Will Mercury Hit Earth Someday?

Messenger's Mercury
Mercury as seen by Messenger on January 14, 2008, from about 17,000 miles away. Might this inner-solar-system body someday destroy all life on Earth? Perhaps.
NASA / JHU-APL / Carnegie Inst. of Washington
First, the bad news: the inner solar system is unstable. Given enough time, Jupiter's gravity could yank Mercury out of its present orbit.

Two new computer simulations of long-term planetary motion — one by Jacques Laskar (Paris Observatory), the other by Konstantin Batygin and Gregory Laughlin (University of California, Santa Cruz) — have both reached the same disturbing conclusion.

Says Laughlin, "The solar system isn't as stable as we'd thought." Both teams have found that Jupiter's gravity can increase Mercury's orbital eccentricity over time. Mercury's path around the Sun is already nearly as elliptical as Pluto's. But Jupiter can make Mercury's orbit so out of round that it overlaps the path of Venus. A close encounter between them could send the innermost planet careening off wildly.

"Once Mercury crosses Venus's orbit," Laughlin says, "Mercury is in serious trouble."

So is Earth.

At that point, the simulations predict Mercury will suffer generally one of four fates: it crashes into the Sun, gets ejected from the solar system, it crashes into Venus, or — worst of all — crashes into Earth.

To call this catastrophic is a gross understatement. Such an impact would kill all life on our planet. Nothing would survive. By contrast, the asteroid that doomed the dinosaurs 65 million years ago was likely just 6 miles in diameter; Mercury is 3,032 miles across. The last time an object about that size hit the Earth, the resulting debris formed our Moon.

Think we'll escape the chaos by fleeing to Mars? Think again. Even Mars might not be safe. In one of the computer simulations, the Red Planet was tossed into the cold of interstellar space.

Now, the good news: there's only about a 1% chance that Mercury will go crazy before the Sun bloats into a red giant billions of years from now. "If you're an optimist," says Laughlin, "then you say the glass is 99 percent full."

Laskar, who discovered that Mercury could go wild back in 1994, will publish his paper in Icarus; Batygin (who's still an undergraduate) and Laughlin will publish theirs in The Astrophysical Journal.

Ken Croswell is the author of a new book about the solar system, Ten Worlds: Everything That Orbits the Sun (Boyds Mills Press, 2007).

24 thoughts on “Will Mercury Hit Earth Someday?

  1. Melanie

    Okay, that’s a scary thought, even if there is only a 1% chance.
    But if it did, how soon would it happen?


    There’s no exact way to know, since the long-term motion is chaotic — even small effects like modest impacts or (as Laughlin told me) launching a spacecraft can affect Earth’s motion enough to influence the ultimate outcome. But as this plot from Batygin and Laughlin’s paper shows, Mercury doesn’t “lose it” for the better part of a billion years. — Kelly Beatty

  2. Enrico the Great

    A one percent chance of getting hit by Mercury AFTER the Sun becomes a Red Giant, a time long before which the oceans of Earth will have boiled away (600 Million Years from know). Even if Earth and Mercury are not reduced to vapor or at least glowing cinders. While interesting as an exercise in celestial mechanics, this is NOT keeping me up at night. Can this be nore Impact Porn??? Where is Charles Lyell when you need him!Between Creationists on one side and neo-catastrophists on the other, where can one find the beauty and wonder of Science?

  3. Dieter Kreuer

    Yes, that’s what I also thought when I just read this in the science column of my favourite German on-line news magazine, Spiegel Online, which is usually quite accurate. IThey also had a video and created the impression, that this scenario could happen within 40 million years. I thought, this must be a hoax, so I double-checked here.

    In the associating Spiegel text article (http://www.spiegel.de/wissenschaft/weltall/0,1518,549271,00.html), it is stated that “scientists can only guarantee the stability of the planetary orbits for the next 40 million years” which is in sharp contrast to the plot kinldy provided by Kelly Beatty. I wonder where they (Spiegel Online) got the 40 million year figure from?

    Anyway, I’m not very much worried about this “threat”. Hardly any species on Earth has ever survived for longer than 10 million years. Concerning the global problems that we are facing nowadays, from nuclear armament in the middle to global warming, I doubt that this 10 million year figure applies to mankind at all. We have other things to worry about than “Worlds in Collision”.

    1. The Realist

      Humans were no where near alive on our planet at that time, you god botherers really need to realize that a “god” did not just create everything all at once. But gravity combined with chemical reactions between fundamental particles over quite a long period of time, are what created the universe we live in.

      We have scientific evidence, you have a story written by some bloke over 2000 years ago.

  4. Steve

    Well – not quite. We didn’t exist the last time it happened… The moon was created very very early in the Earth’s history, almost 4.5 Billion years ago according to Moon Rock dating.

  5. Joel-MarksJoel Marks

    Shades of Philip Wylie and Edwin Balmer ‘s When Worlds Collide, still a great read after all these years and now more scientifically sound than ever.

  6. M Carter

    Poor Sad Scientists!
    You put the figures in to the Computer, then get worried when it predicts disaster!
    Grow up!
    If you knew that much about Celestial mechanics you would give dates and times, I think NOT!
    Please keep your daydreams to yourself where they worry no one but your sad selves.
    This is Sudoscience.

  7. Tom

    Let’s have some fun with this… 800 million years from now (+/- 200 mil) the sun will brighten a teensy bit and boil away the oceans and all life on the earth. 2 billion years from now, we will begin tidal interaction with the Andromeda Galaxy. If we though Jupiter was messing with the Solar System, wait till this exciting event comes to pass.

    As George Carlin once said, “the weather radar is picking up a fleet of incoming ICBM’s so I wouldn’t sweat the thunderstorms.”

  8. Allan Holmgren

    If Mercury was lost to the Sun or if it collided with Venus does this effect the orbital paths of Earth or the other planets? If it does, we’re in for 100 million years of bombardment again.

  9. Michael C. Emmert

    I saw that happen plenty of times using a commercial program while I was simulating the situation at Neptune’s Lagrange points. I was in contact with the author of that program and he was quite frank about what happened.

    His program calculated the gravitational pull of all the bodies on the board, their motion, and where they would be (in this case) 65536 seconds later. Then it would recalculate the positisons of all the objects on the board. Neptune’s position had hardly changed at all, whereas racing Mercury was in a considerably different position. If I’d included the Moon, the situation would have been a lot worse.

    All computer programs will do this.

    I wonder if he programed in relativity? Probably. It would make his computer run longer.

    I’m more worried about the Sun burning out. But that’s really not a problem unless mankind loses interest in spaceflight.

  10. ivan SMITH

    I would have thought that, though we have developed after the agreed formation of the Moon four billion plus years ago, dating the resultant moon-rocks does not indicate exclusively whether we, as a lifeform, didn’t or couldn’t have formed due to that event.

    That we exist now at least proves it was always possible. And the age of the rocks itself does not indicate when it happened, just how old those samples are. They were “rocks” before being re-arranged by events that resulted in the formation of the Moon.


  11. John.St

    Whatever happens to Mercury I am going to stay indoor starting 300 million years from now and until we are absolutely sure that Sirius B does not turn into a supernova type Ia.

  12. Mike

    NEWS FLASH! Jimmy Snortsquiggle, a 5th grader from Pelvis Elementary School in Nubspaggle, Tennessee has found an error in recent orbital calculations of Mercury by Laskar and Laughlin. Jimmy says that Earth is in greater peril than previously estimated, and that Mercury has a 79% chance of colliding with Earth in the next two weeks. But that won’t matter because Jimmy’s calculations show that Venus will have collided with three geosynchronous satellites and our Moon by next weekend and destroyed all life on Earth, so that Mercury will only be impacting a lifeless, molten wasteland anyway. And only 5 months after that, Jimmy says that the Sun will begin orbiting with Alpha Centauri and start sucking more and more stars in and a new globular cluster will be formed.


    News of this eminent disaster is rapidly making headlines all over the world, featuring Jimmy’s crayon drawing of the disasters. NASA and university astrophysicists are just shaking their heads in shame at missing such an obvious thing.

    :o) Mike

  13. tony

    i think that would be a once in a life sight at least we scientist will be greatly honoured in after life for given a correct prediction.moreover, it better the world ends that way than in a big crunch.

  14. M Carter

    A great new opportunity for more really BAD American disaster movies, let’s run with this!
    An encounter with a stray Star from the (Future) merging of the Megallanic clouds, strips the Earth from the Suns orbit, and it’s in orbit around a Flare star that erupts every 100 years.
    OR the Sun gets captured by an Unseen Globular Cluster when it plunges through the Galactic subs & Earth has 10.000.000 Stars shining on it 24/7.
    What’s wrong with any of this nonsense?
    If you instruct a computer to simulate it, it will!

  15. Ben

    Ok i think this is one of those things, unlike global warming, that we can in all good conscience, ignore for future generations, if anything can be done about that it sure as hell isn’t now, and there are bigger problems..BTW- this is the kind of thing people read and get all worked up about because they don’t know all the facts, however the notion that Earth and the only life we know of, not that there isn’t other, is closer to the end then the beginning is quite depressing

  16. Ben

    I’d also like to point out that I believe in the human species and i think they can survive anything short of a black hole if we are aware of it early enough, Including the galactic collision

  17. Art Riaf

    Not on my top ten list of things to worry about or even think about. By that time if we as a species aren’t off this rock and out in the local area of our galaxy living and thriving we’re history already.

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