Privileged Planet: how the magnetic field protects us (Introduction)

by David Turell , Thursday, May 31, 2018, 22:55 (2368 days ago) @ David Turell

It is by heating up electrons as we orbit in to the solar wind:

https://phys.org/news/2018-05-earth-solar-gentle-breeze.html

"As Earth orbits the sun at supersonic speed, it cuts a path through the solar wind. This fast stream of charged particles, or plasma, launched from the sun's outer layers would bombard Earth's atmosphere if not for the protection of Earth's magnetic field.

"Just as a motorboat creates a bow-shaped wave ahead of itself as the hull pushes through the water, Earth creates a similar effect—called a bow shock—as it pushes through the solar wind. Scientists have sought to explain how Earth's magnetic field can shove aside the powerful solar wind without unleashing calamity. They have known part of the answer for a long time: the bow shock converts energy from the solar wind to heat stored in electrons and ions. But now, researchers have important new clues about how this process occurs.

"A University of Maryland-led study describes the first observations of the process of electron heating in Earth's bow shock. The researchers found that when the electrons in the solar wind encounter the bow shock, they momentarily accelerate to such a high speed that the electron stream becomes unstable and breaks down. This breakdown process robs the electrons of their high speed and converts the energy to heat.

"The results add an important new dimension to scientists' understanding of Earth's magnetic field and its ability to protect the planet from harmful particles and radiation.

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"'If you were to stand on a mountaintop, you might get knocked over by a fast wind," explained Li-Jen Chen, lead author of the study and an associate research scientist in the UMD Department of Astronomy. "Fortunately, as the solar wind crashes into Earth's magnetic field, the bow shock protects us by slowing down this wind and changing it to a nice, warm breeze. We now have a better idea how this happens."

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"Seizing on this advantage, the researchers observed the solar wind's electron stream before, during and after meeting with the bow shock. The electron stream accelerated by the shock only took 90 milliseconds to destabilize and fully break down.

"'The study of electron heating is important not just for understanding how the bow shock protects Earth, but potentially for satellites, space travel and maybe exploring other planets in the future," Chen said.

"By giving the first clear picture of what electrons at the bow shock are doing, Chen and her collaborators hope to encourage other scientists to perform computer simulations, further space observations and laboratory experiments on electron heating. Chen also looks forward to delving further into the mechanisms by which the bow shock accelerates the electron stream."

Comment: We continue to find reasons why he Earth is perfectly designed for life.