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Neutrino trackers solve a cosmic ray puzzle

Blazar and neutrino
In this artistic rendering, a blazar is accelerating protons that produce pions, which produce neutrinos and gamma rays. One neutrino’s path is represented by a blue line passing through Antarctica, while a gamma ray’s path is shown in pink. (IceCube / NASA Illustration)

An array of detectors buried under a half-mile-wide stretch of Antarctic ice has traced the path of a single neutrino back to a supermassive black hole in a faraway galaxy, shedding light on a century-old cosmic ray mystery in the process.

The discovery, revealed today in a flurry of research papers published by the journal Science and The Astrophysical Journal, marks a milestone for the IceCube Neutrino Observatory at the National Science Foundation’s Amundsen-Scott South Pole Station.

It also marks a milestone for an observational frontier known as multi-messenger astrophysics, which takes advantage of multiple observatories looking at the sky in different ways. Thanks to IceCube’s alert, more than a dozen telescopes were able to triangulate on the neutrino’s source.

“No one telescope could have done this by themselves,” said IceCube lead scientist Francis Halzen, a physics professor at the University of Wisconsin at Madison.

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Our view of black holes may change … again

Brian Greene
Columbia physicist Brian Greene delves into Albert Einstein’s theory of relativity in “Light Falls,” a theater piece that made its debut at the World Science Festival. (Greg Kessler Photo / World Science Festival)

After decades’ worth of mystery, it feels as if physicists are finally closing in on the nature of black holes, thanks to Nobel-winning breakthroughs like the first detections of black hole mergers at the Laser Interferometer Gravitational-wave Observatory.

But Columbia University physicist Brian Greene warns that those matter-gobbling monsters may have a few surprises in them yet.

“To watch the history of this subject unfold from a purely theoretical idea to one that now is driving observational tests is enormously exciting,” Greene told GeekWire.

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Number crunchers are on the trail of dark energy

Saul Perlmutter
Berkeley astrophysicist Saul Perlmutter discusses the implications of the universe’s accelerating expansion at the University of Washington. (GeekWire Photo / Alan Boyle)

Big data just might give astronomers a better grip on the answer to one of the biggest questions in physics: Exactly what’s behind the mysterious acceleration in the expansion rate of the universe, also known as dark energy?

And that means the number crunchers at the University of Washington’s DIRAC Institute have their work cut out for them.

The role of data analysis in resolving the mystery came to the fore on May 14 during a talk given at the DIRAC Institute’s first-ever open house on the UW campus. The speaker was none other than Berkeley astrophysicist Saul Perlmutter, who won a share of the Nobel Prize in physics in 2011 for finding the first evidence of dark energy.

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Stephen Hawking’s ‘Final Theory’ gets published

Hertog and Hawking
Belgian physicist Thomas Hertog meets with Stephen Hawking in 2015. (KU Leuven / Facebook)

Weeks after the death of British physicist Stephen Hawking, his final research paper on the nature of our universe and its place in the wider multiverse was published today in the Journal of High-Energy Physics.

Now it’s up to his co-author, Belgian physicist Thomas Hertog, to keep an eye out for observational evidence for or against Hawking’s “Final Theory.”

The pre-print version of the paper — titled “A Smooth Exit From Eternal Inflation?” — has been circulating for months. It addresses the rather mind-blowing idea that our universe is merely one of the many possible manifestations in a multiverse.

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Even after death, Stephen Hawking stirs up a fuss

Stephen Hawking
Physicist Stephen Hawking visited the Large Hadron Collider’s underground tunnel in 2013. (CERN Photo / Laurent Egli)

The ashes of the late British physicist Stephen Hawking will get a fitting resting place in Westminster Abbey, near the graves of Isaac Newton and Charles Darwin.

But you could argue that the true monuments to Hawking’s memory are his books and theoretical papers, delving into the nature of black holes, the big bang and other cosmic mysteries. And as was often the case during his life, the last paper he completed is stirring up a fuss just days after his death.

Hawking’s so-called “Final Theory” is a paper written with Belgian collaborator Thomas Hertog, and titled “A Smooth Exit from Eternal Inflation?” It hasn’t yet been published in a journal, but it’s said to be under review and is available for inspection on the ArXiv pre-print server.

The paper focuses on hypotheses having to do with cosmic inflation and the idea that our own cosmos is just one of many universes in a multiverse.

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Scientists say they’ve detected birth of first stars

First stars
This artist’s rendering shows the universe’s first, massive, blue stars embedded in gaseous filaments, with the cosmic microwave background just visible at the edges. (NSF Illustration / N.R. Fuller)

Astronomers have detected radio waves from a time within 180 million years of the Big Bang, and they say they see signs of what may be the first stars to coalesce in the infant universe.

The detection was made using an array of radio antennas that was set up in Australia for a project known as the Experiment to Detect the Global Epoch of Reionization Signature, or EDGES. Astronomers from Arizona, Massachusetts and Colorado reported their discovery in this week’s issue of the journal Nature.

“Finding this minuscule signal has opened a new window on the early universe,” lead investigator Judd Bowman of Arizona State University said in a news release. “Telescopes cannot see far enough to directly image such ancient stars, but we’ve seen when they turned on in radio waves arriving from space.”

Although the signal was difficult to detect, it was twice as dramatic as computer models predicted for the startup of the first stars. If the findings hold up, the models would have to be adjusted to account for the effect, and one possible explanation could involve interactions with dark matter.

“If that idea is confirmed, then we’ve learned something new and fundamental about the mysterious dark matter that makes up 85 percent of the matter in the universe,” Bowman said. “This would provide the first glimpse of physics beyond the standard model.”

Some astronomers counseled caution.

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Cosmic mappers win share of glitzy spotlight

WMAP map of cosmos
A color-coded projection map of the full sky shows temperature variations as measured by NASA’s Wilkinson Microwave Anisotropy Probe. (NASA Photo)

This year’s Breakthrough Prizes, cast as the “Oscars of Science,” are going to genetic engineers, disease fighters, math whizzes — and the scientists on the cosmos-mapping team behind the Wilkinson Microwave Anisotropy Probe, or WMAP.

Today’s award of $22 million in prizes is being wrapped into a ceremony at NASA’s Ames Research Center that combines Hollywood glitz with Silicon Valley brainpower.

Oscar-winning actor Morgan Freeman is the host for the show, which is being televised by National Geographic and streamed live via Facebook and YouTube at 7 p.m. PT tonight. Celebrity presenters include Ashton Kutcher (“That ’70s Show”); his wife, Mila Kunis (“Bad Moms”); and Kerry Washington (“Scandal”).

The prize program was established in 2012 by Russian billionaire Yuri Milner and his wife, Julia Milner, in league with Google co-founder Sergey Brin, 23andMe CEO Anne Wojcicki, and Facebook CEO Mark Zuckerberg and his wife, Priscilla Chan.

It ranks among science’s richest award programs, with seven $3 million prizes being awarded this year in life sciences, fundamental physics and mathematics. Another $1 million is going out to early-career scientists, students and teachers.

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This galaxy is made of 99.99% dark matter

Image: Dragonfly 44
The dark galaxy Dragonfly 44 appears to have about as much mass as our own Milky Way galaxy, but only 0.01 percent of that mass is in the form of stars and normal matter. The rest is dark matter, scientists say. (Credit: Pieter van Dokkum and Roberto Abraham / Gemini Observatory / AURA)

About 85 percent of the mass of the universe consists of mysterious stuff known as dark matter, but a galaxy called Dragonfly 44 appears to be even darker: 99.99 percent dark, according to newly published findings.

Dragonfly 44, which lies about 300 million light-years away in the Coma galaxy cluster, is the subject of a study published in the Astrophysical Journal Letters.

“It has so few stars that it would quickly be ripped apart unless something was holding it together,” Yale astronomer Pieter van Dokkum, the study’s lead author, said in a news release.

Van Dokkum and his colleagues tracked the motions of the stars in the galaxy using the Keck Observatory and the Gemini North telescope in Hawaii. The stars’ motions told the astronomers about the gravitational field surrounding Dragonfly 44.

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Maybe black holes aren’t as bad as we think

Image: Black hole
Here’s one concept for the look of a black hole. Image: Ute Kraus, [CC BY-SA 2.5] via Wikimedia Commons
Black holes may have gotten a bad rap. And wormholes just might be a realistic way to travel Star Trek-style after all.

Years ago, the traditional wisdom about those exotic cosmic phenomena was pretty forbidding: Once something fell into a black hole, it was gone for good. Not a trace of the information describing that thing could ever be recovered. This view gave rise to a famous saying from physicist John Wheeler: “Black holes have no hair.”

And wormholes? Sure, maybe you could theoretically create an extradimensional shortcut between two points in spacetime. But it would take loads of never-seen negative energy, and anything you sent through the wormhole would be blasted to bits by extreme tidal forces. Hence, movies ranging from “Contact” to “Star Trek” and “Interstellar” are far more fanciful than factual.

Two recently published studies run counter to those bits of traditional wisdom. They may shed new light on black holes – but don’t expect to rev up the wormhole time-travel machine anytime soon.

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Hubble sets new mark for farthest-out galaxy

Image: GN-z11
This image locates galaxy GN-z11 in the northern hemisphere field of the Hubble GOODS survey, which takes in tens of thousands of galaxies stretching far back into time. GN-z11, shown in the inset, is seen as it was 13.4 billion years in the past, just 400 million years after the big bang, when the universe was only 3 percent of its current age. (Credit: NASA / ESA / Oesch et al.)

Like the rockers in “This Is Spinal Tap,” astronomers cranked the dials on the Hubble Space Telescope up to 11 to identify what they say is the farthest-out galaxy ever detected, from a time when the universe was a mere 400 million years old.

The light from the galaxy in the constellation Ursa Major, known as GN-z11, was sent out 13.4 billion years ago, astronomers report in a study to be published in theAstrophysical Journal. That light-year measurement surpasses the distances that were recorded for two faraway galaxies over the past year.

The researchers say this record is likely to stand until NASA’s next-generation James Webb Space Telescope comes online.

“We’ve taken a major step back in time, beyond what we’d ever expected to be able to do with Hubble,” Yale astronomer Pascal Oesch said in a news release.

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