UW-Madison: Dark energy to be topic of Space Place event

"To Infinity and Beyond: The Accelerating Universe," a live broadcast from the World Science Festival about dark energy, an antigravitational force that confounds the conventional laws of physics, will be hosted on the evening of May 28 by UW-Madison'sSpace Place.

Originating from New York and moderated by internationally known theoretical physicist and bestselling author Lawrence Krauss, the broadcast will take place from 7 to 8:30 p.m. Thursday. Space Place, the UW-Madison astronomy outreach outpost, is located in the Villager Mall, 2300 S. Park St. The event will be held in the mall atrium.

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IceCube telescope: Extreme science meets extreme electronics

Junko Yoshida
EE Times

MADISON, Wis. — The world’s largest telescope, currently under construction more than a mile beneath the Antarctic ice, is on schedule to be completed next year, according to a researcher at the University of Wisconsin, the lead institution for a scientific project called IceCube.

Ninety-five percent of the IceCube telescope, consisting of thousands of digital optical modules developed for scientists working to understand the universe, is already installed and operating at the South Pole, said Albrecht Karle, a physics professor at the University of Wisconsin-Madison in an interview with EE Times.

The IceCube telescope is no ordinary apparatus. With a volume of one cubic kilometer, the instrument is pointed not to the sky, but downward towards the center of the Earth, buried beneath tons of ice in the coldest spot in the world. No one will ever “look through” this telescope. Instead, it will convey its findings through vast arrays of digital sensors.

Scientists backed by the National Science Foundation are looking for very small, very elusive particles called neutrinos that can tell scientists much more about the universe than photons or charged particles.

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Femtoseconds lasers help formation flying

The National Physical Laboratory (NPL) has helped to establish that femtosecond comb lasers can provide accurate measurement of absolute distance in formation flying space missions.

NPL, along with collaborators, produced technical reports for the European Space Agency (ESA). The conclusions demonstrated that the lasers were a suitable method for measurement in such missions.

Formation flying missions involve multiple spacecraft flying between tens and hundreds of metres apart, which autonomously control their position relative to each other. The benefit of such missions is they can gather data in a completely different way to a standard spacecraft – the formation can effectively act as one large sensor.

Measuring absolute distance between the formation spacecraft is critical to mission success. Femtosecond comb lasers are an accurate way of making such measurements. The lasers emit light with very short pulses – each lasting just a few femtoseconds (a femtosecond is one billionth of one millionth of a second). The short pulses allow time of flight measurements to be used to determine distance to a few microns.

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UWM lab crunches data to seek mysterious gravitational waves


Posted: March 9, 2008

From outside Room 223, you can hear Nemo roar.

Open the door and a deafening drone emanates from 780 gleaming metallic computers and the fans tirelessly cooling them, and the air conditioners keeping the whole room from cooking like a hundred space heaters. Blue lights blink like distant stars from one group of computers; green lights blink from another. The machines in the University of Wisconsin-Milwaukee's physics building have been networked together to form the supercomputer dubbed Nemo.

Nemo represents mankind's best effort to find a gravitational wave.

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Wow! Astronomers Explode a Virtual Star

Jeanna Bryner
Staff Writer
SPACE.comThu Mar 22, 5:30 PM ET

For years astronomers have tried in vain to blow up an Earth-size star using strings of computer code. Finally, mission accomplished. And the resulting 3-D simulation has revealed the step-by-step process that fuels such an explosion.

Dubbed white dwarfs, stars about the size of Earth and weighing as much as the Sun end their lives with quite a show. When their core furnace begins to burn out, white dwarfs explode in so-called type-1a supernovas that astronomers say could be responsible for producing most of the iron in the universe.

Until now, a peek beneath the hood of such a white-dwarf explosion has been tricky.

Prior attempts to produce the simulated explosion required scientists manually tell the computer model to detonate the star, which meant the model was not quite right or it would have generated its own cataclysm. With more tweaking of models, University of Chicago scientists generated natural detonations of white dwarf stars in simplified, two-dimensional simulations.

"There were claims made that it wouldn't work in 3-D," said Don Lamb, director of the University of Chicago's Center for Astrophysical Thermonuclear Flashes. With some extreme computing, the team produced a 3-D detonation.

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Lunar dust 'may harm astronauts'

By Paul Rincon
Science reporter, BBC News, Houston

Scientists are investigating the possible threat posed to astronauts by inhaling lunar dust.

A study suggests the smallest particles in lunar dust might be toxic, if comparisons with dust inhalation cases on Earth apply.

Teams hope to carry out experiments on mice to determine whether this is the case or not.

Nasa has set up a working group to look into the matter ahead of its planned return to the Moon by 2020.







A team at the University of Tennessee (UT) in Knoxville is also looking at ways of using magnets to filter dust from the living environments of lunar bases and spacecraft.





The health effects of inhaling lunar dust have been recognised since Nasa's Apollo missions.



Astronaut Harrison H (Jack) Schmitt, the last man to step on to the Moon in Apollo 17, complained of "lunar dust hay fever" when his dirty space suit contaminated the habitation module after an energetic foray on the lunar surface.



The US space agency (Nasa) is now keen to assess the effects of more prolonged exposure and to address the problem before humans are sent back to the Moon in just over a decade.



Details of the work were presented to the Lunar and Planetary Science Conference in Houston, Texas.

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Privateer Elon Musk has launched his budget rocket, Falcon-1, from the Kwajalein Atoll in the South Pacific.

The 21m-long vehicle lifted off at 1810 California time (0110 GMT) and rose to an altitude of 320km (200 miles).

Mr Musk, who co-founded the internet financial system PayPal, wants to lower the cost of access to space.

The flight did not achieve all its goals, but the he said it demonstrated the vision of his Space Exploration Technologies Corporation (SpaceX).

The mission was the second attempt to loft the rocket; the first, in March 2006, ended when a fire fed by a fuel leak led to the shut down of the main-stage engine just 29 seconds after lift-off.

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UW-Madison stellerator a step forward in plasma research

March 9, 2007

A project by University of Wisconsin-Madison researchers has come one step closer to making fusion energy possible.

The research team, headed by electrical and computer engineering Professor David Anderson and research assistant John Canik, recently proved that the Helically Symmetric eXperiment (HSX), an odd-looking magnetic plasma chamber called a stellarator, can overcome a major barrier in plasma research, in which stellarators lose too much energy to reach the high temperatures needed for fusion.

Published in a recent issue of Physical Review Letters, the new results show that the unique design of the HSX in fact loses less energy, meaning that fusion in this type of stellarator could be possible.

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Probe studies 'extreme physics'

By Paul Rincon
Science reporter, BBC News, Seattle

A pioneering US space agency spacecraft is set to launch on a mission to explore the most energetic phenomena in the Universe.
The Gamma-ray Large Area Space Telescope (Glast) has been described as an "extreme physics" laboratory.

The probe is due to launch from Florida's Cape Canaveral base in November on a Boeing Delta II rocket.

The team presented details of the mission at the meeting of the American Astronomical Society in Seattle.

As its name suggests, Glast will detect the emissions of gamma rays in space. Gamma rays are the most energetic form of radiation known to science.
Examples of energetic phenomena to be probed by Glast include active galaxies, which spew massive amounts of energy from their centres.

This explosive outpouring is thought to be powered by supermassive black holes.

Other targets for Glast include pulsars - rotating neutron stars which emit radio waves - as well as the remnants of exploded stars, and galaxy clusters.

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Very high frequency radiation makes dark matter visible

The stars and gas which are seen in galaxies account for only a few percent of the gravitating material in the Universe. Most of the rest has remained stubbornly invisible and is now thought to be made of a new form of matter never yet seen on Earth. Researchers at the Max Planck Institute for Astrophysics have discovered, however, that a sufficiently big radio telescope could make a picture of everything that gravitates, rivalling the images made by optical telescopes of everything that shines (online: 28. November 2006).

As light travels to us from distant objects its path is bent slightly by the gravitational effects of the things it passes. This effect was first observed in 1919 for the light of distant stars passing close to the surface of the Sun, proving Einstein's theory of gravity to be a better description of reality than Newton's. The bending causes a detectable distortion of the images of distant galaxies analogous to the distortion of a distant scene viewed through a poor window-pane or reflected in a rippled lake. The strength of the distortion can be used to measure the strength of the gravity of the foreground objects and hence their mass. If distortion measurements are available for a sufficiently large number of distant galaxies, these can be combined to make a map of the entire foreground mass.

This technique has already produced precise measurements of the typical mass associated with foreground galaxies, as well as mass maps for a number of individual galaxy clusters. It nevertheless suffers from some fundamental limitations. Even a big telescope in space can only see a limited number of background galaxies, a maximum of about 100,000 in each patch of sky the size of the Full Moon. Measurements of about 200 galaxies must be averaged together to detect the gravitational distortion signal, so the smallest area for which the mass can be imaged is about 0.2% that of the Full Moon. The resulting images are unacceptably blurred and are too grainy for many purposes. For example, only the very largest lumps of matter (the biggest clusters of galaxies) can be spotted in such maps with any confidence. A second problem is that many of the distant galaxies whose distortion is measured lie in front of many of the mass lumps which one would like to map, and so are unaffected by their gravity. To make a sharp image of the mass in a given direction requires more distant sources and requires many more of them. MPA scientists Ben Metcalf and Simon White have shown that radio emission coming to us from the epoch before the galaxies had formed can provide such sources.

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