A month back, we ran an article that argues how unlikely it is for humans to ever travel back in time unless they want to find a black hole and plunge headlong into certain doom in a foolhardy effort to go through a wormhole that hopefully leads to some desolate corner of the universe in a time almost indeterminable.

Sounds real tough, doesn't it? Not really, says physicist John Cramer of the University of Washington. For starters, he says it's theoretically possible to conduct an experiment that may spawn a different approach using an old Einstein paradox. By splitting light particles called photons, he could test what forces bind the sub atomic pieces such that they remain "entangled" even when light years apart.

To put it into context, Cramer says the ideas of the most famous physicist of this generation, Stephen Hawking, regarding time are wrong. Hawking has long fathered the idea that time travels in a straight and linear path through the time-space continuum. The theory essentially suggests that time moves only forward and going against it to travel to the past is impossible. The theory also says that travel to the future is a possibility as long as a body travels in the speed of light or faster.

Cramer agrees about the part concerning future travel, but he says time can ping back both ways in the laws of quantum mechanics, a study that deals with the actions and motions of the smallest particles known to man. He says that by using the Einstein paradox as a model, we can see that split particles influence each other no matter how far apart. This, Cramer says, is only possible if a signal or energy pattern binding the particles transcends time by traveling forward and backwards.

Experiments could have been underway, but neither NASA's Institute of Advanced Concepts (NIAC) nor the Defense Advanced Research Program Agency (DARPA) would cough up the US$ 20,000 that Cramer is asking for. The NIAC is on its way to closing down and the DARPA says the Cramer study is just too strange. Incidentally, DARPA is involved in developing liquid robots and cyborg beetles.

"We're about to hit the wall if we don't get funding," he said. "It would be a shame because even if this doesn't work, I'm sure we'd learn something from trying," says a dejected Cramer.  To find out more about the UW study, follow the read URL.

One of the challenges engineers face in designing a Mars Expedition craft is how to shield astronauts from radiation during the long voyage. The obvious solution - heavy metal protective panels - would add substantial mass to the spacecraft, requiring far more fuel and reducing the amount of resources that could be taken along.

Astronauts in the vacuum of outer space are constantly exposed to cosmic rays. Some of these come from the Sun; others from outside our solar system. In low orbit, the Earth's magnetic field provides protection, but on a journey to Mars, the astronauts would suffer full exposure. These cosmic rays could result in a number of illnesses, including cancer.

John Slough of the University of Washington in Seattle believes the answer lies in a few grams of hydrogen in the form of a plasma surrounding the spacecraft. NASA's Institute for Advanced Concepts (NIAC) has awarded Slough's team $75,000 to explore the idea's feasibility. Basically, a high voltage device on the spacecraft's surface would tear the hydrogen into its constituent protons and electrons. The resulting plasma would then be ejected into space, creating a protective cloud around the spacecraft. A wire mesh outside the spacecraft would enclose the plasma cloud. Electricity supplied to the mesh would keep an electrical current running in the plasma cloud, confining it near the spacecraft.

According to Slough the plasma's magnetic field would deflect harmful cosmic rays, as effectively as several inches of aluminium shielding.

Researchers are currently trying to determine  the optimum size of the plasma bubble.  Slough believes the cloud should be about 100 metres across. At that size, the mesh would have to be stowed for launch and deployed once the craft reached in space. The wire mesh would made of superconducting material that could operate at  high temperatures, since it would be exposed to naked sunlight.

Future spacecraft may be powered by advanced engines that use plasma as a propellant. In that case, the discarded plasma could be recycled. According to Slough, "You're protected by your own exhaust."