Stories tagged Earth and Space Science
It seems that there has been a bit of a kerfuffle about this paper in the Journal of Cosmo
Cyanobacteria: Could cells like these have been found in space rocks?Courtesy Microbial Diversity, Rolf Schauder and David Graham, © 1997logy, an online-only publication apparently known for publishing controversial points of view endorsing, among other things, the hypothesis that life began outside of the Earth. The paper in question, by NASA researcher Richard Hoover, discusses structures found in three meteorites that visually and chemically resemble bacteria. If these meteorites really contain bacteria whose origins are extraterrestrial (rather than plain old Earth bacteria that contaminated the meteorite samples), it's clear that Hoover has made the kind of discovery that will represent a revolution in scientific thinking.
But that's an awfully big "if". Critics suggest that contamination is vastly more likely (see a nice collection of comments here), and generally criticize the research, the publication, and various other facets of this story.
This whole affair can be read a number of ways: as an illustration of the rule of thumb that "extraordinary claims require extraordinary evidence"; as an example of the politics that sometimes surround scientific research and publication; or even as evidence that people have a way of seeing what they want to see given ambiguous evidence.
But despite all the criticism, I confess that anything suggesting the possibility of extraterrestrial life sets my little heart a-flutterin'. Very few ideas have the same power to catch the imagination as that of alien life: that something so impossible might actually be possible, that science fiction might have some truth, that our understanding of the universe might still be completely and profoundly overturned by something so simple as a few cells inside a space rock. Remember when NASA teased this story about a revolution in astrobiological thinking? I was on pins and needles for days, hoping that they were going to announce definitive evidence of alien life. And, admit it, when you saw this story's headline you were secretly hoping for the same thing...
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Archaeopteryx: Thermopolis specimen.Courtesy Mark RyanThis year marks the 150th anniversary of the announced discovery of the first fossils of Archaeopteryx, a remarkable chimera of both bird and reptile traits. The first evidence identified was a single feather discovered at a limestone quarry in Solnhofen, Germany. This was in 1860. The German paleontologist Hermann von Meyer described the fossil in 1861, naming it Archaeopteryx lithographica. That same year, the first skeletal remains came to light, and although headless, the London specimen, as it became known, showed clearly both avian and reptilian characteristics.
The unique and iconic fossil appeared just two years after publication of Charles Darwin’s On the Origin of Species and helped bolster the naturalist’s theory of evolution through natural selection because its appeared to be a transitional fossil between reptile (dinosaur) and bird. Could Darwin have asked for any better evidence?
Since then nine other specimens have been found, including the Berlin specimen around 1877, which is considered one of most complete. For many years some Archaeopteryx specimens languished in collection drawers because they had been initially misidentified as another creature entirely. In 1970, Yale paleontologist John Ostrom was investigating a so-called pteradactyl fossil at a museum in the Netherlands, when he realized it had been misidentified and was actually an Archaeopteryx. The fossil had been found at Solhofen in 1855, five years prior to the feather! The museum curator was so shaken by Ostrom’s announcement, he clumsily wrapped the specimen in a paper bag and presented it to Ostrom so he could take it back to Yale for further study. Ostrom, by the way, re-ignited the “birds are dinosaurs” debate in the 1960s after his discovery of Deinonychus and his comparison of its structural features with those of birds.
The Thermopolis specimen, the latest Archaeopteryx fossil, became known around 2005 and was donated anonymously to the Wyoming Dinosaur Center in Thermopolis, Wyoming. I happened to visit the museum in June of 2007 during the first week the fossil went on public display, and was able to see the spectacular specimen firsthand. The small fossil (about 1.5 feet square) was displayed behind a small, glass opening in the wall. There was no crowd to speak of so I was able to take in and photograph the fossil for a long stretch of time by myself. Looking at it, your eye is immediately drawn to the distinct feather impressions evident on both its wings and tail. The head, arms, and legs are spread out across the slab, and even though it died 150 million years ago, it looks as flat and fresh as road kill on a modern highway.
About the size of a large crow, Archaeopteryx was an odd amalgam of both bird and reptile. It had slightly asymmetrical flight feathers, wings, and a furcula (wishbone) - all traits found in birds. But its pelvis, skull and sharp teeth were reptilian (although some skull features are bird-like), and it ha a long tail like a reptile. Its bones weren’t hollow, like the bones of modern birds are, nor is its sternum (breastbone) very pronounced; it’s flatter and without a large keel where, in birds, muscles flight are attached. And it also possesses gastralia (“belly ribs”), a feature found in reptiles and dinosaurs. The inner toe (the hallux) in the Thermopolis specimen doesn’t appear to be reversed so it couldn't grasp or perch and was probably more earth-bound than arboreal. Interestingly, its second toe was extensible – meaning it could be pulled back and elevated for tearing into flesh, just like the middle toes of such dinosaurs as Troodon and Velociraptor. Truth be told, if its feathers hadn’t been preserved, Archaeopteryx would have been classified a carnivorous bipedal dinosaur. In fact, one of the existing Archaeopteryx fossil was first identified as a Compsognathus until preparation revealed its feathers.
Solnhofen and much of Europe in the Late Jurassic: A cluster of islands off the coast of the North American continent.Courtesy Ron Blakey, NAU GeologySo what kind of environment did Archaeopteryx live in, and why are its fossils so well preserved? Well, during the Late Jurassic, southern Germany and much of the rest of Europe were pretty much a group of large islands poking out of the Tethys Sea off the coast of North America. What is today the Solnhofen quarry was then part of an island lagoon protected by a barrier reef. Geological evidence in the strata suggests the lagoon dried up several times followed by periods of re-flooding with seawater. Mixed into a brackish soup of coral debris and mud, and in a warm climate conducive to rapid evaporation, the lagoon’s bottom water levels became anoxic, that is depleted of oxygen. Low oxygen meant less bacterial activity and subsequently slow decomposition of any organism that happened to die or get swept into the stagnant lagoon. Burial in the carbonate muck was swift, leaving fresh carcasses no time to be pulled apart by currents or scavengers.
Solnhofen limestone has been used for centuries as a building stone. Because the rock’s matrix is so fine and splits so evenly (sediment deposition likely occurred in very calm waters), the material was later quarried to produce stones for lithography, a printing technique first developed in 1796, and the source of Archaeoperyx’s species designation. Many early scientific illustrations, including some of the first images ofArchaeopteryx were preserved as lithographs created using Solnhofen limestone.
Archaeopteryx commorative coin: Germany will issue the 10 Euro coin in the summer of 2011Courtesy Federal Republic of GermanySolnhofen’s fossil record shows that the lagoon’s biological population was diverse. Fish, turtles, lizards and insects, crocodiles, crustaceans, ammonites, squid and starfish, mollusks, pterosaurs, and even the soft remains of jellyfish are preserved in the fine-grained limestone. But the premiere creature is of course the Archaeopteryx, which remains the earliest bird (or most bird-like dinosaur, if you will) known to date. As research on existing specimens continues and new fossils appear it's exciting to imagine what advances will take place in the dinosaur-bird connection debate. Whatever happens, Archaeopteryx lithographica will remain one of the most significant and iconic fossils ever discovered. It's no wonder that later this year on August 11th, the Federal Republic of Germany will issue a 10 Euro silver coin to commemorate the 150th anniversary of the discovery of its most famous fossil.
SOURCES and LINKS
Witmer Lab Archaeopteryx blog
UCMP Archaeopteryx page
Solnhofen limestone of the Jurassic
The great-great-grandfather of galaxies: This could be the oldest object in our universe.Courtesy NASA/ESA/Garth Illingworth (UCSC)/Rychard Bouwens (UCSC/Leiden University)/HUDF09 TeamThe Hubble Space Telescope has captured what astronomers are claiming is the oldest galaxy in the universe. Here's some of what NASA's Hubble website says about the discovery:
The farthest and one of the very earliest galaxies ever seen in the universe appears as a faint red blob in this ultra-deep–field exposure taken with NASA's Hubble Space Telescope. This is the deepest infrared image taken of the universe. Based on the object's color, astronomers believe it is 13.2 billion light-years away.
The dim object is a compact galaxy of blue stars that existed 480 million years after the Big Bang, only four percent of the universe's current age. It is tiny and considered a building block of today's giant galaxies. Over one hundred such mini-galaxies would be needed to make up our Milky Way galaxy.
Think of that - the light from this object we're seeing now took 13.2 billion years to reach our eyes. That's mind-boggling. We're actually looking back in time. Anyway, the study which appears in the journal Nature, was led by Rychard Bouwens at the Leiden Observatory in the Netherlands, and Garth Illingworth, of the University of California, Santa Cruz. The tiny smudge of light will be further studied and confirmed when the infrared-optimized James Webb Space Telescope is up and running in 2014.
By the way, the Hubble Space Telescope is featured in one of five films at this year's Omnifest playing now through February 17th here at the Science Museum of Minnesota. Take it from me, the images in the film are quite spectacular and worth seeing.
PterodactylsCourtesy Mark RyanA recently discovered pterodactyl fossil is providing lots of new information about the flying reptiles. The 160 million year-old fossil slab contains the remains of an adult specimen known as Darwinopterus, and was brought to light by a farmer who discovered it in Jurassic-aged deposits in China. Pterodactyls - also known as pterosaurs – populated the skies of the Mesozoic Era and were contemporaries of their distant relatives, the dinosaurs. Remains of pterodactyls aren’t uncommon and have been found in many parts of the world. What makes this fossil so unusual and valuable is that it also contains an unhatched egg, evidence that strongly suggests the adult is a female. The research team, made up of scientists from Great Britain and China, nicknamed the specimen “Mrs. T”.
Extensive examination of the fossil revealed that the adult specimen has wide hips, but is without a crest on its head. This contrasts with other known specimens of pterodactyls that have both large crests and narrow hips.
"Mrs T shows two features that distinguish her from male individuals of Darwinopterus,” said David Unwin, a paleobiologist from the University of Leicester who was involved with the study. “She has relatively large hips, to accommodate the passage of eggs, but no head crest. Males, on the other hand, have relatively small hips and a well developed head crest. Presumably they used this crest to intimidate rivals, or to attract mates such as Mrs T.”
Bird eggs are relatively large and hard-shelled, but the Darwinopterus egg is small and appears to be soft-shelled, like that of a crocodile. Dinosaurs, crocodiles and pterosaurs split off from a common archosaur ancestor during the Permian age about 250 million years ago.
This all means paleontologists will be now able to separate male pterodactyls from female pterodactyls. Until this recent discovery many had been categorized as separate species. The study appears in the journal Science.
SOURCES
Science Daily story
NY Times story
Comet Temple 1Courtesy NASA/JPL-Caltech/UMDThe following is from a listserv I am on that I thought was interesting.
On February 14, NASA's Stardust-NExT (New Exploration of Tempel 1) mission will encounter Comet Tempel 1, providing a unique opportunity to measure the dust properties of two separate comets (Wild 2 and Tempel 1) with the same instrument for accurate data comparison. The encounter will also provide a comparison between two observations of a single comet, Tempel 1, taken before and after a single orbital pass around the sun.
NASA's Stardust spacecraft will fly within 200 kilometers (about 124 miles) of Comet Tempel 1 on February 14, 2011, at about 8:36 p.m. Pacific Standard Time.
NASA's Deep Impact mission observed Comet Tempel 1 in the summer of 2005, as the comet was inbound toward the Sun on its approximately 5.5-year orbit between Mars and Jupiter. Deep Impact's primary mission was to deliver a special impactor spacecraft into the path of Comet Tempel 1. The spacecraft -- and many ground-based observers -- observed the impact and the ejected material. Scientists were surprised the cloud was composed of a fine, powdery material, not the expected water, ice, and dirt. The spacecraft did find the first evidence of surface ice on the surface of a comet instead of just inside a comet.
The Stardust-NExT mission is a low-cost use of an in-flight spacecraft redirected to a new target. Prior to its tasking for Tempel 1, the Stardust spacecraft successfully flew through the cloud of dust that surrounds the nucleus of comet Wild 2 in Jan. 2004. The particles of cometary material and gathered during this flyby were then returned to Earth aboard a sample return capsule which landed in the Utah desert in January 2006.
The monthly JPL "What's Up" video podcast (above) features the January Quadrantids, which is a meteor shower that peaks in the morning hours of Tuesday January 4th. It's a good night with no moon, and while the shower will look best for our friends in Europe, if it's clear and you are awake, you should be able to spot it between and below the big and little dippers.
I thought it interesting that the meteor shower was named after a constellation that has been demoted. You're not alone Pluto - that International Astronomical Union is a cold-hearted bunch.
Generally interested in meteor showers? Here's a meteor shower calendar.
SpiritCourtesy xkcdThe current Mars rovers are, not surprisingly, still on Mars. The surprising bit is that one, Opportunity, is still operating, nearly seven years after landing. The other, Spirit, is stuck, possibly in a hibernation mode, and could "wake up" during the Martian summer solstice , this coming March. It’s pretty incredible that these rovers operated so long after they landed – in Opportunity's case 20 times longer and counting.
And, orbiting above the rovers is the Odyssey spacecraft, which last week broke the record for longest-working spacecraft at Mars. The previous record was set by NASA's Mars Global Surveyor, which orbited Mars from 1997 to 2006.
And amidst all this history, a little under a year from now, the Mars Science Laboratory Curiosity will be launched and is scheduled to land in August 2012. Curiosity is also a rover, but is larger than either Opportunity or Spirit. Its mission is to assess whether Mars ever was, or is still today, an environment able to support microbial life.
If it had hands: it would be holding your life in them. Just saying.Courtesy splorpGather ‘round, Buzzketeers, so that I might tell you all a story.
“What story,” you ask?
Is it the one about the little blond girl who is killed by bears for breaking and entering? No, not that story.
Is it the one about the boy who killed an acromegalic man by cutting down the tree that held his fort? No, it’s not that story either.
Could it be the story about the little Blood member who couldn’t tell the difference between a wolf and her own grandmother, and was subsequently devoured by that very wolf? Oh, I wish it were, but it’s not that story.
No, the story I have for you all is even more enduring and horrifying than all of those. It is the story of biodiversity, and how it will freaking destroy you if you mess with it.
Sure, snort dismissively if you must, but you’ll soon be singing a different tune. A sad tune about how everything you ever knew and loved has been taken away from you.
“But how can a concept—and a boring concept like “biodiversity”—hurt me?” Ah, see, but what you don’t know can hurt you. You’re like the little blond girl, screwing around in a house that belongs to bears. She might not have known that it was a bear house (although it’s hard to imagine that she could have missed all the signs), and yet she was destroyed. So listen up.
You see, all biodiversity is is the degree of variation of living things in an ecosystem. Lots of biodiversity in an ecosystem, lots of different things living there. Little biodiversity in an ecosystem, few species living there. And biodiversity includes all forms of life, from your vampire bats and hagfish, to your streptococcus and your slime molds.
At the moment, biodiversity on the planet is on its way down. Lots of the things we do these days make life harder for other species, until there are very few or none of them left. And, sure, no one wants to see a panda get hit by a train, or watch an eagle being run over by road grading equipment, but who cares about the smaller, grosser stuff, like algae or germy things? We could probably do with a few less of those, right? Right?
Wrong, Goldilocks! An attitude like that is bound to get you turned into bear meat.
And here’s where my story begins (again)…
Once upon a time, long, long ago, everything died.
Well, not everything-everything, but pretty well near everything. It was called “the Permian extinction” (we’ve talked about it on Buzz before: here), and more than 90% of all marine (water) species and 70% of all terrestrial (land) species on the planet went extinct. It was way worse than the extinction that would eventually kill off the dinosaurs, and it took the planet a lot longer to recover from the Permian extinction.
What caused the Permian extinction? Oh, you know, a lot of stuff. Probably a lot of stuff. See, while we can more or less say that the dinosaurs were killed off by a giant space rock, it’s harder to say what did in the creatures of the Permian period. After all, the Permian ended almost two hundred million years before the extinction of the dinosaurs. But people have plenty of good guesses: maybe a few smaller space rocks hit the planet, maybe massive volcanic eruptions in what would become Asia kicked dust and poisonous gas into the atmosphere, maybe the oceans suddenly released massive amounts of methane… probably it was a combination of these things and more, and the extinction probably happened in waves before the planet became a good place to live again.
But here’s another straw for that dead camel’s back: the algae died. Not all of it, but lots and lots of the algae died. But why, and why did it matter? After all, it’s just algae.
Scientists aren’t sure exactly what cause so much alga—microscopic plant-like ocean life that turns sunlight into food—to die, but it looks like a sudden rise in the levels of sulfur in the oceans might have had something to do with it. It could be that there was an explosion in the population of sulfur using, hydrogen-sulfide releasing bacteria in the oceans, which would poison the algae.
In any case, there was a large die off of the sort of species we don’t give a lot of thought to. And what happened? The bear meat hit the fan!
Because they turn so much sunlight into so much food, algae act as the basis for most marine food chains. When the algae were gone, photosynthetic bacteria took its place to some extent, but the bacteria were a poor substitute, and the oceans were left with much, much less food. Also, algae produce a significant amount of the planet’s oxygen, and their absence would have created atmospheric changes as well.
This alone might have been enough to cause extinctions, and combined with the other natural calamities of the end of the Permian, it’s no wonder there was such a massive extinction event.
What a good story, eh? Now, if someone asks you what’s so great about biodiversity among the slimier and more boring species, you can just repeat this post, word for word. Or you can repeat this, the short version, word for word: “Because, Mom, if the algae die, we’ll be left choking and crying among the ruins of humanity for the rest of our short lives. And happy birthday.”
Example of cross-bedding: Red Rock Canyon sandstone near Las Vegas, Nevada shows the effects of wind on the sand dunes from which it was formed.Courtesy Mark RyanIn Homer’s epic poem, the Odyssey , the ruler of wind Aeolus gives the hero Odysseus a leather bag containing all the winds except the west wind. Odyssus keeps its contents secret but his men grow suspicious that he’s withholding treasure from them so they open the bag while Odysseus sleeps. The unleashed winds nearly destroy their ship and send it off course to the other end of the world.
In aeolian geology (sometimes spelled eolian), scientists study how landforms are created by wind, either through transportation, sedimentation, or erosion. Sand dunes, dune migration, cross-bedding, and scouring are some of the ways wind can shape the landscape. On Earth, discernible wind patterns in deserts are plainly visible from space, and similar patterns have been seen on other planets, such as Mars, leading scientists to conclude that wind played a role in forming those same landscape features there.
This informative webpage illustrates how some of it works, and how wind can be a powerful shaping force.
This same force was at work this past weekend in Minnesota. As seen in the above video, a winter blizzard barreled across the state bringing with it the usual high winds, low visibility, and drifting and blowing snow.
Snow-wind patterns 1Courtesy Mark Ryan
Snow-wind patterns 2Courtesy Mark Ryan
Snow-wind patterns 3Courtesy Mark Ryan
Snow-wind patterns 4Courtesy Mark RyanAfter the weather system moved out, it left in its wake (besides a collapsed stadium and lots of white stuff to shovel) some very cool (and familiar) aeloian shapes and patterns in the snow.With the help of the low-angled winter sun and my trusty camera, I was able to capture some of these wind-borne creations.
ADDITIONAL AEOLIAN GEOMORPHOLOGY PHOTOS
Sand transport
Aeolian dunes
Dune bedding
Cross-bedding
The University of Minnesota's Institute on the Environment has made some great movies examining what they call "big questions."
Big question: Feast or famine?
IonE's first Big Question asks: How do we feed a growing world without destroying the planet?
Big question: Is Earth past the tipping point?
Have we pushed our planet past the tipping point? That's a critical issue the IonE explores in our second Big Question video.
Big question: What is nature worth?
Plants, animals, even entire ecosystems are disappearing. So what? "What is Nature Worth" offers a three-minute look at what we’re REALLY losing – and what we can do about it.
Interesting problems, right? If you're intrigued, and want to know more about the folks posing the questions and trying to find the solutions, jump over to Future Earth.
