Stories tagged Earth and Space Science

Oct
22
2014

Partial eclipse over Lake Calhoun: Minneapolis, MN
Partial eclipse over Lake Calhoun: Minneapolis, MNCourtesy Mark Ryan
A partial eclipse of the sun will be visible over much of North America tomorrow (October 23rd, 2014), including here in the Twin Cities. Note that this won't be a total eclipse, so it won't be safe to view the eclipsed sun without protective solar filters for your eyes. I have a piece of #14 arc-welder's glass (available at welding supply stores) that I've used to view solar eclipses safely in the past. You can also purchase special eclipse glasses online or from some local retail outlets. About 51 percent of the sun will be blocked by the moon but even directly viewing a 99 percent eclipsed sun can damage your eyes. So it's important that you make sure you use eye protection. Probably the safest way to view the eclipse is by poking a pinhole in a sheet of paper or piece of cardboard and projecting the sun's image though it onto another flat surface.

Map for Oct. 23, 2014 partial eclipse
Map for Oct. 23, 2014 partial eclipseCourtesy F. Espenak, NASA
Solar eclipses can take place two to five times each year but since the Earth's surface is covered mostly by water, they're often viewable only from obscure and hard-to-get-to locations. Solar eclipses occur three ways: partial, total, and annular. During a partial eclipse only a fraction of the Sun's surface is covered by the Moon; during a total eclipse the Moon covers the full face of the Sun; during an annular eclipse the Moon is farther from Earth and relatively too small to completely block out the solar disk thus creating a ring of sunlight around the Moon's limbs. It's rare, but sometimes all three types can occur during a single event called a hybrid eclipse.

In the Twin Cities, the eclipse will start at 4:23pm and hit maximum eclipse at 5:35pm. About 51 percent of the sun will be blocked by the moon. The weather forecast calls for possibility of rain in the morning, with slow clearing and a high of around 64°F. If we're lucky, the clouds will scatter by eclipse time and provide some excellent viewing opportunities of the eclipsed sun low in the western sky. One of the interesting phenomenons to look for during a partial eclipse is the pinhole effect leaves and other objects make with their shadows - fringing the edges with miniature crescents. I'll try to get some good photos if weather permits.

Coming up in the summer of 2017, the first total eclipse of the sun visible in the lower 48 states in nearly 40 years will will sweep across the US along a line from Oregon to South Carolina. Don't miss it if you can - it's one of the greatest natural events you'll ever witness in your life. But in the meantime, get outside and enjoy a partial warm-up tomorrow.

SOURCES and LINKS
Eclipse info at Space.com
How to safely watch a partial eclipse
Eclipse visibility map

Oct
05
2014

Yes, that’s a whale skull! Whale skulls and solar panels – things you don’t normally see together.
Yes, that’s a whale skull! Whale skulls and solar panels – things you don’t normally see together.Courtesy OMSI
Researcher Nick Day checking on the solar panels.
Researcher Nick Day checking on the solar panels.Courtesy OMSI
You don’t really smell the whale bones drying in the sun, unless you’re close to them. I’m on the roof of Science Building 2 at Portland State University in Portland, Oregon. I’m not here to check out the whale bones (which are pretty cool!) but to see the PSU Photovoltaic Test Facility.

Plants and solar cells both need sunlight. Roofs can be great places for capturing sunlight if they aren’t shaded by tall trees or buildings. PSU professors Carl Wamser, David Sailor, and Todd Rosentiel wondered if putting green roofs and solar panels together could increase the effectiveness of both. Researchers from the Wamser, Sailor, Rosentiel, and Erik Johansson labs have been experimenting with different plants in the green roofs, irrigating the plants, and different roofing materials to see how they affect the power produced by the solar panels and how much energy the building uses.

As it gets hotter, photovoltaic solar panels become a little less effective. About 80% - 90% of the solar panels in use today in the US are crystalline silicon photovoltaic panels. Over temperatures of 25°C (77°F), these solar panels drop 0.4-0.5% in power for every 1°C that the temperature rises. How can green roofs help solar panels? Plants and soil give off water in a process called evapotranspiration. As the water evaporates, it cools the air. The PSU researchers wondered if that temperature drop is enough to cool solar panels. They are still analyzing the results, but the plants do cool the solar panels a little, with sedum plants doing a better job than a mix of sedums and grasses.

While analyzing the data, researchers Matt Smith and Hanny Selbak noticed that there was an unexplained power spike in the solar panels one day. After trying to figure out what caused that increase in power, they traced it to biologists in the Rosentiel lab irrigating the plants. The water ran over the solar panels on the way to the plants. The solar panels cooled, and their power went up. Serendipity!

From that observation, researchers from the labs devised an experiment where they pumped water continuously over a solar panel using a 7 watt aquarium pump. This cooled the panel from about 55°C (131°F) to 40°C (104°F). After subtracting the power used by the pump, the average net gain in power was around 5%. The cooling system cost about $15 in materials per panel. If a home owner with an average 3 kilowatt solar panel system used a similar cooling system, she could generate an additional 150 watts of power. That’s enough to run most televisions or computers.

Find out more about the green roof and solar panel project here: http://www.sciencebuzz.org/topics/green-roofs-solar-panels-better-together

Meet some of the researchers and find out why they do what they do here: http://www.sciencebuzz.org/topics/meet-scientist

Sources and Links:
To read this article click here:

Smith, Matthew K., H. Selbak, C.C. Wamser, N.U. Day, M. Krieske, D.J. Sailor, T.N. Rosentiel. Water Cooling Method to Improve the Performance of Field-Mounted, Insulated, and Concentrating Photovoltaic Modules. Journal of Solar Energy Engineering 2014; 136(3).

Sep
12
2014

Paleontologist Ernst Stromer: Discoverer of original Spinosaurus aegyptiacus.
Paleontologist Ernst Stromer: Discoverer of original Spinosaurus aegyptiacus.Courtesy Public domain via Wikipedia
Back in 1911, German paleontologist Ernst Stromer discovered and described the remains of a then new Cretaceous dinosaur he named Spinosaurus aegyptiacus. The strange beast sported a huge sail framed around a series of giant spines that ran down its back. Unfortunately, all Stromer's fossil evidence was destroyed during the hostilities of WW II, when the British Royal Air Force bombed the Munich museum where the fossils were stored. Only a few scientific drawings and a single photograph remain.

Ninety years later an international team of researchers led by paleontologist Nizar Ibrahim returned to Stromer's original dig site and discovered additional specimens of Spinosaurus aegyptiacus, and in studying their fossils have come to some startling new conclusions about the strange dinosaur.

Spinosaurus aegyptiacus
Spinosaurus aegyptiacusCourtesy University of Chicago Fossil Lab
Spinosaurus was a big boy - nine feet longer than the largest known Tyrannosaurus rex. And despite a long-held notion that dinosaurs were strictly terrestrial - i.e. they only dwelled on land (although like us, they probably occasionally swam in water), S. aegyptiacus appears to have spent much of his life in water, feeding on fish, and when on land (e.g to lay eggs) probably walked on all-fours, unlike every other known predatory dinosaur.

The new findings are published online on the Science Express website, and in the October issue of National Geographic.

Paul Sereno, vertebrate paleontologist at the University of Chicago and a member of the research team, explains some of the new knowledge gleaned from the newly discovered fossil bones.

SOURCES and LINKS
University of Chicago report
Science Daily story

Sep
01
2014

A walking test rock in Death Valley: A test rock fitted with a GPS unit shows evidence of movement across the ice covered Racetrack Playa in Death Valley.
A walking test rock in Death Valley: A test rock fitted with a GPS unit shows evidence of movement across the ice covered Racetrack Playa in Death Valley.Courtesy Mike Hartmann via PLoS One
Since the 1940s the "walking rocks" of Death Valley's Racetrack Playa have mystified visitors and scientists alike. Rocks of various size (up to 700 lbs!) somehow move across the dry lakebed. Nobody ever seemed to witness their actual movement, but the rocks definitely did move, leaving long telltale tracks behind. What was the cause? High winds? Slippery slopes of algae? Aliens? No one could say for certain.

Now, a research team from Scripps Institution of Oceanography at the University of California-San Diego has tackled the problem and seems to have solved the mystery.

The unusual phenomenon, it turns out, requires a special sequence of events that the environment at Racetrack Playa evidently provides.

The first step requires the playa's basin to fill with just enough water to surround the rocks but not too deep to cover them. Next, as nighttime temperatures fall, the water freezes into a quarter-inch thick sheet of ice. In the morning, as the rising sun begins to melt the ice sheet, it causes it to break into smaller floating panels. Finally, light winds - as light as 10mph in strength - gently blow these panels into the rocks and push them across the playa at a speed of only a few inches per second. Since the movement of the rocks is synchronized, even if someone was observing the phenomenon directly, they may not notice the rocks are moving.

In 2011, the research team, led by co-authors Jim Norris and Richard Norris, positioned their own sample blocks of limestone on the dry lakebed each fitted with a GPS unit to record movement (park authories wouldn't allow them use any native rocks). A high-resolution weather station was also set up to measure wind velocity. A magnet positioned beneath each sample rock triggered the GPS devices once the rocks began to move. Since all the special conditions had to be met in order for the rocks to move, the researchers were somewhat suprised when they returned two years later to see a pond of three inches of water covering the playa. It was a perfect set-up to study their hypothesis. Eventually ice formed on the pond's surface, and at the very end of 2013 it began to break up and move the rocks in the process. A camera recorded timelapse of each event.

"We documented five movement events in the two and a half months the pond existed and some involved hundreds of rocks," said Richard Norris, "So we have seen that even in Death Valley, famous for its heat, floating ice is a powerful force in rock motion."

Read the entire study online in the journal PLoS One.

SOURCE and LINKS
Story on CNET.com
Mystery of the Racing Rocks
Study on PLoS One.

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

Aug
06
2014

Bison painting at Altamira cave in Spain: Is it not amazing that we can instantly view on our computers this digital image of a bison painted 22,000 years ago by some unknown Paleolithic artist in a Spanish cave located 4300 miles from St. Paul, Minnesota? Just an observation.
Bison painting at Altamira cave in Spain: Is it not amazing that we can instantly view on our computers this digital image of a bison painted 22,000 years ago by some unknown Paleolithic artist in a Spanish cave located 4300 miles from St. Paul, Minnesota? Just an observation.Courtesy Public domain via Wikipedia
After being closed for a dozen years, officials at the famous cave at Altamira in Spain - known for its wonderful prehistoric paintings - have once again been allowing the public to view its fantastic painted images of bison, horses, and other imagery created by unknown artists some 22,000 years ago.

The state-owned Altamira is subsidized by Spain's Culture Ministry, and testing has been in the works to determine whether limited visitors would have damaging effects on the rare prehistoric art. Random visitors to the site are selected by lottery and suited up in protective clothing before entering the cave. Test-run entries has been going on regularly since February.

The cave was discovered in 1879 by amateur archaeologist, Marcelino Sanz de Sautuola. Visitors swarmed to view the discovery until officials closed it a hundred years later so scientists could study the effects of exposure to human traffic. It reopened for a while but only with limited access. It closed again in 2002 after mold was spotted forming on some of the walls and paintings.

A museum containing exact replicas of parts of the chamber and artwork were built near the cave entrance where visitors could experience the wonders of the paintings without fear of damaging them. The replicated experience has been popular with tourists (a quarter-million visitors per year) but, as some complain, the experience just isn't the same as seeing the real thing.

“It is the kind of difference in emotions that we might feel when we look at a painting of Rembrandt or the sunflowers of van Gogh but are then told that the paintings are in fact fakes,” said Altamira museum director, José Antonio Lasheras.
The last group of lucky participants will be allowed into the cave later this month and results of the testing is scheduled to be published in September.

SOURCES and LINKS
NYT story
UNESCO's Altamira information
Guardian story on cave reopening

Jul
25
2014

Last week oil company passengers flying in a helicopter spotted and videotaped a mysterious crater located in a remote area of northern Siberia. The crater which measures 80-100 meters across, seems to have appeared over night. Authorities have puzzled over its origin, and once the video appeared on-line, wild speculations flared up across the Internet regarding its origin. Did a meteorite create it? Is it the site of a crashed alien spaceship? Could it be another Tunguska event? Or a sinkhole? Or simply the result from a huge release of natural gas?

A group of Russian scientists from Russia's Academy of Science and the State Scientific Center of Arctic Research finally reached the extremely isolated location on the appropriately named Yamal peninsula (Yamal means "end of the world"). The peninsula is home to reindeer and indigenous reindeer herders but sets atop a vast natural gas reservoir which means a gas belch might be the most likely cause. One of the scientists, Anna Kurchatova from the Sub-Arctic Scientific Research Centre, speculates that climate change and warming climate may be causing the permafrost in the area to melt and become unstable, and in the process popping like a Champagne cork under the high underground pressures. But the researchers won't jump to any conclusion; they've been busy examining the sudden phenomenon, scaling its walls, measuring its dimensions, and collecting water and soil samples. Satellite images will also be examined to see if the exact time of origin has been captured by orbiting cameras.

It will be interesting to see what their study reveals. I'm going with the internal forces theory - some sort of fiery gas burp probably caused it. In the meantime, the scientists have also been taking lots of photographs at the site, which can be viewed on the Siberian Times website.

SOURCES
Siberian Times story
Geology Page story

Jul
06
2014

Indication of massive injury on Allosaurus foot bones: ; University of Wyoming Geological Museum, Laramie, WY.
Indication of massive injury on Allosaurus foot bones: ; University of Wyoming Geological Museum, Laramie, WY.Courtesy Mark Ryan
British paleontologist Phil Manning from Manchester University has been using 21st century technology to study prehistoric injuries on dinosaur bones.

Cathartes aura: archosaurian descendent of Allosaurus.
Cathartes aura: archosaurian descendent of Allosaurus.Courtesy Mark Ryan
Manning and his team of researchers employed a particle accelerator called a synchrotron rapid scanning X-ray fluorescence (SRS-XRF) to analyze and compare the chemical compositions of both healed and healthy bone of a 150 million-year-old Allosaurus fragilis, and those of a modern turkey vulture (Cathartes aura). Both animals are members of a group known as archosaurs that includes pterosaurs, and alligators and other crocodilians. The SRS-XRF directed intense beams of light ten billion times brighter than our sun onto areas of fossilized dinosaur bone that showed signs of injuries (pathologies) and healing that had occurred while the creature was alive. The same instrument was used previously to analyze the remains of both Archaeopteryx and Green River Formation fossils, revealing organic traces not detectible in visible light.

In the current study. thin sections made from the toe bones of Allosaurus fragilis unearthed from the Cleveland-Lloyd quarry in Utah were prepared at a Temple University facility in Pennsylvania, and then sent to the Stanford Synchrotron Radiation Lightsource in California for scanning. The Allosaurus sample was also analyzed at the Diamond Light Source (DLS) in Oxford, England.

During the analysis, a suite of trace-metal enzymes - copper, zinc, and strontium- all integral to the process of healing bone were detected. Copper plays a role in the strengthening the structure of collagen, zinc aids in ossification (the creation of new bone material), while strontium inhibits the break-down of bone cells. Enzymes composed from the same three elements are used for growth and repair in our own bones.
Normally when a bone suffers some kind of trauma, such as a fracture, the body repairs it by rebuilding new bone in much the same way it did when the skeleton first formed. Manning's fossil bone sections exhibited chemical ghosts of these essential elements in elevated amounts in the injured bone section than seen in the healthy bone surrounding it.

Allosaurus: ; University of Wyoming Geological Museum, Laramie, WY.
Allosaurus: ; University of Wyoming Geological Museum, Laramie, WY.Courtesy Mark Ryan
“It seems dinosaurs evolved a splendid suite of defense mechanisms to help regulate the healing and repair of injuries," Manning said. "It is quite possible you've got a reptilian-style repair mechanism combined with elevated metabolism, like that you'd find in alligators and birds respectively. So you've got a double whammy in a good way. If you suffer massive trauma, you've got the perfect set-up to survive it."

The SRS-XRF provides scientists with a superior method in analyzing and comparing the chemical processes involved with bone-building and healing that weren't discernible in the older histological examination methods used in studying thin sections, and could lead to further knowledge of how not only dinosaur bones - but our own - grow and repair themselves.

“The chemistry of life leaves clues throughout our bodies in the course of our lives that can help us diagnose, treat and heal a multitude of modern-day ailments. It’s remarkable that the very same chemistry that initiates the healing of bone in humans also seems to have followed a similar pathway in dinosaurs,” Manning said.

The study was published in a recent issue of the Journal of the Royal Society Interface.

SOURCES and LINKS
Science News story
Mother Nature Network story
Planet Earth Online story
Phil Manning research profile

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.

Jun
24
2014

A dye absorbing blue light from a laser pointer
A dye absorbing blue light from a laser pointerCourtesy OMSI
Dye-sensitized solar cell ready to be tested
Dye-sensitized solar cell ready to be testedCourtesy OMSI
Did you know that you can make small solar cells out of things like berries, tea, and doughnuts – yum! Berries and teas have dyes (organic molecules that absorb light) that give them color. Instead of using berries, there are researchers synthesizing dyes to use in solar cells. These solar cells are called dye-sensitized solar cells - DSSC for short. DSSCs convert sunlight energy into electrical energy. They work like this. Love that Scottish accent!

Most commercial solar panels are made with silicon because silicon absorbs much of the light spectrum in sunlight. Silicon solar cells absorb a wider range of the light spectrum than DSSCs currently do. The best silicon solar cells are about 20% efficient. The best DSSCs are about 11% efficient. Why use dyes instead of silicon to make solar cells? Dyes are much cheaper and less resource intensive to make. Most silicon cells are made from purified single-crystal silicon. About 40% of the crystal is lost as it is sliced into thin wafers.

I recently met scientists at Portland State University (PSU) in Portland, Oregon who are working on making dye-sensitized solar cells more efficient. Alex Rudine has been manipulating porphyrin dyes to get them to absorb more of the light spectrum. The advantage of using porphyrins is that they absorb light well and their structure is versatile and relatively easy to manipulate.

In a DSSC, as sunlight hits the dye, an electron is excited and moves to an electron acceptor. An electron flows from the electron donor to fill the hole, creating an electrical current. One of the challenges of DSSCs is that a wet solution of iodide is the typical medium for the electron donor. There are labs working on synthesizing a solid state medium. Carl Wamser’s lab at PSU in Portland, Oregon is one of those. They have synthesized a porphyrin with a nanofiber structure with a very high surface area. A high surface area means there are more places where the energy conversion can happen.

One of the things limiting more wide-spread use of solar energy is the higher set-up costs of solar panels compared to fossils fuels. If researchers can develop a commercially successful DSSC, it would be a cheaper, more sustainable source of solar energy. Unlike burning fossil fuels which releases heat-trapping gases, solar is a clean energy source that doesn’t contribute to global warming. Enough sunlight falls on the Earth in one hour that if we could collect it, we could power for one year all the machines on Earth. That’s an amazing amount of potential clean energy we could tap into.

Researchers at PSU also have a pretty cool experiment running that combines silicon photovoltaic panels with green roofs. Click here to find out more.

Sources and Links

To read this article click here:
Walter, Michael G. and Carl C. Wamser. Synthesis and characterization of electropolymerized nanostructured aminophenylporphyrin films. Journal of Physical Chemistry C 2010: 114, 7563 -7574.

To read this article click here:
Walter, Michael G., Alexander B. Rudine, and Carl C. Wamser. Porphyrins and phthalocyanines in solar photovoltaic cells. Journal of Porphyrins and Phthalocyanines 2010; 14: 759 -792.