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The gullies on a Martian sand dune in this trio of images from NASA’s Mars Reconnaissance Orbiter deceptively resemble features on Earth that are carved by streams of water. However, these gullies likely owe their existence to entirely different geological processes apparently related to the winter buildup of carbon-dioxide frost.

Scientists at the University of Arizona, Tucson, and at Johns Hopkins University Applied Physics Laboratory, Laurel, Md., compared pairs of images from before and after changes in such dune gullies. They determined that the changes occur in Martian winter, during periods of carbon-dioxide frost, rather than during warmer seasons when frozen water, if present, might somehow melt and flow.

Each of the three images here shows an area about 1.2 kilometers (three-fourths of a mile) across. The dunes lie inside Matara Crater, at 49.4 degrees south latitude, 34.7 degrees east longitude. The images are portions of observations by the High Resolution Imaging Science Experiment (HiRISE) camera on the Mars Reconnaissance Orbiter. HiRISE took the top one on March 14, 2008, which was mid-autumn in Mars’ southern hemisphere, the middle one on July 9, 2009, in the first half of the next southern-Mars summer, and the bottom one on October 4, 2010, in the late part of the following (and most recent) winter season.

Illumination is from the upper left. Gullies run leftward downhill from a dune crest in the upper right corner.

Arrows indicate places where changes appeared between observations. Each year, the alcoves at the dune’s crest and the channel beds widened during the Martian winter as material moved down slope and lengthened the apron at the bottom. Very new deposits (formed sometime in September 2010) are visible in the bottom image as the darker material extending from the channels and obscuring the pre-existing ripples on the dune’s surface. Additionally, on the upper gully, material first filled-in part of the channel (between 2008 and 2009) and then re-incised the channel into the apron (between 2009 and 2010).

The rest of the story is here.

The Mars Rover Spirit got stuck, probably forever, last year, but the little guy has not given up doing science!!!!
Continue reading Spirit Finds Water, Still Stuck →

… maybe….

Not in a black hole, where it is supposed to constitute the ‘evaporation’ of photons across the hole’s event horizon, but rather, in a refractive index perturbation style event horizon, in the lab. It is made in glass.

… researchers using a CCD camera detected a peculiar kind of photon emission at a 90-degree angle to the glass. … researchers arranged the experiment in a way to strongly suppress or eliminate other types of radiation.

“Experimental evidence of photon emission that on one hand bears the characteristics of Hawking radiation and on the other is distinguishable and thus separate from other known photon emission mechanisms,” the physicists wrote in their study. “We therefore interpret the observed photon emission as an indication of Hawking radiation induced by the analogue event horizon.”

More details here

A collection of meteor videos for your amusement and amazement:
Continue reading An Internet meteor shower →

By now, this news is a few days old, but there was something I wanted to check on before noting it. Here’s the story:
Continue reading Kepler Finds Two Planets Transiting the Same Star →

Then I saw this:
Continue reading I used to not worry that much about asteroids hitting the Earth. →

Did you know that galaxies can die? They are apparently declared dead by astronomers when they stop making new stars. But a recent finding suggests that this kind of death is not the end of the road for at least some galaxies.

Astronomers have found mysterious, giant loops of ultraviolet light in aged, massive galaxies, which seem to have a second lease on life. Somehow these “over-the-hill galaxies” have been infused with fresh gas to form new stars that power these truly gargantuan rings, some of which could encircle several Milky Way galaxies.

The discovery of these rings implies that bloated galaxies presumed “dead” and devoid of star-making can be reignited with star birth, and that galaxy evolution does not proceed straight from the cradle to the grave.

“In a galaxy’s lifetime, it must make the transition from an active, star-forming galaxy to a quiescent galaxy that does not form stars,” said Samir Salim, lead author of a recent study and a research scientist in the department of astronomy at Indiana University, Bloomington. “But it is possible this process goes the other way, too, and that old galaxies can be rejuvenated.”

Read the rest here.

Astronomer Dimitar Sasselov and his colleagues search for Earth-like planets that may, someday, help us answer centuries-old questions about the origin and existence of biological life elsewhere (and on Earth). How many such planets have they found already? Several hundreds.

Continue reading How we found hundreds of Earth-like planets →

The Rover Spirit is hibernating on a dark slope on the winter end of the planet Mars. Solar panels may be providing enough energy to keep its clock going. If not, it will become suspended in time and not know to wake up and send a signal that it is ‘alive.’ The panels may or may not keep the battery temperatures above 40 degrees below zero Celsius so that batteries survive the Martian winter, which is said to be almost as bad as the Minnesota winter. But probably not. And for now, the mission controllers are waiting for a beep that could come any time.
Continue reading Lost in time, freezing cold … unable to utter the simplest “beep” →

If you do, now is when you should do something about it. The Planetary Society is asking for Americans to contact their Senators, RIGHT NOW.
Continue reading Do you support Big Space Science? →

This is Lutetia, as photographed by the European Space Agency’s Rosetta Probe. Details.

Well, it is. But the Proton “got smaller” just now. And, by “got smaller” I mean that the accepted measurement of the proton has been adjusted slightly. The new measurement for the proton’s diameter is about 0.00000000000003 mm (0.03 femtometers less than it was before. This is important:

Continue reading Wait, I thought the Universe was expanding, not shrinking! →

It must have been very difficult to get the Universe to stand still for this photograph, but the European Space Agency managed it . Check it out.

Here is a web site that shows you what the sky looks like when viewed in different wavelengths, or using different energy sources.

It’s one of those hitch hiking deals:

NASA’s Deep Impact/EPOXI spacecraft will fly past Earth this Sunday (June 27). Mission navigators have tailored this trajectory so the spacecraft can “hitch a ride” on Earth’s gravity field, which will help propel the mission toward its appointment with comet Hartley 2 this fall. At time of closest approach to Earth, the spacecraft will be about 30,400 kilometers (18,900 miles) above the South Atlantic.

“Earth is a great place to pick up orbital velocity,” said Tim Larson, the EPOXI project manager from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “This flyby will give our spacecraft a 1.5-kilometer-per-second [3,470 mph] boost, setting us up to get up close and personal with comet Hartley 2.”

Press release is here.

I dislike the term “god particle” but I could not resist the play on words … as researchers at Fermilab suggest that there may be five different versions of the Higgs boson, not just one. This would require, apparently, some rewriting of the Standard Model.

Continue reading It may turn out that Teh Physics is polytheistic →