Magnetic field allows interstellar space to be fluffy

Wednesday, 30 December 2009 - 6:06pm IST | Place: Washington | Agency: ANI
Approximately 10 million years ago, a supernova cluster detonated nearby, generating a huge bubble of million-degree gas.

The Voyager probes have discovered that interstellar fluff is more magnetized than previously believed, a factor that seems to allow its very existence.

The 'Local Fluff', which is a nickname for the Local Interstellar Cloud, is a vast, wispy cloud of hot hydrogen and helium stretching 30 light-years across.

Our solar system is powering its way right through the Local Fluff and Voyagers 1 and 2 are currently traversing the boundary that separates the bubble of space surrounding our sun and interstellar space, which is also known as the heliosphere. 

These two probes, which were launched in the 1970's to explore the outermost reaches of the solar system and then cruise into the unknown, have been making measurements of their surroundings during this transition through the boundary region, or the 'heliosheath'.

Approximately 10 million years ago, a supernova cluster detonated nearby, generating a huge bubble of million-degree gas.

Researchers have been very confused as to why the Local Fluff remains intact; it should have been blown away by the ferocious supernovae exhaust long ago.

According to a report in Discovery News, a magnetic field may be helping the wispy Local Fluff to remain intact.

"Voyager data show that the Fluff is much more strongly magnetized than anyone had previously suspected - between 4 and 5 microgauss," said Merav Opher, a NASA Heliophysics Guest Investigator from George Mason University.

"This magnetic field can provide the extra pressure required to resist destruction," he added.

Astrophysical magnetic fields are often measured in units of gauss; the Earth has a magnetic field of approximately 0.5 gauss (or 500,000 microgauss).

Therefore, 4 to 5 microgauss may seem pretty weak in comparison, but this field covers astonishing scales, appearing to wrap around a very tenuous hydrogen/helium gas, possibly helping the Local Fluff maintain its structure.

The Local Interstellar Cloud isn't the only cloud of fluff out there, and now Opher theorizes that other interstellar cloud formations may be highly magnetized too.




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