On Jan. 7, 2014, the Sun’s surface erupted with an unusually large explosion, called coronal mass ejection (CME), with NOAA releasing a significant false alarm geomagnetic storm at Earth. Credit: NASA
When the sun hurls a billion tons of high-energy particles and magnetic fields into space at speeds of >a million miles/ hour and the ‘space weather’ conditions are right, the resulting geomagnetic storm at Earth can wreak havoc on communication and navigation systems, electrical power grids, and pose radiation hazards to astronauts and airline passengers and crew.
University of New Hampshire’s Space Science Center (SSC) scientists are now adding some powerful tools to the predictive toolbox using data from NASA’s MErcury Surface, Space ENvironment, Geo-chemistry, and Ranging, or MESSENGER, spacecraft, which orbited our solar system’s innermost planet, Mercury, beginning in March 2011 until its planned crash into the planet on April 30, 2015.
MESSENGER investigated the sun’s powerful interstellar coronal mass ejections (ICMEs) close to the source in an effort to track and analyze the evolution of these solar storms and improve the forecasting of their arrival times at Earth. It’s onboard magnetometer also collected a wealth of data relative to ICME magnetic fields, which is what the UNH researchers are using in hopes of improving space weather prediction.
Currently, scientists don’t know exactly where on average ICMEs stop slowing down and continue towards Earth at a constant speed – a critical missing piece of the puzzle. “From MESSENGER’s data we know the deceleration phase continues beyond Mercury’s orbit and stops before it gets to Earth, but where it reaches that point of constant speed is unclear,” Winslow says. “And if we want to be able to forecast ICME arrival times at Earth more accurately we need to have a better handle on the deceleration of ICMEs beyond Mercury’s orbit.”
As the orientation of an ICME’s magnetic field is crucial to the potential strength of an ensuing geomagnetic storm, the UNH scientists are also using the MESSENGER data to help determine how these magnetic fields might evolve and change direction during their passage to Earth. “You want that forecasting power so you can say, ‘Even though we know this ICME will hit the Earth, its magnetic field direction is aligned in such a way that it’s not going to cause a geomagnetic storm.’ That’s something we’re testing right now with the observations from MESSENGER.” http://www.eurekalert.org/pub_releases/2015-08/uonh-usp081115.php
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