Neutrino telescopes launch new era of astronomy

This image shows the highest energy neutrino ever observed (1.14 petaelectronvolts), which scientists named ‘Ernie,’ as seen by the IceCube Neutrino Observatory at the South Pole on Jan. 3, 2012. Image released Nov. 21, 2013. (ICECUBE COLLABORATION)

The recent discovery of neutrino particles bombarding Earth from outer space has ushered in a new era in neutrino astronomy, scientists say.

Neutrinos are produced when cosmic rays interact with their surroundings, yielding particles with no electrical charge and negligible mass. Scientists have wondered about the source of cosmic rays since they were discovered, and finding cosmic neutrinos could provide clues about the origin of the mysterious rays.

In November, a team of scientists announced the discovery of cosmic neutrinos by the giant IceCube Neutrino Observatory in Antarctica. [Neutrinos from Beyond the Solar System Found (Images)]

“We now have the opportunity to determine what the sources are, if we are indeed seeing sources of cosmic rays,” said Francis Halzen, principal investigator of the IceCube observatory and a theoretical physicist at the University of Wisconsin-Madison. “The big difference why it’s new astronomy is that we are not using light, we are using neutrinos to look at the sky.”

Cosmic visitors
Neutrinos are the social misfits of the particle world — they rarely interact with matter. Produced in some of the most violent, but unknown, events in the universe, they travel to Earth at close to the speed of light and in straight lines, which reveals information about their origin. Supernovas, active galactic nuclei and black holes are some of the possible sources for these ghostly particles.

Until recently, scientists had only detected neutrinos beyond Earth from the sun or from a supernova in the Large Magellanic Cloud in 1987. No neutrinos from distant cosmic sources had been seen.

But in April 2012, IceCube recorded two neutrinos with extremely high energies — almost a billion times that of the ones found in 1987 — that could only have come from a high-energy source outside the solar system. After looking deeper into the data, scientists found a total of 28 high-energy neutrinos with energies greater than 30 teraelectronvolts (TeV), reporting their finding in the journal Science.

The finding opens the door to a new kind of astronomy that would “image” the sky in the light of neutrinos, rather than photons. “Each time we find another way to make a picture of the sky — using gamma rays, X-rays, radio waves — you have always been able to see things you never saw before,” Halzen told SPACE.com.

The successful completion of IceCube and the prospect of other telescopes on the horizon have set the neutrino world abuzz.

“It is the point in time when it becomes real,” said Uli Katz, an astrophysicist at the University of Erlangen-Nuremberg in Germany, who is helping spearhead KM3NeT, a planned neutrino telescope in the Mediterranean Sea.

Neutrino telescopes
The idea of neutrino detectors goes back to the 1950s, when Clyde Cowan and Frederick Reines first detected neutrinos from a nuclear reactor. Later, scientists detected solar neutrinos and atmospheric neutrinos.

Because neutrinos interact so weakly with other particles, you have to have a very large amount of matter in order to detect them. When neutrinos smash into protons or neutrons inside an atom, they produce secondary particles that give off a blue light called Cherenkov radiation. You need a large, transparent detector shielded from daylight to see them, so scientists build them deep underwater or embedded in ice.

The Deep Underwater Muon And Neutrino Detector  (DUMAND) Project was a proposed underwater neutrino telescope in the Pacific Ocean near the island of Hawaii. The observatory would have stretched nearly 0.25 cubic miles of ocean more than 3 miles beneath the surface. Started in 1976 but canceled in 1995, DUMAND paved the way for successor projects.

Scientists built the Antarctic Muon And Neutrino Detector Array (AMANDA) in the ice beneath the South Pole, which ultimately became part of the IceCube observatory. IceCube, which was completed in 2010, consists of a cubic kilometer grid of sensors embedded below 4,900 feet of ice.

In Europe, scientists are developing plans for KM3NeT, which will span 1.2 cubic miles in the Mediterranean. And scientists at the Baikal Neutrino Telescope in Russia’s Lake Baikal, the largest freshwater lake by volume in the world, are planning to build the Gigaton Volume Detector (GVD), which would be one cubic km.

The latest neutrino telescopes will enable more than just new astrophysics. Scientists are starting to use them to look for dark matter, the unknown substance that makes up roughly 85 percent of the total matter in the universe. In addition, being able to detect high-energy neutrinos will enable new particle physics that even the best particle accelerators can’t achieve.

“I expect lot of effort will be invested to increase this field in its capabilities,” Katz said.

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New Exoplanet Hunter Directly Images Alien Worlds

Gemini Planet Imager’s ‘first light’ image of Beta Pictoris b, an exoplanet orbiting the star Beta Pictoris.

A new instrument, attached to one of the most powerful telescopes in the world, has opened its infrared eye for the first time, taking snapshots of a nearby planet orbiting another star and a ring of proto-planetary stellar dust.

The sophisticated car-sized instrument, called the Gemini Planet Imager (GPI), is attached to the 8-meter Gemini South telescope in Chile and represents a new era in exoplanetary discovery. The GPI, which has been in development since 2003, is capable of not only resolving the dim light from an exoplanet orbiting close to its parent star; it can also analyze the planet’s atmospheric composition and temperature.

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The majority of ground-based exoplanet surveys watch for stars’ “wobbles” to betray the gravitational presence of massive exoplanets in orbit — known as the “radial velocity technique.” Another powerful technique for discovering smaller exoplanets in tight orbits around their star is employed by NASA’s Kepler space telescope. As an exoplanet passes in front of its host star, a small dip in brightness can be detected by Kepler’s sensitive optics – this is known as a “transit.”

Other methods for exoplanetary detection are possible (such as microlensing), but the “Holy Grail” for astronomers is to use a powerful telescope to directly image star systems, picking out tiny dots of light in orbit. This feat has been achieved a handful of times (most notably the 2008 Hubble and Keck/Gemini announcements of directly imaging exoplanets around the stars Fomalhaut and HR 8799) its wholesale use as an effective exoplanet-hunting tool has been limited by technology, a limit that the GPI has now dramatically lifted.

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Through the ingenious combination of adaptive optics — a laser system used on some observatories that can actively counteract the blurring effects of turbulence in the Earth’s atmosphere — and an active obscuring coronagraph perfectly covering the star (to counteract the glaring effect of the starlight), GPI has the power to distinguish star from exoplanet to unparalleled precision.

“Most planets that we know about to date are only known because of indirect methods that tell us a planet is there, a bit about its orbit and mass, but not much else,” said Bruce Macintosh of the Lawrence Livermore National Laboratory, who led the team that developed GPI. “With GPI we directly image planets around stars — it’s a bit like being able to dissect the system and really dive into the planet’s atmospheric makeup and characteristics.”

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Photos from Shackleton’s expedition found in Antarctica ice

This recovered image shows Alexander Stevens, the chief scientist and geologist of the Ross Sea Party, on the deck of the Aurora in McMurdo Sound, Antarctica. (ANTARCTIC HERITAGE TRUST, WWW.NZAHT.ORG)

Antarctic Heritage Trust conservators recently made a stunning discovery: a box of 22 exposed but unprocessed negatives, frozen in a block of ice for nearly one hundred years.

The negatives were recovered from a corner of a supply hut that British explorer Robert Falcon Scott established to support his doomed expedition to the South Pole from 1910-1913. Scott and his men reached the South Pole but died on the trip home.

The hut was next used by the Ross Sea Party of Sir Ernest Shackleton’s 1914-1917 Imperial Trans-Antarctic Expedition after they were stranded on Ross Island when their ship, the Aurora, blew out to sea.

This party is believed to have left behind the undeveloped negatives.

 

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Ancient textile may contain lost Biblical blue dye, Israeli researcher says

Dec. 31, 2013: A nearly 2,000-year old textile that appears to contain a mysterious blue color described in the Bible, one of the few remnants of the ancient color ever discovered. (AP PHOTO/CLARA AMIT, ISRAEL ANTIQUITIES AUTHORITY, HOPD)

JERUSALEM –  An Israeli researcher says she has identified a nearly 2,000-year old textile that may contain a mysterious blue dye described in the Bible, one of the few remnants of the ancient color ever found.

Naama Sukenik of Israel’s Antiquities Authority said Tuesday that recent examination of a small woolen textile discovered in the 1950s found that the textile was colored with a dye from the Murex trunculus, a snail researchers believe was the source of the Biblical blue.

Researchers and rabbis have long searched for the enigmatic color, called tekhelet in Hebrew. The Bible commands Jews to wear a blue fringe on their garments, but the dye was lost in antiquity.

Sukenik examined the textile for a doctorate at Bar-Ilan University and published the finding at a Jerusalem conference Monday.

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