Hello,

We noticed you're browsing in private or incognito mode.

To continue reading this article, please exit incognito mode or log in.

Not an Insider? Subscribe now for unlimited access to online articles.

Emerging Technology from the arXiv

A View from Emerging Technology from the arXiv

Jupiter Impact Raises Likelihood of Future Asteroid Strikes

The strike on Jupiter last year raises the likelihood of future impacts by an order of magnitude, says a new study. But what does it mean for the Earth?

  • May 18, 2010

Last July, an amateur astronomer noticed that a mysterious dark bruise about the size of the Earth had suddenly appeared on the surface of Jupiter. Within hours, amateurs and professionals alike were training their instruments on the great planet to work out what had happened.

The consensus was that Jupiter had been hit by a comet or asteroid. But the surprise was that it had happened so soon after the Shoemaker-Levy comet strike observed in 1994. The worry was that this strike must have important implications for the likelihood of future impacts.

Today, Agustin Sánchez-Lavega from the University of the Basque Country in Bilbao and pals, publish their analysis of the impact and how it changes the probabilities of future impacts. They say the impactor was probably an icy object about 1 kilometre in diameter which came either from a group of main belt asteroids called Hilda asteroids or from a group of comets called the Jupiter Family.

Estimating the likelihood of such impacts is hard for a gas giant like Jupiter because the events leave no long-lasting scars on the surface. Jupiter’s bruise has already faded away.

So astronomers have to rely on historical records. Before last year’s impact, astronomers knew only of the Shoemaker-Levy impact and a possible impact observed by the Italian astronomer Giovanni Cassini in 1640. Together with other evidence such as crater counts on Jupiter’s large moons and various theoretical calculations, astronomers guessed that Jupiter was liable to a strike perhaps as rarely as once in every 350 years.

Sánchez-Lavega and co say that last year’s strike significantly changes these numbers. Seeing two strikes in 15 years means that that Jupiter may be liable to be hit as often as once a decade. The reason we haven’t seen impacts before is simple: digital cameras and image processing techniques have only become easily available to amateurs in the last ten years. (Before that, even professionals often had to rely on hand drawn pictures of the planets.)

What Sánchez-Lavega and co do not address are the implications for the likelihood of Earth impacts, which is strange given the huge importance and public interest in such an event. The Shoemaker-Levy impact on Jupiter changed the way astronomers think about possible impacts and generated huge interest.

Clearly Jupiter is at greater threat of future impacts than Earth: it is bigger and more massive by far and so is bound to attract more hits. But it can also send bodies our way.

The current thinking is that a 1-kilometer object ought to hit Earth every 500,000 years or so. Needless to say, such an event would change our civilisation beyond recognition.

If last year’s impact on Jupiter increased the probability of another strike by an order of magnitude, by how much does it increases the probability of a strike on Earth? The public deserves an answer to this question and the fact that this team are silent on the matter is worrying.

Let’s hope Sánchez-Lavega and his colleagues are working on an answer as a matter of urgency.

Ref: arxiv.org/abs/1005.2312: The Impact Of A Large Object With Jupiter In July 2009

Couldn't make it to EmTech Next to meet experts in AI, Robotics and the Economy?

Go behind the scenes and check out our video
Want more award-winning journalism? Subscribe and become an Insider.
  • Insider Plus {! insider.prices.plus !}* Best Value

    {! insider.display.menuOptionsLabel !}

    Everything included in Insider Basic, plus the digital magazine, extensive archive, ad-free web experience, and discounts to partner offerings and MIT Technology Review events.

    See details+

    Print + Digital Magazine (6 bi-monthly issues)

    Unlimited online access including all articles, multimedia, and more

    The Download newsletter with top tech stories delivered daily to your inbox

    Technology Review PDF magazine archive, including articles, images, and covers dating back to 1899

    10% Discount to MIT Technology Review events and MIT Press

    Ad-free website experience

  • Insider Basic {! insider.prices.basic !}*

    {! insider.display.menuOptionsLabel !}

    Six issues of our award winning print magazine, unlimited online access plus The Download with the top tech stories delivered daily to your inbox.

    See details+

    Print Magazine (6 bi-monthly issues)

    Unlimited online access including all articles, multimedia, and more

    The Download newsletter with top tech stories delivered daily to your inbox

  • Insider Online Only {! insider.prices.online !}*

    {! insider.display.menuOptionsLabel !}

    Unlimited online access including articles and video, plus The Download with the top tech stories delivered daily to your inbox.

    See details+

    Unlimited online access including all articles, multimedia, and more

    The Download newsletter with top tech stories delivered daily to your inbox

/3
You've read of three free articles this month. for unlimited online access. You've read of three free articles this month. for unlimited online access. This is your last free article this month. for unlimited online access. You've read all your free articles this month. for unlimited online access. You've read of three free articles this month. for more, or for unlimited online access. for two more free articles, or for unlimited online access.