New Mars Forums

Thanks, Stu, for that Aug. 18th post linking to the 3-D image. I must have missed that somehow. The vertical relief is spectacular!
    And thanks, Cindy, for the image of the heavily eroded crater. It makes you think, doesn't it? It appears that powerful erosive forces must have been at work over long periods for such varied relief and geology to come about. The erosion of most of the 1000 m high wall of a crater 53 kilometres wide is enough in itself to indicate the power of the forces involved, but that could have been a sudden massive flood of water. How about the 15 km diameter raised circular structure, described as inverted relief? According to the geologists, this probably started life as a crater which gradually filled with 'sediment' (sediment implies material deposited in water, generally). How long might that have taken? Then the sediment became compacted and hardened. How long would that take? Then the walls of the crater gradually eroded down, lower than the remains of the hardened sediment. How long would that take? And, if you look at the structure as it is today, you can see that even this hardened 'core' of sedimentary material has begun to erode away quite extensively.
    To me, all this doesn't sit well with the idea that Mars had about a billion years of 'weather' and then things became much like the Moon during the last 3.5 billion years, with little or no change. Something's definitely not right here.
                                          ???

Despite the obvious contamination of the samples brought back by Genesis, I think there may be hope for at least some of the science to be salvaged.
    We have a very good understanding of the kinds of isotope ratios of nitrogen and oxygen etc. that we find on Earth. If some of the probe's sample plates, or fragments thereof, have pristine examples of quite different isotope ratios, then I believe such examples can be confidently assumed to be the 'Real Solar McCoy'.
    In this way, and perhaps in others, it seems likely the scientific community can piece together information which will be scientifically acceptable. In other words, while the literal contamination of the samples must have a metaphorically contaminating effect on the absolute validity of the data, I think there is still hope for useful science to come from all this.
                                             

What a bitter old man is Jeff Bell!   
    He's saying, essentially, that Mars exploration is finished, other than with remote sensors on vehicles like the MERs, i.e. no crewed landings and no sample returns.
    But this gloomy summary is based on faulty logic and what appears to be a serious personality clash with Dr. Zubrin. He cites two different arguments put forward by Bob Zubrin, which are separate, and ridicules them because they're "blatantly self-contradictory"! The two arguments are meant to be seen as two different scenarios demonstrating the vanishingly small risk of damaging interaction between any martian life and that of Earth.
    If martian microbial life were to be entirely alien, based on a different set of amino acids, or no amino acids at all, then there is no chance of it 'infecting' our kind of life or devouring us - which amounts to the same thing. You may as well expect a computer virus to give you influenza! That's the first scenario. Period.
    Now, if there is impact transfer of intact biological material - and, despite Jeff Bell's protestations that "there is no hard evidence", it has been demonstrated that crustal material is exchanged regularly and that that material definitely need not be subjected to sterilising conditions in the process - then Earth and Mars have not been biologically isolated these past 4 billion years or more. In fact, martian bacterial spores have almost certainly been landing intact on Earth as often as every few months or less, and, to a lesser extent perhaps, vice versa. If so, and I believe the evidence in favour of this is overwhelmingly compelling, then terrestrial microbes and martian microbes (if any) will be close relatives. In fact, there's probably much more chance of terrestrial bacteria, isolated for millions of years deep underground and brought to the surface by oil drilling, causing a raging epidemic than there is of martian bacteria doing the same. That's the second scenario. Period.
    What Dr. Zubrin was trying to do was to establish that, either way, there is no significant danger. He knows the two hypothetical situations are "blatantly self-contradictory" ... they're meant to be!!

    Maybe I'm as mad as Dr Zubrin(! ) but, to me, the chances of life on Mars are better than good. The chances of it being the result of a separate genesis are approximately zero. The chances of it being sufficiently like terrestrial life, but sufficiently different to wreak havoc on terrestrial life is, again, about zero.
    As I have said before, I would go to Mars tomorrow morning and I would be no more afraid of catching a lethal martian bug than I am of catching a terminal disease here on Earth.
    Current plans for a manned trip to Mars entail a surface stay of some 500 days - an ample incubation period. If I'm wrong and the one-in-a-billion worst case scenario comes to pass, our astronauts will all die of 'martian measles' right there on Mars. No one will be bringing the infection home because no one will be coming home!

    Jeff Bell evidently has some kind of a chip on his shoulder and is allowing it to interfere with his rational thought processes.
                           

Just looking at Opportunity's position on my topographic globe of Mars, I'm struck by the elevation of the site in comparison to nearby regions.
    The landing site is now thought, at least by some, to be in the location of a large body of water - perhaps as large as Earth's Baltic Sea. But, looking at the local topography, it's clear there is no continuously higher land between this purported ancient sea-bed and the lower plains of Chryse Planitia and Acidalia Planitia. In other words, if there were once a sea at Opportunity's landing site, there's nothing that could have prevented the water from promptly draining into the depths of the much lower northern plains.
    Assuming no intervening massive remodelling of martian topography, the inescapable conclusion we must draw from this is that a sea at the Opportunity landing site can only have been a part of a very much greater ocean to the north. 
    If not, then we must assume that water on Mars flows uphill!!      

    This must have occurred to Brian Hynek at the University of Colorado, too, but he chose not to pursue the logic too far in the article I linked to above. Scientists sure are loath to speculate, aren't they? Even when it is plainly obvious that what they are presenting in a paper leads inexorably to a further conclusion.
    Is it proper scientific reserve or are they really scared of the establishment ridiculing and/or ostracising them?
                                        ???   

Such a pity.   
    The loss of all that scientific information, gathered so patiently and carefully ...  And you're right, Cindy, about how the cost of the mission will now become headline news - this kind of mishap only serves to fuel the Luddites' arguments against space exploration.

    I know this was a pet project of yours, Cindy, so please accept my sympathy. It's a dark day for all of us, of course.
                                          :bars:

Some researchers are saying the Opportunity landing site may have been at the bottom of a large sea. They believe the sediments in the area are probably about 1/3rd of a mile deep, ~0.5 km, and that this indicates a very large body of water may have persisted there for a long time.
    They're comparing the area of the water with that of Earth's Baltic Sea, and speculating it could have been much bigger!
    For the full story, http://www.colorado.edu/news/releases/2 … html]CLICK HERE.
                                          :up:   

I'm a long-time supporter of the wars in Afghanistan and Iraq and I neither resile from that nor apologise for it. I accept CC's evaluation of the situation that it has created a 'beach-head', of sorts, in the Middle East.
    Deposing arab despots, in my view, is not something separate from the war on terror. The islamic leaders in these countries, despite their religious facades, aren't there because they were democratically elected; they seized power. The Middle East is essentially devoid of democracies.
    Up until recently, it has been convenient for the West to ignore the 'running sore' of despotic theocracies in these disgraceful places, where dogs are treated better than women. "It's their country", after all; let 'em get on with it.
    But, in recent years, the radical wings of these theocracies have been making a nuisance of themselves. For example, they've destroyed a sizeable sector of downtown Manhattan, killing some three thousand people of various nationalities, mainly American, made a pretty good attempt at genocide in East Timor (Australia had to step in to save the East Timorese), killed about 200 people in Bali (many of them young Australians), and, as we speak, are engaged in their own barbaric version of 'ethnic cleansing' in Sudan. Oh yes, and I shouldn't forget the hundreds of men, women, and innocent children butchered in Beslan only the other day.
    Activities like these require a great deal of backup in the form of logistical and financial support. Middle Eastern theocracies are the covert backers for this monstrous ideological cancer or, at the very least, create the breeding grounds and home bases for its continued existence. It makes sense to carry the war to the heartland of the enemy, rather than sit around waiting for the next atrocity on your own soil.

    Afghanistan was an obvious target because of its terrorist training grounds. Iraq, weakened by the first Gulf War and years of sanctions, was the next most attractive target in this politico-military strategy.
    But what now?
    It seems likely that Iran will have nuclear weapons in the near future, perhaps as soon as the end of 2005, in spite of its denials. And it has the technology to launch those weapons on missiles. Unless something is done to stop it happening, we will have our first nuclear-armed, Middle Eastern, islamofascist state before you can say "death to the infidels".
    Both Iran and Syria have been implicated in terrorism for many years and have provided a base for destabilising influences in Iraq these last twelve months too. It's hard to believe the free world will sit idly by and watch as the likes of them arm themselves with atomic missiles.

    I'm wondering whether the hot topic for discussion in the Pentagon right now might not be the latest situation in Iraq at all, but a brand new war in Iran and Syria.
    What an impact such a daring pre-emptive strike would have on the psyches of islamic despots everywhere. None of them would ever feel safe in their beds again!
                                               ???

No, Stephen, I think it's just a circular impression in the soil.
                           

Hi Chat!
    It looks like you and I are using the same criteria to justify two opposing standpoints!
    You're saying there's too much variability in the possible physical parameters for life on a SuperEarth (linear domensions 2x) to be likely, which is probably true, but I'm simply saying that the parameters could be just right and life could develop on such a planet.
    All I'm saying is there's no obvious show-stopper, in my view, which precludes all possibility of life.

    You say in your last post that a 2x Earth, with a 1 bar atmosphere, at 1 a.u. around a Sun-like star, will experience extra solar heat retention. I've been thinking about that but I can't see why it should be so. Can you enlighten me on this point?
    Another point I'd like to bring up, concerns the extra volcanism. This SuperEarth has 8x the volume but only 4x the area, so one might expect volcanism to be twice as common at the surface. Presumably, this means outgassing of about twice as much CO2 per unit area, which might be expected to increase the greenhouse effect, as compared to Earth. However, we've accepted the possibility, for argument's sake, that SuperEarth may well have 8x the volume of water but only 4x the surface area, compared to Earth. This, we decided, should lead to a greater percentage of SuperEarth being water covered - perhaps 90% or more. That volume of water, together with its greater surface area, should be very efficient at mopping up atmospheric CO2 and sequestering it away as carbonate rocks, which makes me think SuperEarth might tend to have a lower concentration of that gas in its air than we have here on Earth. While this dearth of CO2 would be offset to some extent by the generally higher humidity on SuperEarth (water vapour being an effective greenhouse gas in its own right), I can imagine our hypothetical planet, at 1 a.u., being somewhat cooler than Earth ... not warmer.
                                               

Thanks, Robert.
    The story sure sounds different when Seth Shostak tells it!
                                                 

[I think I preferred the other version.      ]

Hi Karov!
    Excuse me butting in here but I'm puzzled.
    Earth can't retain helium because its gravitational field is too weak and it's too close to the Sun (too warm).
    Venus has a weaker gravitational field than that of Earth and greater solar heating, which means helium escapes from it even faster than it does here.

    Assuming you can somehow introduce 30-40 bars of He into the venusian atmosphere, what's the point? It would immediately start to leak away, quite quickly, into outer space.
    Or do you propose to replace the losses as quickly as they occur? If so, you will have to be sure of your technology because any breakdown in the re-supply of helium would allow its partial pressure to start  falling towards the point at which the oceans of liquid CO2 become unstable and begin explosive vapourisation, flooding the lower atmosphere with lethal concentrations of the gas and killing all the colonists.
    This constant heavy reliance on technology to maintain a planet's habitability seems to me to be less than prudent. The situation on such a 'terraformed' world is inherently unstable and therefore unsafe.
    I wouldn't want to live there!
                                                 

Excellent article, Spacenut!   :up:

    Advances in production of usable CNT materials are coming thick and fast, which is what I expected based on various things I've read over the past few years.

    I understand your reservations about the space elevator cable degrading in use, SBird, but I believe human ingenuity will find a way around that. You, yourself, have come up with an idea to circumvent wear-and-tear of the cable in your own post, though it seems like a fairly drastic solution.
    In the absence of breakthrough propulsion techniques, we're left with the prospect of riding 'Roman Candles' into space indefinitely. The space elevator promises a whole new world of transportation to space and requires no new physics along the way - it's just engineering.
    If there's one thing we humans are good at, it's gradually improving our engineering. What was impossible 50 years ago is ho-hum-routine today and the lead-time for new developments is shortening at an accelerating pace.

    Arthur C. Clarke has famously pilloried the faint-hearted for being too pessimistic about the future. Most people, when asked to predict technological advances, have erred significantly on the conservative side.

    No. I think the space elevator's time has come and I predict it will be built sooner than you think ... unless the U.S. military finds the prospect of unrestricted access to space, for everyone, too unpalatable .. for national security reasons .. !