

The ideas you mentioned above sound good.  I've heard that there are indeed local "umbrellas" of magnetic field on the surface.  It sounds reasonable to create one around the cities but terraforming plans could on global plant growth, it may be better to shoot for a global shield from the solar wind.  I'm only half way through Blue Mars but I've heard that they do something like the global power line idea.  I have no idea how much power that would take though and it might be daunting.

Here's my crazy idea.  Place a monumental electromagnet at LaGrange point 1 between the Sun and Mars to act as a shield before the wind hits Mars.  It would have to have a small silhouette so it wouldn't block too much sunlight of course.  It could either be solar powered or fission or fusion powered depending on how strong the field would have to be.  It should attract H3 from the solar wind which might be fed into the fusion reactor or used as propellant to keep it in place at L1 with an ion drive or some other means of propulsion.

The big magnet idea is probably riddled with problems but I?d be interested to hear what people think if they have a better physics background than me.

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#4 2003-11-25 19:34:54

Earthfirst
Member
From: Phoenix Arizona
Registered: 2002-09-25
Posts: 343

Re: Solar wind! - Mars is not protected like earth.

Those are good ideas, having an small deflitor magnete could stop a lot of the solar wind from hitting mars.
I have never read blue Mars before I just thought of the idea.
If a small eltromegnete works why not on a large scale, the wires could close to each other. A mile wide band of coil around mars could make a big field.
A new idea I came up with is to have a very strong electromegnete. You turn it on then you melt the surface rock in the field, when the rock cool it becomes a premitly magnet. In area that lack iron minerals poor liqued iron, or other metals. If you did this you could have a perment strong megnet band that spans the planet. No power would be needed to maintian the field.
This idea could work for a small area too, but there would have to be some oranization other wise rival field could cancel each other out.
This is easyer than biulding lots of power planets, also the solar wind could be directed to a small area to genterate power.
This happens on the earth in cannda, long power lines span cannda and absorb excess current from the solar wind that is forced their by the magnetsphere. Also it causes blacks by shorting out the system.
What do you think? smile


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#5 2014-08-17 13:25:03

knightdepaix
Member
Registered: 2014-07-07
Posts: 239

Re: Solar wind! - Mars is not protected like earth.

This post solely provides a link on chemical compositions of solar wind.

http://solar-center.stanford.edu/FAQ/Qsolwindcomp.html

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#6 2014-08-17 20:44:13

idiom
Member
From: New Zealand
Registered: 2004-04-21
Posts: 312

Re: Solar wind! - Mars is not protected like earth.

This is a question that has been bugging me...

Does the moon contribute to the heating of the Earth core through gravitational tides?

If so, could an artificial moon at Mars melt the core and produce a magnetic field?


Come on to the Future

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#7 2014-08-17 22:10:24

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,782
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Re: Solar wind! - Mars is not protected like earth.

What would you build the artificial moon from?

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#8 2014-08-18 07:26:59

Terraformer
Member
From: Ceres
Registered: 2007-08-27
Posts: 3,800
Website

Re: Solar wind! - Mars is not protected like earth.

No need to build it, just tug an existing asteroid into a highly elliptical orbit... a very large undertaking, yes, and it probably won't provide much tidal heating, but it will provide tides and, if close enough, stabilise the tilt.


"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony

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#9 2014-08-18 09:14:17

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,782
Website

Re: Solar wind! - Mars is not protected like earth.

Ceres is the largest asteroid. Today it's called a dwarf planet. According to Wikipedia it's mass is (9.43±0.07)×10^20 kg, so 0.0128 times that of Earth's Moon. That's 1/80th. How close would that have to be to Mars to cause any tidal heating? If you use regolith from Ceres as propellant to move it, how much mass would you lose?

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#10 2014-08-19 01:44:30

idiom
Member
From: New Zealand
Registered: 2004-04-21
Posts: 312

Re: Solar wind! - Mars is not protected like earth.

I have no idea... thats why I am asking the people with time on their hands to do the math tongue

You could glue Ceres, and some other things together.

It just seems easier than most of the other ideas for terrraforming.


Come on to the Future

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#11 2014-08-19 04:14:07

Terraformer
Member
From: Ceres
Registered: 2007-08-27
Posts: 3,800
Website

Re: Solar wind! - Mars is not protected like earth.

I'm sure we discussed the issue before, and the asteroids we were talking about were 2-300km diameter. The minimum distance it could orbit would be the Roche limit, but I can't remember what that is.


"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony

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#12 2014-08-19 07:46:21

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,782
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Re: Solar wind! - Mars is not protected like earth.

As I recall, last time no one did the math. No numbers. I'm asking the questions that were left unanswered.

The Roche limit is a good place to start. The link is Wikipedia, but that page actually has formulae.
6e206bd6ab50f52a8839d9ca16ad3a55.png
For Ceres orbiting Mars, M(subscript capital M) is mass of Mars, M(subscript lower case m) is mass of Ceres, and Rm is radius of Ceres. Mars has mass 6.4185×10^23 kg. Ceres equitorial radius is 487.3±1.8 km, which is the important figure for this calculation.
Plugging in:
d = 1.26 * 487.3 km * (6.4185×10^23 kg / 9.43×10^20 kg) ^ (1/3)
solve:
d = 5401 km
Mass of Ceres has three siginficant figures, so you should round off the result to three significant figures.
This means Ceres must orbit greater than that distance from Mars.

Next question: how much mass do we need? Can we get by with something smaller? How small? How close would it have to orbit to be effective? What are we trying to achieve? Is it just tidal heating, or are we trying to create differential rotation speed between Mars inner core vs crust/mantle to ensure the outer core is a liquid bearing? Current theory is this is what happens in Earth's core, and what organizes convection cells to become a dynamo. Of course doing that on Mars requires melting the outer core. That starts with tidal heating. How big a moon would this require, and how close?

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#13 2014-08-19 08:29:29

karov
Member
From: Bulgaria
Registered: 2004-06-03
Posts: 953

Re: Solar wind! - Mars is not protected like earth.

On 5000km away from Mars, Ceres would:

1. be a 4 times smaller then Luna body on 70 times lesser distance - how big would it look from Martian surface? The lenght of such orbit would be ~16 000km, so a 1000km wide body would cover 1/16th or 22.5!!! linear degrees!!! This: http://www.1728.org/angsize.htm gives me 11.421 Degrees for Ceres @Mars on 5000km orbit, compared with  0.38197 Degrees for Sun from Earth!!! or 0.28648 Degrees for Sun from Mars!!!

So close orbiting around Mars Ceres would look 40 TIMES bigger then the Sun from Martian surface???

2. tidally - 70 times closer, but 0.0128 in mass compared with the Moon. 70 times closer = proportion of 70 cubed times stronger tidal effect factored by 0.0128 of mass, am I right?

WHAAAT! 70^3 * 0.0128 = 4390 TIMES stronger tidal action??!!! Where I'm going wrong?

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#14 2014-08-19 15:32:16

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,782
Website

Re: Solar wind! - Mars is not protected like earth.

Another problem is chemistry of the core. Earth's lower mantle is believed to be predominantly perovskite, which is an iron magnesium silicate: (Mg,Fe)SiO(3). The outer core is liquid metal, and inner core is solid metal. However, Mars outer core may be iron sulfide: FeS.

Earth's Core-Mantle Boundary: Results of Experiments at High Pressures and Temperatures.

APS X-rays reveal secrets of Mars' core

The scientists found that when heated at martian core pressures, FeS undergoes a phase change from a crystal structure with low symmetry to a hexagonal form called FeS-IV, and determined its density under those extreme conditions.

Phase relationships and equations of state for FeS at high pressures and temperatures and implications for the internal structure of Mars

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