Friday, 17 August 2007

Moving to the Sun's Rythm

Scientists from the Ulysses mission have proven that sounds generated deep inside the Sun cause the Earth to shake and vibrate in sympathy. They found that Earth’s magnetic field, atmosphere and terrestrial systems, all take part in this cosmic sing-along.

The HISCALE experiment on board Ulysses, a joint mission between ESA and NASA, present evidence that proves that Earth moves to the rhythm of the Sun. They show that distinct, isolated tones, predicted to be generated by pressure and gravity waves in the Sun, manage to reach Earth and are detectable in our environment.

Just as seismologists on Earth use sound waves to probe the interior of our world, solar scientists would like to use g-modes to probe the core of the Sun, if only they could detect them. G-modes have been undetectable optically.

The team examined a wide range of data sets covering natural phenomena and technological systems in fields as diverse as telecommunications and seismology and continued to find new evidence of discrete tones with characteristics of solar oscillations in what was previously considered background “noise”. This added to the puzzle posed by the Ulysses findings.

David Thomson from the Ulysses team believes that the key to the problem is magnetism. He suggests that the g-mode vibrations are picked up by the magnetic field at the Sun’s surface. Part of this magnetic field is then carried away from Sun into interplanetary space by solar wind, where it can be detected by space probes like Ulysses.

The magnetic field of the solar wind in turn interacts with the Earth’s magnetic field and causes it to vibrate in sympathy, retaining the characteristic g-mode signals. The motions of the geomagnetic field then couple into the solid Earth to produce small, but easily detectable, responses as Earth, with many of its technological systems, moves to the rhythm of the Sun.

Ulysses is a joint ESA/NASA mission studying the interplanetary medium and solar wind in the inner heliosphere, beyond the Sun's equator, for the first time.

Read more Moving to the Rythm of the Sun from ESA
How Solar Neutrinos make the Sun's heart beat @ Scientific Blogging
Voyager Interstellar Mission Proceeds from Centauri Dreams

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