An illustration of the four spacecraft that detected a magnetic reconnection. (NASA/Goddard/Conceptual Image Lab)
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NASA Finally Caught This Crazy Space Weather in Action
The interactions between the Earth and the Sun’s magnetic fields drive explosive space weather
As tempting as it may be to think of space as empty, nothing could be further from the truth. In fact, interactions between invisible forces create all kinds of weather in the space beyond our atmosphere all the time, from radiation produced by the sun to magnetic storms. Now for the first time, NASA scientists have witnessed the fundamental forces that trigger one of the most mysterious (and destructive) forms of space phenomena they have come across.
Scientists believe that for the most part, the Earth’s magnetic field shelters us from things like radiation and solar winds, which would otherwise whisk an unprotected atmosphere away. Because it moves in the opposite direction to the Sun’s magnetic field, they usually repel each other. However, once in awhile fractions of the two magnetospheres realign and will briefly connect. Although these linkages are short-lived, they create powerful bursts of energy, Maddie Stone reports for Gizmodo.
“When the two magnetic fields link up, then that allows the solar energy to flow straight into the magnetosphere,” Jim Burch, vice president of the space science and engineering at the Southwest Research Institute, tells Loren Grush for The Verge. “It sets the entire field in motion.”
As these connections occur, bursts of highly-energized particles from the sun flow straight from our star into the Earth’s magnetic field. The result can range from downed power grids and disabled satellites to triggering auroras and geomagnetic storms in the Earth’s atmosphere. But while scientists have witnessed the effects of magnetic reconnection for decades, the phenomenon is extremely difficult to study in the lab because it happens very quickly and on a miniscule scale, Daniel Clery reports for Science magazine. At the same time, past attempts to catch a glimpse of these events with satellites hasn’t worked out because the devices weren’t quick enough.
“From previous satellites’ measurements, we know that the magnetic fields act like a slingshot, sending the protons accelerating out,” Burch said in a statement. “The decades-old mystery is what do the electrons do, and how do the two magnetic fields interconnect. Satellite measurements of electrons have been too slow by a factor of 100 to sample the magnetic reconnection region.”
In order to try and witness a magnetic reconnection in action, Burch and his colleagues worked with NASA to develop four spacecraft that were sent into orbit around the Earth. Called the Magnetospheric Multiscale (MMS) mission, the spacecraft contain sensitive instruments that are able to measure the movement of ions electrons as wells as distortions in the Earth’s magnetic field caused by the phenomenon, Cleary reports. They didn’t have to wait long: the satellites were launched into orbit in March, 2015 and registered a magnetic reconnection the following October.
By taking measurements of the phenomenon every 30 milliseconds, the scientists were able to learn a lot about how energy transfers during reconnection. They also realized that the power generated during magnetic reconnection is the result of electrons being supercharged during the energy transfer, Stone reports.
“This is valuable insight,” Amitava Bhattacharjee, a Princeton University astrophysicist who was not involved in the study, tells Grush. “It’s testing past theory and is certainly bringing to light that certain features were in fact predicted by theory.”
With this new data, researchers hope that magnetic reconnection will shed new light on space weather, stars with strong magnetic fields, and even the magnetic environments inside earthbound nuclear reactors, Stone writes. One day, scientists might even be able to predict when magnetic reconnection will occur.
“If you understand the underlying physics that drives space weather,” Burch tells Grush. “I expect you can do a better job of predicting storms.”
source : Smithsonian