A Sublime Landslide on Mars

The entire universe in blog form
Oct. 31 2013 2:52 PM

A Cascading Slice of Martian History

landslide on Mars
A landslide on Mars leaves behind a dark streak of material down a cliff's edge. Click to enaresenate.

Photo by NASA / JPL / University of Arizona

Every now and again, I get a sudden reminder that Mars is not just an ochre point of light in the sky. It’s a world.

Points of light have no dimension, just color and magnitude. But worlds are rich, diverse, with varying terrains, geography, forces in motion and in balance. The difference between viewing a planet from afar and from up close is the difference between seeing it and knowing it.

Phil Plait Phil Plait

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

Advertisement

Mars is like that. I’ve seen it countless times by eye and by telescope. Even when it’s relatively close to Earth it still appears small, and features as big as continents are fuzzy. Don’t misunderstand me: It’s still astonishing, seeing a planet unfold through the eyepiece, knowing the light entering your eyes traveled across millions of kilometers of space. But again, to truly know this planet, we go there.

HiRISE is a camera on board the Mars Reconnaissance Orbiter, and has been taking high-resolution images of the planet for years. I am a great admirer of the camera and the humans who designed, built, and operate it; I’ve written about its images dozens of times.

That’s why I was thrilled to be asked to record an audio caption for one of their image releases: “Spring Slide”. You can listen to my recording, or watch this short video they put together:

The image at the top of this post is from that release: It shows a flow of dark material down a steep scarp, or cliff. When sunlight hits the incline it warms the ground, causing the carbon dioxide ice under the surface to turn directly into a gas. This undermines material above it, dislodging it and sending it cascading down the slope. Sometimes these can cause avalanches, many of which have been caught in progress by HiRISE as they spill down to the land below, creating giant dust clouds.

The image here is part of a much larger, sweeping region of the scarp:

wider view of the scarp
A wider view of the scarp showing multiple landslides.

Photo byNASA / JPL / University of Arizona

You really need to click that and see it in full resolution. It’s stunningly beautiful. The feature is located at a latitude of 85° north on Mars, just 300 kilometers (180 miles) from the north pole. The image covers a region about 30 kilometers across.

How long has that scarp sat there? I don’t know. Like most things on Mars, it’s probably very old, tens of millions of years old. Perhaps much more. Over the eons the thin air, fast winds, and changing seasons have eroded it. It changes, just very very slowly. We are seeing a razor-thin slice of time carved out of ancient history.

And this is precisely what I mean: Mars is a world, worthy of our exploration. HiRISE lets us do that, and I’m glad I got to share a small part of it.

TODAY IN SLATE

Doublex

Crying Rape

False rape accusations exist, and they are a serious problem.

Scotland Is Just the Beginning. Expect More Political Earthquakes in Europe.

Why Men Can Never Remember Anything

The XX Factor
Sept. 19 2014 1:11 PM Why Men Can Never Remember Anything

The Music Industry Is Ignoring Some of the Best Black Women Singing R&B

How Will You Carry Around Your Huge New iPhone? Apple Pants!

Medical Examiner

The Most Terrifying Thing About Ebola 

The disease threatens humanity by preying on humanity.

Television

The Other Huxtable Effect

Thirty years ago, The Cosby Show gave us one of TV’s great feminists.

There’s a Way to Keep Ex-Cons Out of Prison That Pays for Itself. Why Don’t More States Use It?

No, New York Times, Shonda Rhimes Is Not an “Angry Black Woman” 

Brow Beat
Sept. 19 2014 1:39 PM Shonda Rhimes Is Not an “Angry Black Woman,” New York Times. Neither Are Her Characters.
Behold
Sept. 19 2014 11:33 AM An Up-Close Look at the U.S.–Mexico Border
  News & Politics
Foreigners
Sept. 19 2014 1:56 PM Scotland’s Attack on the Status Quo Expect more political earthquakes across Europe.
  Business
Moneybox
Sept. 19 2014 12:09 PM How Accelerators Have Changed Startup Funding
  Life
Inside Higher Ed
Sept. 19 2014 1:34 PM Empty Seats, Fewer Donors? College football isn’t attracting the audience it used to.
  Double X
The XX Factor
Sept. 19 2014 1:11 PM Why Men Never Remember Anything
  Slate Plus
Slate Picks
Sept. 19 2014 12:00 PM What Happened at Slate This Week? The Slatest editor tells us to read well-informed skepticism, media criticism, and more.
  Arts
Movies
Sept. 19 2014 2:06 PM The Guest and Fort Bliss How do we tell the stories of soldiers returning home from war?
  Technology
Future Tense
Sept. 19 2014 12:38 PM Forward, March! Nine leading climate scientists urge you to attend the People’s Climate March.
  Health & Science
Medical Examiner
Sept. 19 2014 12:13 PM The Most Terrifying Thing About Ebola  The disease threatens humanity by preying on humanity.
  Sports
Sports Nut
Sept. 18 2014 11:42 AM Grandmaster Clash One of the most amazing feats in chess history just happened, and no one noticed.