While Earth spins around the sun at around 67,000 mph, the sun rotates around the Milky Way galaxy at a zippy 140 miles per second. With such a massive force moving through space, there's bound to be a trail of cosmic dust following behind, but it's always been a mystery -- until now. For the first time, scientists have combined the observations of NASA's Interstellar Boundary Explorer (IBEX) satellite and mapped the solar system's tail, but the length remains unclear.
Capturing the tail, which is composed of solar wind plasma and magnetic field, required three years of observation based upon data from IBEX's powerful energetic neutral atom imaging system. As neutral atoms (and other particles) from other parts of the galaxy flow through our solar system, those atoms eventually collide with faster charged particles -- usually carried by solar winds -- and exchange an electron.
According to NASA, when this exchange occurs, it can produce a slow charged particle and a fast neutral atom. While many of these neutral atoms go on their merry way, some eventually return to the inner heliosphere and collide with IBEX's imaging technique. IBEX detects where the neutral atoms came from and scientists use that data to create heliotail imagery.
"By collecting these energetic neutral atoms, IBEX provides maps of the original charged particles," said IBEX principal investigator David McComas. "The structures in the heliotail are invisible to our eyes, but we can use this trick to remotely image the outermost regions of our heliosphere."
The IBEX team, led by McComas, announced the stellar findings in the paper "The Heliotail Revealed by the IBEX," which was recently published by The Astrophysical Journal.