Stories tagged Earth and Space Science

Aug
18
2014

Hallucigenia sparsa fossil: from the Burgess Shale
Hallucigenia sparsa fossil: from the Burgess ShaleCourtesy M. R. Smith / Smithsonian Institute
One of the strangest and more mysterious critters that scurried across the Middle Cambrian seafloor has baffled paleontologist since it was first identified in the 1970s. Was it a worm? Which side was up? Did it have legs or spikes or both? Was its head actually its tail? Did it have any extant descendents or was it an evolutionary dead-end? The worm-like creature was so baffling and so bizarre, it was given the very apropos name of Hallucigenia.

The tubular, spiked-worm possessed seven or eight pairs of legs and ranged in length from 2/5th of an inch to one and 1/4 inches and looks like something out of a bad dream. Early interpretations of their fossils were all over the map. The stiff spikes on it back were first thought to be its legs, and its legs misidentified as tentacles. What was thought to be its tail ended up being its head.

Using modern imaging technology, researchers from the University of Cambridge have been closely studying fossils from the famous Burgess Shale quarry located high in the Canadian Rockies, and are uncovering Hallucigenia's secrets. By studying the claws at the end of its legs they have been able to link it to modern velvet worms (onychophorans). Scientists have long suspected the two were somehow related but until now have failed to find anything significant to prove it. By studying Hallucigenia's claws they've determined that they're constructed of nested cuticle layers, very similar to how the jaws of velvet worms are organized. The similarity is no surprise since jaws are known to have evolved from a modified set of front legs.

But besides giving Hallucigenia a place in the lineage of life on Earth, the Cambridge team during the course of their study also discovered something else: that arthropods - which include crustaceans, spiders, insects and trilobites - aren't in fact as closely related to velvet worms as previously thought.

“Most gene-based studies suggest that arthropods and velvet worms are closely related to each other," said co-author Dr Javier Ortega-Hernandez. "However, our results indicate that arthropods are actually closer to water bears, or tardigrades, a group of hardy microscopic animals best known for being able to survive the vacuum of space and sub-zero temperatures – leaving velvet worms as distant cousins.”

SOURCE and LINKS

University of Cambridge story
Previous Buzz Post on Hallucigenia
The Cambrian Explosion
More about Tartigrade

Jun
27
2014

Why not dig a dinosaur this summer?
Why not dig a dinosaur this summer?Courtesy Mark Ryan
After exploring the Ultimate Dinosaurs exhibit here at the Science Museum of Minnesota, you might say to yourself, "Gee, I wish I could be on one of those swell dinosaur digs."

Of course, the movies and other media have created the impression that working on a dinosaur dig is a romantic and thrilling endeavor full of excitement and constant discovery. In reality, it most likely involves long, sweaty hours with a shovel, removing tons of overburden, walking for miles and finding nothing or lying in the dirt, under a boiling hot sun, carefully uncovering crumbling fossil bones or wrapping them in a sticky concoction of burlap strips dipped in plaster. Afterwards you get to help lift several 3/4-ton blocks of encased bones and rock onto the back of a flatbed truck. If it happens to rain during your time in the field, you'll spend hours, maybe days, stuck inside a humid tent getting to know all about Larry from Cedar Rapids' chronic hip pain, and eating hard tack. Sounds like a blast, doesn't it?

So, if you're still interested, then you'll be happy to learn that there are lots of opportunities available out there to join an actual dinosaur dig. Here's a list of several organizations that will be more than happy to let you pay them to do their manual labor for them. Most are located out West where conditions and rock exposures are most ideal for dinosaur fossils but some digs originate with a museum or fossil related organizations in the East or Midwest.

Now that I think of it, it does sound like a blast. And who knows? Maybe, if you're lucky enough, you'll stumble upon something completely unknown like a Haplocanthosaurus skull or even the next, great "largest dinosaur ever found" (there seems to be a new one each month).

SOURCE
io9 story

Additional Digs
(PLEASE NOTE: Neither I nor the Science Museum of Minnesota endorse the above or following field trips. The links are offered only as a service. Readers are responsible in ascertaining that each organization listed is reputable before sending any money for deposit or downpayment.)
Judith River Dinosaur Institute
Baisch’s Dinosaur Digs, LLC
ZRS Fossils Field Trip
Frommer's suggested digs
Paleo World Research Foundation
Wild West Vacations & Travel
The Hideout in Shell, Wyoming
Prehisoric Planet
And for all the homebodies out there.

Feb
17
2014

Kilauea at night: a massive magma chamber has been detected beneath the volcano's East Rift Zone.
Kilauea at night: a massive magma chamber has been detected beneath the volcano's East Rift Zone.Courtesy Mark Ryan
Researchers from the University of Miami Rosentiel School of Marine and Atmospheric Science have detected a new, massive magma chamber beneath Kilauea, the most active volcano in the world.

By analyzing seismic waves that traveled through the volcano, scientists from the school's geology and geophysics departments have been able to piece together a 3-dimensional velocity model of what's taking place deep below the volcano's caldera.

"It was known before that Kilauea had small, shallow magma chambers," said Guoqing Lin, lead author of the study. "This study is the first geophysical observation that large magma chambers exist in the deep oceanic crust below."

Located in oceanic crust between 5 and 6.8 miles beneath the volcano's East Rift Zone, the new chamber has been determined to be several kilometers in diameter. The seismic data also revealed that it's lava is composed of a slushy mixture of about 10 percent magma and 90 percent crystal.

According to co-author and professor of geology and geophysics, Falk Amelung, the information is useful in understanding magma bodies and a high priority for the researchers because of the possible hazards created by the volcano.

"Kilauea volcano produces many small earthquakes and paying particular attention to new seismic activity near this body will help us to better understand where future lava eruptions will come from," he said.
Kilauea has been active for more than 30 years and is located in Hawaii Volcanoes National Park on the Big Island of Hawaii.

The paper appeared in a recent edition of the journal Geology.

SOURCES and LINKS
Science News story
LiveScience story
2007 video of Kilauea erupting
More about Kilauea

Nov
21
2013

3D printed dinosaur bone
3D printed dinosaur boneCourtesy Radiological Society of North America
Using state-of-the-art medical scanning and printing technology, German paleontologists have been able to scan and reconstruct a dinosaur vertebrae that survived a World War II bombing raid that left hundreds of fossils unidentified. Dug out of a clay pit south of Halberstadt, Germany in the early 20th century, the fossil was jacketed in plaster (for protection during transportation from the field) and stored in the basement of the Museum für Naturkunde in Berlin along with numerous other fossils from Halberstadt in southern Germany and another dig site in Tanzania. When the Allies made a bombing raid over Berlin during WWII, a portion of the museum was hit and collapsed, leaving the poorly labeled fossils in one big messy pile of plaster jackets and rubble. Museum workers sorted the jacketed fossils from the rubble but which fossil came from which dig? The labeled plaster jackets gave no clue.

Plateosaurus mount: Early postcard of a Plateosaurus skeleton seen in a museum in Stuttgart, Germany.
Plateosaurus mount: Early postcard of a Plateosaurus skeleton seen in a museum in Stuttgart, Germany.Courtesy Mark Ryan
Modern technology came to the rescue from technicians from the Department of Radiology at Charité Campus Mitte in Berlin. One of the jacketed fossils was first scanned with a CT (computed tomography) scanner - similar to those used to scan and diagnose medical patients. Because the radiation absorption (attenuation) of the fossil differs from that of the surrounding matrix - the rocky material in which the fossil is encased - making it easy to outline and create a digital copy of the fossil. The resulting image was compared to field drawings from the two expeditions and identified as a vertebrae of a Triassic Period prosauropod known as a Plateosaurus. The dataset was entered into a computer, cleaned up a bit, and then fed into a 3D printer where - layer by plastic layer - an exact replica of the hidden and unprepared fossil was "printed" in 3-dimensions.

CT scanning and 3D printing of fossils has been in use for a while now but this is a first time paleontologists have been able to identify and copy a dinosaur bone still encased in a matrix wrapped in a plaster field jacket.

In the past, this couldn't have been done without first cutting open the field jacket and spending long hours of detailed lab preparation - i.e. removing all the matrix from around the fossil. Making copies of fossils usually entails creating molds using rubber or something similar, then filling the void with plaster or other casting materials. Now with 3D printing technology, exact (or scaled) duplicates of important fossils can be created and shared with scientists or schools for study and comparison. The dataset of the scan can serve the same purpose.

Both the cost and size of the technology have been reduced in recent years, making it both affordable and portable for many museums. The following videos show the processes in action. Desktop scanning of dinosaur bones and the printing a dinosaur skull with a simple desktop 3D printer.

SOURCES and LINKS
Story on Science Daily
Live Science story

Oct
23
2013

With the announcement of the Ultimate Dinosaurs: Giants of Gondwana exhibit comming to the Science Museum of Minnesota, I was thinking back to all the questions I have had regarding dinosaurs. Tyrannosaurus rex: the Tyrant Lizard King on display at the Royal Tyrrell Museum in Drumheller, Alberta.
Tyrannosaurus rex: the Tyrant Lizard King on display at the Royal Tyrrell Museum in Drumheller, Alberta.Courtesy Mark Ryan

Questions like: "Who gets to name Dinosaurs?" "What is this dinosaur named after?" and "What does this name mean?". I thought that I'd take some time here to answer these questions.

Oct
07
2013

Enrolled trilobite: The trilobite's strategy of rolling itself up into a ball for protection dates back to some of its earliest known ancestors in the fossil record. This fossil trilobite (Isotelus?) was found in Late Ordovician shale in St. Paul, Minnesota.
Enrolled trilobite: The trilobite's strategy of rolling itself up into a ball for protection dates back to some of its earliest known ancestors in the fossil record. This fossil trilobite (Isotelus?) was found in Late Ordovician shale in St. Paul, Minnesota.Courtesy Mark Ryan
A new study appearing in Biology Letters shows that trilobites - everyone's favorite prehistoric water bug - developed an effective survival strategy much earlier than previously thought.

Trilobite fossils from Early Cambrian rock formations in the Canadian Rockies and elsewhere lend evidence that some of the earliest trilobites used enrollment (i.e rolling themselves up into a ball like an armadillo) to protect themselves from predators or the environment. Trilobite fossils found here in Minnesota are several million years younger dating back to the Late Cambrian through Late Ordovician Periods (500 - 430 mya) and are often found enrolled. It was an effective survival strategy.

Trilobites were arthropods, which meant they possessed exoskeletons, segmented bodies and jointed appendages. Their closest extant relative is the horseshoe crab. Trilobite bodies - for the most part - were comprised of a head (cephalon) positioned on a body (thorax) that was divided into three lobes: essentially an axial dividing a left and right pleura, and a tail (pygidium). The mouth (hypostome) was located on the underside. It's thought that most early trilobites were predators and/or scavengers who spent their lives roaming the sea floors looking carcasses, detritus or living prey to feed upon. Most trilobites possessed complex eyes (although some were eyeless). Like other arthropods (e.g. today's lobsters), trilobites would outgrow their exoskeletons, discarding them (molting) as they grew in size or changed shape. Their newly exposed soft skin soon hardened into a new, tough, outer casing. Once hardened, their segmented exoskeletons (composed of calcium carbonate) were ventrally flexible, giving them the ability to roll up into a ball should they need sudden protection from whatever threatened them.

Some early trilobite forms from Middle Cambrian-aged fossils had been viewed as incapable of enrolling but the new research based on much older fossils found in mudstones in the Canadian Rockies in Jasper Park pushes back the origins of the strategy to some of the earliest trilobites to appear in the fossil record (Suborder Olenellus). These appeared 10-20 million years earlier at the very beginnings of the Cambrian Period and show evidence of having already developed the ability to enroll.

Trilobites in some form or another existed across a span of more than 270 million years, a very successful run by any measure. The enrollment strategy certainly contributed to their longevity. Although trilobites were already in decline, the last of their kind were wiped out in the great extinction event that marked the end of the Permian Period and the start of the Triassic. They weren't the only casualty of the extinction: nearly 90 percent of Earth's species were terminated along with them.

Even though trilobites are extinct (they died out in the Permian Mass Extinction along with around 90 percent of Earth's species) they were an extremely successful and adaptable life form. No wonder they remain today a favorite among fossil collectors.

SOURCE and LINKS
Paper at Biology Letters
Major Trilobite features
A Guide to the Orders of Trilobites

Oct
02
2013

Gravity: Do they get the science right in the new action film Gravity?
Gravity: Do they get the science right in the new action film Gravity?Courtesy Wikipedia
Film goers will have the chance to travel through space this weekend with the blockbuster movie "Gravity" hitting the theaters. Its a ficticious story about two American astronauts dealing with disaster during a space shuttle mission.

I've come to expect Hollywood to place loose and easy with actual science when it comes to movies with scientific themes. And then today I stumbled upon this article in Time by Jeffrey Kluger, the co-author, with astronaut Jim Lovell, of Lost Moon: The Perilous Voyage of Apollo 13, which was the basis of the Apollo 13 movie released in 1995.

He applies his extensive space knowledge to fact check what's depicted in the new George Clooney/Sandra Bullock film. Here's his analytical summary: "So, that’s a lot that Gravity gets wrong. But you know what? So what? The shuttle, space station and spacesuits are painstakingly recreated; the physics of moving about in space—thrusts requiring counterthrusts, spins requiring counterspins, the hideous reality that if you do go spiraling off into the void your rotation never, never stops—are all simulated beautifully, scarily and accurately."

Click on the link above to get detailed analysis of what's scientifically right and wrong with Gravity.

Have you seen the film? What do you think about its accuracy in portraying the science of living and traveling in space?

Aug
07
2013

A long-buried, underwater forest of Cypress trees was recently discovered in the Gulf of Mexico. The forest, estimated to be about 50,000 years old, was once buried under tons of sediment, heading toward possible fossilization, until the natural forces (most likely 2005's Hurricane Katrina) riled up the Gulf Coast waters and uncovered it again. Hundreds of stumps and fallen logs - some huge - covering 1.3 square kilometers can now be seen in 60 feet of water, 10 miles off the coast of Alabama. The Cypress forest once populated the area around the Mobile-Tensaw Delta when the Gulf's coastline was farther south, and the water level was 120 feet lower than it is today. As the climate began to warm, rising sea levels eventually drowned the forest. The trees all died but oxidation and decomposition were halted as a constant rain of delta silt covered the forest for thousands of years. When cut, the well-preserved wood still smells as fresh as living Cypress, but now that the forest has been uncovered again, wood-boring marine animals are back at work tearing it down.

Live Science story

Apr
20
2013

I had an interesting discussion related to the many and dramatic ways a person would perish when exposed to the vacuum of space recently. We discussed the many dramatic and horrific things that would happen. Blood boiling, eyes popping out... Turns out to be a lot less dramatic. Here is what NASA has to say about what happens to the body when exposed to the vacuum of space.

If you don't try to hold your breath, exposure to space for half a minute or so is unlikely to produce permanent injury. Holding your breath is likely to damage your lungs, something scuba divers have to watch out for when ascending, and you'll have eardrum trouble if your Eustachian tubes are badly plugged up, but theory predicts -- and experiments confirm -- that otherwise, exposure to vacuum causes no immediate injury. You do not explode. Your blood does not boil. You do not freeze. You do not instantly lose consciousness.

Various minor problems (sunburn, possibly "the bends", certainly some [mild, reversible, painless] swelling of skin and underlying tissue) start after ten seconds or so. At some point you lose consciousness from lack of oxygen. Injuries accumulate. After perhaps one or two minutes, you're dying. The limits are not really known.

You do not explode and your blood does not boil because of the containing effect of your skin and circulatory system. You do not instantly freeze because, although the space environment is typically very cold, heat does not transfer away from a body quickly. Loss of consciousness occurs only after the body has depleted the supply of oxygen in the blood. If your skin is exposed to direct sunlight without any protection from its intense ultraviolet radiation, you can get a very bad sunburn.

At NASA's Manned Spacecraft Center (now renamed Johnson Space Center) we had a test subject accidentally exposed to a near vacuum (less than 1 psi) in an incident involving a leaking space suit in a vacuum chamber back in '65. He remained conscious for about 14 seconds, which is about the time it takes for O2 deprived blood to go from the lungs to the brain. The suit probably did not reach a hard vacuum, and we began repressurizing the chamber within 15 seconds. The subject regained consciousness at around 15,000 feet equivalent altitude. The subject later reported that he could feel and hear the air leaking out, and his last conscious memory was of the water on his tongue beginning to boil.

So, bad things clearly happen. Just not the very dramatic bad things I, and lots of others, had previously imagined.