NASA Reveals First Images of Solar System's Tail

NASA has recently released stunning images of the solar system's downwind region. With the Interstellar Boundary Explorer (IBEX) spacecraft, the space agency has captured new pictures that reveal a unique and unexpected structure located in the area.

Researchers have long believed that like a comet, a "tail" trails the heliosphere--the giant bubble in which our solar system resides--as it moves through interstellar space. In order to learn whether or not this was the case, scientists sent the IBEX spacecraft to take images of the region. The first pictures, which were released in 2009, showed an unexpected ribbon of surprisingly high energetic neutral atom (ENA) emissions circling the upwind side of the solar system.  Over time, the researchers also saw a structure dominated lower energy ENAs, which was identified as the heliotail; yet this structure was quite small.

Yet these new images show a little bit more about the area. The next two years of IBEX data filled in the observational hole in the downwind direction, revealing a second tail area to the side of the previously identified one. These two regions act more like "lobes" rather than a single, unified tail as expected.

"We chose the term 'lobes' very carefully," said Dave McComas, IBEX principal investigator, in a news release. "It may well be that these are separate structures bent back toward the downwind direction. However, we can't say that for certain with the data we have today."

The images don't just show the structure of the heliotail, though. They also reveal that the heliotail is the region where the Sun's million mile per hour solar wind flows down and ultimately escapes the heliosphere. It then slowly evaporates because of charge exchange. The faster solar wind flows down the lobes at high northern and southern latitudes while the slow solar wind flows down the tail in the port and starboard lobes and low- and mid-latitudes.

"We're seeing a heliotail that's much flatter and broader than expected, with a slight tilt," said McComas. "Imagine sitting on a beach ball. The ball gets flattened by the external forces and its cross section is oval instead of circular. That's the effect the external magnetic field appears to be having on the heliotail."

The findings reveal a little bit more about this interesting and unusual structure. The images are hopefully the first of many from IBEX, which will continue to send data to provide the first global views of our solar system's interaction with interstellar space.

The findings are published in The Astrophysical Journal.

Want to see more images? Check them out here.