Saturday, April 11, 2009

The First Time Machine (Discovery Channel)

Clip from the Discovery Channel documentary "The First Time Machine"

Recently reports of a laser array experiment to create temperatures much hotter than the sun were reported. Such an expensive experiment makes little sense -- until this physics principle is understood (see minute 1:30). Light bends time. It does so better than motion. And with the help of lasers...

High-Intensity Lasers that Curve
Researchers defy the laws of physics by making a laser beam bend
Ultra-intense lasers hold much promise for improving scientific tools such as laser-induced breakdown spectroscopy (LIBS), and deepening researchers' under-standing of atomic, molecular, optical, and plasma physics. The enormous intensity of these lasers (attributed to the brief but powerful pulses of energy they emit), however, makes it difficult for scientists to fully characterize and understand them.

Researchers at the University of Arizona in Tucson (U.A.) and the University of Central Florida in Orlando (U.C.F.) report in Science this week that they have found a way to bend a high-intensity pulsed laser beam, a breakthrough they are hoping will help them better understand how ultra-intense laser pulses travel through the air and find potential new uses for the technology.

"People expect lasers to do certain things, like propagate in a straight line," says lead researcher Pavel Polynkin, an associate research professor at U.A.'s College of Optical Sciences. "The fact that a laser beam actually curves is quite unusual." More>>

World's Largest Laser Ready to Fire

Artist's rendering shows a National Ignition Facility (NIF) target pellet inside a hohlraum capsule with laser beams entering through openings on either end. Photo: Lawrence Livermore Nationa Security, LLC, Lawrence Livermore National Laboratory, and the Department of Energy.

After more than a decade of work and $US3.5 billion ($AU5.2 billion), US engineers have completed the world's most powerful laser, capable of simulating the energy force of a hydrogen bomb and the sun itself.

The US Energy Department will announce today that it has officially certified the National Ignition Facility at the Lawrence Livermore National Laboratory in California, clearing the way for a series of experiments over the next year that eventually is hoped will mimic the heat and pressure found at the centre of the sun.

The facility, the size of a football field, comprises of 192 separate laser beams, each travelling 300m in a one-thousandth of a second to converge simultaneously on a target the size of a pencil eraser.

While the NIF laser is expected to be used for a wide range of high-energy and high-density physics experiments, its primary purpose is to help government physicists... More>>

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