Transcripts of G2013-062_IBEX_heliotailv2

(music) (music) Like a comet, our solar system has a tail. It has never actually been observed. Until now. NASA's Interstellar Boundary Explorer, or IBEX recently mapped the boundaries of the solar system's tail, called the heliotail. By combining observations from the first three years of IBEX imagery, scientists have mapped out a tail that shows a combination of fast and slow moving particles. IBEX can map such regions because it uses a technique called energetic neutral atom imaging. An energetic charged particle in the outer heliosphere hits a hydrogen atom, stealing its electron and becoming neutral. It then travels straight, though some of them come back toward the inner heliosphere. They're they collide with IBEX, and are detected. By plotting out such neutral atoms and where they came from, IBEX has recently been able to describe the tail streaming behind the solar system. The tail is composed of solar wind plasma and magnetic field. The solar wind streams out from the sun in all directions, out past the farthest planets. It eventually slows down, bending back along the tail, due to pressure from the interstellar gas and magnetic field. Based on the map of the heliotail, if we could look straight down the tail, we would see a shape a little like a four-leaf clover. The two side leaves are filled with slow moving particles, and the upper and lower leaves with fast ones. This is in line with how the sun releases fast solar wind near its poles, and slower wind near its equator. The four-leaf clover does not align perfectly with the solar system. The entire shape is rotated slightly. This indicates that as it moves farther away from the sun's magnetic influence the charge particles have begun to be pulled into a new orientation, aligning with the magentic field of the local galaxy. Scientists still do not know how long the tail is, but think that it eventually fades away and becomes indistinguishable from the rest of interstellar space. Together, data from instruments in space and analysis at labs on the ground will continue to improve our understanding of the comet-like tails streaming out behind us. (beeping) (beeping) (beeping)