Saturday, March 12

Dust Devil report

Alan Boyle, who runs a very fine blog on MSNBC called Cosmic Log, has reported on these dust devil sightings, it turns out. He has a good story on it HERE, that was posted yesterday.

Dust devils to the rescue! Martian squeegee guys caught?

This is an interesting development: In a story HERE today by ace space reporter Leonard David, he reports that Spirit saw a major, sudden power boost, restoring it to almost its original power level (from 60 percent to 93 percent, almost instantly), apparently as a result of a dust devil cleaning the dust off the solar panels. This is a terrific boon to the mission, giving them a lot more power to work with.
But, interestingly, there is no mention in the story of any visual sighting of the dust devils, just the inference that they must be responsible, and must be especially active now. I'm not sure exactly when the power surge was, but as far as I can tell it was yesterday (Thursday), same as the sightings.
The piece does quote one unnamed scientist saying that "Gusev was alive with dust devils," partly because the rover's tracks kept getting wiped clean. Nothing about seeing them.
There's a joking reference in the story to Martian squeegee men having cleaned off the solar panels. Well, now it turns out the surveillance cameras may have caught the Martian squeegee men in the act!

Friday, March 11

First rover views of Martian dust devils?

Some keen-eyed observers, scanning the latest raw images coming back from the rover Spirit in Gusev Crater, have located several images that seem to be the first yet to show the long-awaited dust devils in action. Nobody from the rover teams has commented yet -- I'll ask them about it at the LPSC in Houston next week.
It's too soon to say, but this may turn out to be another case like the original discovery of Martian dust devils, during the Pathfinder mission. The discovery was made not by NASA scientists, but by someone downloading the fresh images online and analyzing them before the science team had noticed.
It'll be interesting to see how this story unfolds. We know there are dust devils in Gusev, their tracks are all over the place, but we should be able to learn a lot by seing them in action -- for one thing, get a better handle on their frequency, size and distribution. This could be very important.
For example, Sushil Atreya of the University of Maryland has done an analysis, presented at last fall's Division of Planetary Sciences meeting, that suggests dust devils could be producing prodigious amounts of peroxides in the atmosphere, which would immediately precipitate out as grains of peroxide ice to coat the surface -- perhaps accounting for the long-hypothesized, but never detected, peroxides that were assumed to explain the Viking results in 1976 without the need for living organisms.
Anyway, Atreya thinks the peroxide is destroying methane, which would mean there's really much more methane being produced on Mars than would be assumed based on the present levels in the atmosphere. This could make all the difference in trying to figure out whether the methane is a signature of life. And those calculations, in turn, depend crucially on exactly how large, how frequent and long-lasting and how fast-moving the dust devils are. All of this might eventually be easier to gauge once there's a real sampling of Spirit camera data.
One speculation is that the dust devils may have been around all along, but were only detected because Spirit has climbed high enough to give a better angle, with the dust devils profiled against the dark plain. Against the pale sky, they would not be noticeable, although now that they've been seen someone might go back and reprocess a lot of images and find earlier cases.
So far, I've seen at least four or five examples that show one thing that I believe is almost certainly a dust devil, very clearly silhouetted, and two or more other possible ones, all within minutes of each other. That certainly suggests a very active dust-devil season may be underway.
Someone has constructed a very good view, blinking back and forth between the view with and without the pale funnel of the dust devil. HERE is the link.

Meanwhile, here's the basic image. See if you can find it -- it's not easy.
It's right at the horizon, very small and pale.

Wednesday, March 9

Mapped moon, cracked moon, smacked Earth

Spectacular new pictures today of two of Saturn's moons from the Cassini mission:
- A large-scale photomosaic of the surface of Titan, by far the sharpest image ever of that enigmatic and strangely Earthlike frozen world. It shows Titan's dramatic, sweeping arc of what appears to be a coastline between a light continent and a vast dark sea -- which may be slush or swamp rather than open liquid, since it doesn't seem to show the mirrorlike reflections expected from a liquid surface. Sure, it may be water-ice continents by the shores of a liquid-methane sea, but it's certainly visually the most tantalizingly Earthlike other place we've ever seen.
- Close-up views of the totally frozen moon Enceladus, showing icy cracks and striations, including one long, straight dark crack that looks like the whole moon is cracking in two -- not possible, I'm sure, but it's a striking visual image.

Hot off the press: This is one of a set of new raw images taken during yesterday's encounter, the closest it will have with Enceladus.

Meanwhile, a fascinating new paper is appearing today in Nature (described in this press release), clinching the last bit of the century-long puzzle of Arizona's Meteor Crater (or Barringer Crater). It took more than half a century before the site was proved to be a meteor impact crater, but the mystery of what happened to most of the iron impactor has remained. H. Jay Melosh of U. of Az. seems to have solved the enigma, showing that the material spread out in small fragments because the object was travelling much less rapidly than had been assumed (only about 12 km/sec., close to the slowest possible impact speed). Nice detective work, mystery solved, case closed. Somewhere, Gene Shoemaker is smiling.

Aerial view of Meteor Crater, Arizona.

Opportunity makes fast tracks

Opportunity has been setting all kinds of speed records lately, using its onboard autonomous navigation capabilities to cover the smooth, undulating plain of Meridiani at an unprecedented clip. Over one three-day stretch it covered 390 meters, mostly on its own brainpower. (My New Scientist story is here).

The view ahead: a very shallow 90-meter diameter crater, with a white rim, is just ahead in this picture taken yesterday.

Opportunity looks back at the tracks of its rapid run.

Tuesday, March 8

Guess which planet

The European Space Agency's Rosetta space probe hurtled past the Earth last Friday, on its way to a date with a comet. It took some unusual views of our home planet on the way by.

One of my favorite planets

Monday, March 7

A stellar mind leaves this planet

My wife and I met Hans Bethe briefly about 12 years ago, at a two-day symposium at Cornell University celebrating Carl Sagan's 60th birthday. We were both struck by just what a sweet, quiet delightful and unassuming man he was -- a real mensch, as they say. I was greatly saddened to hear of his passing today at the age of 98. A nice obit from the New York Times is here.
Among other things, Bethe was one of the key people in figuring out the nuclear processes that power the stars.

Hans Bethe

Sunday, March 6

Meanwhile, on the other side of Mars...

Compare this view from the rover Spirit, up in the Columbia Hills in Gusev Crater, with the one below from Opportunity. Both, I believe, are in true color, though that one looks black and white.

The vast rippled plain of Meridiani

Meridiani Planum

There are some lovely recent Mars images like this one at the What on Mars blog.
This one, a picture by the rover Opportunity of Meridiani Planum, sure looks like the continental shelf of an ancient vast ocean, which is what I suspect it is. There may be news about this in the next couple of weeks.

Idle US astronauts, Europeans to Mars

A few tidbits of recent news:
An AP story today talks about the plight of NASA's current crop of astronauts, some of whom may wait a decade before flying and some may never get a chance, with the current grounding of the space shuttle and its planned retirement in five years.
Also, a story on Mars Today reports that the European Space Agency says it will beat all others in sending humans to all planets of the inner solar system, and especially to Mars. And apparently they are talking seriously about searching for signs of life on Mars, something NASA has pretty much refused to do for the last 29 years. I'll have more to say about that soon.
More details of the ESA plan are here.