STS-119

Backdropped by the blackness of space and the thin line of Earth’s atmosphere, the International Space Station is seen from Space Shuttle Discovery as the two spacecraft begin their relative separation. Earlier the STS-119 and Expedition 18 crews concluded 9 days, 20 hours and 10 minutes of cooperative work onboard the shuttle and station. Undocking of the two spacecraft occurred at 2:53 p.m. (CDT) on March 25, 2009.

Moqui Marbles and Martian Blueberries

The photo above shows Moqui Marbles in their native habitat of southern Utah. These curious rocks are actually concretions having iron (hematite) rinds.

Very similar rocks, called blueberries, have been observed repeatedly on Mars by the rovers. Click here to see an image taken by the Opportunity rover of the blueberries. Some scientific papers implicate the possibility of life on Mars playing a role in their formation while others do not.

Discussions about the pros and cons of their formation have been quite lively at times. However, the consensus seems to be that both the marbles and the blueberries were created beneath the surface as naturally occurring substances, most likely minerals, precipitated from flowing groundwater. Pictured with the marbles is a Devil’s-Claw cactus (Sclerocactus parviflorus). — Bret Webster

Summer is Coming!

Summer is slowly coming to Saturn’s northern hemisphere. The north pole, which was in the midst of a 7-year-long winter when Cassini arrived in 2004, is now seen basking in the sunlight of mid-spring. Cassini is taking full advantage of the sunlight to capture these amazing views of the north polar hexagon and the myriad of storms, large and small, that comprise the weather systems in the polar region.

This view is centered on terrain at 75 degrees north latitude, 322 degrees west longitude. The image was taken with the Cassini spacecraft wide-angle camera on Feb. 26, 2013 using a spectral filter sensitive to wavelengths of near-infrared light centered at 752 nanometers.

The view was acquired at a distance of approximately 383,000 miles (616,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 48 degrees. Image scale is 21 miles (33 kilometers) per pixel.

Physicists Find Way to Measure Earth’s Rarest Element

A fundamental property of the rarest element on Earth, astatine, has been discovered for the first time, scientists say.

Astatine occurs naturally; however, scientists estimate much less than an ounce in total exists worldwide. For a long time, the characteristics of this elusive element were a mystery, but physicists at the CERN physics laboratory in Switzerland have now measured its ionization potential — the amount of energy needed to remove one electron from an atom of astatine, turning it into an ion or a charged particle.

The measurement fills in a missing piece of the periodic table of elements, because astatine was the last naturally occurring element for which this property was unknown. Astatine, which has 85 protons and 85 electrons per atom, is radioactive, and half of its most stable version decays in just 8.1 hours, a time called half-life. In 1953, Isaac Asimov estimated the worldwide total of astatine in nature was 0.002 ounces (0.07 grams).

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So Long, Kepler: NASA’s Crack Exoplanet-Hunter Falls to Mechanical Failure

In the science press, the obituaries are already rolling out. Though many scientific experiments teach us something new about the world, few have been able to so clearly redefine our place in the universe as Kepler. Decades ago, the planets in our solar system were all we knew. Now, we’re practically swimming in them

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Deep Canadian mine yields ancient water

Scientists working 2.4 kilometres below Earth’s surface in a Canadian mine have tapped a source of water that has remained isolated for at least a billion years. The researchers say they do not yet know whether anything has been living in it all this time, but the water contains high levels of methane and hydrogen — the right stuff to support life.

Micrometre-scale pockets in minerals billions of years old can hold water that was trapped during the minerals’ formation. But no source of free-flowing water passing through interconnected cracks or pores in Earth’s crust has previously been shown to have stayed isolated for more than tens of millions of years.

“We were expecting these fluids to be possibly tens, perhaps even hundreds of millions of years of age,” says Chris Ballentine, a geochemist at the University of Manchester, UK. He and his team carefully captured water flowing through fractures in the 2.7-billion-year-old sulphide deposits in a copper and zinc mine near Timmins, Ontario, ensuring that the water did not come into contact with mine air.

To date the water, the team used three lines of evidence, all based on the relative abundances of various isotopes of noble gases present in the water. The authors determined that the fluid could not have contacted Earth’s atmosphere — and so been at the planet’s surface — for at least 1 billion years, and possibly for as long as 2.64 billion years, not long after the rocks it flows through formed. The study appears today in Nature.

‘Extremely strange’

“The isotopic compositions that they see in these samples are extremely strange, and the preferred explanation in the article seems to me the most likely one,” says Pete Burnard, a geochemist at the Centre of Petrographic and Geochemical Research in Vandœuvre-les-Nancy, France. “For the moment, I think we have to conclude that there are 1.5-billion-year-old fluids trapped in the crust.”

The findings are “doubly interesting”, Ballentine says, because the fluid carries the ingredients necessary to support life. The isolated water supply, he says, provides “secluded biomes, ecosystems, in which life, you can speculate, might have even originated”. His colleagues are now working to establish whether the water does harbour life.

The findings may also have implications for life on Mars, Ballentine says, though he acknowledges that the idea is speculative. The surface of Mars once held water and its rocks are chemically no different from those on Earth, he says. “There is no reason to think the same interconnected fluids systems do not exist there.”

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A U.S. Spy Agency’s Leftover, Hubble-Sized Satellite Could Be on Its Way to Mars:

Last year the National Reconnaissance Office—the U.S. government’s spy satellite program—surprised the world when it let on that it had two unwanted, Hubble-sized spy satellites just sort of sitting around. The Hubble Space Telescope, the great eye in the sky that has given us some of the best photographs in the universe, has a 7.9 foot-wide mirror. The NRO’s two leftover spy satellites also had 7.9 foot-wide mirrors. For satellites, the bigger the mirror the more detail in the photo.

Where Hubble was designed to look off into space, the spy satellites were meant to look down at us. Some rough calculations by UNC-Charlotte associate professor Greg Gbur (otherwise known as Dr Skyksull) let us known that this telescope would be able to see things that are just 5 inches across. With some computer processing, you could probably pick out things on the ground that are just 2.5 inches wide. From space.

But, the spy agency doesn’t want these satellites anymore, so they gave them to NASA. For the better part of a year, says Astronomy Now, NASA has been trying to figure out what exactly to do with these new satellites. Now, says Space.com, the idea is being floated that one of the satellites could be shipped to Mars.

Scientists have proposed sending one of the powerful telescopes to Mars orbit, where it could look both up and down, giving researchers great views of the Red Planet’s surface as well as targets in the outer solar system and beyond.

From orbit around Mars, says Space.com, researchers expect the satellite would be able to take photos that capture around 3.1 inches of the Red Planet per pixel. Such high-resolution imagery could help them build maps and study the planet in unprecedented detail.

But that’s just one possible future for the NRO’s leftover satellites. NASA might also use them to hunt for dark energy or search for exoplanets. Or use them for any one of a number of other projects. Trust us, NASA has plenty of ideas for what to do with two gigantic satellites.

Climate Change Is Making the Whole Planet Tip

Climate change is changing the planet. Yes, it’s doing it in all those ways that you already know about: rising seas, rising temperatures, changing rainfall patterns, more extreme weather. But climate change is changing the planet in another dramatic way, too: It’s actually causing the entire crust of the Earth to shift. According to new research by Jianli Chen and colleagues, climate change–induced glacier melt and sea level rise have thrown the whole planet off-kilter.

The Earth is a ball that floats in space, and the Earth’s surface—the tectonic plates that make up the land—are like a shell that floats on the mantle below. Just like the hard chocolate coating can slip and slide on your soft serve ice cream, the crust of the Earth can slide over the mantle. This is different than continental drift. This is the whole surface of the planet moving as one. The rotation axis of the Earth stays steady, the land masses shift around it. The idea is known as “true polar wander,” and its occurrence is a part of the planet’s history.

The Earth is not a perfect sphere—it’s kind of fat at the middle—and changing how the mass on the surface is distributed changes how the tectonic plates sit in relation to the planet’s rotation axis. By melting Greenland and other glaciers, say the researchers, the Earth’s geographic North Pole has drifted to the east at around 2.4 inches each year since 2005. Nature:

From 1982 to 2005, the pole drifted southeast towards northern Labrador, Canada, at a rate of about 2 milliarcseconds — or roughly 6 centimetres — per year. But in 2005, the pole changed course and began galloping east towards Greenland at a rate of more than 7 milliarcseconds per year.

Seasonal shifts in how ice and water are spread around the world mean that the North Pole is always sort of wandering around. But drift triggered by climate change is new. It’s a sign that global warming isn’t just changing how we might live in the world, but the very face of the world itself.

Scientists Report First Success in Cloning Human Stem Cells

It’s been 17 years since Dolly the sheep was cloned from a mammary cell. And now scientists applied the same technique to make the first embryonic stem cell lines from human skin cells.

Ever since Ian Wilmut, an unassuming embryologist working at the Roslin Institute just outside of Edinburgh stunned the world by cloning the first mammal, Dolly, scientists have been asking – could humans be cloned in the same way? Putting aside the ethical challenges the question raised, the query turned out to involve more wishful thinking than scientific success. Despite the fact that dozens of other species have been cloned using the technique, called nuclear transfer, human cells have remained stubbornly resistant to the process.

Until now. Shoukhrat Mitalipov, a professor at Oregon Health & Science University and his colleagues report in the journal Cell that they have successfully reprogrammed human skin cells back to their embryonic state. The purpose of the study, however, was not to generate human clones but to produce lines of embryonic stem cells. These can develop into muscle, nerve, or other cells that make up the body’s tissues. The process, he says, took only a few months, a surprisingly short period to reach such an important milestone.

Nuclear transfer involves inserting a fully developed cell – in Mitalipov’s study, the cells came from the skin of fetuses – into the nucleus of an egg, and then manipulating the egg to start dividing, a process that normally only occurs after it has been fertilized by a sperm. After several days, the ball of cells that results contains a blanket of embryonic stem cells endowed with the genetic material of the donor skin cell, which have the ability to generate every cell type from that donor. In Dolly’s case, those cells were allowed to continue developing into an embryo that was then transferred to a ewe to produce a cloned sheep. But Mitalipov says his process with the human cells isn’t designed to generate a human clone, but rather just to create the embryonic stem cells. These could then be manipulated to create heart, nerve or other cells that can repair or treat disease.

“I think this is a really important advance,” says Dieter Egli, an investigator at the New York Stem Cell Foundation. “I have a very high confidence that versions of this technique will work very well; it’s something that the field has been waiting for.” Egli is among the handful of scientists who have been working to perfect the technique with human cells and in 2011, succeeded in producing human stem cells, but with double the number of chromosomes. In 2004, Woo Suk Hwang, a veterinary scientist at Seoul National University, claimed to have succeeded in achieving the feat, but later admitted to faking the data. Instead of generating embryonic stem cell lines via nuclear transfer, Hwang’s group produced the stem cells from days-old embryos, a technique that had already been established by James Thomson at University of Wisconsin in 1998.

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Earth’s Rotating Inner Core Shifts Its Speed

Earth’s solid-metal inner core is a key component of the planet, helping to give rise to the magnetic field that protects us from harmful space radiation, but its remoteness from the planet’s surface means that there is much we don’t know about what goes on down there. But some secrets of the inner core are being revealed by acoustic waves passing through the planet’s heart and iron squeezed to enormous pressures in the lab.

Two new studies, both detailed online May 12 in the journal Nature Geoscience, reveal that Earth’s inner core may actually be softer than previously thought, and that the speed at which it spins can fluctuate over time.

Under the liquid-metal outer layer of the Earth’s core is a solid ball of superhot iron and nickel alloy about 760 miles (1,220 kilometers) in diameter. Scientists recently discovered the inner core is, at 10,800 degrees Fahrenheit (6,000 degrees Celsius), as hot as the surface of the sun.

Churning in the liquid outer core results in the dynamo that generates Earth’s magnetic field. Geoscientists think interactions between the inner and outer cores may help explain the nature of the planet’s dynamo, the details of which remain largely unknown.

“The Earth’s inner core is the most remote part of our planet, and so there is a lot we don’t know about it because we can’t go down and collect samples,” said Arianna Gleason, a geoscientist at Stanford University in California. 

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Barns Are Painted Red Because of the Physics of Dying Stars

Have you ever noticed that almost every barn you have ever seen is red? There’s a reason for that, and it has to do with the chemistry of dying stars. Seriously.

Yonatan Zunger is a Google employee who decided to explain this phenomenon on Google+ recently. The simple answer to why barns are painted red is because red paint is cheap. The cheapest paint there is, in fact. But the reason it’s so cheap? Well, that’s the interesting part.

Red ochre—Fe2O3—is a simple compound of iron and oxygen that absorbs yellow, green and blue light and appears red. It’s what makes red paint red. It’s really cheap because it’s really plentiful. And it’s really plentiful because of nuclear fusion in dying stars. Zunger explains:

The only thing holding the star up was the energy of the fusion reactions, so as power levels go down, the star starts to shrink. And as it shrinks, the pressure goes up, and the temperature goes up, until suddenly it hits a temperature where a new reaction can get started. These new reactions give it a big burst of energy, but start to form heavier elements still, and so the cycle gradually repeats, with the star reacting further and further up the periodic table, producing more and more heavy elements as it goes. Until it hits 56. At that point, the reactions simply stop producing energy at all; the star shuts down and collapses without stopping.

As soon as the star hits the 56 nucleon (total number of protons and neutrons in the nucleus) cutoff, it falls apart. It doesn’t make anything heavier than 56. What does this have to do with red paint? Because the star stops at 56, it winds up making a ton of things with 56 neucleons. It makes more 56 nucleon containing things than anything else (aside from the super light stuff in the star that is too light to fuse).

The element that has 56 protons and neutrons in its nucleus in its stable state? Iron. The stuff that makes red paint.

And that, Zunger explains, is how the death of a star determines what color barns are painted.

Colorful phytoplankton blooms off the coast of France.  Nasa writes:

Blooms can be a blessing to other marine species, as these tiny floating plants often feed everything from zooplankton to fish to whales. But some algae and plankton blooms can turn dangerous, either through the production of chemical toxins or by severely depleting the oxygen supply in the ocean and creating “dead zones” that suffocate marine creatures.