New EINSTEIN@HOME effort launched March 25, 2009Posted by jcconwell in Astronomy, Neutron Stars.
Tags: Astronomy, neutron star
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Einstein@Home, based at the University of Wisconsin–Milwaukee (UWM) and the Albert Einstein Institute (AEI) in Germany, is one of the world’s largest public volunteer distributed computing projects. More than 200,000 people have signed up for the project and donated time on their computers to search gravitational wave data for signals from unknown pulsars.
Today, Prof. Bruce Allen, Director of the Einstein@Home project, and Prof. Jim Cordes, of Cornell University and Chair of the Arecibo PALFA Consortium, announced that the Einstein@Home project is beginning to analyze data taken by the PALFA Consortium at the Arecibo Observatory in Puerto Rico. The Arecibo Observatory is the largest single-aperture radio telescope on the planet and is used for studies of pulsars, galaxies, and the Earth’s atmosphere. Using new methods developed at the AEI, Einstein@Home will search Arecibo radio data to find binary systems consisting of the most extreme objects in the universe: a spinning neutron star orbiting another neutron star or a black hole. Current searches of radio data lose sensitivity for orbital periods shorter than about 50 minutes. But the enormous computational capabilities of the Einstein@Home project (equivalent to tens of thousands of computers) make it possible to detect pulsars in binary systems with orbital periods as short as 11 minutes.
“Discovery of a pulsar orbiting a neutron star or black hole, with a sub-hour orbital period, would provide tremendous opportunities to test General Relativity and to estimate how often such binaries merge,” said Cordes. The mergers of such systems are among the rarest and most spectacular events in the universe. They emit bursts of gravitational waves that current detectors might be able to detect, and they are also thought to emit bursts of gamma rays just before the merged stars collapse to form a black hole. Cordes added: “The Einstein@Home computing resources are a perfect complement to the data management systems at the Cornell Center for Advanced Computing and the other PALFA institutions.”
Astronomy Club: Gamma Ray Bursts March 23, 2009Posted by jcconwell in Astronomy, Gamma Ray Bursts.
Tags: Astronomy, EIU, Gamma Ray Burst
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Gamma Ray Bursts will be the topic of Robert Gaki’s talk this Wednesday at 8:00PM in Room 2153, Physical Science Building. Robert, who’s a club member, will be discussing, what many people think, are the most mysterious and violent explosions short of the big bang.
Still more space debris! March 16, 2009Posted by jcconwell in Astronomy, Uncategorized.
Tags: Space Shuttle
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(From CNN) A piece of an old Soviet-era satellite spinning through space could threaten the International Space Station overnight, NASA said Monday. On its current course, the piece of the Russian Kosmos 1275 will arrive about a half a mile (.79 kilometers) from the space station at 2:14 a.m. CDT Tuesday, said Bill Jeffs, a spokesman at Johnson Space Center in Houston, Texas.
NASA may decide to conduct a “debris avoidance maneuver,” which involves firing rockets so that the space station moves in a direction away from the debris’ path, Jeffs said. Officials were monitoring the debris closely and planned to decide by 6 p.m. whether to carry out the maneuver.Jeffs said the dimensions of the satellite debris are not known.
Three people are on the space station, astronauts Mike Fincke and Sandy Magnus and cosmonaut Yury Lonchakov .
Last week, a piece of debris forced the crew to take shelter in its escape capsule, a rare close call for the orbiting platform, NASA said.
Extreme Universe: Magnetic Fields and Magnetars March 12, 2009Posted by jcconwell in Astronomy, Extreme Universe, Gamma Ray Bursts, Neutron Stars.
Tags: Astronomy, Gamma Ray Burst, magnetar, neutron star
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Neutron Stars are extreme to begin with, but magnetars add a whole new level of extreme to these exotic objects. Magnetars, as the name implies, are neutron stars with ultra high magnetic fields. As a matter of fact, the most extreme magnetic fields ever found in the universe!
There are about 15 magnetars known, they are all examples of a class of objects called “soft gamma repeaters” . The most magnetic one, and the most magnetized object in the known universe is SGR 1806-20. The magnetic field of this magnetar is estimated to be about 2 x 1011 Teslas or 2 x 1015 gauss, one Tesla being equal to 10,000 gauss.
Now, to give you some sense of how big this is, the Earth’s magnetic field is about 1/2 gauss or .00005 Tesla. The magnet in a hospital’s MRI is about 3.2 Tesla or 32,000 gauss, and the largest sustained magnetic field created in a lab is about 40 Tesla.
So we’re talking about magnetic fields 1000 trillion times bigger than the Earth’s field. Very weird things can happen with fields this large. One thing that’s interesting is how much energy is stored in such a field. So let’s break out an equation from physics and use an example I did in my electricity & magnetism class last week. If you look it up, you’ll find the energy per cubic meter, or energy density, of a magnetic field is given by:
u = B2/2 μ0
u is the energy density given in Joules per cubic meter. A Joule is the energy you use to lift a kilogram about 10 centimeters off the ground.
B is the strength of the magnetic field given in Teslas, and μo is a constant that has a value of 4π x 10-7 (it has units , but we’ll ignore them). Using a field of B = 2 x 1011 Teslas, the most powerful magnetar, we will get a huge number…
1.6 x 1028 Joules/(cubic meter)
or every cubic meter contains this amount of energy. To put this in context, the largest hydrogen bombs have a yield of 20 Megatons of TNT, which is about 1017 Joules of energy. So in each cubic meter of magnetic field has the stored energy of 160,000,000,000 (160 billion), 20 Megaton bombs.
Since we’re having so much fun, lets think about it this way. Einstein showed mass and energy are equivalent, so how much mass would one cubic meter of this HUGE magnetic field have? Well…
or m = E/ c2 = 1.6 x 1028 Joules/(3 x 108m/s)2 = 1.78 x 1011kilograms
Each cubic centimeter of magnetic field would have a mass of 178 metric tons!!! If you multiply this by the number of cubic meters in the Magnetar, about 40 trillion, assuming the whole neutron star is magnetized, you get a lot of magnetic energy stored in Magnetar.
To give you an idea of what a small amount of this energy would do, consider the events of December 27, 2004. On that day the magnetar we’ve been using as a example, SGR 1806-20, under went a “superflare”. The “superflare,” from a magnetar named SGR 1806–20, irradiated Earth with more total energy than a powerful solar flare. Yet this object is an estimated 50,000 light-years away in Sagittarius. During that flicker of time it outshone the full Moon by a factor of two. The gamma rays struck the ionosphere and created more ionization which briefly expanded the ionosphere. Assuming that the distance estimate is accurate, the magnetar must have let loose as much energy as the Sun generates in 250,000 years.
Astronomy Club Tonight: INFLATION March 11, 2009Posted by jcconwell in Astronomy.
Tags: Astronomy, EIU
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Not the economic type! Come to Room 2153, Physical Science Building, at 8:00PM. and hear Josh Hawkins talk about the inflationary universe.
Tags: Archeoastronomy, Astronomy, Doudna, EIU, International Year of Astronomy, IYA 2009
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Come join us at 7:00pm tonight. Learn about the recently discovered Anasazi astronomical shrine sites, with Professor Jim Krehbiel, chair of Fine Arts at Ohio Wesleyan University. The talk is in the new Doudna fine arts center Lecture hall, room 1210.
Come see the IYA gallery in Physical Science March 3, 2009Posted by jcconwell in Astronomy, IYA 2009.
Tags: Astronomy, EIU, International Year of Astronomy, IYA 2009
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Come to the second floor of the physical science building and see the Physics department’s astronomical murals in celebration of the International Year of Astronomy (IYA). These are full color, full resolution pictures (at least 100 megabytes each ), over four feet on a side, with explanation of each photo. Five are now up, with more being added weekly.
IYA at EIU: Prof. Jim Krehbiel, One Week From Today March 2, 2009Posted by jcconwell in Astronomy, IYA 2009.
Tags: Doudna, EIU, International Year of Astronomy, IYA 2009
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Art and Archaeoastronomy:
Anasazi Astronomical Shrine Sites
Our second speaker for the International Year of Astronomy at Eastern is Jim Krehbiel M.F.A. , Chair of Fine Arts at Ohio Wesleyan University. Professor Krehbiel will talk about his exploration, photography and subsequent artwork regarding architecture, art and astronomy of the Ancestral Pueblo People (Anasazi) in the canyons of Cedar Mesa, Utah.
The illustrated presentation, which is part of International Year of Astronomy events at EIU, will take place in the Doudna Fine Arts Center’s Lecture Hall (Room 1210), at 7 p.m. Monday, March 9, at Eastern Illinois University. It is free, and the public is invited.