Monthly Archives: February 2007

Fascinating article about physicist Lene Hau and her work, care of the Harvard Gazette web site:

Lene Hau has already shaken scientists’ beliefs about the nature of things. Albert Einstein and just about every other physicist insisted that light travels 186,000 miles a second in free space, and that it can’t be speeded-up or slowed down. But in 1998, Hau, for the first time in history, slowed light to 38 miles an hour, about the speed of rush-hour traffic.

Two years later, she brought light to a complete halt in a cloud of ultracold atoms. Next, she restarted the stalled light without changing any of its characteristics, and sent it on its way.

Now Mallinckrodt Professor of Physics and of Applied Physics, Hau has done it again. She and her team made a light pulse disappear from one cold cloud then retrieved it from another cloud nearby. In the process, light was converted into matter then back into light. For the first time in history, this gives science a way to control light with matter and vice versa.

It’s a thing that most scientists never thought was possible. Some colleagues had asked Hau, “Why try that experiment? It can’t be done.”

In the experiment, a light pulse was slowed to bicycle speed by beaming it into a cold cloud of atoms. The light made a “fingerprint” of itself in the atoms before the experimenters turned it off. Then Hau and her assistants guided that fingerprint into a second clump of cold atoms. And get this – the clumps were not touching and no light passed between them.

“The two atom clouds were separated and had never seen each other before,” Hau notes. They were eight-thousandths of an inch apart, a relatively huge distance on the scale of atoms.

The experimenters then nudged the second cloud of atoms with a laser beam, and the atomic imprint was revived as a light pulse. The revived light had all the characteristics present when it entered the first cloud of atomic matter, the same shape and wavelength. The restored light exited the cloud slowly then quickly sped up to its normal 186,000 miles a second.

Continue reading…

I came very close to buying a Playstation II, just so I could play Guitar Hero. Looks like there’s no need, as it’s coming out for the Wii.

From The Tanooki:

That’s right, during Activision’s conference call on Wednesday, CEO Mike Griffith stated that Guitar Hero will be making it’s way to the Wii:

“The key difference in our strategy versus the prior cycle, is that in addition to full support on Sony and Microsoft platforms, we will aggressively target the Nintendo platforms consistent with our multi-platform strategy and Nintendo’s expected growth. In fiscal 2008, we will double our offerings on the DS and the Wii, including Spider-Man, Shrek, Transformers, and Guitar Hero.”

No other details were given during the 60+ minute conference call. Since the announcement was given by the President of Activision, I think the chances are high for an official press release in the future.

From LiveScience:

A trip to the beach means sand between your toes, salt water in your mouth and that aromatic sea air in your nose. But what gives the ocean air that delightful and distinctive smell? Scientists have not known the full story until now.

The smell comes from a gas produced by genes recently identified by researchers in ocean-dwelling bacteria.

Scientists had long known that bacteria could be found consuming decay products and producing a gas called dimethyl sulfide, or DMS, in places where plankton and marine plants such as seaweed were dying. This pungent gas is what gives ocean air “sort of a fishy, tangy smell,” said study author Andrew Johnston of the University of East Anglia.

But while “it was known that quite a lot of bacteria could [produce DMS], no one had thought to ask how,” Johnston told LiveScience.

So that’s exactly what he and his colleagues set out to do.

The team took samples of mud from the salt marshes along Britain’s coast, and isolated a new strain of bacteria. After sequencing its genes and comparing the genetic structure to other known bacteria, they were able to identify the gene involved in the mechanism that converts the plants’ decay products, called DMSP, into DMS.

The mechanism responsible “was absolutely not what anyone expected,” Johnston said. The study’s findings are detailed in the Feb. 2 issue of the journal Science.

Scientists had thought that a simple enzyme would be used to break down the DMSP into DMS, but the process turned out to be more complicated as the DMSP proved tougher to breakdown than suspected.

As with many other processes, the bacteria are cleverly conservative: the mechanism stays off until decaying plankton are around. But when a plankton bloom in the ocean is, for example, killed off by a viral attack, the bacteria rush in to reap the benefit.

“The bacteria will only switch on the genes to break down DMSP if the DMSP is around,” Johnston said.

Johnston and his team were also able to clone the gene and transfer it to bacteria that lacked it, including E. coli, giving the bacteria the ability to produce DMS gas.

This mechanism is neither the only way, nor the primary way, that bacteria break down the estimated 1 billion tons of DMSP in the ocean, Johnston said, but it is important nonetheless as DMS releases over the open ocean influences cloud formation, which can influence Earth’s climate.

Some seabirds rely on DMS as a homing scent to find food. On one occasion during their field research, Johnston and his team opened a bottle filled with the DMS-producing bacteria only to be bombarded by hungry seabirds..