Secret of Earth's magnetic shield unravelled

[Althalus]

PARIS (AFP) - American and European spacecraft have stumbled upon a secret of the magnetosphere, the magnetic field which shields the Earth from harmful particles blasted out by the Sun, the European Space Agency said.

Scientists believe they can now explain an enigmatic phenomenon, "dayside proton auroral spots," in which bright ultra-violet spots show up in the atmosphere.

Data sent back by NASA's orbiting spacecraft Image and ESA's four Cluster spacecraft have now confirmed for the first time that the phenomenon occurs thanks to cracks that briefly open up in the Earth's magnetic field, it said in a press statement.

The so-called solar wind spewed out by the Sun comprises a constant bombardment of hydrogen atoms, whose constituent pieces are protons and electrons, and from which we are shielded by the magnetosphere.

When hydrogen electrons enter our atmosphere, they collide with and excite the atoms in the air, and the energy is transformed into light, creating the aurora "curtains" familiar to people who live in extreme latitudes.

The auroral spots are different, though: they occur when protons "steal" electrons from atmospheric molecules, and the energy is released in a shining blob of light.

The breakthrough occurred on March 18 last year, when sensors aboard Image detected a bright "spot" that was generated as a jet of solar protons wacked into the atmosphere, ESA said.

By great good luck, the Cluster spacecraft were passing overhead at that very moment, making a routine sweep of the Earth's magnetic field.

"An extensive analysis of the Cluster results has now shown that the region was experiencing a turbulent event known as 'magnetic reconnection'," ESA said.

"Such a phenomenon takes place when the Earth's usually impenetrable magnetic field fractures and has to find a new stable configuration.

"Until the field mends itself, solar protons leak through the gap and jet into Earth's atmosphere creating the dayside proton aurora."

The discovery will be published this week in a specialist journal, Geophysical Research Letters, ESA added.

Yahoo News

[Kismit]

Wow!! I love coming in here and learnin stuff Thanx Al

[CASTOR]

Great article Althalus, where do you find this stuff? Do know where i can go to see pics of what happened? if so, please let me know.

CASTOR

[Magikman]

It's not really much to look at, but here you go, Castor. It's towards the bottom of the page;

CLICK HERE

[Homer]

Thanks Al, that's an excellent article

Dayside proton auroral spots are cool

[SpaceyKC]

Another fascinating and beautiful part of nature!

Thank you Al and MM

[FreyKade]

cool

[djdodo]

Very Cool