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Friday, 31 May, 2002, 09:22 GMT 10:22 UK
Mission to Mars: Ask the expert

  Click here to watch the forum.  


UK scientists say they could win the race to find proof of life on Mars, if new signs of water turn out to be true.

A British-led effort will get the first chance next year to dig for evidence.

The Beagle 2 project plans to land a spacecraft on the surface of Mars, where it will be able to burrow under rocks looking for signs of past or present life.

Vast amounts of water-ice have been detected by the US Mars Odyssey probe, which went into orbit around the Red Planet last year.

The finding significantly boosts the chances that life may once have existed on the planet - and may cling on in places even today.

What does this mean for the chances of life on Mars? What are the chances of sending a manned mission to the Red Planet? What will Beagle tell us?


The BBC's Science correspondent Dr David Whitehouse answered your questions in a LIVE forum.


The topics discussed in this forum were:

  • Water
  • Life on Mars?
  • Manned expedition
  • Cost
  • Inhabiting Mars
  • Beagle 2
  • Contamination
  • Impact of findings



    Newshost:

    It's one of the most commonly asked questions in science - is there life on Mars? This week there has been a very important discovery made about that planet. Vast quantities of water-ice have been found there by the Nasa probe Mars Odyssey which went into orbit around the planet last year. Next year, or maybe a bit a longer, a British-led effort Beagle 2 is planning to land a space craft to find out and to look at some of these signs to see what's true and what's really going on, on the surface of the planet. Now we've received hundreds of e-mail questions from you and with me to help answer them is the BBC's science correspondent, Dr. David Whitehouse.

    Water

    Let's get straight on to some of the e-mails that we've got here. This one from Klatoo, Hong Kong How did such a massive quantity of water get underground in the first place?


    Dr David Whitehouse:

    What we've seen on Mars is that Mars obviously in the past was very wet and was very warm - there are signs all over the surface of running water. But Mars at the moment is dry therefore its obviously going through a hydrological cycle - a water cycle - and there must be times when there is water on the surface and there must be times when it gets cooler when the water disappears.

    What it was thought was happening is that the water from the oceans would have gone into the atmosphere and would have frozen out near the poles. It would have somehow got in between the spaces in between the rocks and the soil and when it reached cold surfaces would have frozen out and therefore that would have moved all the water from the atmosphere into little ice crystals nears the poles. That bears up with the calculations until you calculate just how much water-ice there is at these poles and there turns out to be far more than you can explain that way. So we don't really understand how there is so much water-ice locked up where it is but we do think that's the remains of Mars' oceans.


    Newshost:

    So Mars, you're saying, used to have oceans therefore it used to be a lot warmer. Briefly when roughly in space time are we talking about and what's the evidence that we've got for this?


    Dr David Whitehouse:

    When the first space craft arrived at Mars, in the late 1960s and early 1970s, they found on the surface evidence of flowing water. They found canyons, they found dried up river beds, they found evidence of lakes but the water was absent - the marks were still there but the water was gone. Therefore, there must have been at some time quite a way in the distance - billions of years ago - when Mars was wet and warm and had an atmosphere.

    It's always been a problem - where has the water gone? Did it escape from the planet completely or is it locked up somewhere on that planet? We now know it's still there. But how it gets there and how Mars goes through long-term cycles of millions of years because Mars' pole axis wobbles in space and therefore there are times when it is warmer than it is now and we thought that at those times perhaps the water could emerge and actually go back onto the surface and cut some channels - some very sharp channels we've seen recently.

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    Life on Mars?


    Newshost:

    Ray Copeland, San Jose, USA Is it possible that Mars formed life millions of years before it was formed on Earth and that what we are looking at now is an extinct planet?


    Dr David Whitehouse:

    That's a very good question. Certainly astronomers think that billions of years ago when the Earth and Mars were young, they were very similar. They could have had very similar conditions; a lot of water, warm, oceans, rain and temperatures fairly similar. So it would be a puzzle if life started on one planet and didn't start on the other. So certainly since then Mars has become dry and cold and the Earth has blossomed. So it may well be that life started on both worlds because if it started on the Earth then if Mars was similar, it may have started there as well and that life on Mars is hanging on and it hasn't been made extinct.

    But there's a complication there because if life started on Mars or on the Earth, there actually is an exchange of rocks between the two. As asteroids hit the Earth or Mars, they chuck rocks up into space and they land on the other planet. So it may well be if life started on one, it could have seeded the other - so it's a complicated story.

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    Manned expedition


    Newshost:

    Neil Swanton, London, UK A lot of fanciful talk has been about a manned expedition to Mars and colonising the planet. What are the stages and the timescale that could realise this dream?


    Dr David Whitehouse:

    Clearly discovering all this water-ice on Mars doesn't do any harm to those who want to put men on Mars. But Mars is not like going to the Moon - Mars is 1,500 times further away. The Moon is three days travel, Mars is 300 days. We do not have either the technology to go to Mars or the understanding of the planet when we get there.

    So you have to look towards the American Space Agency and say if they wanted to put men on Mars in 20 years time, how would they go about doing it and you have to say that in the next decade when they're trying to understand the planet to know the ground truth of Mars is the way you would have to do it. You have to do at least a decade of homework on the planet and at the same time develop the technology to man a mission to Mars. This is not a 10 year dash like the trip to the Moon. This is a lot further a lot more difficult and a lot more dangerous.

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    Cost


    Newshost:

    Alain Chartrand, Montreal, Canada Do you think it is worth to spend billions of dollars on missions to Mars when that money can be spent elsewhere? Will the scientific discoveries brought by manned mission prove to be a good investment?


    Dr David Whitehouse:

    There are several answers to this. The first answer is, where else do you spend the money? When you go into space - when you go to the Moon or go to Mars - you don't spend the money in space, you spend the money on the ground. You spend it in economies, families of employees spend it and you spend it in developing technologies. It was thought in the 1960s with the Moon programme that for every one dollar put into the Moon programme the American economy as a whole benefited to the tune of $6. So you could say this is a good thing to do economically because it creates jobs and wealth.

    Now whether or not it's a good thing to do in terms of, should we go there - is it desirable? I would say yes, because this is one of the great adventures of mankind and its one of the things that our generation will be known for. We have, in the next few decades, the ability to be the first on Mars and that only happens once.


    Newshost:

    It's the duty of exploration.


    Dr David Whitehouse:

    Well, yes if it's there it's part of our spirit. These things actually, although you can look at them and say they cost an awful lot of money, in context as to what everything else costs, they don't actually cost an awful lot of money. It's probably going to be cheaper to go to Mars than stage an Olympics.


    Newshost:

    What are we talking about - a few tens of billions of pounds?


    Dr David Whitehouse:

    It is difficult to say because technology changes so quickly and what is expensive now with the development of technology, electronics and computers, could be cheaper. But you're probably talking about at least $100 billion.

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    Inhabiting Mars


    Newshost:

    Russell, USA: We have been pumping greenhouse gasses into our planet's atmosphere, slowly heating it up for a while now. What are the possibilities of purposefully doing the same on Mars to heat it up enough to melt the ice?


    Dr David Whitehouse:

    If you find a way to warm Mars - either if it happened naturally or you could induce it - then clearly all that ice would melt and the water vapour and the water would move onto the surface and into the atmosphere and Mars would be a different world - Mars would be very much more like the Earth. Would you want to do that deliberately? Is it our planet to adjust and to play with? Would you want to change the conditions on Mars before we understand it? These are questions for debate.


    Newshost:

    What's the gravity on Mars like?


    Dr David Whitehouse:

    Well, it's in between the Moon and the Earth. The Earth has one gravity, the Moon has one-sixth and Mars has roughly one-third - 30 - 40% of the Earth's gravity. So you would feel invigorated because you could move a lot quicker.

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    Beagle 2


    Newshost:

    Richard Crawford, Stevenage, England Is it too late to change the destination of Beagle 2 so that it will land somewhere known too have ice below the surface?


    Dr David Whitehouse:

    Well, you can't do that - although you can change the landing site of Beagle 2 - it's actually landing near the equator and Beagle 2 the lander has got some severe constraints on the temperature and the pressure in which it can operate. So it has to land fairly low down on Mars in a dip near the equator because the pressure and temperature on Mars varies quite dramatically from the equator to the poles and it would not survive where the ice is, which is the near the poles. So if you want to put a lander down where the ice is - which is what America tried to do in 1999 with Mars Polar Lander and unfortunately that spacecraft crashed - you have to design it specifically to go to the poles. We could do it - we could do it again.


    Newshost:

    Is that being planned by anybody - a polar lander?


    Dr David Whitehouse:

    Not at the moment. The amazing thing is, the Mars Polar Lander, which should have landed in December 1999 would have found this ice, would have dug into the soil and looked at this ice and been three years ahead. It's a shame that mission failed and it may well be that at some stage, with this discovery now, they revamp that mission and fly it again.


    Newshost:

    Kieran Carson, UK What happened to Beagle 1?


    Dr David Whitehouse:

    The reason it's called Beagle 2 is because Beagle 1 was the ship that carried Charles Darwin around the world in the 19th century and made a great voyage of discovery and found the secrets of life.

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    Contamination


    Newshost:

    John Farquhar, UK Is it possible that Mars has already been contaminated with bacteria from Earth carried by previous probes to the planet?


    Dr David Whitehouse:

    I suppose that is possible.


    Newshost:

    But would they survive?


    Dr David Whitehouse:

    That's an interesting question - would they survive? There have been several landers on the planet - American and Russian - and you have to say that some of the Russian landers in the 1970s may not have been sterilised as effectively as we could do these days.


    Newshost:

    Do they sterilise landers?


    Dr David Whitehouse:

    Yes, they sterilise anything that lands on the Moon because of the contamination problems but this was not done as efficiently in those days as we would today. But remember that to get to Mars you would have to be in space for the best part of a year in the vacuum of space and that may be a sterilisation process. But it is not inconceivable that bacteria could have hitched a ride and survived on Mars. We have to be careful about these things.


    Newshost:

    Tony Martin, UK How do we know that a Nasa mission would not bring back a plague of some sort from the Red Planet?


    Dr David Whitehouse:

    Nasa has got an officer who's job it is to protect the Earth from contamination - not only from Mars - if you bring Moon rocks back or samples of a comet or an asteroid - you really can't take the chance. That's a good question - when you do bring back the first Mars samples in 10 years time, you've got to be very careful not only to protect the Earth from that but also to make sure you don't contaminate them because otherwise you invalidate the science and the observations if these are exposed to life on the Earth.

    Return to the top of the page


    Impact of findings


    Newshost:

    George, Fairfax, USA How would the discovery of microscopic life on the Red Planet impact the way we view ourselves and the theories we have about the evolution life?


    Dr David Whitehouse:

    That's a big question. If we find life on a second planet in our solar system, that would be amazing. Now there's a question of whether or not that life is independent - whether or not one planet seeded the other - and that would be difficult to sort out although you may have to look at the similarities between the two forms of life on Earth and Mars and see if they could be related in some way. But finding life, even primitive microscopic life on another world, would be an amazing discovery. We would know life then on two planets in this solar system. We've known for the last 10 years that there are planets everywhere in outer space, around other stars. So if there are planets out there and we find life on planets here then that would change our outlook as to how much life there is out there in space.


    Newshost:

    It seems to me that it's considerably less shocking than it would have been 50 years ago - that people are almost being, not deliberately softened up but I suppose as we move away from a more theologically based society to something arguably more scientifically based, that people would be less surprised - in fact some people are saying, I'd be surprised if there wasn't.


    Dr David Whitehouse:

    Yes, you're quite right. Some people are saying that there'd be something wrong if there wasn't life on Mars. But these things go in waves. The Victorians were quite happy to think of Mars as being inhabited by the people who made canals and by intelligent beings. They saw no problem with that and as we've found out more about the planet, we realise that that wasn't the case. So yes it's very interesting that some generations are very against life in space whereas other generations can take it as natural and why shouldn't it be. But this is the first generation when we can actually go and find out for sure.

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  • Mars Odyssey

    Future frontiers

    Past failures

    Talking Point

    Forum
     VOTE RESULTS
    Would you sign up for a Mars mission?

    Yes
     82.40% 

    No
     17.60% 

    14817 Votes Cast

    Results are indicative and may not reflect public opinion

    See also:

    27 May 02 | Science/Nature
    23 Jul 02 | Science/Nature
    27 May 02 | Science/Nature
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