New Mars Forums

Orbital Megastructure:
The two previous posts hint at scaling back the effort, in order to achieve reasonable results with less effort.

In this case, I am going to suggest a much more fantastic method.  It would have to have a fantastic payout to be worth it.

If it was decided to have a very advance space going civilization on Mars, then I suggest an orbital ring of metal with additional features.

Before I get pilloried I want to point out that this board puts up with talk about space elevators and shell worlds and so on.

If there ever are space elevators on Mars, I would like to keep them away from this orbiting ring, since if they break, the backlash might destroy the ring.

In this case, if a magnetic field were produced from the ring, it would be aiding the fossil field I would think.

I have some things to associate with the ring.  For instance tethers.  I know they break.  The longer they are the more of a loss that is, so I consider a enormous number of tethers, of shorter length, upward from the ring in the solar wind to generate electrical power.  Some tethers downward,
into the upper atmosphere to extract atmospheric gasses, and to I supposed provide some friction.

The energy to maintain orbit I hope could be primarily the expansion and contraction of the ring as it is eclipsed by the planet Mars.  Something like a split phase induction motor, already started, so the same spin direction is maintained.
Since the ring is already "Started", (Orbiting in one direction), it does not need a starting mechanism.

So, as the part of the ring in shadow contracts, it will draw mass from both directions of the ring in light.  Then that cooled portion will orbit into sunlight, fall towards the suns gravitational field, and begin to heat up.  At past noon, it is at it's warmest, it will expand, and give it's slack to the shadowed portion of the ring.  This will involve orbital energy, so perhaps I will find or be told that it will not work, but I would not be the first person to mess up here.  I think it would work. 

If it would work, then the danger is that it would collect excessive energy, which needs to be dissipated some way, or it would fly apart.

So the tethers:
https://en.wikipedia.org/wiki/Electrodynamic_tether

*A caution some articles talk about needing a planets magnetic field to work, and some talk about using them for a starship to provide electric energy (By loosing speed), and to some degree propulsion by applying electric energy (That has some limitations it seems.

Anyway I will continue with the bull droppings. 

I will make it simple for now, until I can do more research.
The ring might acquire electric power by:
-Tether, possibly needing to impose a magnetic field excitation field from the ring (Which is intended anyway).  The movement of the solar wind relative to the tethers as generators.
-Electric difference between the plasma in the sunlight and the shadow (Very tentative thinking).

Some tethers would depend downward, and would be used to bring a plasma from the upper atmosphere up.

I need to understand how to convert that plasma to gas/liquid/solids.

Anyway, this mess is an attempt to collect electrical power from the solar wind, to create a magnetic field to protect the planet, while extracting atmosphere for space propulsion (I am thinking escaping Hydrogen).

I surely do not have sufficient completion of the idea, and it could fall apart, but it is an interesting think.

And it is definitely a mega project.

And yes, for sure with this post I am goofing.  I think some is right, maybe most, but I am prepared to learn from it crashing as well.

I have noticed that this is a particular favorite of yours Spacenut.

I also see that it has gone quiet, so I will post.

Why is only half of Mars Magnetized?
http://www.planetary.org/blogs/emily-la … /1710.html

Knowing "Why" can help is diagnose "What is it like, and what to do about it".  Otherwise I am more interested that it is like that.

Quote (From the linked article):

And apparently the fossil field is in the southern hemisphere and not the north.

The loss rates are typically listed as 100 grams a second.

The loss method is said to involve the fossil magnetic fields of Mars and the solar wind.  Large chunks of atmosphere are removed when the solar wind does a reconnection with the fossil Martian fields.  See this link:
http://science.nasa.gov/science-news/sc … plasmoids/

http://science.nasa.gov/media/medialibr … dslide.jpg

I have been suspicious as to why the Martian surface pressure averages near 6 mb, the triple point of water.

I think that as the atmosphere is removed, and the pressure drops, the forces that would sublimate water from ice increase, and ice sublimates, adding water vapor to the atmosphere, where it is split by UV light.  Then the Hydrogen floats away, and Oxygen from ice eventually replaces the Oxygen in CO2, as Oxygen is removed from CO2 in the uppermost atmosphere.

So, as long as you have ice you have hopes of keeping an atmosphere on Mars.  If you terraformed the planet to warm it up, this would no longer operated, but there would be more moisture in the air, so "Water" would replenish the lost Oxygen.

So one way to keep this going would be to bring in more water, or just to not care, thinking there was enough water for human the human time scale.

But you want to protect the Martian atmosphere from the solar winds ravages, so I will go back to that.

At first it seems rational to make a planetary magnetic field which aids the existing field which exists primarily in the southern hemisphere.

At first it seems sensible to make an artificial field which aids the existing partial field, but: (From the first linked article)
[Quote:]

I don't know how strong the field would have to be in that case to ward off the solar wind.  So, maybe an aiding field would make sense.

But I see that it might be worthwhile to consider instead using local opposing fields, to try to nullify the fossil fields.

Either an opposing field must be maintained, or perhaps if you are really good at it you could degauss the existing fields. (I have serious doubts about that however).

You would only do this if it suited your purposes more than creating an aiding field.  It seems to me opposing a field of 1500 nanotesla across 40% of the planet might be easier than creating an aiding field across the whole of the planet.

The result would not be perfect, but if you could do it you would possibly get rid of the major method of atmospheric losses.

I am going to make further posts that will possibly annoy you and perhaps one of our members would describe as bull droppings, but with greater verbage.   You can choose to ignore them if you like.  I hope this particular post shines more light on the subject.

But those links are from a while ago, perhaps Mavin has disputed the claims.  In that case I apologize for the bull droppings.

https://en.wikipedia.org/wiki/Seasonal_ … ian_slopes

It seems that the latest is that they are moistened salt a wafer thin.

However, as a member has mentioned, the press is full of B.S. and it is becoming common to have contradictory articles.
They just want to print something, and often they go to one extreme and then some other article will go to another.

I actually have been interested in non-tidally locked worlds myself, but Proxima Centauri is a very tiny star, even in the category of "M"/"Red Dwarf" stars.

I am aware of three ways it might not be tidal locked.

One theory about why Mercury and Venus have the spins they do is that they interact with each other.

Another has it that for Venus, the wind causes the planets spin.  It is claimed that if it had a atmosphere like Earths, it would spin 10 times as fast as it does now.  If I understand the idea in my way, it would be that cooler dense air falls from the night side, and imposes a friction on the surface (Mountains also), in one direction.  It is falling towards the sun, but of course the gravity of Venus holds on to it.  Similarly, hotter air from the day side "Floats" away from the suns gravity, being displaced by the cooler air from the night side, and presumably applies torque to the planet in the same direction.  But this "Theory" makes me wonder then why Mercury is not tidally locked.

Going with the "Wind" notion, it is believed that such a world would rotate once at a rate of weeks or months.  (Of course worlds further out may not risk tidal locking at all).

So, to me that would be a very interesting world as well.

And of course there is the notion that these planets were hit by objects that made them spin.

https://en.wikipedia.org/wiki/Proxima_Centauri_b

Because of the previous complaint, I will quote quite a lot of the article:
Quote:

Interestingly, the mass of 1.27 is a minimum.  I have seen other articles that suggest that it could be as high as 2.0.
This article seems to allow for even more, if I am not reading it wrong.

For Robert, encouragement.  I am quoting from towards the end of the above quote:

This is a very interesting sub-quote:

I would imagine that the larger the planet is, the longer it took to either become tidally locked or locked into a 3:2 resonance.  So, a large spinning planet, would supposedly have a better possibility to have a robust magnetic field during that 100-200 million years.  (On second thought, I don't know).  It's a good question.  Does a larger planet take longer to go to tidal locking or the 3:2 ratio, from the original spin it had?

I though the greatest danger of loss of atmosphere was the magnetic qualities of the star when it was young.  Perhaps I have something more to learn on this.

But you are probably right GW, its good to put restraints on how far speculation goes.

I'm having a strange night, so I will reply now.

Mars and Venus do not have significant Ozone.  Robert specified an atmosphere of N2, CO2, Ammonia, and Methane.

I think that CO2, Ammonia, and Methane would react with any Ozone formed, and destroy it.

Should the mix be different, say N2 with a pinch of CO2 and a sufficient water vapor content, lets say a humid troposphere, then the U.V. might very likely turn it into a N2/O2 atmosphere, and it would do it without life existing on the planet.  This could generate an Ozone layer as well.  However, it is thought that a solar flare could destroy the Ozone layer, so it would have to rebuild.  Until the rebuild, the daylight side of the planet would be relatively hostile to life on the surface in the "Light".

Therefore for the day side, I recommend full scale covered cities where the inhabitants could still live with relative comfort until the event corrected itself.  I did not specify for a full civilization however, so I figured out what would be the best deal for a first settlement, where they could have what they needed, and have relative safety.

As for the ice cap, it seems you may be cherry picking.  You cannot assume that the ice cap will be entirely over open water.  Our Antarctica is not.  And the plateau of Antarctica is "Miles" high.  Approximately 2 miles high.

We know that during the last ice age the continental shelves were near exposure.  That water then was locked up in north and south ice sheets.  If you know that Proxima b will have approximately ~.75 times as much solar energy as Earth, then you can model Earth to guess about it.  Move the Earth 1/2 way to Mars so that it has about that warming.  You can anticipate that water from the oceans will end up in Antarctica.
I have read that the Troposphere at the poles is about 4.3 miles high.  That is probably the limit of how high the vapor could "Try" to pile snow.
I am sure that the rate of deposition would slow down quite a bit before the ice piled up to 4.3 miles.  In the Earth model, however we have not yet factored in the higher gravity, or the thermal difference.  On your side, the higher gravity of Proxima b would likely cause glaciers to drain faster, putting a greater restraint on the possible thickness of an ice cap.

Against you however, is the fact that Antarctica has a summer of up to 6 strait months which warms it a bit.   Proxima b's dark side can be presumed to be eternally (Sort of, eternity is a long time) in the dark of night and an "Eternal" winter.  This will stiffen the ice.

In your favor is the notion that if ice is piled high enough that pressure helps to liquefy it's base.  That would make the glaciers flow faster to a degree, but then again once you get to the incline of a glacier, you are loosing altitude, and therefore pressure, so I am not sure how much ice pressure is going to help.

Presuming that Proxima b had a different profile such as that of Mars, High Southern Hemisphere (The sun side), and what looks like an ocean basin in the Northern Hemisphere (The dark side) might work out different as I expect more of a very thick "Ice Pack" over water, and less or no "Grounding" of the ice cap.  It would "pancake" over the water. 

Good night.

I think that in many cases invasive life would be at a disadvantage.

Usually invasive species are a problem, because the are distributed to a habitat that is similar to their natural one.

If you put Alligators in the Antarctic ocean, the Penguins and seals win.

Hi Elderflower.

I guess you could be right.  If what you say is true, then I can presume the north pole pointed at Proxima Centauri can be an arbitrary assignment I have designated.

My purpose was to make an "Earth" like model which would be in contrast to a presumed "Mars" like model.  The Earth model presumes that ocean water might flow basin to basin to the high noon position, where the Mars model supposes that the oceans will be more restricted to a dark hemisphere, and possibly the margins of the terminator.

So then this provides different outcomes, and different terraforming treatments I would presume.  These would after all be "Earth" and "Mars" similar planets, so exact replication of such information is worthy of mention, and perhaps the models should be modified, but I had to start somewhere.

I wanted to wind the clock, and see what we get.

Do you have modifications to suggest?

Karov, Tom, and others.

I will try to add something complementary to what I think you and Tom may champion.  My anticipation is you will lean towards the H.W.M. and Tom towards orbital solutions.  My purpose will not be to impede such efforts, but to try to add something else.

I am working from recollections, without posted references.

I recall an article which indicated that terrestrial spinning planets appear to arrange themselves by a particular alignment, where the high mass side ends up at one pole, and the low mass at the other.

An example would be Mars, and I think Earth, in opposite ways.  Mars has its highlands at the south pole, and the Earth by my reckoning has it's highlands at the north pole.  That is there seems to be more continental mass in the northern hemisphere of Earth than the southern.

So, we may have two models to run by.  The Earth has Tectonics, and Mars does not seem to.  We could imagine sizing them up to the estimated size of Proxima b, and reason how they would operate.

Other alterations to the models:
-Tidal Locking, I think with the greater mass hemisphere pointing at Proxima Centauri.

*So, Earths Northern Hemisphere would be the day side, and the Mars Southern Hemisphere would be the Martian analog day side.

-Gravitation will > 1 g.  So perhaps it is reasonable to expect that there would be less topographical altitude difference from the high to low elevations in both models.

-Water: Most articles I read seem to suspect that red dwarf worlds will be inclined to have less water than Earth by proportion.

But I will presume that both examples have a similar surface area covered by liquid water as Earth.  That is if some of it is not tied up in ice.  Of course, under those conditions, there would be a massive polar ice cap of ice on the dark side, so the liquid portion of water would be reduced.

For the Earth model, perhaps we could suppose that the ocean levels would be 100's or 1000's of feet lower.  (Sorry for the units).  But for the Earth model, the typical ocean floor is 10,000 feet deep.  So there is a good chance that liquid water could be sufficient to overflow even into the north polar basin.  So, all the way to the high noon position.  I justify this presumption because as well as wind, water currents could be constantly eating away at the night side ice cap and ice shelves, even as water vapor would be often accumulating as snow in many places on the dark side.

The Mars model would be somewhat contrasting, as perhaps only the Mariner Rift Valley, and a fringe of ocean at various places would be exposed to sunlight, and that would likely all be near the terminator line.

The Mars model would resemble Pangea (One big continent on Earth).

*Which raises the question, "Would the suns pull tend to compress the separated land masses together on the sunward side, acting against the tectonic forces"?

Atmosphere: I think that Venus has managed to exhibit 3.5 bars of Nitrogen, and for a planet with photosynthesis we could suppose that some Oxygen could be added to that.  So, lacking other information, I will speculate that it might be possible for a terrestrial planet to generate up to 4 bar of Nitrogen/Oxygen for an atmosphere.  This is just a gestimate based on the evidence Venus provides.  I am sure the value can be variable.

We think that "Our" Mars could have an Earth-Like average climate if it had 2 bars of Nitrogen/Oxygen, and that is because the luminosity at the orbit of Mars is approximately 1/2 that of Earth.

So, I presume that if we could have a 4 bar atmosphere, our model might have a Earth similar climate with a luminosity of about 1/4 that of "Our" Earth.

So, on that basis, I am going to violate the stated habitable zone and say that the outer limit is too restricted.  For Proxima B, the atmosphere would likely only have to be a bit thicker than 1 bar, to have an Earth similar average temperature.  (Leaving out other factors such as a possible cloud deck on the day side).  My reading says that to limit an atmospheres volume you either have to have a limit on the gasses available, or you have to have running rivers to intern excess gasses, so I presume that often atmospheres will self regulate to provide the correct amount of rivers for a stable thermal system for the planet.

But I include that prior information because there is a suspicion of another planet in the system, and that might be a big one, and further out.

I could ramble on and on, but I will try to limit my further additions.

For my part, I would see no reason not to employ wind power on the surface of both models, where it was suitable.  It would be particularly useful on the night side.  As for the day side, for the day side, solar power of course, and perhaps pipelines and water pumped uphill, and cities which could still provide adequate shelter for the population even if the Ozone layer got destroyed during a flaring event.

So, as promised, I have left the H.W.M. and the orbital mechanisms for you and Tom (Karov).  What would you want to do with those two models?

I think I have reasoned out how a tidal locked world could retain habitability after the first hazardous stages of it's solar system have passed.

Taken separately, two ideas about tidal locked worlds around red dwarf stars, seem to indicate hazard to the possibility of a biosphere as we know it.
1) The magnetic activity of the young star will severely erode the young planets atmosphere.
2) The tidal locking may cause the atmosphere to collapse on the dark side.

But I think taken together with other factors, it can be a recipe for later success, particularly with the so far described Proxima b.

I am going to start with some presumptions about the newborn Proxima b.
a) It is not tidal locked at first.
b) It's original atmosphere may in part be composed of Hydrogen and Helium.  (This is not necessary to my argument, but it is helpful).
c) As newborn, the planet has more internal heat than would be true now.
d) Proxima Centauri although more magnetically active, will be less thermally active (This could be untrue, if it still has heat of condensation, but lets just say the scenario begins when the star first starts up fusion).

So Proxima b is spinning initially, (And this offers better chances earlier for a magnetic field), it has an atmosphere, it is hot inside, but Proxima Centauri is trying to strip its atmosphere, and finally the surface of Proxima b should be cold, both because it is further out in it's habitable zone than Earth, and because the newborn star is not shining as brightly as it is now.

Since the planet is spinning the "Cold Traps" will be at the poles, until the planet becomes tidally locked.  Therefore condensable substances from the atmosphere will accumulate in the cold traps.  Water for sure, and perhaps CO2, Ammonia, Nitrous Oxide, and other substances.

I expect water vapor to form from contact with Hydrogen in the atmosphere with hot surface materials.  And that will largely migrate to the "Cold Traps".

Other than with ground heat, there will be little chances of an ocean or sea.  Even if the ground heat melted water, it would likely create ice covered reservoirs.  So the atmosphere will be dry, most likely composed of N2, and maybe Hydrogen and Helium.  Many substances will be protected from being stripped from the atmosphere by the stars wind because they will be locked in condensates on the surface.

After the planet is tidally locked, the "Cold Trap" will be on the dark side of the planet, and the ice caps should migrate there, for the most part.

Any Hydrogen and Helium will tend to be stripped away preferential by the stars magnetic wind, in part protecting the Nitrogen in the atmosphere (I presume), until the Hydrogen and Helium loose significance in the atmosphere, and then the N2 will begin to be stripped away, if the magnetic field of the planet is not sufficient.

Preservation of Nitrogen for the planet will be harder than the other atmospheric substances.  I see ways however.  I mentioned Nitrous Oxide, and Ammonia.  With a large ultraviolet flux, I see the possibility that these could be synthesized in a cold Nitrogen atmosphere, particularly if some water vapor and Hydrogen were available.  They would also not tend to last very long, unless they ended up sequestered in the "Cold Traps".

N2 itself might be able to be condensed on the dark side finally, if the atmosphere were sufficiently eroded away.  The ideal scenario would be for a atmospheric component of Hydrogen and Helium to persist long enough for the Nitrogen to condense out.

Finally dust layers, to lock down the deposits in the "Cold Traps".

Mars shows that a cold dry world can have enormous dust effects in it is wind with Aeolian deposits made from that process.

I would anticipate Proxima b to be very windy, even if it is very cold in it's initial stage, and to have lots of dust, including volcanic dust.  Some of this should get deposited on the dark side of the planet in layers over the frozen ices.

Even if the whole remainder of atmosphere were then stripped away, this should protect to a degree from the magnetic winds then stripping the materials from the dark side.

The situation would remain stable for the most part then until Proxima Centauri reached a threshold of radiance, and some event triggered a run-away release of the stored materials.  Such an event could be an asteroid impact after the stars radiance had reached sufficiency.

The hope would be that by then the magnetic wind would have quieted down sufficiently to be more permissive to an atmosphere.

As it happens, reading I have done seems to indicate that Proxima Centauri is not that much of a threat to an atmosphere now.

Josh,

I am not very interested in lightning at this time.

Antius and Robert,  I think as Robert has sort of indicated, a means to deal with dust accumulation should be available.  The cleaning events on the rovers suggest this.  Also, suggested methods previously mentioned for dust removal from solar collectors points to it.