Science Now
Discoveries from the world of science and medicine
Astronomers find 'new' dwarf galaxy in Milky Way's neighborhood

Hey, neighbor! Astronomers searching the sky with NASA’s Hubble Space Telescope have discovered an odd little dwarf galaxy in our very own backyard -- a mere 7 million light years away.

The findings, described in the Monthly Notices of the Royal Astronomical Society, add a new member to the more than 50 galaxies in our Local Group (part of the Laniakea supercluster), which includes Andromeda and our own Milky Way.

While only just recently discovered using Hubble's Advanced Camera for Surveys, the galaxy known as KKs3 has been around for a long while. Astronomers led by Igor Karachentsev of the Special Astrophysical Observatory in Karachai-Cherkessia, Russia, showed that some 74% of KKs3’s star mass was formed in the universe’s early years, at least 12 billion years ago. Most of the tiny galaxy’s stars are old and dim, making it a fascinating fossil that could help astronomers understand what ancient galactic environments looked like.

Carrying just 23 million solar masses’ worth of...

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Of mice and men: Researchers point to differences in cell development

Scientists say they have discovered a key factor in the lab formation of human primordial germ cells -- the precursors to egg and sperm -- and that it differs significantly from experiments involving rodent cells.

In a paper published Wednesday in the journal Cell, researchers at the University of Cambridge in England and the Weizmann Institute of Science in Israel said their discovery raises questions about how much mouse experiments can tell us about early human cell development.

The research, according to study authors, suggests that "mechanisms of early cell fate decisions in mice cannot be safely or wholly extrapolated to specification events during early human development."

Mouse cells have been used to study primordial germ cells, or PGCs, for well over a decade, and up until recently, the only PGC cells created in the lab were created using mouse cells. 

In nature, PGCs arise early in the growth of an embryo, as embryonic stem cells begin to differentiate into basic cells. PGCs...

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Dazzling! NuSTAR captures sun's portrait in solar X-rays

It’s time to see the sun in a whole new light – X-ray light. NASA’s NuSTAR space telescope has taken a stunning portrait of our home star in high-energy X-rays.

The related research, presented at the American Geophysical Union meeting in San Francisco this month, could offer scientists a new tool to investigate the mysterious dynamics of the sun.

NASA’s Nuclear Spectroscopic Telescope Array was launched in 2012 to study the high-energy physics of the universe, from black holes to supernovas. So when UC Santa Cruz solar physicist David Smith, a NuSTAR team member, asked lead scientist Fiona Harrison whether they could use the space telescope to observe the sun, the Caltech astrophysicist was dubious at first.

“I was quite skeptical,” Harrison said in an interview. After all, NuSTAR was meant to explore distant, high-energy targets, not the one star we can see all day long.

But Harrison soon came around to the idea, because NuSTAR could solve a long-standing mystery about the sun: How...

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Rosetta postcard: Could you jump from these cliffs?

While Philae rests quietly on the dark surface of comet 67P/Churyumov-Gerasimenko, the European Space Agency's Rosetta orbiter is continuing to snap amazing images of the comet's nucleus and beam them back to Earth.

The picture above was taken Dec. 10 by Rosetta's NavCam when the orbiter was 12.5 miles away. The smaller lobe of the rubber-duck-shaped comet is on the right side of this picture, and the larger lobe is on the left. The smooth-looking slope with the boulders is the comet's skinny neck.

NASA's website featured a slightly altered image of the cliffs as its astronomy picture of the day Tuesday. NASA's version highlights the steepness of the jagged cliffs seen above. 

The authors of the NASA page write that the wall of the cliff rises about 1 kilometer (0.6 of a mile) high. That may sound treacherous, but because the comet's gravity is low -- Earth's gravity is several hundred thousand times stronger -- a person could probably jump off the edge and land without getting hurt....

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FDA to ease longtime ban on blood donations from gay men

For the first time since the early days of the AIDS epidemic, gay and bisexual men will be permitted to donate blood under rules set for release next year by the Food and Drug Administration.

Officials at the federal agency said Tuesday that they would relax their long-standing ban on donations from men who have had sex with another man at least once since 1977. Instead, these men will be allowed to roll up their sleeves if they are free of HIV and have not engaged in homosexual activity for at least one year.

Though less visible than the struggle to allow gays to serve openly in the military or the effort to legalize same-sex marriage, the campaign to end the 31-year ban on blood donation has become an important cause for those who see it as homophobic and unfair. The FDA was caught between the civil rights of prospective gay donors and its mandate to protect public health.

The FDA’s decision came a few weeks after a panel of independent experts concluded that imposing a waiting...

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Invasive species get by with a little help from their alien friends

Scientists call it "invasional meltdown," and it's the theory that once an alien species takes root in a new land, it opens the door to intrusions from other invading organisms.

In a paper published Tuesday in the Proceedings of the Royal Society B, Canadian researchers suggest that just such a meltdown may be occurring  in some North American forests.

Specifically, a tiny, stinging Eurasian invader is hastening the spread of a greater celandine, a yellow-flowered herb that entered North America from Europe, according to researchers.

"Ecologists think invasive species might help each other to spread," said senior author Megan Frederickson, an evolutionary biologist at the University of Toronto.

"Our results suggest that invasional meltdown could be happening right under our noses here in Ontario," she said in a statement.

In a series of lab and outdoor experiments, Frederickson and her colleagues focused their attention on the behavior of Myrmica rubra, or the European fire ant, which...

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