It has long been believed that our solar system has a tail, just like any other object moving through another medium. This movement causes particles to form a tail behind it. However, the tail of our heliosphere has been a theory, something never seen. NASA's Interstellar Boundary Explorer (IBEX) has mapped this tail, something that might have once been considered impossible.
The tail, which scientists are calling the heliotail, was mapped out after combining observations from three years of images taken by IBEX. Looking at these images, astronomers discovered that the heliotail consists of two lobes of slower particles on its sides with faster particles above and below that. This gives the tail a twisted appearance as it undergoes the pushing and pulling of magnetic fields outside the solar system.
David McComas, principal investigator for IBEX at Southwest Research Institute in San Antonio, Texas, said:
“By examining the neutral atoms, IBEX made the first observations of the heliotail. Many models have suggested the heliotail might be like this or like that, but we’ve had no observations. We always drew pictures where the tail of the heliosphere just disappears off the page, since we couldn't even speculate about what it really looked like.”
Tails around stars have been spotted by telescopes before, but it has been difficult to see our own. Conventional methods to view the heliotail have been difficult because the particles in the tail and throughout the heliosphere don't shine. However, IBEX can map this area by measuring neutral particles created by collisions at the edge of the heliosphere. This data about what the heliotail looks like offers a new understanding of our movement through the galaxy.
“The tail is our footprint on the galaxy, and it’s exciting that we’re starting to understand the structure of it,” said Eric Christian, IBEX mission scientist at NASA’s Goddard Space Flight Center. “The next step is to incorporate these observations into our models and start the process of really understanding our heliosphere.”