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

Fog Discovered at Titan's South Pole

The discovery is the first direct evidence of an Earth-like hydrological cycle.

  • September 1, 2009

We’ve suspected for many years that something remarkable is going on on Titan, and yet the evidence to nail this conjecture has been strangely difficult to find.

The idea in question is whether Titan’s atmosphere actively shapes its surface, as occurs on Earth. There’s no shortage of evidence that hints at a complex, vibrant climate with rains that have carved streams and rivers into the surface of Saturn’s largest moon, creating lakes and shorelines in the process.

But all this could be misleading, say Mike Brown at Caltech and a few pals. They put it like this:

“It is possible that the identified lake features could be filled with ethane, an involatile, long-term residue of atmospheric photolysis; the apparent stream and channel features could be ancient from a previous climate; and the tropospheric methane clouds, while frequent, could cause no rain to reach the surface.”

The drizzle that astronomers have seen appears at such a high altitude that it probably evaporates before it hits the ground.

In this context, the importance of the discovery of fog at Titan’s south pole cannot be underestimated (coming courtesy of images from the Cassini spacecraft).

On Earth, fog can form in a number of ways, but most of these mechanisms cannot work on Titan. “Fog on Titan can only be caused by evaporation of liquid methane,” the team says. “The detection of fog provides the first direct link between surface and atmospheric methane.”

And that’s important why? First, because it’s evidence of a hydrological cycle in which an evaporating liquid on the surface enters the atmosphere. And second, because it finally confirms Titan as an active meteorological body in its own right.

Ref: arxiv.org/abs/0908.4087: Discovery of Fog at the South Pole of Titan

Want to go ad free? No ad blockers needed.

Become an Insider
Already an Insider? Log in.
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.