Woman's 'Embryonic Twin' Not Really an Embryo, Or a Twin

An Indiana woman's brain tumor turned out to contain hair, bone and teeth, and has been dubbed her "embryonic twin" — but experts say that such tumors are not actually twins, nor are they embryos.

The 26-year-old patient, Yamini Karanam, underwent brain surgery in Los Angeles after she started having problems understanding conversations and things she read, according to NBC Southern California. Doctors discovered she had a teratoma, a type of tumor that can contain all three of the major cell types that are found in an early stage human embryo.

Although these tumors can originate during embryonic development, they aren't embryos, and they are not a person's "twin." They arise from germ cells, which are the cells that go on to later develop into a person's gametes (such as sperm and eggs). At early states, germ cells have the ability to turn into any cell in the body.

The type of tumor that Karanam had occurs "when a person's own germ cell multiplies abnormally and differentiates into various different, normal tissues, in an abnormal place," said Dr. Cathy Burnweit, chief of pediatric surgery at Nicklaus Children's Hospital in Miami. "It has many of the components that a normal body would have, but it is in no way a twin," Burnweit said. Rather, identical twins occur when a fertilized egg divides in two, she said.

Because teratomas can have all three of the cell types found in the developing embryo, they can contain a variety of tissues, including cartilage, bone and hair, said Dr. Amir Dehdashti, director of cerebrovascular neurosurgery research at North Shore University Hospital in Manhasset, New York.

Teratomas can even contain lung or muscle tissue, or tissue of the gastrointestinal tract, said Dr. Adrienne Bonham, an associate professor of obstetrics and gynecology at the University of Rochester Medical Center.

Typically, during the development of a human embryo, germ cells migrate to the gonads. Teratomas are what can result if these germ cells end up in the wrong place, according to the Dana-Farber Cancer Institute. The most common places for teratomas are the ovaries, testes and the tailbone, according to the National Cancer Institute.

Read more at Discovery News

'Spider' Patterns on Pluto Await Spacecraft

Pluto is entering its ice geyser season – a time when sunlight hits the dwarf planet's icy north pole and triggers eruptions of nitrogen ice and gas that spray across the surface, possibly leaving dark spidery patterns.

That's what some astronomers and planetary scientists hope to see, anyhow, when the New Horizons spacecraft makes its flyby of the mysterious dwarf planet in July.

The evidence of lurking Plutonian spiders has come from some remarkable observations made over many years with ground telescopes and the Hubble Space Telescope, which can't resolve any details of Pluto's surface, but can confirm that unprecedented color and lighting changes have been underway in the last four years.

"We are pretty certain there is some kind of movement of frost," said Bonnie Buratti of NASA's Jet Propulsion Laboratory. The evidence is light curves collected by telescopes which show how the planet reflects light as it spins on its axis.

Those curves were compared to simulated light curves which assume there is no frost rising from polar ice caps and depositing in other places – darkening some places while lightening others. The modeled light curves do not match what astronomers have been seeing in recent years on the real Pluto.

"We compared it and for the last four years we've had substantial changes," Buratti told DNews.

The changes are happening at a time when Pluto is moving further from the sun, but it's also at a time when the north pole of the tilted planet is being turned towards the Sun. That creates a northern summer in the same way that summers happen on Earth. Buratti is the lead author on a paper about Pluto's discovery which has been accepted for publication by Astrophysical Journal Letters.

"We are pretty close to polar summer – so there is a lot of frost there to sublimate," she said, referring to the process where solid ice turns directly into gas, skipping the liquid phase.

The sun's rays – even at Pluto's current position 32 times further from the sun than Earth – should be enough to penetrate the nitrogen ice that's likely covering Pluto's polar cap. The ice could trap enough energy to covert some of the ice into pockets of gas. That gas would build up pressure until it blasts through the surface, spraying crystals of nitrogen ice all about in a sometimes spidery looking pattern.

This spider-making process would seem far-fetched, except that researchers have seen it before on other worlds.

"There are good analogues on the polar caps of Mars," said astronomer Will Grundy of Lowell Observatory in Arizona.

Vast amounts of carbon dioxide sublimate from martian polar caps when they are warmed by the sun, not only leaving telltale patterns on the surface, but also seasonally ramping up the atmospheric pressure of the entire Red Planet.

An even better analogue, however, is Triton, Neptune's giant moon. Triton is much colder and further from the sun than Mars, and it's thought to be a veritable twin of Pluto. Like Pluto, the primary gas at work on Triton is nitrogen (on Mars it's carbon dioxide). Two gas eruptions on Triton were witnessed by the Voyager 2 spacecraft way back in 1989.

Read more at Discovery News

Teeth Implicate Humans in Neanderthal Extinction

Ancient teeth from Italy suggest that the arrival of modern humans in Western Europe coincided with the demise of Neanderthals there, researchers said.

This finding suggests that modern humans may have caused Neanderthals to go extinct, either directly or indirectly, scientists added.

Neanderthals are the closest extinct relatives of modern humans. Recent findings suggest that Neanderthals, who once lived in Europe and Asia, were closely enough related to humans to interbreed with the ancestors of modern humans — about 1.5 to 2.1 percent of the DNA of anyone outside Africa is Neanderthal in origin. Recent findings suggest that Neanderthals disappeared from Europe between about 41,000 and 39,000 years ago.

Scientists have hotly debated whether Neanderthals were driven into extinction because of modern humans. To solve this mystery, researchers have tried pinpointing when modern humans entered Western Europe.

Modern human or Neanderthal?

The Protoaurignacians, who first appeared in southern Europe about 42,000 years ago, could shed light on the entrance of modern humans into the region. This culture was known for its miniature blades and for simple ornaments made of shells and bones.

Scientists had long viewed the Protoaurignacians as the precursors of the Aurignacians — modern humans named after the site of Aurignac in southern France who spread across Europe between about 35,000 and 45,000 years ago. Researchers had thought the Protoaurignacians reflected the westward spread of modern humans from the Near East — the part of Asia between the Mediterranean Sea and India that includes the Middle East.

However, the classification of the Protoaurignacians as modern human or Neanderthal has long been uncertain. Fossils recovered from Protoaurignacian sites were not conclusively identified as either.

Now scientists analyzing two 41,000-year-old teeth from two Protoaurignacian sites in Italy find that the fossils belonged to modern humans.

"We finally have proof for the argument that says that modern humans were there when the Neanderthals went extinct in Europe," study lead author Stefano Benazzi, a paleoanthropologist at the University of Bologna in Ravenna, Italy, told Live Science.

The researchers investigated a lower incisor tooth from Riparo Bombrini, an excavation site in Italy, and found it had relatively thick enamel. Prior research suggested modern human teeth had thicker enamel than those of Neanderthals, perhaps because modern humans were healthier or developed more slowly. They also compared DNA from an upper incisor tooth found in another site in Italy — Grotta di Fumane — with that of 52 present-day modern humans, 10 ancient modern humans, a chimpanzee, 10 Neanderthals, two members of a recently discovered human lineage known as the Denisovans, and one member of an unknown kind of human lineage from Spain, and found that the Protoaurignacian DNA was modern human.

"This research really could not have been done without the collaboration of researchers in many different scientific research fields — paleoanthropologists, molecular anthropologists, physical anthropologists, paleontologists and physicists working on dating the fossils," Benazzi said.

Killing off Neanderthals

Since the Protoaurignacians first appeared in Europe about 42,000 years ago and the Neanderthals disappeared from Europe between about 41,000 and 39,000 years ago, these new findings suggest that Protoaurignacians "caused, directly or indirectly, the demise of Neanderthals," Benazzi said.

It remains unclear just how modern humans might have driven Neanderthals into extinction, Benazzi cautioned. Modern humans might have competed with Neanderthals, or they might simply have assimilated Neanderthals into their populations.

Moreover, prior research suggests that Neanderthals in Europe might have been headed toward extinction before modern humans even arrived on the continent. Neanderthals apparently experienced a decline in genetic diversity about the time when modern humans began turning up in Europe.

"The only way we might have proof of how modern humans caused the decline of Neanderthals is if we ever find a modern human burying a knife into the head of a Neanderthal," Benazzi joked.

Read more at Discovery News

Virtual Telescope Readies to Image Black Hole's 'Ring of Fire'

With the addition of a telescope at the southern-most point of Earth, the Event Horizon Telescope (EHT) now spans the diameter of our planet and, when the vast project goes online, astronomers will get their first glimpse of the bright ring surrounding a supermassive black hole.

Using a method known as Very Long Baseline Interferometry, or VLBI, astronomers can combine the observing power of many telescopes situated at distant locations around the planet. The distance between those observatories, known as the “baseline,” then mimics a virtual telescope of that diameter. So, if you have telescopes dotted across one hemisphere of the globe, spanning 5,000 miles, you are, in effect, mimicking a giant telescope with a gargantuan diameter of 5,000 miles.

Of course, it isn’t a “simple” task of networking a bunch of telescopes and pointing them at a celestial object in the hope of gaining some usable data, but as interferometer communications hardware and computational software becomes more sophisticated, grand projects such as the EHT are starting to see the light of day. Or, in this case, the light generated by the invisible boundary surrounding a supermassive black hole.

Now, in an attempt to make direct observations of the supermassive black hole in the center of our galaxy, located at a powerful radio emission source called Sagittarius A*, the South Pole Telescope (SPT) at the National Science Foundation’s Amundsen-Scott South Pole Station has been linked to the EHT and the stage is set for a historic new era of exploring the most extreme objects in the known universe.

The SPT is a 10-meter telescope that is sensitive to millimeter wavelengths of radiation tasked with the day job of making high-resolution images of cosmic microwave background radiation, or CMB. By linking the observatory with the EHT, this telescope’s unique location will give the vast VLBI project a huge boost.

“Now that we’ve done VLBI with the SPT, the Event Horizon Telescope really does span the whole Earth, from the Submillimeter Telescope on Mount Graham in Arizona, to California, Hawaii, Chile, Mexico, Spain and the South Pole,” said Dan Marrone of the University of Arizona. “The baselines to SPT give us two to three times more resolution than our past arrays, which is absolutely crucial to the goals of the EHT. To verify the existence of an event horizon, the ‘edge’ of a black hole, and more generally to test Einstein’s theory of general relativity, we need a very detailed picture of a black hole. With the full EHT, we should be able to do this.”

It is predicted that when the EHT goes online, it will be 1,000 times more powerful than the Hubble Space Telescope and it will need all the power it can muster if we are to resolve the bright ring or crescent thought to surround the supermassive black hole in the Milky Way’s core. Although the supermassive black hole is 4 million times the mass of our sun, at a distance of 26,000 light-years, its predicted size will be tiny from our perspective.

“Because it is smaller than Mercury’s orbit around the sun, yet almost 26,000 light-years away, studying its event horizon in detail is equivalent to standing in California and reading the date on a penny in New York,” writes a University of Arizona press release.

But, should the EHT be able to achieve this monumental task, astrophysicists are getting excited for what we’ll see.

If our current understanding of how black holes work — and if some of the finer details of Einstein’s general theory of relativity holds up in the region immediately surrounding the black hole — we have a basic idea of what we’ll see. Although the event horizon is the point of no escape even for light and we shouldn’t see anything, just above the event horizon, extreme physics generate powerful radiation. In which case, the EHT should resolve a partial or full ring-like structure; energetic radiation glowing around a very definite dark shadow — this shadow being the event horizon.

And the best thing is, at that moment, when the event horizon ring is finally resolved, we’ll know whether or not black holes act as we expect. This will also be the first ever direct observations of the structure surrounding a black hole.

Read more at Discovery News

Hubble at 25: Space Telescope's Top Science Discoveries

Dark Energy

Hubble’s scientific bounty has benefited a wide range of astronomical and astrophysical fields, including the study of planets, moons and small icy bodies in the outer solar system and the cosmological history of the universe. Here’s a look at a few of Hubble’s greatest hits.

While scientists have published nearly 13,000 papers on Hubble-related studies, one topic earned researchers the 2011 Nobel Prize in Physics. In a pair of related investigations, astrophysicists Saul Perlmutter, with NASA’s Goddard Space Flight Center, Brian Schmidt, with the Australian National University, and Adam Riess, with Johns Hopkins University, discovered that the speed with which the universe is expanding is increasing.

The still-unexplained phenomenon, which would be akin to throwing a ball up in the air and having it pick up speed and keep going, is referred to as “dark energy.” Scientists used Hubble and ground-based telescopes to inventory a type of exploding star that puts out the same amount and type of radiation wherever it is found. The supernova can serve as a yardstick, since like a line of streetlamps, the closer ones will appear brighter than the lights of the same brightness that are farther away. Hubble has found these “standard candle” supernovas in nearby and very distant galaxies.

Exoplanets

Another field that didn't even exist when Hubble was launched 25 years ago is the study of planets beyond the solar system. Astronomers discovered the first so-called exoplanet in 1992. In 2008, a year before NASA’s planet-hunting Kepler space telescope was launched to look for Earth-sized worlds around distant stars, Hubble took the first visible-light snapshot of a planet beyond the solar system.

Estimated to be no more than three times Jupiter's mass, the planet, called Fomalhaut b, orbits the bright southern star Fomalhaut, located 25 light-years away in the constellation Piscis Australis (the Southern Fish). Astronomers followed up images of the star’s planet-forming dust ring with a photograph of a point source of light lying 1.8 billion miles inside the ring's inner edge.

Search for Life

The search for planets beyond the solar system is strongly motivated by the age-old question about whether life exists beyond Earth, a quest that also underpins the robotic exploration of Mars and the monitoring of radio waves for signs of extraterrestrial intelligence, among other projects.

Much of the cutting edge research uses a planet-hunting technique successfully demonstrated by NASA’s Kepler space telescope, which found thousands of planets as they passed in front of their parent stars, relative to the telescope’s line of sight. Hubble scientists used the so-called “transit” technique to chemically analyze starlight shining through a planet’s atmosphere. So far, Hubble has found carbon dioxide, organic molecules and even water vapor in the atmospheres of exoplanets.

Black Holes

Black holes, as the term implies, can’t be directly detected, so jammed full of matter that their gravitational fists traps even photons of light. But they leave telltale footprints on the stars, gas and dust that they encounter and consume. Hubble’s ability to make out the motions of stars and dust and the centers of galaxies provided evidence that a supermassive black hole lies at the heart of almost all galaxies (including our own Milky Way.) Astronomers believe galaxies and black holes grew up together, though exactly how that process unfolds is still a mystery.

Read more at Discovery News

Stunning Hubble Silver Anniversary Picture Unveiled

NASA kicked off a series of Hubble anniversary tributes Thursday by unveiling a new image taken by the telescope, which was launched into orbit on April 24, 1990.

Managers chose a display of celestial fireworks in a giant cluster of stars known as Westerlund 2, located about 20,000 light-years away in the constellation Carina.  The cluster, comprised of about 3,000 stars, is very young by astronomical standards, just about 2 million years old.

“This spectacular image shows a cloud of dense gas and dust, the gas is collapsing forming new stars,” said NASA’s chief scientist John Grunsfeld, an astronomer and former astronaut who was part of three different Hubble repair and servicing crews.

“It’s a very vigorous breeding ground for new stars … and it contains some of the galaxy’s hottest, brightest and most massive stars that we know of,” added Hubble project scientist Jennifer Wiseman, with NASA’s Goddard Space Flight Center in Greenbelt, Md.

“What’s great about Hubble’s sharp resolution, is that we can differentiate star from star even in crowded regions like this cluster. This helps us scientifically to be able to understand what kinds of stars are in this cluster, how they’re different from one another, how the population may have formed in the first place. We can study the characteristics because of Hubble’s exquisite sensitivity and resolution,” Wiseman said.

The image blends visible-light and near-infrared wavelengths. In the surrounding dust clouds, red represents hydrogen and the bluish-green hues are mostly oxygen.

“This is really an exciting a week for astronomers and people who love astronomy all over the world,” Wiseman said.

Read more at Discovery News

What Male and Female Stegosaurus Looked Like

Paleontologists are just now confirming what has long been suspected: male and female dinosaurs sometimes — and perhaps always — looked different from each other.

At least that appears to be true for Stegosaurus, a large plant-eating dinosaur living 150 million years ago, that sported rows of bony plates on top of its long back, and formidable-looking spikes at the end of its tail.

Authors of the new research, published in the journal PLOS One, argue it’s first convincing evidence for sexual differences in a species of dinosaur.

Initially, scientists Michael Benton and Evan Saitta thought that certain Stegosaurus-like skeletons represented different species. Then they started to realize that they were actually looking at male and female members of the same species.

“Evan made this discovery while he was completing his undergraduate thesis at Princeton University,” Benton, who is director of the Masters in Paleobiology Program at the University of Bristol, said in a press release.

Anatomical differences between males and females of the same species are collectively known as “sexual dimorphism.” Not all species exhibit this, but it’s obviously very common among living animals. Think of the manes of male lions, for example, or the antlers of male deer.

In the case of Stegosaurus, it appears that the primary difference had to do with the look and arrangement of their bony plates. Some Stegosaurus had wide plates while some had tall, with the wide plates being up to 45 percent larger than the tall plates.

Benton and Saitta studied Stegosaurus fossils unearthed in Montana. Puzzled by the plate variations, they CT-scanned samples from the plates, to see if the observed differences might reflect distinct growth stages. This was ruled out, however, because the bone tissues had ceased growing in both types.

The researchers also noted that the skeletal differences were not associated with a separation of ecological niches, which would have been expected if the two types were different species.

With these and other possibilities ruled out, Saitta concluded that the best explanation for the two varieties of plates is that one type belonged to males and the other to females.

“As males typically invest more in their ornamentation, the larger, wide plates likely came from males,” he explained. “These broad plates would have provided a great display surface to attract mates. The tall plates might have functioned as prickly predator deterrents in females.”

Read more at Discovery News

Dinosaur Egg Stash Found During China Roadwork

Road work in the southern China city of Heyuan was interrupted on Sunday when construction workers noticed something unusual in the ground — a fat stash of dinosaur eggs — 43, to be exact.

The discovery adds to an already impressive collection of dinosaur eggs discovered in the city, which calls itself "Home of Dinosaurs."

The Heyuan Dinosaur Fossil Museum was recognized with a Guinness World Record in 2004 for housing the largest collection of dinosaur egg fossils. That record was 10,008. Now that number will grow by 43.

Among the newly recovered eggs, 19 were fully intact and the largest was more than 7 inches in diameter.

Why so many dinosaur eggs in Heyuan? Was there something appealing there for brooding dinos back in the day? Apparently it has to do with the region’s soil.

Du Yanli, the museum's curator, told CCTV News, "The eggs were found in the rock strata of red sandstone, an environment in which other dinosaur egg fossils have also previously been found."

Most of the dinosaur eggs currently in the city's museum were deposited by oviraptorid and duck-billed dinosaurs, which roamed the Earth 89 million years ago. Cu Yanli said they will need to further examine the new eggs to determine what species of dinosaur laid them millions of years ago.

From Discovery News

Our 'Pale Blue Dot'

Check out the image above. Doesn't seem like much, does it? Maybe someone snapped a picture while the lens cap was still on.

Take another look. On closer examination, the picture resolves into four bands of light. Check out the band farthest to the right. Look about halfway down. There is a small dot, brighter than its surroundings. It isn't a speck of dust, it isn't a smudge on the camera lens or on your monitor.

It's us.

It's all of us.

It's Earth.

In 1990, at the request of famed astronomer and broadcaster Carl Sagan, NASA sent a command to the Voyager 1 spacecraft, on its way out of the Solar System, to turn its camera in the direction from which it came. The above image is the result.

The picture is frequently referred to as the "pale blue dot," and provided both the frontispiece and the title for one of Sagan's most celebrated books, published in 1994. Sagan himself, as was his wont, expressed its significance with an eloquence to which most of us can only aspire:

From this distant vantage point, the Earth might not seem of particular interest. But for us, it's different. Look again at that dot. [...] On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.

Read more at Discovery News

First Exoplanet Discovered by Reflected Visible Light

Astronomers have detected an exoplanet's visible-light spectrum directly for the first time ever, a milestone that could help bring many other alien worlds into clearer focus down the road.

The scientists used the HARPS instrument on the European Southern Observatory's 3.6-meter telescope at the La Silla Observatory in Chile to study the spectrum of visible light reflected off the exoplanet 51 Pegasi b, which lies about 50 light-years from Earth in the constellation Pegasus.

51 Pegasi b, a "hot Jupiter" gas giant that orbits close to its parent star, was spotted in 1995, when it became the first alien world ever discovered around a sunlike star. (The first exoplanets of any type were found in 1992 around a superdense, rotating stellar corpse called a pulsar.)

Researchers most often study exoplanet atmospheres by analyzing the starlight that passes through them when worlds cross their stars' faces from Earth's perspective. This method, known as transit spectroscopy, is restricted to use on systems in which the stars and planets align.

The new strategy used with 51 Pegasi b, on the other hand, does not depend on planetary transits and could thus find broader applicability, researchers said.

The technique offers other scientific advantages as well.

“This type of detection technique is of great scientific importance, as it allows us to measure the planet’s real mass and orbital inclination, which is essential to more fully understand the system," study lead author Jorge Martins, of the Instituto de Astrofísica e Ciências do Espaço (IA) and the Universidade do Porto in Portugal, said in a statement.

"It also allows us to estimate the planet’s reflectivity, or albedo, which can be used to infer the composition of both the planet’s surface and atmosphere," Martins added.

The new data suggest that 51 Pegasi b is highly reflective, a bit larger in diameter than Jupiter and about half as massive as our solar system's biggest planet, researchers said.

Read more at Discovery News