Archive for April 2007

Mathematician suggests extra dimensions are time-like

In a recent study, mathematician George Sparling of the University of Pittsburgh examines a fundamental question pondered since the time of Pythagoras, and still vexing scientists today: what is the nature of space and time? After analyzing different perspectives, Sparling offers an alternative idea: space-time may have six dimensions, with the extra two being time-like.
Sparling’s paper, which was published in the Proceedings of the Royal Society A, lays the groundwork for his theory. He explains how spatial dimensions contain positive signs (e.g., Pythagoras’ 3D space is expressed as the sum of the squares of the intervals in three directions, x, y, and z). Minkowski’s time-like dimension, on the other hand, combines these three dimensions with the square of time displacement, which contains an overall negative sign.

“In three dimensions, the formula reads s2 = x2 y2 z2,” Sparling explained to PhysOrg.com. “Our standard spacetime has four dimensions, but the formula has a critical minus sign: s2 = x2 y2 z2 – t2. The Lithuanian Hermann Minkowski invented this idea, which was published just six weeks before he died. Indeed, [Sir Roger] Penrose, for one, says that special relativity was not a finished theory until Minkowski’s famous Raum und Zeit [‘Space and Time’] paper.”

Up until now, Sparling explains, most theories concerning extra dimensions have dealt with space-like rather than time-like dimensions, which results in a “hyperbolic” rather than an “ultra-hyperbolic” geometry. However, Sparling notes that there are no a priori arguments for a hyperbolic geometry, and he looks into the possibility of a “spinorial” theory of physics, where six dimensions of space-time arise naturally.

Mathematician suggests extra dimensions are time-like

Reflections of Absolute Zero

If you want to really see quantum mechanics in action, you’ve got to turn the temperature down so low that even atoms stop moving. Physicists have come close to achieving this “absolute zero” state by using precision-tuned lasers, but the technique has only allowed researchers to freeze small groups of atoms at a time. Now members of an international team say they have managed to cool a dime-sized mirror to within one degree of absolute zero, the lowest laser-induced freeze yet achieved with a visible object.

One of the greatest enigmas in physics is how matter can be governed by the four basic forces of nature–electromagnetism, which governs light, heat and electricity; the strong and weak nuclear forces, which bind atoms together; and gravity–and still follow the rules of quantum mechanics, which operate only at the subatomic level. In other words, scientists want to know how solid objects keep from flying apart when their atoms are also influenced by the chaotic nature of quantum physics. The major research obstacle has been that natural forces overwhelm quantum effects. The only way to cancel those forces entirely is to cool an atom down to absolute zero (-273 degrees Celsius), where quantum forces apply exclusively.

Reflections of Absolute Zero — Berardelli 2007 (409): 1 — ScienceNOW

Cassini Images Bizarre Hexagon on Saturn

Pasadena, Calif. — An odd, six-sided, honeycomb-shaped feature circling the entire north pole of Saturn has captured the interest of scientists with NASA’s Cassini mission.

NASA’s Voyager 1 and 2 spacecraft imaged the feature over two decades ago. The fact that it has appeared in Cassini images indicates that it is a long-lived feature. A second hexagon, significantly darker than the brighter historical feature, is also visible in the Cassini pictures. The spacecraft’s visual and infrared mapping spectrometer is the first instrument to capture the entire hexagon feature in one image.

“This is a very strange feature, lying in a precise geometric fashion with six nearly equally straight sides,” said Kevin Baines, atmospheric expert and member of Cassini’s visual and infrared mapping spectrometer team at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “We’ve never seen anything like this on any other planet. Indeed, Saturn’s thick atmosphere where circularly-shaped waves and convective cells dominate is perhaps the last place you’d expect to see such a six-sided geometric figure, yet there it is.”

The hexagon is similar to Earth’s polar vortex, which has winds blowing in a circular pattern around the polar region. On Saturn, the vortex has a hexagonal rather than circular shape. The hexagon is nearly 25,000 kilometers (15,000 miles) across. Nearly four Earths could fit inside it.

The new images taken in thermal-infrared light show the hexagon extends much deeper down into the atmosphere than previously expected, some 100 kilometers (60 miles) below the cloud tops. A system of clouds lies within the hexagon. The clouds appear to be whipping around the hexagon like cars on a racetrack.

“It’s amazing to see such striking differences on opposite ends of Saturn’s poles,” said Bob Brown, team leader of the Cassini visual and infrared mapping spectrometer, University of Arizona, Tucson. “At the south pole we have what appears to be a hurricane with a giant eye, and at the north pole of Saturn we have this geometric feature, which is completely different.”

JPL.NASA.GOV: News Releases – Cassini Images Bizarre Hexagon on Saturn

Einstein was right, probe shows

It will take another eight months to determine whether he got the other correct say scientists analysing data from Nasa’s Gravity Probe B satellite. The spacecraft was launched into orbit from California, US, on 20 April 2004. The mission’s chief scientist presented details at a physics meeting in Jacksonville, Florida.

Gravity Probe B uses four ultra-precise gyroscopes to measure two effects of Einstein’s general relativity theory. One of these effects is called the geodesic effect, the other is called frame dragging. A common analogy is that of placing a heavy bowling ball on to a rubber sheet.

The bowling ball will sit in a dip, distorting the rubber sheet around itself in much the way a massive object such as the Earth distorts space and time around itself. If the bowling ball is then rotated, it will start to drag the rubber sheet around with it. In a similar way, the Earth drags local space and time around with it – ever so slightly – as it rotates.

Over the course of a year, these effects would cause the angle of spin of the gyroscopes to shift by minute amounts. The data from Gravity Probe B’s gyroscopes clearly confirm Einstein’s geodesic effect to a precision of better than 1%. The scientists from Stanford are still trying to extract its signature of frame-dragging from the data. They plan to announce the final results of the experiment in December 2007, following eight more months of data analysis.

Physicists have been unable to incorporate gravity into a unified theory to describe all that is known about the fundamental forces between elementary particles in nature. Modifications to general relativity could be important steps towards a unified theory. “There is an expectation that at some level we will expose a departure from pure general relativity as envisaged by Einstein,” Professor Sumner said.

“One of the areas of general relativity that is less well founded is when you get into very intense gravitational field interactions. Some astrophysical objects will be in very high field situations such as pairs of massive black holes orbiting one another.”

A joint mission between Nasa and the European Space Agency called Lisa (Laser Interferometer Space Antenna) will study gravitational waves coming from binary systems such as these.

BBC NEWS | Science/Nature | Einstein was right, probe shows

Galaxy’s Ghostly Arms Finally Explained

Scientists have discovered the source of a galaxy’s two extra, ghostly spiral arms that show up only in some telescope images, cracking a 45-year-old mystery.

M106 (also known as NGC 4258), a stately spiral galaxy 23.5 million light-years away in the constellation Canes Venatici, appears in visible light images to have just two prominent arms emanating from its nucleus and spiraling outward.

“But in radio and X-ray images, two additional spiral arms dominate the picture, appearing as ghostly apparitions between the main arms,” said Andrew Wilson, part of a University of Maryland team of astronomers that used data from four space telescopes to arrive at an explanation of the strange phenomenon.

The “anomalous arms” consist mostly of regions of gas that are being violently heated by shock waves from a pair of jets of particles originating at the galaxy’s core, said Yuxuan Yang, who headed up the research, which will be detailed in the May 10 issue of the Astrophysical Journal.

In 2001, Wilson, Yang and Gerald Cecil of the University of North Carolina, Chapel Hill, noted that the jets are tipped 30 degrees with respect to the galaxy disk. If one could vertically project the jets down onto the disk, they would line up almost perfectly with the anomalous arms

SPACE.com — Galaxy’s Ghostly Arms Finally Explained

New Earth-like Planet ‘Habitable’

Astronomers have found the first Earth-sized world circling its mother star at a distance suitable for life. It also has good prospects for liquid surface water — believed to be a key ingredient for life.

“This planet will most probably be a very important target of the future space missions dedicated to the search for extra-terrestrial life,” said Xavier Delfosse, with Grenoble University in France.

It will be years before more sensitive instruments are developed to glean additional clues about whether life exists on the planet.

“It is not possible with current telescopes and instruments yet,” Xavier Bonfils, an astronomer with the Lisbonne Observatory in Portugal, wrote in an e-mail to Discovery News. “But in the next decade, we may have the tools to answer this question.”

The planet, which is about 50 percent larger than Earth, circles a star in the constellation Libra known as Gliese 581, about 20.5 light-years away. Light travels in a vacuum at about 187,000 miles per second.

Discovery Channel :: News – Space :: New Earth-like Planet ‘Habitable’

Intelsat Satellite over Indian Ocean hacked

The Tamil Tigers in Sri Lanka have been hacking the Intelsat that hangs over the Indian Ocean to transmit propaganda. Intelsat is trying very hard to figure out how they did it, and then keep them from doing it again.

Adding to the idea that no system is safe, Intelsat is on the hook today to protect its in orbit systems from being hacked to transmit propaganda. In the world of cyber warfare, the ability of the Tamil Tigers to hack Intelsat is something that people who plan for or otherwise work in long range global telecommunications needs to be thinking about. Intelsat issued a tersely worded statement today about the ongoing problem:

“Intelsat does not tolerate terrorists operating illegally on it satellites. Since we first learned of the LTTE’s signal piracy, we have been actively pursuing a number of technical alternatives to halt the transmissions. We are clear in our resolve to ending this terrorist organisation’s unauthorised use of our satellite,” Intelsat, the world’s largest provider of fixed satellite services, said in a statement. Source: Daily News

This is not the first time that this kind of thing has happened either, the falungong in 2002 hacked AsiaSat to broadcast their propaganda as well. Taking the TV airwaves from the Chinese government so that they could spread their word using the TV signal from the system.

IToolbox Blogs / Dan Morril : Hack a Satellite while it is in orbit

Massive star burps, then explodes

BERKELEY – Tens of millions of years ago, in a galaxy far, far away, a massive star suffered a nasty double whammy.

Signs of the first shock reached Earth on Oct. 20, 2004, when the star was observed letting loose an outburst so enormous and bright that Japanese amateur astronomer Koichi Itagaki initially mistook it for a supernova. The star survived for nearly two years, however, until on Oct. 11, 2006, professional and amateur astronomers witnessed it blowing itself to smithereens as Supernova (SN) 2006jc.

“We have never observed a stellar outburst and then later seen the star explode,” said University of California, Berkeley, astronomer Ryan Foley. His group studied the 2006 event with ground-based telescopes, including the 10-meter (32.8-foot) W. M. Keck telescopes in Hawaii. Narrow helium spectral lines showed that the supernova’s blast wave ran into a slow-moving shell of material, presumably the progenitor’s outer layers that were ejected just two years earlier. If the spectral lines had been caused by the supernova’s fast-moving blast wave, the lines would have been much broader.

Another group, led by Stefan Immler of NASA’s Goddard Space Flight Center in Greenbelt, Md., monitored SN 2006jc with NASA’s Swift satellite and the Chandra X-ray Observatory. By observing how the supernova brightened in X-rays, a result of the blast wave slamming into the outburst ejecta, they could measure the amount of gas blown off in the 2004 outburst: about 0.01 solar mass, the equivalent of 10 Jupiters.

Berkeley.edu : – Massive star burps, then explodes

Water Found in Extrasolar Planet’s Atmosphere

Astronomers have detected water in the atmosphere of a planet outside our solar system for the first time.

The finding, to be detailed in an upcoming issue of Astrophysical Journal, confirms previous theories that say water vapor should be present in the atmospheres of nearly all the known extrasolar planets. Even hot Jupiters, gaseous planets that orbit closer to their stars than Mercury to our Sun, are thought to have water.

The discovery, announced today, means one of the most crucial elements for life as we know it can exist around planets orbiting other stars.

“We know that water vapor exists in the atmospheres of one extrasolar planet and there is good reason to believe that other extrasolar planets contain water vapor,” said Travis Barman, an astronomer at the Lowell Observatory in Arizona who made the discovery.

HD209458b is a world well-known among planet hunters. In 1999, it became the first planet to be directly observed around a normal star outside our solar system and, a few years later, was the first exoplanet confirmed to have oxygen and carbon in its atmosphere.

HD209458b is separated from its star by only about 4 million miles (7 million kilometers)—about 100 times closer than Jupiter is to our Sun—and is so hot scientists think about it is losing about 10,000 tons of material every second as vented gas.

“Water actually survives over a broad range of temperatures,” Barman explained. “It would need to get quite a bit hotter to completely break the water molecules apart.”

SPACE.com — Water Found in Extrasolar Planet’s Atmosphere

‘Explosive’ results at CERN, LHC

A £2 billion project to answer some of the biggest mysteries of the universe has been delayed by months after scientists building it made basic errors in their mathematical calculations.

The mistakes led to an explosion deep in the tunnel at the Cern particle accelerator complex near Geneva in Switzerland. It lifted a 20-ton magnet off its mountings, filling a tunnel with helium gas and forcing an evacuation.

It means that 24 magnets located all around the 17-mile circular accelerator must now be stripped down and repaired or upgraded. The failure is a huge embarrassment for Fermilab, the American national physics laboratory that built the magnets and the anchor system that secured them to the machine.

It appears Fermilab made elementary mistakes in the design of the magnets and their anchors that made them insecure once the system was operational.

Last week an apparently furious and embarrassed Pier Oddone, director of Fermilab, wrote to his staff saying they had caused “a pratfall on the world stage”. He said: “We are dumb-founded that we missed some very simple balance of forces. Not only was it missed in the engineering design but also in the four engineering reviews carried out between 1998 and 2002 before launching the construction of the magnets.”

The machine, the Large Hadron Collider (LHC), aims to recreate the conditions of the Big Bang, when the universe is thought to have exploded into existence about 14 billion years ago. However, the November start-up may now have to be delayed until next spring.

News-UK-TimesOnline – Big Bang at the atomic lab after scientists get their maths wrong

AJAX Apps Ripe Targets for JavaScript Hijacking

from eWeek : AJAX Apps Ripe Targets for JavaScript Hijacking

Fortify Software has documented what the security firm is calling a “pervasive and critical” vulnerability in Web 2.0 applications—specifically, in the ability of an attacker to use a JavaScript vulnerability to steal critical data by emulating unsuspecting users.

The vulnerability—which allows an exploit called JavaScript Hijacking—can be found in the biggest AJAX frameworks out there, including three server-integrated toolkits: Microsoft ASP.Net AJAX (aka Atlas), Google Web Toolkit and xajax—the last of which is an open-source PHP-class library implementation of AJAX.

Client-side libraries that Fortify inspected and found to be vulnerable are the Yahoo UI, Prototype, Script.aculo.us, Dojo, Moo.fx, jQuery, Rico and MochiKit.

Of the AJAX frameworks and client-side libraries Fortify inspected, only DWR 2.0 (Direct Web Remoting 2.0) has mechanisms to prevent JavaScript Hijacking.

ANI Zero Day Takes New Turns to the Uber-Nasty

Security Watch – Exploits and Attacks – ANI Zero Day Takes New Turns to the Uber-Nasty

If you’re reading this with Internet Explorer on a Windows machine, don’t. The Windows animated cursor zero-day attack that was coming through on IE 6 and 7 running on fully patched Windows XP SP2 is now also hitting Windows 2000, Server 2003 and Vista. As F-Secure advises, better to use some other combination.

Proof-of-concept code for the attack was released after business hours on Friday, according to SANS.

Blocking .ani files won’t help. SANS has picked up reports of the vulnerability being exploited in the wild with .ani files renamed as JPEGs.

Microsoft today posted security advisory 935423 about the exploit. Here’s the full list of vulnerable systems:

Microsoft Windows 2000 Service Pack 4
Microsoft Windows XP Service Pack 2
Microsoft Windows XP 64-Bit Edition Version 2003 (Itanium)
Microsoft Windows XP Professional x64 Edition
Microsoft Windows Server 2003
Microsoft Windows Server 2003 for Itanium-based Systems
Microsoft Windows Server 2003 Service Pack 1
Microsoft Windows Server 2003 with SP1 for Itanium-based Systems
Microsoft Windows Server 2003 x64 Edition
Microsoft Windows Vista

[see more]