August 29, 2008
The Mars rover Opportunity is making its way back out to the Martian plains nearly a year after descending into a large Martian crater, Victoria, to examine exposed ancient rock layers.
“We’ve done everything we entered Victoria Crater to do and more,” said Bruce Banerdt, of NASA’s Jet Propulsion Laboratory in Pasadena, California who is project scientist for Opportunity and its rover twin, Spirit.
Opportunity is now preparing to look at loose cobble rock on the plains which are approximately fist-size and larger, which were thrown long distances when objects hitting Mars blew deep craters into the planet; even deeper than the recently explored Victoria crater.
“Our experience tells us there’s lots of diversity among the cobbles,” said Scott McLennan of the State University of New York, Stony Brook. McLennan is a long-term planning leader for the rover science team. “We want to get a better characterization of them. A statistical sampling from examining more of them will be important for understanding the geology of the area.”
Opportunity entered Victoria Crater on Sept. 11, 2007, after a year of exploring from the rim. Once a drivable inner slope was identified, Opportunity used contact instruments on its robotic arm to inspect the composition and textures of accessible layers, then drove close to the base of a cliff called “Cape Verde,” part of the crater rim, to capture detailed images of a stack of layers 20 feet tall. The information Opportunity has returned about the layers in Victoria suggest the sediments were deposited by wind and affected by groundwater.
“The patterns broadly resemble what we saw at the smaller craters Opportunity explored earlier,” McLennan said. “By looking deeper into the layering, we are looking farther back in time.” At approximately a half mile in diameter, it is the deepest seen by Opportunity.
Engineers are programming Opportunity to climb out of the crater at where it entered. A spike in electric current drawn by the rover’s left front wheel last month settled debate about whether to keep trying to get closer to the base of Cape Verde on the steep slope. The spike resembled one seen on Spirit when that rover lost the use of its right front wheel in 2006. Opportunity’s six wheels are all still working after 10 times more use than they were designed to perform, but the team took the spike in current as a reminder of the pitfalls involved. Yet, unbelievably, the rover is still working well.
“If Opportunity were driving with only five wheels, like Spirit, it probably would never get out of Victoria Crater,” said JPL’s Bill Nelson, a rover mission manager. “We also know from experience with Spirit that if Opportunity were to lose the use of a wheel after it is out on the level ground, mobility should not be a problem.”
Opportunity drives with its robotic arm out of the stowed position because a shoulder motor has degraded over the years to the point where the rover team didn’t want to risk having it stop working while the arm is stowed on a hook. If the motor were to stop working with the arm unstowed, the arm would remain usable; not a good thing.
“Both rovers show signs of aging, but they are both still capable of exciting exploration and scientific discovery,” said JPL’s John Callas, project manager for Spirit and Opportunity.
August 28, 2008
“In fact, it’s cold as hell,” according to Elton John’s song Rocket Man.
Even in the middle of the Martian summer, it’s cold as hell. The sun does not set above the arctic circle of Mars during this time.
The period of maximum solar energy is past as of the 86th Martian day after the Phoenix landing. The sun finally set in total behind a slight rise to the north for about half an hour. This red-filter image taken by Phoenix’s Surface Stereo Imager, shows the sun rising on the morning of sol 90, Aug. 25, 2008, the last day of the Phoenix nominal mission.
The Phoenix Mission has been extended through September, rather than the 90-sol duration originally planned. This image was taken at 51 minutes past midnight local solar time during the slow sunrise that followed a brief 75 minute “night.” The skylight in the image is light scattered off atmospheric dust particles and ice crystals.
Image credit: NASA/JPL-Caltech/University of Arizona/Texas A&M University
August 21, 2008
The good old stalwart, takes a licking keeps on ticking, Hubble Space Telescope, has discovered the answer to a long perplexing puzzle by resolving giant but delicate filaments shaped by the strong magnetic field around the active galaxy NGC 1275; a most striking example of the influence of these immense tentacles of extra-galactic magnetic fields, according to scientists.
Credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration
Acknowledgment: A. Fabian (Institute of Astronomy, University of Cambridge, UK)
NGC 1275, an active galaxy, lies at the center of the Perseus Cluster of galaxies. It hosts a supermassive black hole at its core that blows bubbles of radio-wave emitting material into the surrounding cluster gas and its most interesting characteristic is the lacy filigree of gaseous filaments extending out beyond the galaxy into the multi-million degree X-ray emitting gas that fills the cluster.
These filaments provide important clues about how giant black holes affect their surrounding environment and are the only visible-light evidence of the intricate relationship between the core’s black hole and the surrounding cluster gas.
A team of astronomers using the NASA/ESA Hubble Space Telescope Advanced Camera for Surveys (ACS) have for the first time resolved individual threads of gas which make up the filaments. The amount of gas contained in a typical thread is about one million times the mass of our Sun. And at a mere 200 light-years wide, are unusually straight, extending out for up to 20 000 light-years distant. The filaments are formed when cold gas from the galaxy’s core is dragged out in the wake of rising bubbles blown by the black hole.
A challenge for astronomers is to understand how the delicate structures have withstood the hostile high-energy environment of the galaxy cluster for more than 100 million years. One would have expected them to have heated up, dispersed, and evaporated over a very short period of time, possibly collapsing under their own gravity to form stars. Also, the fact that they haven’t been ripped apart by the strong tidal pull of gravity in the cluster’s core is unusual.
Andy Fabian from the University of Cambridge, UK, published a new study in Nature today, August 21, 2008 that proposes the magnetic fields hold the charged gas in place and resist forces that would distort the filaments. This skeletal structure has been able to contain and suspend these peculiarly long threads for over 100 million years. “We can see that the magnetic fields are crucial for these complex filaments – both for their survival and for their integrity,” said Fabian.
The new Hubble data also allowed the strength of the magnetic fields in the filaments to be determined from their size. Thinner filaments are more fragile, requiring stronger magnetic fields for support. However, the finer the filaments, the more difficult they are to observe.
The filamentary system in NGC 1275 provides the most striking example of the workings of extra-galactic magnetic fields so far and is a spectacular by-product of the complex interaction between the cluster gas and the supermassive black hole at the galaxy’s heart. Similar networks of filaments are found around many other, even more remote, central cluster galaxies. They cannot be observed in anything like the detail of NGC 1275, so the team will apply the understanding gained here to interpret observations of these more distant galaxies.
August 17, 2008
Just published this month, and just purchased by myself over the weekend is the new book by Michael Brooks titled “13Things That Don’t Make Sense: The Most Baffling Scientific Mysteries of Our Time.” This is just his opinion of course, but it piqued by interest, and being a sucker for such books, I purchased it. It looks to be an interesting book, and serves as a nice recap of 13 important scientific problems that science is working on cracking.
I’ve only just started reading, so this is not a review, except to say it is an accessible book, easy to read, not bound up tightly in a lot of scientific jargon. The chapters aren’t overly long, and succinctly put each science problem in an informative narrative.
In the table below, I’ve listing the chapter titles and sub-titles.
||The Missing Universe
|| We can only account for 4% of the cosmos
||The Pioneer Anomaly
|| Two spacecraft are flouting the laws of physics
|| Destabilizing our view of the universe
|| Nuclear energy without the drama
|| Are you more than just a bag of chemicals?
|| NASA scientists found evidence for life on Mars. Then they changed their minds.
||The WOW! Signal
|| Has ET already been in touch?
||A Giant Virus
|| It’s a freak that could rewrite the story of life
|| Evolution’s problem with self-destruction
|| There are better ways to reproduce
|| Your decisions are not your own
||The Placebo Effect
|| Who’s being deceived?
|| It’s patently absurd, so why won’t it go away?
I plan to take my time on this book to soak it in; also I working on reading a couple of other books at the same time. I’m especially looking forward to reading chapters 5, 9 and 11 and may post some comments after I’ve finished those chapters.
Again, just thought I’d give this book a mention as many of its chapters, at least five I believe, concern subject matter I’ve written about in previous posts.
If you’ve read it or are planning too, I’d be interested in your comments.
August 14, 2008
The robotic arm of the Phoenix Lander put Martian soil through a narrow opening to a screen above the No. 5 oven on the lander’s Thermal and Evolved-Gas Analyzer (TEGA). A few particles of the sample were delivered through the screen last Thursday, however, there is not enough to fill the oven and allow for analysis of the sample. The Phoenix team sent commands for TEGA to vibrate the screen again last Friday which allowed more soil to reach the oven, but still not enough to begin the analysis.
“There appear to be clumps blocking the opening,” said Doug Ming, the Phoenix team’s science leader based at NASA’s Johnson Space Center in Houston. “However, we have seen in the past that when this soil sits for a while, it disperses. We intend to fill an oven with this material, either by additional vibration of the same screen or by opening doors to one of the other TEGA cells.”
The conductivity measurements were completed last Wednesday. A fork-like probe inserted into the soil checks how well heat and electricity move through the soil from one prong to another.
I especially liked the picture above, provided by NASA/JPL-Caltech/University of Arizona/Texas A&M University. It shows the deep reddish color of the Martian soil and how it clumps together, though the picture is a false-color image, it’s probably fairly accurate, perhaps a bit redder than its true state. You can see by looking at the American flag at upper left that there is a reddish tint to the picture.
August 9, 2008
This sucks. This sucks partly because I’m older than Bernie Mac. It also sucks because no one should die of pneumonia and no one should die at 50. I liked Bernie Mac, even though I’m not big on ‘raunch’ comedy but he had a decent comedy series on tv and he seemed like a decent guy. I thought he was funny most of the time.
I don’t get it, seems to me evolution f-upped somewhere along the way. I can understand cancer, somewhat. Cells multiply out of control, destroying neighboring cells, and generally ruining your insides. Defective code. Cells, like a machine out of control, spitting out too many copies, defective copies, like an atomic pile melting down that can’t be stopped.
Bacteria and viruses like pneumonia, seems like they are intent on killing their host organism. What’s up with that? Doesn’t make sense to me when viewed in evolutionary terms. Seems to me the perfect disease is a parasite; feeding on a living body but not killing it. If a virus kills its host, it dies too. What kind of evolutionary sense does that make? Of course they say a virus isn’t alive anyway. Still, if it kills its host, it fades away too.
There has been much news about antibiotics losing their effectiveness because bacteria has adapted into new resistant strains. In fact, there is a lengthy article in this weeks, (or was it last weeks?) New Yorker about drug resistant bugs. Scary. But why must they destroy a living organism? Where’s the guy in charge of evolution? Seems to me he or she has some ‘splaining to do. Shouldn’t these bugs have evolved to the point where they can ensure they own survival? Hey, they’ve had eons to work on this. Someone needs to be fired.
Getting back to Bernie, sorry ’bout the rant, but I still say it sucks. He had other health problems apparently, so maybe the pneumonia took advantage of the weakened defenses in his body. Still, it doesn’t seem right. No more Bernie, no more pneumonia. Pneumonia must be pretty damn stupid.
If anyone knows who I can complain to, please let me know.
August 6, 2008
Posted by hyakutake1957 under Astronomy
| Tags: Echostar
, GPS satellites
, International Space Station
, Iridium satellite
, satellite tracking
, weather satellites
Feeling a little nerdy? Want to know where your favorite satellite is right now? The web site http://www.n2yo.com/?s=33053 provides a live motion map and links to monitor the whereabouts of your favorite satellite.
The link above directs you to the GLAST satellite page which is where I was looking around just now. On this page you can navigate over to other satellites and see where they are currently. You see track weather satellites, Echostar satellites, browse by launch date, read satellite news, or click the “What’s up?” link to see all the satellites overhead in your part of the country at this moment.
It’s pretty cool. Even the ISS can be tracked, the International Space Station. Right now it is moving from southern Illinois into southern Kentucky and northern Tennessee. It’s actually motoring along pretty quickly. It’s already entering South Carolina.
Check it out!
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