New Mars Forums

Humble apologies, MarsGuy2012.
    I noticed your question about what substances burn in CO2 but ignored it. I was expecting someone to jump in and give you a chemistry lecture, so I thought I'd just keep out of the way!

    Until someone here at New Mars mentioned burning silane in Mars' atmosphere (it might've been RobS or Robert Dyck, I'm not sure now), I didn't know it could be done.
    I did attempt a very brief google search for other chemicals that would burn in CO2 but had no luck. I decided I knew way too little to get involved in this kind of discussion and left it alone.

    You're quite right not to let the deafening silence about your question bruise your ego. It was a good question! It's just that I, for one, was too stupid to know the answer and, in retrospect, too rude to say so!
    Sorry.
                                   

Hi Dicktice!
    I can't imagine anyone getting comfortable in the device you mention. When we need to sleep, we do our best to find somewhere flat to lie down. One of the reasons is that during sleep our metabolic rate drops - our pulse slows and blood pressure decreases etc. It's much easier for the body to rest completely if it doesn't have to pump blood against the pull of gravity, so we lie down .. which is the closest we can get on Earth to neutralising gravity's pull on our cardiovascular system.
    What you suggest would be almost like sleeping standing up. Blood would try to pool in the lower limbs and the heart would have to work against that. I know that 'working' the heart is a desirable thing in a zero-g environment but trying to sleep through it might prove difficult.

    My opinion is essentially biased though, because I'm a 'tether and rotation' man, myself! Your point about the temptation to store stuff in the burnt-out upper stage shouldn't be a problem. All that's in the upper stage, apart from the engine, is fuel - storing stuff in it would be impossible until the fuel is used up and , by then, you're on your way to Mars.

    To my way of thinking, unless newly developed nuclear propulsion can reduce the total Mars mission time to something like 400 days, instead of Mars Direct's 860+, we'll be needing good 'centrifugal gravity'.
    I've always maintained that humans won't be able to cope with 180 days in zero-g outbound, 500 days in 0.38g at Mars, and another 180 days in zero-g coming home. Nearly 2.5 years away from Earth's gravity would probably make rehabilitation at the end of the trip impossible. Spinning the Hab once a minute, attached via a 1.8 kilometre cable to the burnt-out upper stage mentioned, would give a full 1g of artificial gravity and keep our astronauts strong and healthy.
                                     

Hear hear!!

    Undiluted common sense from HeloTeacher, as usual.
                                     

Gennaro writes:-

    Thanks Gennaro! It's good to hear another non-American express exactly the view I've occasionally tried to throw into these discussions myself. 
    [I suppose at this point we'll get a long list of actions and atrocities, attributed to America, which purport to show she has no "admirable traditions" at all! The acrimony directed towards the US never ceases to amaze me - the finger wagging bitterness of the criticism is really something.]

    America is indisputably the most benign nation ever to wield such phenomenal power. People like Alexander are, of course, quite correct to point out the many flaws in US policy and behaviour and I defend their right to do so. But I feel they need to step back and see US actions in the context of the Machiavellian world we inhabit. Politics have always been dirty, nations will rise and fall, power will be abused and wars will be fought. The UN is probably a passing phase, like the League of Nations, because it's run by people and people never change. Power and money - that's all there is for a lot of people. The UN is only as just and moral as the humans who run it and we all know how quickly morality goes out the window when personal interests become involved!
    Hoping that the UN will always do the right thing, and marching and praying for peace, are all well and good. But in an imperfect world where genuinely evil people decline to play by the rules, we sometimes have to get down and dirty ourselves in order to avoid a descent into an even worse mess.

    Dicktice, I'm lost in admiration at your capacity for understatement:-

                                     
    You said it!!
    But, all joking aside, I do agree with your comments.

    Thank God for America!   

I agree with Clark. Cindy's arguments are well put and well taken.
    I suppose, then, we're just stuck with this horrible drug mess - the gangs, the violence, the theft, the impure drugs, the overdoses and poisonings, the wrecked lives etc. etc.

    Sometimes I just don't know which is worse, the horror story I've outlined above or the one Cindy tells us.
                                         

    How about we simply execute every pusher we pick up (plus the cartel big boys) until either the rest of them get the message or until they're all dead!!
                                       :angry:

I think I understand your point of view and consternation at people seeming to play God. But I think it's all a matter of degree in this case rather than anything absolute and fundamental.
    Earth's Moon is a monster! As you know, it's way bigger by comparison with its primary than any other moon in the solar system. In addition, it has played a pivotal role in the development of life here on Earth. It still largely controls our ocean tides, lights our dark nights, beautifies our skies, and provides a romantic backdrop for courting couples! We need and love our Moon!

    The moons of Mars are comparative tiddlers - small bits of cosmic detritus which happen to have found themselves orbiting a planet in a region of the solar system far from their point of origin. They raise no tides - even if there were seas again on Mars, they still wouldn't raise tides! They may help to make the skies marginally more interesting but they provide little light and are too small to have played a part in the development of any Martian life-forms. From large areas of the Martian surface, you can't even see Phobos!
    If you are prepared to fundamentally alter the environment of a whole planet (terraforming Mars), can moving a couple of stray asteroids from one orbit to another really be such a moral watershed? I'm not trying to be facetious or scathing in any way, I assure you, and I'm perfectly willing to listen to arguments contrary to this line of thinking. (Remember I've been married 23 years ... I'm more than used to the airing of arguments contrary to my own!!! )

    Some people here at New Mars have advocated mining Phobos and Deimos for volatiles - using them as 'gas stations' for our inner solar system transportation needs. Some have suggested hollowing them out for space stations and living inside them!
    Up until now, nobody has expressed any regret at the thought of exploiting them mercilessly. Given their insignificance and apparent interloper status, it's actually quite surprising to hear a voice raised in their defence!

    I, personally, don't have a problem with utilising or shifting the Martian moons to achieve our ends but I'm sure there will be others not so cold-blooded about it. I guess I'm addressing one of them right now?!!
                                     

At least the main thrust of my argument, that any collision between Mars and Phobos is too far in the future to worry about, still holds water.
    A substantially bulkier Martian atmosphere resulting from terraforming activity will, millibar for millibar, be a 'tall' atmosphere in comparison to Earth's because of Mars' weaker gravity. It will still increase atmospheric drag at Phobos's altitude and hasten the satellite's fall - though maybe to a lesser extent than I had in mind originally.
    In any event, it seems likely that the human species will be gone (one way or another) before Phobos meets its fate!

    And if humanity manages to survive in some form we would still recognise as human (and still lives here in this solar system on planetary surfaces) I feel confident our technology would be more than sufficient by then to counteract such natural disasters with ease.
                                       

Thanks for the very kind words, Cindy!
    However, in this case I certainly don't deserve them. For the second time this week (and it's only Tuesday! ), I have to partially retract a post.

    My comments about the effect of tidal forces on Phobos are incorrect. There is a degree of air resistance at Phobos's altitude, and Phobos is indeed a 'lightweight body' - but the air resistance is too weak and Phobos too heavy for these factors to be the most significant in the 'spiralling-in' process.

    The tidal forces thing had been going round and round (very appropriately! ) in my head since I read your link. Something was telling me I'd made a mistake and spoken too soon. Then I re-read some old material and light dawned!! I'd been considering the effect of Mars on Phobos but not the effect of Phobos on Mars!   
    A satellite raises tides on its parent body, obviously - Earth's oceans being the prime example. But even a small body like Phobos raises tiny tides in the actual crust of Mars. The thing about Phobos is that it is below the areosynchronous orbit and is therefore orbiting faster than Mars rotates. The tiny bulge in the Martian crust lags slightly behind Phobos as it speeds around the planet. Therefore, there's very slightly more mass just behind Phobos than in front of it. Also, of course, there is some dissipation of energy involved in the flexing and relaxing of the Martian crust itself. Hence, Phobos is losing angular momentum and spiralling in.
    The opposit occurs with Deimos which is above the areosynchronous orbit. The surface of Mars, as it rotates, is moving faster than Deimos orbits and the minute tide it raises in the crust actually moves slightly ahead of the satellite in this case. This tends to accelerate Deimos and propel it into a higher orbit with greater angular momentum. But Deimos is smaller than Phobos, further away from Mars, and very close to the areosynchronous orbit - all of which tend to minimise energy transfer. So Deimos's orbit is, comparatively, very much more stable than Phobos's.

    There! I feel so much better now ... as though I've confessed my sins or righted a wrong!   

    Our much-loved highschool geography teacher had a favourite directive to the class: "Always ensure the brain is in gear before operating the mouth." My original comments about tidal effects on Phobos's orbit were an example of what can happen when you fail to heed the advice of your elders!!
                                       

    My apologies. ~Hangs head in shame~

Hi Soph!
    I have tried to track down the information you need about Phobos and Deimos, without success.
    They both have stunningly circular orbits - Phobos has an eccentricity of 0.01% and Deimos zero% !  And they have only tiny orbital inclinations - Phobos 1 degree, and Deimos 0.9-2.7 degrees.
    But whether or not the point where they cross the equator is constant (which seems unlikely to me) or gradually migrating around Mars' circumference, is not clear from the information I've been able to locate so far.

    The fact that people like Clarke and Robinson have seen fit to devise complex oscillations of their fictional elevators, indicates to me that migration of the equatorial crossing points is most likely. Otherwise, we could simply erect our 'beanstalk' at an equatorial position which would forever be out of harm's way.
    And life, unfortunately, is rarely that simple!!
                                         

Cindy writes:-

    Yep!! I think that in the Magnificently Muddled Moon Madness Contest of the Century, your tale is almost certainly in the lead!!
                                :laugh:

    But, who knows, somebody here may have a real rip-snorter of a yarn about Triton which will just have to take out the grand prize ... an all expenses paid one-way trip to a large building in its own grounds in the countryside, escorted by amiable and powerfully built men in white coats. But wait, there's more! Our sponsors have agreed to throw in a magnificent, exclusive, Gucci wardrobe of clothing, all with the unique fasten-at-the-rear feature so popular in 'homes' across the nation!
    Stay tuned!
                                     

Wccmarsface raised a point I've often thought about: If every human died today (heaven forbid), and a new species of intelligent beings appeared in, say, 500,000 years (maybe descended from bonobo chimps or something), would they find irrefutable proof that we existed?
    Half a million years is too short a time for geological processes to remake the surface, so I suppose many of our major earthworks would still be apparent - especially from the air. Let's assume the new intelligence hasn't achieved space travel yet, so they haven't found the Apollo landing sites on the Moon.

    Just how long would it take before all identifiably artificial traces of our existence are erased from the Earth?

    Answering this question would probably place significant constraints on TEM's proposed lost Martian civilisation because there seems to be no irrefutable evidence of artificiality on Mars' surface. Even if the Face is supposed to be artificial, where are the other buildings, the roads, earthworks (sorry ... marsworks! ). If they are all so worn away as to be incapable of definite identification, how old would these hypothesised features have to be?

    I've got a feeling that, even on Earth where erosion and tectonic activity is vigorous, you would still be able to see plainly the evidence of our civilisation a million years from now.
    Any thoughts?
                                       ???

Welcome to New Mars, Zhou Jie!
    It was nice of you to drop in and say hello. We hope you will stay with us and join in our discussions.