back to article Mars projected to collide with Earth

Forget sending astronauts to Mars, the planet may come crashing right here to Earth if gravitational interactions substantially agitate its now-stable orbit. A new study in the June 11 issue of Nature predicts there's a real, albeit slim possibility of a planetary smash-up inside the inner solar system, largely thanks to …


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  1. Johnny Canuck

    Oh No!

    OMG what will we do - oh wait a minute, I thought you said a MILLION years.

  2. Anonymous Coward


    Jacques Laskar and Mickael Gastineau need to get their heads examined. We know the orbital parameters of the planets to perhaps four decimal place accuracy. Numerical integration methods, regardless of which one you choose -- 4th order Runge-Kutta, Predictor-Corrector, etc. -- all have inherent cumulative round-off error. By the time their computer programs have calculated a few hundred orbits, the results are getting so far away from reality that they're useless. Now, you want us to believe that they can predict a collision 1.76 billion years in the future? Hahahahahahahahaaaaaa! Hahahahahaha!

  3. John Tserkezis

    I'm prepared.


    And people laugh at me for packing too early.

    My plan is to be dead before it gets here, so at least for me, it won't be a problem.

  4. unitron

    Waiting for the next edition

    "...(with the edition of Pluto and Earth's moon)..."

    No thanks, I'll wait for the edition that says "...(with the addition of Pluto and Earth's moon)..."

    " Earth's about half way to retirement..."

    So does that make this Middle Earth?

    Mine's the one with a copy of "The Hobbit" annotated by Strunk and White in the pocket.

  5. Andrew Tyler 1

    Let me be the first to say...


  6. Herby

    Danger (Will Robinson)

    We all know the collision will happen before any effects of Al Gore's global warming, so we ought to prepare for the worst spending a couple of Exadollars on the problem. a couple of rockets timed properly ought to do it.

  7. Winkypop Silver badge

    Time repeats

    Mars, the bringer of war!

    Can you get Planet Insurance I wonder?

  8. Alphabet Soup 1

    If Cole Porter's right ...

    ... it'll happen next July.

    What a swell party this is!

    (OK, leaving now, I'm on my way to the cloakroom)

  9. Scott 26

    so what....

    ... 400 years or so will see us being irradiated by Betelguise going supernova ;)

  10. ThePerson

    2501 Scenarios?

    Good to see the puppet master is keeping busy.

  11. Dave Ball


    Mars? Mercury? "largely thanks to the Mercury's distinctly lopsided orbit"?

    Not sure about 'edition' for that matter.. post-pub article?

    I suppose the Hitchhikers Guide planetary billiards reference is obligatory .. mine's the one in the rather nifty superintelligent shade of blue..

  12. Anonymous Coward
    Anonymous Coward

    Mid Life?

    Sooo. . . given that the earth is roughly middle aged now . . . does global warming mean "Mother Earth" is going through menopause?


  13. TeeCee Gold badge

    Earth, Mars, Mercury *and* Venus?

    I dunno, you wait 5 billion years for a planet to collide with something and then four come along at once.

    Forget God. This solar system was obviously created by London Transport.

  14. Anonymous Coward
    Anonymous Coward

    Before or after...

    ... Earth is swallowed by the sun's expansion?

  15. Anonymous Coward

    @AC Pffft!: Not just a numerical stability problem

    More fundamentally, a lot of work is done using a Taylor expansion which is not known to converge, so , what the heck, just truncate it after N terms and intergrate. Of course it is safe to assume that a .38 mm nudge is significant, but all terms after t^20 are not.


  16. The Fuzzy Wotnot

    Not really a problem though...

    Isn't the universe supposed to be chewed up by dark matter in about 30bn years anyway? Something like I heard once!

  17. Anonymous Coward

    So Velikovsky was right after all

    Mine's the one with a copy of Worlds In Collision in the pocket.

  18. Rod MacLean

    I've checked my calendar

    ...and it looks like I'll be busy sleeping underground in a wooden box when all this happens.

    Can one of you wake me up in time to see the fireworks?

    Seriously though, how can Mercury's gravitational tug pull Mars towards the Earth? This seems like abject fantasy and needs more explaination. Mercury is tiny (in cosmic terms all the planets are tiny) surely the gravity of the sun will hold it more or less in place...?

  19. Leslie Greenhalgh

    Take the Space 1999 approach

    Suggest we pile radioactive barrels into an unpopulated area of the earth, then exploded them just before Mars impacts, thus propelling the earth out of harms way. Either that or me get Bruce Willis out of Cryogenic suspension.

  20. Ken Hagan Gold badge

    Re: Pffft

    Solar system stability is a problem that has been seriously addressed for at least a hundred years. (I think both Lagrange and Poincaré had a go, and they certainly weren't idiots.)

    I would expect that the equations being driven forward are not the equations of motion for big lumps of rock, which would indeed require Quite Stonking (tm) levels of precision in the original data and a Pretty Impressive (tm) bignums numerical integration package. A much better idea would be to start with the equations for the time-evolution of the orbital elements. These equations are, to a first approximation, d{elements}/dt=0, which even I can solve. To a second-or-subsequent approximation they are something else and I'm way out of my depth, but at least I know that you don't tackle this by sticking the physics onto a gaming GPU and cranking the handle.

  21. James 5

    Just wait till Good Old Labour ...

    .. hears about this! If you thought anti-terrorist laws and activities were bad just wait till they put together their anti-planetary collision task forces.

    Pity the poor companies with the name Mercury in them - "Mercury implicated in massive planetary collision plot"....

    At least it'll divert attention from old Gordie for a few minutes....

  22. Luis Ogando

    May I Be The First... welcome our apocolypse-bringing Red Planet overlord...

  23. Avalanche

    Reminds me

    Reminds me of an orbital mechanics simulation I programmed in Pascal (in high school btw). The most fun was to put in the right numbers to have all planets slingshotted out of the the solar system.

    Of course most of those effects were (partly) from my limited understanding of orbital mechanics, and due to rounding issues inherent to floating point numbers, but nevertheless I can see why astronomers would enjoy simulating this :)

  24. jeffrey 1


    Will it be like third rock form the sun's scene dividers?

  25. Gav

    Bringing great minds to bear on the problem

    Can we have less of this defeatist talk please. Following the lead of the late, great leader Dubya we have a clear solution; bomb Mercury.

    This should be followed by ten years of incarcerate for Mars, on a charge of guilt by association and a manhunt for the evil mastermind behind it all; Newton. His theories are the root cause of all this agitation.

  26. Tony S

    Hooray for Hollywood

    No doubt we will see a film about this - the deadly Red Planet aiming to destroy the American Way of life as we know it; then saved at the last minute by Bruce Willis setting off loads of precisely positioned and timed "nucular" explosions usng a TV remote because the timing mechanism was damaged.

    I think I'll wait for it to come out on DVD.

    BTW, I'm thinking of using the new system to change my handle to "Cynical Old B****r"

  27. Bumhug

    Who cares?

    By that time we will have trashed the earth, moved onto Mars, trashed that and be living in some far distant galaxy

  28. Alpha Tony

    What's the betting

    ..That Darpa are already working on a plan to blow up mars?

  29. Anonymous Coward
    Anonymous Coward

    What's a billion?

    Is it the American billion (1,000,000,000), or the good old English billion (1,000,000,000,000)? I've always be confused by this when people talk about billions. What's the standard these days?

    I must know because how embarassed would I be if I got my dates wrong for the end of the world?

  30. Anonymous Coward

    This just proves...

    that some scientists have far to much time on their hands..

    *\. Warning you may get information that no one will ever be able to verify.

  31. Anonymous Coward


    Why wasn't I told sooner? If I'd of know I would be dead in 3.5Billion years I'd have started making plans...But there's no time now...were all doomed...DOOMED...Possibly....but probably not...

  32. Matthew 17

    The collision will happen too late

    If Mars did hit the Earth, it would be a billion or so years after all life had left that planet due to the Sun nearing the end of its' life and the radiation levels coming from it would have long since baked everything here.

    Therefore if we'd not already left the Solar System by that point we'd have colonised the now defrosted Mars & the moons of Jupiter.

    We'd have to deliberately destroy the Earth to clear a path for our new home.

  33. Anonymous Coward
    Anonymous Coward

    I've got an idea.

    All the governments of the world put £5 into a kitty each year.

    The save the world fund.

    In a billion years we can just buy whatever's needed to deflect mars.

  34. John H Woods Silver badge

    Re What's a billion

    It's usually safest to assume the short scale billion (10^9) applies. The long scale is unfortunately less popular, even though it made (imho) more sense. Maybe we should talk about Gigayears?

  35. Anonymous John

    Plenty of time.

    Give us a few hundred years and we ought to be able to move planets about. Sorting out Mercury's orbit sound like a good place to start.

    If we can't, we don't deserve to survive.

  36. John70

    @AC: I've got an idea.

    "All the governments of the world put £5 into a kitty each year.

    The save the world fund.

    In a billion years we can just buy whatever's needed to deflect "

    Won't that be just enough money to get us out of the global recession?

  37. David Pollard


    Albeit that further research will be required, initial calculations suggest that a sufficiently large and appropriate change can be made to the Earth's orbit to prevent this calamity; and that this can be achieved both safely and effectively. Magnetohydrodynamic coupling between the Earth's magnetic field and that of the Sun and the solar wind is sufficient to provide appropriate thrust. The necessary orbital adjustments can be arranged conveniently and economically by reversing the orientation of a modest array of gyroscopes on an equinoxial basis. The disc storage array proposed for the UK's national data interception facility would be almost sufficient with only minimal modification. To assure the anciliary protection against collision with Mars only a small increase in cost and functional capacity is required. By providing this dual-purpose functionality the cost-benefit from the surveillance facility will be greatly increased.

    Icon in case any politicians chance to read this.

  38. Neil 40
    Dead Vulture

    This is the least of our problems

    Hmmmm, this is all very irrelevant, I've just prodded a few numbers into my old Casio and I can tell you all now that the Earths population by the year 36000000009 will be...... no wait..... what does 6.56+E79 mean?. I guess we'll be standing on each others shoulders 100 levels deep by then.... can you imagine the queues to the toilets, Takeaway, Bar, NCP carparks etc etc

  39. Anonymous Coward
    Anonymous Coward

    @ Rod MacLean

    'Seriously though, how can Mercury's gravitational tug pull Mars towards the Earth? This seems like abject fantasy and needs more explaination. Mercury is tiny (in cosmic terms all the planets are tiny) surely the gravity of the sun will hold it more or less in place...?'

    It's all down to orbital resonances - how many times Mercury goes round the Sun compared to other planets. Mercury sits in a very - okay - relatively elliptical orbit, the perihelion (closest approach to the Sun) itself progresses around the Sun. Jupiter has a less elongated orbit, but that too has a progressing perihelion. Left long enough, these perihelions begin to align; Mercury *could* find itself receiving an extra tug from Jupiter at the same point in its orbit, which gradually evolves the orbit into an extreme ellipse taking it out into the region of Venus.

    If Mercury's orbit is that disrupted, it begins to create new resonances with Mars' orbit; one scenario being that Mars itself goes into a more elliptical orbit whose perihelion is in the vicinity of Earth.

    But as the second poster pointed out, it's hard to see how these calculations can be at all accurate given our limited knowledge of the planets' orbits over the long term.

  40. Rob


    Now here's a prime reason to keep the Red Dwarf series alive, when it does happen we can unfreeze Dave Lister seeing as he's the 'Prince of the Planet Potters'.

  41. Peyton

    Preemptive strike?

    "In three others, Mercury falls into the Sun."

    So what I take away from this is, if we all get out and push we can lob it into the Sun now and stop worrying about it?

  42. Richard 102

    @AC: Pfft!

    "Now, you want us to believe that they can predict a collision 1.76 billion years in the future? Hahahahahahahahaaaaaa! Hahahahahaha!"

    Why not, they've convinced most people that they can predict the weather accurately 100 years in the future ...

    (Where's the icon for the evil audio-animatronic Al Gore? Probably got too big to fit into the standard image size.)

  43. Gregory O.

    No problem

    I think Mercury already has insurance:

  44. Anonymous Coward
    Anonymous Coward

    This is news?

    From Ian Stewart's "Does God Play Dice" (ISBN 0631232516, 9780631232513)

    In 1887 King Oscar II of Sweden offered a prize of 2,500 crowns for an

    answer to a fundamental question in astronomy.

    Is the Solar System Stable?"

    Poincare's answer was along the lines of, "We can't know".

  45. Michael 82
    Thumb Down

    Here comes Hollywood!

    Ah wait no! "When Worlds Collide" comes to mind.. Ah but wait Hollywood are remaking alot of classics badly... Bugger... there goes another one!

  46. Stevie


    It doesn't matter. We're clever, good at engineering and will simply fix things or move somewhere nicer when Mr Sun has a stretch.

    Thank Azathoth that our scientific community has been tirelessly working toward the goal of a permanent and tenable manned (and womanned) presence in space instead of wasting everyone's time babling about minutiae like Pluto not being a planet or Lake Huron not being a lake, really.


  47. Luther Blissett

    Who threw it then?

    "Venus and Mars are all right tonight."

    "For a while... for a while... for a while... for a while..."

    Rock on. Big rock on. This is Radio Luther broadcasting for ya on SM. All the way. (Where else?). Reflecting your epoc - where simulation is dissimulation. And dissembling creates semblance. And while you cool folks is working out just where you heard those lines first, here's another old but goodie from Radio Luther.

    The Cramps, with Rock on the Moon. Rockabilly gone psycho.

    Ya think that's crazy? Is there a rock on the Moon? Do bears go boo in the woods? Check (don't touch!) that dial. SM see? Semantic modulation - the mod mod mod modulation for a hyperreal world.

  48. Ben 31

    Aaaah, sweet chaos

    Stick a few seemingly simple equations together, watch them run round and round, and realise that you don't have a clue which bits you left out - or, more worryingly, got right.

  49. Don Mitchell

    Laskar's Work

    Questions about dynamics and stability of the solar system are classic. The kind of math needed to answer these qualitative behavior questions has only really existed for the last 50 or 60 years. It's not a simple matter of integrating the equations of motion, you can't simulate a billion years that way.

    Laskar is very respected in his field. A few years ago, he did a calculation about the effects of planetary resonance on the rotation of Venus. He and his coauthor showed that there were two stable rotation rates the planet could fall into, each equally likely, and one of them is almost exactly the current value for Venus. Very nice work.

  50. Dave Morris

    All's good then

    No need for the mission to mars then... it is coming here. Now we can spend that money on something cool.. like a mission to Io or Titan, or nuclear powered main battle hover tanks for our extra-planetary wars....

  51. Anonymous Coward
    Anonymous Coward

    @ John Tserkezis

    Foolish words, man. Have a read through Einstein's Monsters by Martin Amis. There's a bloke in there who didn't expect to be where he was at the appointed time.

  52. Richard Scratcher

    What's happened to this site?

    50 or so comments posted about planetary collisions and not one pun about Uranus.

    Come on!

  53. James O'Brien



    "We will fix things up"

    Bubba Get the duct tape and twine. Gonna need to put Earth back together seeing as Mars just hit us. And God darnnit slap some bondo on that there mountain."

    Ok thank you for bringing that image to mind.

  54. Anonymous Coward

    And I predict...

    That in a billion years time, Gordon Brown may not be our prime minister any longer.

    I think the Mars hitting Earth bet is a little more certain, though.

  55. Adam T
    Black Helicopters

    Nuke Mercury

    I'm sure the US military is already exploring scenarios.

    America always saves the world, it's their duty! :)

  56. Angus Cooke

    No need to worry...

    ... this intergalactic experiment with odd shaped balls and fiery gases we're all unwittingly a part of will come to an end long before any of the equipment breaks.

  57. Alistair 2

    God builds a good Earth

    Quote "Earth's about half way to retirement with only a few dents on her"

    A bit like my car (feels smug)

  58. Anonymous Coward

    "Earth's halfway to retirement"

    Does it get a pension? Where do retired planets go, anyway? Is there a quiet little corner of the galaxy where retired planets sit about on park benches, watching the young starlets desporting themselves on the grass, reminiscing about the days when their climates, too, were hot, hot, hot?

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