NASA : Cave Skylights Spotted on Mars

September 21, 2007: NASA's Mars Odyssey spacecraft has discovered entrances to seven possible caves on the slopes of a Martian volcano. The find is fueling interest in potential underground habitats and sparking searches for caverns elsewhere on the Red Planet.

Very dark, nearly circular features ranging in diameter from about 328 to 820 feet puzzled researchers who found them in images taken by NASA's Mars Odyssey and Mars Global Surveyor orbiters. Using Mars Odyssey's infrared camera to check the daytime and nighttime temperatures of the circles, scientists concluded that they could be windows into underground spaces.

Above: A montage image of the "Seven Sisters"--seven dark openings into cavenrous spaces on the slopes of Arsia Mons. Researchers have nicknamed the features Dena, Chloe, Wendy, Annie, Abby, Nikki and Jeanne. [More]

Evidence that the holes may be openings to cavernous spaces comes from the temperature differences detected from infrared images taken in the afternoon vs. the pre-dawn morning. From day to night, temperatures of the holes change only about one-third as much as the change in temperature of surrounding ground surface.

"They are cooler than the surrounding surface in the day and warmer at night," said Glen Cushing of the U.S. Geological Survey's Astrogeology Team and of Northern Arizona University, Flagstaff, Ariz. "Their thermal behavior is not as steady as large caves on Earth that often maintain a fairly constant temperature, but it is consistent with these being deep holes in the ground."

A report of this discovery by Cushing and his co-authors was published online recently by the journal Geophysical Research Letters.

"Whether these are just deep vertical shafts or openings into spacious caverns, they are entries to the subsurface of Mars," said co-author Tim Titus of the U.S. Geological Survey in Flagstaff. "Somewhere on Mars, caves might provide a protected niche for past or current life, or shelter for humans in the future."

The discovered holes, dubbed "Seven Sisters," are at some of the highest altitudes on the planet, on a volcano named Arsia Mons near Mars' tallest mountain.

Above: Each of the three images covers the same patch of Martian ground centered on skylight "Annie," which has a diameter about double the length of a football field. The left panel shows an ordinary white light view of Annie; right panels show infrared images in mid-afternoon (center) and just before sunrise (right). [More]

"These are at such extreme altitude, they are poor candidates either for use as human habitation or for having microbial life," Cushing said. "Even if life has ever existed on Mars, it may not have migrated to this height."

The new report proposes that the deep holes on Arsia Mons probably formed as underground stresses around the volcano caused spreading and faults that opened spaces beneath the surface. Some of the holes are in line with strings of bowl-shaped pits where surface material has apparently collapsed to fill the gap created by a linear fault.

The observations have prompted researchers using Mars Odyssey and NASA's newer Mars Reconnaissance Orbiter to examine the Seven Sisters. The goal is to find other openings to underground spaces at lower elevations that are more accessible to future missions to Mars.

The Jet Propulsion Laboratory manages Mars Odyssey and Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington. Arizona State University operates the Mars Odyssey's Thermal Emission Imaging System. For additional information about Mars Odyssey and the new findings, visit the Odyssey mission home page.

Universe Today : Galaxy Leaves News Stars Behind in its Death Plunge

Written by Fraser Cain

Quick, look at the picture with this story. Are you looking at a comet? Nope, that's an entire galaxy. But the process is similar. In this case, an entire galaxy is plunging into a galaxy cluster. The interstellar winds are tearing away at its structure, shedding material, and trailing stars behind into a trail 200,000 light-years long. But it's actually a region of creation, not destruction, as millions of new stars are forming behind the galaxy.

The image you're looking at was captured by NASA's Chandra X-ray observatory as well as the Southern Astrophysical Research (SOAR) telescope in Chile. The blue colours are regions bright with X-rays, while the red colours show regions rich in hydrogen gas.

The galaxy is called ESO 137-001, and it's currently falling into the massive galaxy cluster Abell 3627. The pressure from the intergalactic wind coming from the galaxy cluster is causing gas in ESO 137-001 to heat up to millions of degrees. At the same time, though, hydrogen gas is being stripped out of the galaxy and trailing behind for more than 200,000 light years.

From their observations, astronomers can detect that millions of stars are forming in this galactic tail; the interaction between the gas and intergalactic wind is helping it collapse into massive star forming regions.

By galactic standards, these newly forming stars - most are less than 10 million years old - are going to be very lonely. They're much further away from their galactic home than stars can ever normally form. Life that might evolve on worlds in those regions would see a few stars in the night sky, and a large haze for their parent galaxy, but otherwise, the sky would seem black.

Original Source: Chandra News Release

Universe Today : Learning How to Stop Dangerous Asteroids

Written by Fraser Cain

You know the cliche: it's not a question of if an asteroid will strike the Earth, it's a question of when. Why wait for the asteroid impact, let's get out there and learn how to prevent an impact in the first place. Part of this learning process will be to study potential Earth-crossing asteroids in great detail. ESA has just such a mission in the works: Don Quijote.

There are several problems with asteroids. For starters, we don't even know where they all are. But even when we discover their locations and plot out their orbits, it's all game of probabilities. Over time, asteroids interact with other objects, and their orbits get changed in ways which are hard to predict. Not only that, but sunlight heats up asteroids in ways that can give them a tiny thrust, so they can change their orbits all on their own.

Astronomers are working hard to catalog all the asteroids out there; automated surveys should find most of the objects larger than 140 metres (460 feet) by about 2020. But plotting out their exact positions, and thus their future trajectories, is the hard part.

So Europe is planning to reach out and tag an asteroid. With a homing beacon, an asteroid will be much easier to track as it moves across the Solar System.

The mission is called Don Quijote, and it will work in two phases. The first phase will consist of an orbiter which will rendezvous with an asteroid and begin circling it. It will monitor the asteroid for several months, studying its size, shape, mass and gravity field.

In the second stage, an impactor spacecraft would slam into the asteroid at a speed of 10 km/s, which the first spacecraft watches - sort of like what happened with Deep Impact. The orbiter could then study the asteroid again, seeing what changed. Ground observers could also make precise measurements on the asteroid's orbit and determine how its trajectory changed from the impact.

ESA doesn't have a specific asteroid in mind, but they're seriously considering a space rock called Apophis, which will come dangerously close to the Earth in the future.

If the mission is approved, it could launch early in the next decade, and take about 25 months to fly to its target. Maybe then we'll get a much better handle on potentially dangerous asteroids, and learn everything we need to know to prevent them.

Original Source: ESA News Release

Universe Today : Carnegie Mellon's New Prototype Lunar Rover

Written by Fraser Cain

Consider this: there are two rovers crawling around the surface of Mars. Isn't it strange that we don't have anything similar on the surface of the Moon. I mean, come on, it's so close. Well, researchers at Carnegie Mellon are working to fix this problem. They've been tasked by NASA to develop a prototype lunar rover. One which can travel in the low lunar gravity, and hang on tight when it needs to drill down beneath the lunar soil.

The prototype lunar rover is called "Scarab", and it's being built by the Robotics Institute of Carnegie Mellon University's School of Computer Science. Even though it's being built to test out technologies designed for the surface of the Moon, this little rover will never make the trip. But its advances will be incorporated into future technologies for real missions.

Traveling around the Moon is going to be hard. Especially when you're searching for water inside the perpetually darkened craters at the lunar southern pole. You've got regions of perpetual darkness at the lunar poles, where temperatures plunge to hundreds of degrees below zero. Instead of the traditional solar panels, Scarab will use a radioisotope source to generate energy.

It won't get much power, though, probably less than the amount required to operate a 100-watt light bulb. This means that the rover will be operating in nearly complete darkness, relying on low-power, laser-based sensors. And it won't be fast, crawling forward at only 10 cm/second (4 inch/s).

To be efficient, the rover must be light, but at the same time, it'll need to have enough mass to let it operate as a drilling platform on the lunar surface. Engineers have calculated tat it needs to weigh at least 250 kg (550 pounds).

The researchers at Carnegie Mellon have been working on the rover since March, developing the structure and programming its software. They're planning to do a field experiment near the end of the year, where the rover will drive and drill in total darkness.

They've also announced plans to enter the new Google Lunar X-Prize, offering $20 million to the first team to land a privately funded robotic rover on the Moon by 2012.

You can learn more about the rover, and see some videos of it in action at the Lunar Rover Initiative website.

Original Source: Carnegie Mellon News Release

Universe Today : Lisa Nowak is Having Her Day in Court

Written by Fraser Cain

Remember Lisa Nowak? She's the ex-astronaut who drove across the US to confront a rival over the love of another astronaut; a spacey love triangle. Well, things are moving forward now. Nowak testified this week in a court in Orlando, Florida, hoping that key evidence will be thrown out.

Nowak was arrested on February 5th, 2007 after she allegedly sprayed her romantic rival with pepper spray, astronaut Colleen Shipman. Police discovered a bunch of items that could be weapons in her car, including a steel mallet, a serrated knife and a loaded pellet gun. They also found a map of Shipman's home, garbage bags and latex gloves.

During Tuesday's hearing, Nowak put forth a motion claiming that the police illegally searched her car, as they didn't have a warrant. She claimed that she didn't give the police consent to search the car, and actually misunderstood the charges against her; that she was being charged with an attempted carjacking.

She's currently charged with attempted kidnapping, attempted burglary and battery, and the actual trial is scheduled to start next year. Whether prosecutors get to include this evidence is the big question.

Nowak's lawyer has told the court that he's planning to argue that the astronaut was temporarily insane during the incident, and that she suffers from obsessive-compulsive disorder, partner relational problems and insomnia.

Circuit Judge Marc L. Lubet hasn't indicated if he's going to rule on the defense motions yet.

More info, AFP article, ABC News.

Bad Astronomy : Meteorite Mayhem Part II: Maybe Missile Mayhem?

First, go read my first post about a "meteorite" impact in Peru.

OK, got it? I said it didn’t sound like a meteorite; in fact, the impacts reported in the vast majority of news stories have more mundane explanations.

But this one, maybe, has an even weirder explanation! In the newsgroup sci.space.history is a thread discussing this Peruvian event. One of the participants, Pat Flannery, has come up with a very interesting suggestion: this was no space rock, it was a Scud missile gone awry.

Look at the evidence: the crater doesn’t look like a hypersonic impact crater. The shape is wrong, the size is wrong. There has never, not once, in the history of mankind been a meteorite impact that caused people to become ill. No meteorite has yet been found in the crater, despite the incredibly high value of such an object. Circumstantially, too, most impacts are not caused by meteorites.

Now chew on this: in the late 1990s, Peru is rumored to have obtained several Scud missiles [emphasis mine]:

More than 700 `Scud’ launchers were deployed by the former Warsaw Pact nations, each launcher carried one missile and had three reloads available…but it is believed that the SS-1 `Scud’ missiles have been withdrawn from service in Russia and destroyed … `Scud B’ missiles have been exported to Afghanistan, Azerbaijan, Belarus, Bulgaria, Czech Republic, Egypt, Georgia, Hungary, Iran, Iraq, Kazakhstan, North Korea, Libya, Poland, Romania, Slovakia, Syria, UAE, Ukraine, Vietnam and Yemen. Unconfirmed reports in 1995 and 1996 have suggested that `Scud B’ missiles may have been purchased by Armenia, Ecuador, Pakistan, Peru and Democratic Republic of the Congo…

OK, so let’s say Peru has Scuds. So what?

Ah, the fuel used by Scud missiles is called Inhibited Red Fuming Nitric Acid. This is a toxic brew that can cause nausea and skin irritation, the same symptoms reported to have been seen in the people in Peru near the crater. A missile impact would also explain the witnessed fireball and the impact crater! Fuel leaks are not uncommon in missile impacts, especially if something went wrong with the missile (and with Scuds, that’s very common).

As usual, when we get news reports about meteorite impacts in remote areas, all sorts of contradictory information is reported. We’ll see how this goes, but I’ll just bet that investigators will find debris from a missile around the impact site. But if that’s true, chances are the reports will get suppressed, since I sincerely doubt the Peruvian government will want the news leaked that a) they have Scud missiles, and b) they screwed up and dropped one on their own people.

As bad as this is, I hope it doesn’t turn into a Peruvian Roswell.

Anyway, my thanks to Jim Oberg for turning my attention to the sci.space.history discussion, and to Allen Thomson as well for his help!

Space.com : Hope for Water on Mars Dims with Sharp New Images

By Jeanna Bryner Staff Writer posted: 20 September 2007 06:16 pm ET

New images obtained by a sharp-eyed Martian satellite reveal that some Red Planet features once thought to have been carved by flowing water were in fact created by other processes.

The images were taken during the first 100 days of the Mars Reconnaissance Orbiter (MRO) mission and are detailed in a special section of the Sept. 21 issue of the journal Science.

While the results don't confirm or deny the existence of liquid water on Mars' surface, they are no less fascinating, say the scientists involved. For instance, one team found no evidence that flowing water caused bright deposits on the planet. Instead, the scientists proposed dry landslides caused the deposits.

"All findings are good findings," said one team leader Alfred McEwen, a planetary geologist at the University of Arizona.

Philip Christensen of Arizona State University said the MRO results reiterate that "Mars has been fairly dry for the recent past and we need to be careful and not overestimate how much water may have been present, or may have shaped the surface" in ancient times.

"I have been a 'dry Mars guy' for a long time," Christensen said. "These findings are basically saying you look at very high resolution and you do see some evidence for water, there's no disputing that. But you don't see an overwhelming amount of evidence for water."

Lava explosions

The bus-sized MRO orbiting spacecraft, launched in 2005, is equipped with six instruments, including the High-Resolution Imaging Science Experiment camera, or HiRISE, which provides 10 times the resolution of any past Mars imagers. While the MRO images are in some cases inconclusive on the question of Martian water, they are painting a picture of the Martian surface for scientists in unprecedented detail.

In some cases, the images refute past speculation that some of the features were created by flowing water.

A team led by Windy Jaeger of the U.S. Geological Survey in Arizona analyzed HiRISE images of the Athabasca Valles, a young outflow channel system speculated to have been carved out by past catastrophic floods.

"That entire surface is coated with a thin layer of solidified lava, very hard rock that's almost preserved the channel system," Jaeger said, adding: "Catastrophic water floods probably did carve the channel system, but lava flowed through it more recently."

The findings suggest that rather than flooding, steam explosions left behind trails of cone-shaped features found on the floor of Athabasca Valles.

"When water and lava interact it causes a steam explosion," Jaeger told SPACE.com. "And so the lava-covered ground had ground ice in it. And as that water was heated it exploded in steam explosions through the lava."

Dry landslides

McEwen led another research team, which studied a variety of landforms also thought to be associated with past water on Mars. They examined images of gully deposits that had been detected last year by the Mars Global Surveyor. The gully deposits were not present in 1999 images but appeared by 2004. The before-and-after images raised hopes that modern flows of liquid water created the deposits. However, observations from MRO suggest a dry origin, McEwen said.

Both chemical analyses and images of one of the fresh deposits showed no signs of frost or ice and no evidence for even hydrated minerals, all of which could have given the deposits a "bright" appearance.

"We think dry landsliding could've created the bright deposits," McEwen said.

The slopes above this deposit and five other locations are steep enough for sand or loose, dry dust to flow down the gullies, the scientists say. Material uphill could be the source.

In science, discrediting a theory can be just as important as supporting one. "Some science reporters are acting as if we should be disappointed these new bright deposits weren't deposited by water," McEwen said. "We're excited by any advance in understanding Mars no matter what it is."

No ocean

The researchers also ruled out a hypothesis for an ancient ocean on Mars.

The Vastitas Borealis Formation, which covers low-lying northern plains of Mars, was thought to be the result of fine-grained deposits left by an ancient ocean. The new HiRISE images reveal the area, which appeared as flat and featureless in prior missions, is peppered with large boulders.

The mixed-bag of findings intrigue scientists involved.

While Mars is dry now, there remains a lot of water locked up as ice at the poles and beneath the surface away from the poles.

"Ninety-nine percent of Mars is pretty dry and pretty average and not all that exciting," Christensen said. "But the one percent is extremely interesting. So imagine stumbling across an oasis or hot spring out in the middle of a desert. It's a barren desert but gosh that little oasis sure looks attractive."

As an astrobiologist, Christensen says Mars holds plenty of hideouts for life, "I think there are still plenty of places to look for life on Mars."

Space.com : Crossing the Ring Plane of Uranus

By Rebekah Dawson SETI Institute's Research Experience for Undergraduates, Class of 2007 posted: 20 September 2007 06:09 am ET

In late afternoon, the wispy clouds part. For the first time I discern the distant domes, tiny and white, on the peak of blue-grey Mauna Kea, but a heavy cloud hovers above. Dr. Hammel tells me that once the sun sets, this cloud will cool, sink and wrap the telescopes in its fog, unless – there's a small possibility – the cloud sinks all the way beneath the summit, down below the telescopes. Despite the bleak predictions in all the weather forecasts for tonight, I begin to hope that we'll finally get some data.

I am at Keck Observatory in Hawaii for the Uranian astronomer's equivalent of Halley's Comet: ring plane crossing. It is the last night of the observing run for the team greeted by the Keck Observatory staff as "the ring plane crossing dudes": Dr. Imke de Pater of UC Berkeley, Dr. Heidi Hammel of the Space Science Institute, Dr. Mark Showalter of the SETI Institute, and me, Dr. Showalter's summer research student, an eager undergraduate who has just finished her sophomore year at Wellesley College. Earlier this week, as my plane took off from Boston, I watched the plane's shadow on the harbor shrink as we ascended. The airplane turned and as the wing on my side tilted toward the water, the plane's shadow collapsed into a line. This is just what I hope to see in Hawaii, the once-in-forty-two-years geometry of the Uranian ring plane crossing period: as Earth crosses the plane of the Uranian rings, we view the rings edge-on.

Ring plane crossing is a unique time for astronomers to study both the Uranian ring structure and to detect faint moons usually obscured by the glare of the rings. The three nights we're observing, September 6th-8th, are also Opposition, when the Earth lies on a straight line between the Sun and Uranus, a particularly good geometry for viewing faint moons. Small, faint, inner Uranian moons are the subject of my research tonight, as I've spent the summer studying their chaotic motions. Their trajectories, though not random, are so sensitive to initial conditions as to be unpredictable. But the opportunity to study the chaotic Uranian satellite system with the 10-meter Keck II telescope had been jeopardized by the paradigm system of chaos theory, Earth weather. Dr. Showalter had originally invited me to observe with him in August, but that trip was canceled at the last minute due to an approaching hurricane. Now, during this observing run, we have obtained hardly any data because of fog and humidity. Everyone has begun teasing Dr. Showalter because there's always bad weather when he's on the island. But, we have one more night to attempt an observation of Uranus during ring plane crossing at Opposition.

As I anticipate observing Uranus for the first time, I remembered the time I initially observed a planet with moons and rings. At the Whitin Observatory at Wellesley College, on a crisp, clear New England November night, I located the lever in the rare red light and pushed it to rotate the creaking dome until Saturn was in the slit. Using the system of ropes attached to its brass body, I positioned the fifteen foot long, fifteen-thousand pound, one-hundred-and-fifty year old refracting telescope, scrambled up a wheeled-staircase, and pressed my eye to the ice-cold eye piece. As I turned the knob to focus the lens, Saturn sharpened into view, its tiny moons and rings perfect, exquisite and almost unbelievable.

Two years later, I am observing the moons and rings of Uranus in an air conditioned computer lab under the glare of white fluorescent lights. Dr. Hammel is talking to the telescope operator at the summit through a video link, Dr. de Pater is typing commands into the computer that controls an infrared CCD camera attached to the telescope, and Dr. Showalter is optimistically monitoring the output of a humidity measurement instrument at the summit. As we were preparing that afternoon, a staff member wheeled in a new, modern set of ergonomic leather chairs intended to make the long hours spent observing more comfortable. But the most amazing modern marvel at Keck Observatory is the adaptive optics system.

I was shocked when Dr. Showalter told me, "Keck beats out Hubble on a lot of things now." How can observations from Earth even with 10 meter telescope in the thin, dry atmosphere at 14,000 feet possibly be better than observations with the Hubble Space Telescope? When light enters the atmosphere, it is scattered by our turbulent, chaotic atmosphere, and we see a blurred and distorted image; this is why the Hubble Space Telescope, which orbits above the atmosphere, takes such sharp and detailed images. But, for about five years now, light entering the Keck telescopes has been corrected for atmospheric distortion by an adaptive optics system. We cannot predict how chaotic atmospheric turbulence will distort the light, but, with the adaptive optics system, we can measure and correct for the distortion a thousand times a second. Unfortunately, adaptive optics cannot fix bad weather. As we run our preliminary tests the humidity is changing rapidly, and, when the interesting feature on a test image is blurred out on the real exposure, Dr. Hammel suggests with a sigh, "We could draw it, as astronomers did 200 years ago."

Around midnight on our last night, as the humidity drops and the air stabilizes, we finally begin to get some excellent data. Soon the "seeing" (a measure of the image's blurriness) is down to 0.39 arc seconds, the best possible seeing on Earth. "You can never trust the weather predictions," says Dr. de Pater, and I smile to myself because unpredictable weather has given me a chance to observe Uranus' unpredictable moons. Thirty years ago Uranus' rings were discovered during observations from an airplane by detecting a dip in starlight when a star passed behind them; tonight we resolve the different ring bands edge-on from Earth. This night we also observed volcanoes on Jupiter's moon Io; and the moon of asteroid (45) Eugenia, which was discovered in 1999 using the adaptive optics system.

The weather has been perfect, so Dr. Showalter is formally absolved of causing Hurricane Flossie in August. Then the night is over, and as the sun rises I stand outside the observing station looking to the south and see the peak of Mauna Kea is once again obscured by clouds. Suddenly I make the connection between all the chaotic systems that I've struggled to understand tonight – the weather, the atmospheric turbulence, the Uranian moon motions – and realize that this experience wasn't once-in-forty-two-years but once-in-an-eon. Valentine in Tom Stoppard's Arcadia marvels that, "A door like this has cracked open five or six times since we got up on our hind legs." Only recently have we developed the numerical methods and fast computers necessary to understand chaotic systems, systems where, as Valentine says, "the unpredictable and the predetermined unfold together." Not only weather, moons, and atmospheric turbulence but most systems in the real world are chaotic: population growth, water dripping from a faucet, the stock market, traffic, the human heart. As the Earth's orbit passes through the Uranian ring plane, we on Earth are entering a new mathematical and scientific era.

My travel expenses were generously covered by Wellesley College Astronomy Department's Wilson-Birney Fund, Massachusetts Space Grant and the National Science Foundation, which also funded my summer research at SETI