Thursday, February 28, 2008

Geekathon, part one


Okay, I know I've said things like this before but my oh my, this really just pins my coolness meter.

The video is a loop of an electron riding a light wave. Did you get that? It's a video of a flippin' electron.

As MSNBC reported on Monday,
[p]reviously it was impossible to photograph electrons because of their extreme speediness, so scientists had to rely on more indirect methods. These methods could only measure the effect of an electron's movement, whereas the new technique can capture the entire event.
The technology involves generating extremely - and I do mean extremely - short bursts of intense laser light, pulses which are measured in attoseconds. An attosecond is 10-18 seconds, or if you prefer, a billionth of a billionth of a second.
"[A]n attosecond is related to a second as a second is related to the age of the universe," said Johan Mauritsson of Lund University in Sweden. ...

The length of the film Mauritsson and his colleagues made corresponds to a single oscillation of a wave of light. The speed of the event has been slowed down for human eyes.
How cool is that?

There have been pictures of atoms for a while, although initially they were more reconstructions than actual pictures. The first directly interpretable pictures came in 1983 but they were of limited use because the maximum resolution of the electron microscope being used was 1.4 angstroms (abbreviated 1.4Å) and most atoms are pretty much the same size, ranging from one to two angstroms. It would be like trying to use a 12 inch ruler without subdivisions to accurately measure things that run from nine to 18 inches across. You could get a general picture, a pretty good sense, but no more.

To get a good measure of something, the smallest unit on your measuring instrument - in this case the maximum resolution of your microscope - has to be smaller than what is being measured. By 2004, the resolution achieved had improved to 0.6Å, good enough to observe individual atoms of silicon in a crystal.

But this is different. This is not an atom, this is an electron. The classic diameter of a hydrogen atom ("classical" meaning without considering quantum dynamics, which make such measurements kind of wibbly-wobbly) is about a million times that of a classical electron. To make a vague and not to the same scale comparison, its kind of like the difference between being able to observe the Solar System as a whole versus being able to observe Mercury.

Oh, and yes, there have been photographs of electron clouds of elements with multiple electrons as far back as 1993. But this is not an electron cloud, this is an electron. A single bleedin' electron.

Definitely cool.

Footnote: A few days earlier, Cornell University announced that
[a] new electron microscope recently installed [there] is enabling scientists for the first time to form images that uniquely identify individual atoms in a crystal and see how those atoms bond to one another. And in living color.

"The current generation of electron microscopes can be thought of as expensive black and white cameras where different atoms appear as different shades of gray," explained David Muller, Cornell associate professor of applied and engineering physics. "This microscope takes color pictures - where each colored atom represents a uniquely identified chemical species." ...

It allows scientists to peer inside a material or a device and see how it is put together at the atomic scale where quantum effects dominate and everyday intuition fails.
The more we look, the more there is to learn. Sometimes that seems like the only thing that makes life worth it.

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