2010-02-13

Losing Your Hands Makes It Harder To See Nearby Objects

It turns out that you need more than just your eyes to see things that are right in front of you. Neuroscientists have found that we can't accurately judge the distance of nearby objects without also using our hands.

The area within arm's length - in other words, the area with which we can directly interact - is called the "action space." Previous research had indicated that the brain judges distance within the action space in terms of the hands.

However, it had not been confirmed whether the hands merely help our brains better understand spatial positions or if they are actually required to figure out where objects in the action space are.

To test this question, a research team at the Hebrew University of Jerusalem and Hadassah Hospital-Mount Scopus tested a group of people who had had their hands amputated to see how their visual perception of nearby objects had been affected. The volunteers were told to focus on a screen where a cross was projected in the center. On either side were squares of variable distance from the cross. The subjects were asked to judge which of the two squares was farther away.

The results reveal that hand amputations affect visuospatial perception. When the right square was slightly farther away from the center, participants with right-hand amputations tended to perceive it as being at the same distance from the center as the left square; this suggests that these volunteers underestimated the distance of the right square relative to the left. Conversely, when the left square was farther away, left-hand amputees perceived both squares as being equally far away from the center — these participants underestimated the left side of near space.

Interestingly, when the volunteers were seated farther away from the screen, they were more accurate in judging the distances, indicating that hand amputations may only affect perception of the space close to the body.

http://io9.com/5468247/losing-your-hands-makes-it-harder-to-see-nearby-objects



Weight scale for atoms could map 'island of stability'

The mass of an atom heavier than uranium has been measured for the first time (Image: <a href="http://garrisonphoto.org/sxc/">bjearwicke</a>/stock.xchng)Hunting for the universe's heaviest atoms just got a little easier, thanks to a new technique that directly measures the mass of elements heavier than uranium. The method could help find an "island" of unusually stable elements that is thought to extend beyond the current end of the periodic table.

Uranium, which contains 92 protons, is the heaviest element known to occur in nature. But researchers have synthesised a number of even heftier elements, with as many as 118 protons.

These extreme atoms are quite short-lived – many fall apart just milliseconds after they are created. But nuclear theorists suspect that a class of 'super-heavy' atoms, boasting the right combination of protons and neutrons, could have lifetimes of decades or longer (see Hunting the biggest atoms in the universe).

Elements in this so-called island of stability could act as powerful nuclear fuel for future fission-propelled space missions. They might also be exhibit useful new chemical properties. Element 114, for example, has shown hints that it behaves like a gas at room temperature even though it should be a member of the lead family on the periodic table.

http://www.newscientist.com/article/dn18510-weight-scale-for-atoms-could-map-island-of-stability.html?DCMP=OTC-rss&nsref=online-news

'Space diver' to attempt first supersonic freefall

Joe Kittinger set the record for the highest jump in 1960, when he dropped from a helium balloon at an altitude of 31 kilometres (Image: US Air Force Archive)A "space diver" will try to smash the nearly 50-year-old record for the highest jump this year, becoming the first person to go supersonic in freefall. The stunt could help engineers design escape systems for space flights.

On 16 August 1960, US Air Force Captain Joe Kittinger made history by jumping out of a balloon at an altitude of some 31,333 metres. "I stood up and said a prayer and stepped off," he recalled (see Space diving: The ultimate extreme sport).

Since then, many have tried to break that record but none have succeeded – New Jersey native Nick Piantanida actually died trying in 1966. Now Austrian skydiver Felix Baumgartner has announced he will make the attempt, with help from Kittinger and sponsorship from the energy drink company Red Bull.

He will face extreme peril. He should reach supersonic speeds 35 seconds after he jumps, and the resulting shock wave "is a big concern", the project's technical director, Art Thompson, said at a press briefing on Friday. "In early aircraft development, they thought it was a wall they couldn't pass without breaking apart. In our case, the vehicle is flesh and blood, and he'll be exposed to some extreme forces.

"The jump height is above a threshold at 19,000 metres called the Armstrong line, where the atmospheric pressure is so low that fluids start to boil. "If he opens up his face mask or the suit, all the gases in your body go out of suspension, so you literally turn into a giant fizzy, oozing fluid from your eyes and mouth, like something out of a horror film," Thompson explained. "It's just seconds until death."

To protect himself, Baumgartner will wear a more flexible version of the airtight, pressurised spacesuit currently used aboard the space shuttle (see Future spacesuits to act like a second skin). That will let him bend to achieve the standard, belly-down skydiving position needed to decelerate.

Red Bull would not reveal the cost of the project. And though it says it will launch this year from North America, it has not yet specified a date or launch site. This uncertainty depends in part on finding the ideal weather conditions for the flight, Thompson said.

By showing that a person can safely return to Earth from that speed and altitude, the "Stratos" mission team hopes to show that astronauts might survive with similar systems if they needed to bail out of spacecraft.

http://www.newscientist.com/article/dn18427-space-diver-to-attempt-first-supersonic-freefall.html?DCMP=OTC-rss&nsref=online-news