New Mars Forums

Mark:-

    How about that neat transparent aluminium (aluminum, for our U.S. cousins) that they have in Star Trek?!!
                                       

Sounds promising!   
    It certainly would be fascinating to find a planetary system like our own around a star so similar to Sol. But I guess at our stage of technology, it's going to be difficult to detect an Earth-sized planet at that range ... at least until better instruments are launched into orbit.

    I read somewhere the other day that computer simulations are showing interesting limits on the size a rocky planet may attain. Preliminary studies show that a planet not much bigger than Earth is unstable during formation but the details of how it becomes unstable weren't made clear in the very brief article.
    I suppose it's possible that rocky planets don't normally get much bigger than Venus and that maybe Earth is that little bit bigger again because of the impactor which produced the Moon(?).
    I often think about the unlikely sequence of events which gave rise to this beautiful, stable, life-nurturing world we live on, with its seas and tides and moderate temperatures, and wonder whether it's all too quirky to ever be reproduced somewhere else.
    I'd love 18 Scorpii to prove me completely wrong!!
                                           

Weeelll ... I suppose anything's possible if you really set your mind to it! But I think we have a much better chance with Mars than anywhere else.
    I still see the terraforming of Venus as being orders of magnitude more technologically challenging and, while the transforming of Mars might see real progress within as little as a century, I tend to think Venus won't be attempted until much later.
    I suppose I could be wrong.
                                           

Yeah, sorry Rex. I meant to respond to your comments on this but got 'swept away' by other things in all the excitement!
    I did notice what you're referring to but I'm putting it down to pixel problems, at least for the moment.

    I don't know if you've ever visited the Enterprise Mission site but those people have built virtually a whole career out of pixel mirages!  :laugh:  (Mind you, I still scratch my beard over that hominid/leonine Face on the plains of Cydonia ... )
    Anyhow, I think we need to be circumspect about reading too much detail into relatively poor-resolution digitalised images. As a matter of fact, I had a few heated words with a guy called Tripp McCann over what I perceived to be absolutely incredible fantasies derived from over-enhanced digital pictures.
    But that's another story and I certainly don't mean to try to categorise you with either The Enterprise Mission or Tripp McCann.
                                           

    For all I know, that hazy line above the horizon may actually be the top of the martian troposphere, which is what I assume you're implying. But for now I'm thinking digital artifact.

How long can a methane/LOX rocket engine operate on one fuelling?
                             ???

I don't profess to know a great deal about spacesuits but the Mars-skin elastic pressure suit seems to have a lot going for it.
    Why is it that NASA seems to be 'stuck' on the same bulky, heavy unwieldy type of suit it's been using for 30-odd years? Whenever you check out a NASA site looking for advanced Mars EVA suit design, you get the same old 'crab-shell' hard suit with pressurised limbs and rotating metal joints and weighing over 300 lbs here on Earth (maybe 120 lbs on Mars)!
    What's their problem? Why aren't they investigating the mechanical pressure type of suit (elastic)?
                                          ???

Words fail me.
    What a great feeling. If I feel like this for a rover, how will I feel when the first astronaut arrives?!!
                                       

A very interesting site, Stu.
    What caught my eye was the reference to the contentious issue of whether or not there exists a recognisable coastline where the northern plains meet the cratered highlands.
    According to the article you linked for us, the contiguous coverage of the surface by the new camera should be able to confirm or deny the existence of such a feature, which has up to now been hotly debated because the evidence is too inconclusive.

    It's a good thing to be reminded of the excellent science we can look forward to from the Mars Express orbiting craft, regardless of the fate of the Beagle 2 lander. (Still got my fingers crossed for the latter, though! )
                                           

Hi Mark!
    The gravity on Mercury is practically identical to that on Mars; you wouldn't notice any difference. The atmospheric pressure is much lower than on Mars, though, and can be effectively discounted all together as far as human survival is concerned; it's essentially a hard vacuum.
    I'm not sure of the radiation environment. Mercury has a significant magnetic field, which is something of a mystery to scientists because of the planet's small size and what should consequently be an interior too cool for a liquid core. From memory I think Mercury's magnetic field is about 1% of Earth's but that's probably still enough to fend off most of the solar wind, even that close to the Sun. The lack of any atmospheric shielding, though, would leave the surface exposed to cosmic radiation.

    I find Mercury's magnetic field interesting because it ought not to be there according to current theories of planetary magnetism. As we've discussed in other threads here at New Mars, Dr. J. Marvin Herndon has come up with a hypothesis involving large, natural, uranium fission reactors in the centres of rocky planets. He thinks such reactors can explain the internal heat (volcanism) and magnetism of planetary interiors but his ideas have yet to gain general acceptance.
    The old established theory is that a planet's internal heat is a combination of remnant heat from the body's accretion and meteoritic bombardment billions of years ago, together with the nuclear decay of a scattering of radioactive elements and their various isotopes throughout the mass of the planet. The magnetism is believed to arise from the combination of liquid metal in the core and its movement associated with the planet's rotation.
    Mars is thought to be too small to have retained much internal heat over the 4.6 billion years of its existence and this seems to fit well with the observed lack of a global magnetic field. Yet there is good evidence that significant volcanism has continued throughout Mars' history and well into very recent times. If there's a liquid core and a 24 hour rotation period, where's the magnetic field? Mercury should also have little remaining internal heat due to its small size, and its rate of rotation is very much slower than that of Mars. Therefore it has theoretically even less likelihood of maintaining a global magnetic field than Mars, at least according to current wisdom. Yet it has quite a strong one!

    It's always interesting when old established ideas about things no longer fully explain the facts. I sense that Mars and Mercury are going to force a re-think of what makes planets tick and I'm very much looking forward to the results of that.
    Maybe Dr. Herndon is onto something!
                                             

    Incidentally, I've only just realised something about the Bepi Columbo mission to Mercury, due for launch in 2011. Apparently it's supposed to include a lander (presumably solar-powered?) which will follow the terminator around the planet, just like that fictional settlement we've mentioned but without the rails!
    It will advance at 3.6 km/h for a total of 4224 hours, completing one full circumnavigation of the planet.
    How incredible!!
    But what happens if it comes to a sheer-sided rift barring its forward progress and it has to detour sideways for a hundred kilometres or more?
                                                ???

Oops!
    I have read the KSR trilogy and so I should remember that opening section of Green Mars ... but I don't!
    But still, as and when I read 'em again I'll have a better understanding of what I'm reading when I get to that part.
    Thanks guys!
    Your old friend and Alzheimer's victim, Shaun!
                                                               

Jadeheart:-

    Ha-ha!!   :laugh:
    Very nicely put, Jadeheart!

    And you may well be right that President Bush isn't sold on one plan or the other just yet. If everything depends on the success of the Mars Express satellite and the two MERs, I suppose we'd all better start praying for some spectacular results in the coming weeks and months!
                                             

Don't ask me how Dr. Kargel came to that conclusion about the Americas crashing into Euro-Africa; I've taken the details from the article as written. Perhaps he means the Pacific plate will continue to subduct under South America as the Americas head westward. I seem to remember reading somewhere that the Pacific Ocean will eventually shrink and vanish as the Atlantic expands, and 200 million years should be enough to accomplish this.

    The answers to your other questions lie in the fact that the Sun is gradually increasing its output of energy. Eventually, the natural thermostat (negative feedback loop) which keeps temperatures within a certain range will be overwhelmed. When all the CO2 is eliminated from the atmosphere and the temperature continues to rise, then the plants will die.
    As the temperature continues to climb, the oceans will boil off and then the very rocks of the crust itself will soften and liquify, forming a magma ocean.
    This will all happen before the Sun expands in its death throes to become a red giant.

    What's so sobering about this sequence of events is the fact that the demise of terrestrial life is so close at hand, in terms of geological time spans. It appears Earth is approaching old age as far as being a life-supporting planet is concerned; it's supported life for some 3.5 billion years but has only(! ) about a billion years left.