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Posts Tagged ‘magnetic fields

Humans may have — or have had — geomagnetic sight

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“Why is my attention drawn to this woman?”

The ability to see Earth’s magnetic field, thought to be restricted to sea turtles and swallows and other long-distance animal navigators, may also reside in human eyes.

Tests of cryptochrome 2, a key protein component of geomagnetic perception, found that its human version restored geomagnetic orientation in cryptochrome-deficient fruit flies.

Flies are a long, long way from people, but that the protein worked at all is impressive. There’s also a whole lot of it in our eyes.

“Could humans have this cryptochrome heavily expressed in the retina as a light-sensitive magnetoreceptor?” said University of Massachusetts neuroscientist Steven Reppert, lead author of…a study. “We don’t know if the molecule will do this in the human retina, but this suggests the possibility.”

Reppert, whose laboratory specializes in the biological mechanisms underlying long-distance butterfly migration, showed three years ago that cryptochrome allowed fruit flies to geomagnetically orient themselves using light…

Many gaps still remain in cryptochrome theory, but it’s generally thought that the cryptochrome system may be active across the animal kingdom, from fish to reptiles to birds. Humans, however, were thought to be an exception. Our own cryptochrome is considered a piece of circadian machinery, part of our molecular clock rather than any optical compass.

The new study, however, suggests that cryptochrome may be more than a clock…Whether any of this is linked to high levels of cryptochrome in human eyes — and, if so, whether that quantum compass system still works for us — is completely speculative, but it’s speculation that Reppert welcomes…

Reppert himself is now concentrating on how brains read their cryptochrome compass. “At the most fundamental level, we’re interested in how cryptochrome information is transferred to the nervous system,” he said. “Nobody knows how that occurs.”

Yet. Seems like a worthwhile study. Of course, just about any and all basic research is worthwhile. If it’s basic enough – you can’t really foretell where the results will lead.

Written by eideard

June 23, 2011 at 6:00 am

Universal, primordial magnetic fields discovered in deep space

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Scientists from the California Institute of Technology and UCLA have discovered evidence of “universal ubiquitous magnetic fields” that have permeated deep space between galaxies since the time of the Big Bang.

Caltech physicist Shin’ichiro Ando and Alexander Kusenko, a professor of physics and astronomy at UCLA, report the discovery in a paper to be published in an upcoming issue of Astrophysical Journal Letters; the research is currently available online.

Ando and Kusenko studied images of the most powerful objects in the universe — supermassive black holes that emit high-energy radiation as they devour stars in distant galaxies — obtained by NASA’s Fermi Gamma-ray Space Telescope.

We found the signs of primordial magnetic fields in deep space between galaxies,” Ando said.

Physicists have hypothesized for many years that a universal magnetic field should permeate deep space between galaxies, but there was no way to observe it or measure it until now…

The researchers found that the average magnetic field had a “femto-Gauss” strength, just one-quadrillionth of the Earth’s magnetic field. The universal magnetic fields may have formed in the early universe shortly after the Big Bang, long before stars and galaxies formed, Ando and Kusenko said.

Bravo!

There’s more info about Kusenko’s research over here.

Written by eideard

September 23, 2010 at 2:00 am

Ball lightning as a magnetically-induced hallucination. WTF?

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Powerful magnetic fields can induce hallucinations in the lab, so why not in the real world, too?

Transcranial magnetic stimulation (TMS) is an extraordinary technique pioneered by neuroscientists to explore the workings of the brain. The idea is to place a human in a rapidly changing magnetic field that is powerful enough to induce currents in neurons in the brain. Then sit back and see what happens.

Since TMS was invented in the 1980s, it has become a powerful way of investigating how the brain works. Because the fields can be tightly focused, it is possible to generate currents in very specific areas of the brain to see what they do.

Focus the field in the visual cortex, for example, and the induced eddys cause the subject to ‘see’ lights that appear as discs and lines. Move the the field within the cortex and the subject sees the lights move too.

All that much is repeatable in the lab using giant superconducting magnets capable of creating fields of as much as 0.5 Tesla inside the brain.

But if this happens in the lab, then why not in the real world too, say Joseph Peer and Alexander Kendl at the University of Innsbruck in Austria. They calculate that the rapidly changing fields associated with repeated lightning strikes are powerful enough to cause a similar phenomenon in humans within 200 metres…

So what would this kind of lightning-induced transcranial stimulation look like to anybody unlucky enough to experience it? Peer and Kendl say it may well look like the type of hallucinations induced by lab-based tests, in other words luminous lines and balls that appear to float in space in front of the subject’s eyes…

That’s an interesting idea: that a large class of well-reported phenomenon may be the result of hallucinations induced by transcranial magnetic stimulation.

In my teens, the small town I lived in had one neighborhood notorious for ball lightning. But, equally well-known, was that folks never seemed to have seen the same thing.

Hey – could be Peer and Kendl have it right.

Written by eideard

May 11, 2010 at 3:00 pm

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