Some astronomers literally go to the ends of the Earth in search of data. That life-giving layer we know as the atmosphere can also be a plain ol’ nuisance when it comes to visual observing, and can make viewing in some wavelengths such as sub-millimeter, infra-red and X-ray next to impossible. Sure, viewing from space alleviates the problem, but payload weight tends to go at a premium and the line is long to use such premiere space telescopes as Hubble or Chandra. The solution? Many astronomers have taken to the Antarctic in the past decades, were the air is thin, dry, and the wonders of the southern hemisphere abound. Granted, its a harsh environment to operate in; remote, logistically tough to get to, and with wind whipping, bone chilling temps well below -100F, Antarctic astronomy is indeed an extreme sport. Most stations down under are seasonal, as when its winter in the northern hemisphere, its austral summer, and vice versa. Some projects can be operated in the continual daylight of Antarctic summer or remotely, while others require scientists to “winter over” with the skeleton crews at the South Pole and McMurdo station. Anyway, as the winter season comes to a close and spring/summer returns to the south pole, here’s a comprehensive list of whats up in Antarctic astronomy;
AST/RO: A South Pole 1st! (Credit: AST/RO/NSF/Harvard).
-The Antarctic Sub-millimeter Telescope and Remote Observatory AST/RO: This is first permanent observatory established at the South Pole. Sporting a 1.7 meter mirror and operating at sub-millimeter wave lengths, AST/RO was first established in January 1995. This scope has conducted analysis of dust clouds in this and other galaxies.
-South Pole Telescope (SPT): In many ways, AST/RO’s big brother and predecessor, the SPT also operates at microwave/and sub-millimeter wavelengths of 70 to 300 GHz, making the high Antarctic plateau an ideal locale (at 9,000 elevation) for its operation. A collaboration of no less than six universities and the Smithsonian, its funding like most Antarctic telescopes comes from the National Science Foundation (NSF). The scope itself is a 10 meter off-axis Gregorian, and with a 960 element bolometer array, and stands as the largest superconducting Transition Edge Sensor ever built.The SPT’s primary goal is to analyze distant galaxy clusters to pin down the dark energy constraints that are actually speeding up the expansion of the universe.
-Ice Cube Neutrino Observatory: This is literally one of the “coolest” and most exotic observatories “on ice”…(pun intended!) Ice Cube is designed to catch those ghostly particles in the act…neutrinos. With no charge and an infinitesimally small mass, neutrinos and anti-neutrinos are emitted during radioactive decay and fusion reactions such as the proton-proton process occurring in our Sun…monitoring neutrinos could tell us much about the interior solar structure, as well as give us an “early warning” system for detection of supernovae. The only problem is that they are extremely weakly interacting… your average neutrino could zip right through several light-years worth of lead like it was barely there. As you (and hopefully, not an intelligent spam-bot) sits there reading this, about 50 trillion solar neutrinos have passed through you body! Still, with such large numbers, a handful do occasionally interact. Ice Cube detects these by lowering long strings of photo multiplier senors into the ice down to about a depth of over two kilometers. There, the very pressure of the overlaying ice forces any air bubbles out, making it ultra-pure. Although most interactions seen will be caused by muon particles from cosmic rays, these can be identified because they tend to track from overhead. Any neutrinos caught will be coming from below, because the bulk of the Earth acts as an effective filter to strain out any other type of radiation. The last austral summer saw the installation of 19 more strings, bringing the grand total to 59. Ice Cube is now the largest “neutrino telescope” ever built. Construction is set for completion in 2011…now if they could get gangsta rapper Ice Cube as a spokesman…
- Antarctic Muon and Neutrino Detector Array: AMANDA was a forerunner and test bed for Ice Cube, and saw “first neutrino light” in 1996. Now officially incorporated in Ice Cube, AMANDA first proved that detection of cosmic rays and neutrinos in the ice sheet via their signature Cerenkov radiation was possible. Its chief advantage is that it can catch higher energy neutrinos than earlier detectors such as the Super-Kamiokande, owing to its vast volume. Its resolution, however, is lacking, due to its greater spacing. That’s where Ice Cube comes into play. Detectors like AMANDA and Ice Cube may even give us observational proof of String-theory, which would be sure to land a Nobel on someones’ doorstep!
BLAST: As reported in News & Notes a few months back, the Balloon-borne Large Aperture Sub-millimeter Telescope (known collectively as BLAST) was a 2 meter telescope suspended from a balloon and flown in both the Arctic and Antarctic. A very awesome documentary on BLAST has also been recently released, which will be the topic of this weeks’ up and coming astro-review!
Projects out of the National Scientific Balloon facility: Based just outside of the sprawling complex that is McMurdo station, BLAST isn’t the only scientific balloon payload that’s been launched from there as of late;
ANITA: This was the ANtarctic Impulsive Transient Antenna designed to detect extremely high-energy cosmic rays and neutrinos generated by exotic objects such as black holes via the Askaryan effect. Flying at an altitude of 120,000 feet, ANITA was launched in December of 2006.
CREAM: The Cosmic Ray Energetics And Mass experiment, this flew for three seasons starting in 2004 and was designed to detect cosmic ray elemental spectra and serve as a calibration for ground based instruments.
ULDB: Supporting the CREAM instrument payload, the Ultra-Long Duration Balloon (ULDB) could practically be considered a spacecraft in its own right and holds the heavy load duration for a balloon set at 54 days, 1 Hour and 29 minutes.
A space rock is collected and recorded on the ice sheet. (Credit: Linda Martel/NSF/NASA).
Meteor Hunting: Antarctica is prime meteorite hunting country. While meteors in your backyard get mixed in, buried and eroded by on-going environmental processes, extraterrestrial rocks that fall on the Antarctic ice sheet are typically well preserved and periodically calve off and stand out in stark contrast to the bleak icy terrain.The NSF and the Annual Search for Meteorites (ANSMET) run the primary search missions each season..Teams of six conduct scouting sweeps via snowmobile along the Trans-antarctic Mountains, a transition zone where meteorites are continuously flaking off the high plateau onto the vast continental ice sheet. Teams live on the ice for sometimes months at a time. Once a potential space rock is spotted, a GPS reading is taken, the suspect rock is bagged and tagged, and it begins its long journey back to McMurdo, the Johnson Space Center, and ultimately the Smithsonian for storage. Among the more famous meteorites discovered in Antarctica is ALH84001, the controversial “Mars meteorite” thought to contain fossilized Martian bacteria!
The pre-HEAT module. (Credit: Xu Zhou & Zhenxi Zhu).
(Attack of the) Automated Observatories: Of course, some of the observatories on the continent are extremely remote, and robotic, to boot. These are often known as the Automated Geophysical Observatories (AGO). These forlorn outposts scattered about the high plateau are serviced by seasonal teams and silently scan the skies during the long Antarctic winter. Recently, the US, China, and Australia have teamed up to create a fully automated observatory operating in the most pristine skies on Earth; named the Plateau Observatory (or PLATO for short) it sits over 4km above sea level in some of the driest skies on Earth. Solar powered when the Sun is above the horizon, diesel generators hum through the winter. Currently boasting a battery of seven telescopes, a larger 10 inch predecessor to the pre-HEAT telescope, (the High Elevation Antarctic Terahertz telescope) is destined for Dome A in 2010.
As you can see, Antarctic astronomy has really taken off in the past decade. Watch this space for any late breaking discoveries from down under. Indeed, its remarkable what with the pace of cosmological discoveries being made, more isn’t heard from this burgeoning field. Research for this piece was tough, telling us that there is definitely room for more Antarctic science reporting! Any expeditions looking to break new ground with their very own embedded astro-blogger? And of course, let’s not forget the other band of science geeks trapped together for the season in the Arctic; watch for the season 3 premiere for CBS’s Big Bang this September 21st!
Coming up next as part of our “Antarctic astronomy month” here at Astroguyz… Blast! Astrophysics Indiana Jones style!