Friday, June 26, 2009
50 Trillion every second!
According to Wiki,
"Neutrinos (meaning: "Small neutral ones") are elementary particles that often travel close to the speed of light, lack an electric charge, are able to pass through ordinary matter almost undisturbed and are thus extremely difficult to detect. Neutrinos have a minuscule, but nonzero mass. They are usually denoted by the Greek letter ν (nu).
Neutrinos are created as a result of certain types of radioactive decay or nuclear reactions such as those that take place in the Sun, in nuclear reactors, or when cosmic rays hit atoms. There are three types, or "flavors", of neutrinos: electron neutrinos, muon neutrinos and tau neutrinos;
Most neutrinos passing through the Earth emanate from the Sun, and more than 50 trillion solar electron neutrinos pass through the human body every second."According to the IceCube website,
"The IceCube Neutrino Detector is a neutrino telescope currently under construction at the South Pole. Like its predecessor, the Antarctic Muon And Neutrino Detector Array (AMANDA), IceCube is being constructed in deep Antarctic ice by deploying thousands of spherical optical sensors (photomultiplier tubes, or PMTs) at depths between 1,450 and 2,450 meters. The sensors are deployed on "strings" of sixty modules each, into holes in the ice melted using a hot water drill.
The main goal of the experiment is to detect neutrinos in the high energy range, spanning from 1011eV to about 1021 eV. The neutrinos are not detected themselves. Instead, the rare instance of a collision between a neutrino and an atom within the ice is used to deduce the kinematical parameters of the incoming neutrino. Current estimates predict the detection of about one thousand such events per day in the fully constructed IceCube detector. Due to the high density of the ice, almost all detected products of the initial collision will be muons. Therefore the experiment is most sensitive to the flux of muon neutrinos through its volume. Most of these neutrinos will come from "cascades" in Earth's atmosphere caused by cosmic rays, but some unknown fraction may come from astronomical sources. To distinguish these two sources statistically, the direction and angle of the incoming neutrino is estimated from its collision by-products. One can generally say, that a neutrino coming from above "down" into the detector is most likely stemming from an atmospheric shower, and a neutrino traveling "up" from below is more likely from a different source.
The sources of those neutrinos coming "up" from below could be black holes, gamma ray bursters, or supernova remnants. The data that IceCube will collect will also contribute to our understanding of cosmic rays, supersymmetry, weakly interacting massive particles (WIMPS), and other aspects of nuclear and particle physics.
Congratulations! I didn't expect you to actually read this far. Your reward - pictures - are oh so close - Yay!
So, to condense what was described above, Ice Cube is a series of 47 holes, each drilled 1 km deep into the Plateau polar ice. Each hole is stuffed with a string of 60 sensors. The result is a sqaure km 'cube' in the ice, which is used to detect neutrinos. Scientists are searching for the neutrino's that have passed all the way through the Earth, through the Antarctic continent, and through the polar cap. Basically, they are using the polar ice cap as a filter, to distinguish between neutrino's from the sun and neutrino's from elsewhere in the universe. These distant neutrino's, once detected, indicate the location of a massive, distant energy sources.
Inside the red shack is a generator that heats the water for the hot water drill. The km deep holes require a very long hoses to deliver the hot water to the drillhead.
Thursday, June 25, 2009
The Antarctic Tourists
Being baffled about the motivations behind a trip to the Antarctic, however, is something that I came to understand a little better this season.
Each year, the South Pole Station receives a large number of tourists. Some fly in, some drive, and some ski. The first two categories of tourists are people who simply want a picture at the South Pole (That hero shot will cost them tens of thousands of dollars). On the other hand, the breed of tourist that ski's in . . . well, that baffles me for different reasons. To spend 40 or 50 days, trudging through the monotony of the flat white, with no scenery, no sunset, no support, no landmarks, in the most extreme of conditions, risking life and limb, literally, to reach a particular latitude, whose only significance is that mapmakers termed it "The South Pole". This is a strange reason to risk your life, to invest years in fund-raising and training, to drag your loved ones through hell, to push your body to it's limits. The South Pole is a meaningless point on the map, that looks exactly like every other point on the Polar plateau. It baffles me, but I also understand that some people are simply driven to do certain things, to meet certain challenges, to push oneself for the purpose of pushing oneself - its a drive that cannot and should not be ignored.
This season, a man named Todd Carmichael (pictured above) set the land record for unassisted and unaided travel to the South Pole from the coast (over 700 miles in just over 39 days). His story is an incredible one, and I do not have time to do it justice here, but I would recommend reading up on his adventures (this is his website: http://www.subzerosolo.com/). After Todd arrived at the South Pole, dizzied and frost bit, he was welcomed into the station and received medical care. After a brief recovery time, he gave a short presentation about his expedition. Of the many incredible things he spoke of, one thing stuck out in mind. He said, "This is a cool community - I know it because, I've been here for a few days, and nobody has asked my 'why' yet".