Story 2014-03-17 3G5 Planet Mercury is Slowly Shrinking

Planet Mercury is Slowly Shrinking

in space on (#3G5)
story imageAccording to a research published by Nature Geoscience, but not yet online, the planet "Mercury shrunk by more than 7 kilometers in radius over past 4 billion years". Using analysis of NASA's Messenger probe , researchers at the Carnegie Institution for Science say the planet lost seven kilometers (more than four miles) of elevation in some areas, over the course of four billion years. Scientists first suggested the phenomenon in the mid-1970s, when the Mariner 10 probe passed the planet in three flybys.
Reply 9 comments

If only (Score: 2)

by on 2014-03-17 12:57 (#M8)

unravelling the pre-plate tectonic (>2-3 Ga) and plate tectonic (

Re: If only (Score: 3, Insightful)

by on 2014-03-17 13:00 (#M9)

comment truncated even after preview for some reason. Is there a problem with the "less than" symbol?

if only unravelling the pre-plate tectonic (greater than 2-3 Ga) and plate tectonic (less than 2-3 Ga) evolution of Earth were as straightforward as unravelling the shrinking of Mercury. Preservation of a complete record of past surface changes on Earth is a dreamer's paradise.

Re: If only (Score: 2, Funny)

by on 2014-03-18 04:49 (#MY)

If we sucked away the water and atmosphere, it would be easy. Personally I consider a little difficulty in unraveling the geological record a worthwhile tradeoff. ;)

Re: If only (Score: 4, Informative)

by on 2014-03-17 15:32 (#MB)

Interesting, I didn't know any of this stuff. Relevant clip:

"Mercury, on the other hand, has only one solid shell for a crust, rather than Earth's many plates that shift about. As Mercury's molten iron core has cooled over the billions of years since the planet formed, it has contracted and the shell of rock surrounding it has cracked and shifted to accommodate the smaller size. Today, the signs of those changes are written all over the face of Mercury. "Some of these things are really, really big," said Paul Byrne of the Carnegie Institution of Washington and the Lunar and Planetary Institute. "There are some truly gargantuan cliffs on Mercury." Bryne is the lead author of a paper presenting the results in the March 16 issue of the journal Nature Geoscience. The greater shrinkage corresponds to a model of the planet with a much larger iron core, said McKinnon."

I'd love to see an artist's rendering of what those gargantuan cliffs must look like, says the guy who's afraid of heights.

Re: If only (Score: 3, Informative)

by on 2014-03-17 15:38 (#MC)

As usual, Google is your (carefully tracking and note-taking) friend:

There's this but it doesn't give a sense of scale. This NASA video doesn't quite give you the "live from the planet's surface" sense. This one on Uyirvani is the best one I could find (is that Russian?)

Re: If only (Score: 2, Informative)

by on 2014-03-17 17:08 (#ME)

This the messenger website (messenger = MErcury Surface, Space ENvironment, GEochemistry, and Ranging) which gives links to various resolution images for Mercury and the latest DEM (digital elevation model) for its northern hemisphere.

GMT (Generic Mapping Tools) scripts would provide one simple way to generate oblique views down on the DEM.

Re: If only (Score: 1)

by on 2014-03-18 10:19 (#N1)

Those are some really phenomenal images. I'm just diving into the stereographic images and I'm blown away. Many thanks for the tip.

Incredible (Score: 2, Interesting)

by on 2014-03-17 18:17 (#MF)

It's incredible to think of a planet shriveling up like that. Imagine how far it will go. Does anyone know why it's shrinking?

Re: Incredible (Score: 2, Informative)

by on 2014-03-17 19:45 (#MK)

"The innermost world has shrunk as it has cooled over time, its surface cracking and wrinkling in the process." from the BBC

The amount of cooling/shrinking depends on the composition of the planet and is being used to estimate the radius of its core.