mercury sunrise
©Walter Meyers
Mercury Sunrise

There been a lot of media attention over the possibility of asteroids and meteors striking Earth and causing cataclysmic damage, but now some scientists are saying that the planet Mercury (sunrise image above) could also possibly smash into our planet. Huh? That sounds bad.

Jacques Laskar of the Paris Observatory, as well as Konstantin Batygin and Gregory Laughlin of the University of California, Santa Cruz have reached the same unsettling conclusion using separate computer simulations of long-term planetary motion.

According to Laughlin, "The solar system isn't as stable as we'd thought."

Specifically, both teams found that Jupiter's gravity could eventually make Mercury's orbit so out of round that it overlaps with the path of Venus. This kind of close encounter would potentially send the inner solar system into chaos.

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

Laskar, who first discovered that Mercury could become unstable back in 1994, will publish his research in Icarus. Batygin and Laughlin's paper will be published in an upcoming issue of The Astrophysical Journal.

Their models show that Mercury would be forced into one of four unpleasant scenarios if its orbit were disturbed.

Scenario 1: Mercury will crash into the Sun

Scenario 2: Mercury will be ejected from the solar system altogether

Scenario 3: Mercury will crash into Venus

Scenario 4: Worst-case-scenario, Mercury will crash into Earth

If the unpopular scenario 4 turns out to be the case, it would make an asteroid impact sound almost pleasant. In fact, it's doubtful that any form of life on planet Earth would survive the impact. Humans would for sure be goners, but even hardy extremeophile organisms would have a tough time surviving.

Ken Croswell, author of Ten Worlds: Everything That Orbits the Sun points out that "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."

Croswell also notes that we might not be able to rely on the popular idea of colonizing Mars as an escape hatch, since the scientists' computer simulations also showed a possibility that the Red Planet will be thrown into freezing interstellar space.

BUT, don't start worrying just yet. There's only about a 1% chance that any of this will happen before the Sun becomes a red giant billions of years from now (and destroys life on Earth anyway). Even though the inner solar system may not be quite as stable as once supposed, on the other hand, it doesn't appear to be headed for disaster anytime soon.

"If you're an optimist," says Laughlin, "then you say the glass is 99 percent full."

So, yes it's possible though unlikely that Mercury will one day give Earth another moon or so annihilating all life in the process, but it certainly won't happen anytime soon. Plus, on the slightly bright side, if we're around as a species to get demolished by Mercury - that's fantastic news!!

Great Britain's Astronomer Royal and respected professor of astrophysics at Cambridge University claims in his book Our Final Century that humans have only a 50-50 shot of making it through the 21st century - let alone another billion years. If Rees turns out to be THAT wrong, then we will have great reason to celebrate.

In other words, if and when an impact does happen a billion years from now, humans will likely have already been long extinct or have evolved into an extremely advanced space-faring species that defied all odds. On the slim chance that there are still humans on Earth at that point, then it's also quite conceivable that we've evolved to the point where technology would allow our descendents to figure out some sort of awesomely futuristic solution involving either stabilizing the inner solar system or moving on to inhabit other worlds. And if we're REALLY lucky those worlds will turn out to be a lot like the alien worlds of Star Trek - full of scantily clad humanoid hotties that speak English, have strangely strong libidos and don't mind interbreeding.

Unfortunately, those odds are likely a lot worse than 1%.