The Voyager 2 spacecraft has sent back its first message from interstellar space, after having left our solar system late last year. This makes it only the second human-made object to ever reach beyond this point, following sibling Voyager 1, which crossed this threshold in 2012.
Launched on August 20, 1977, Voyager is the longest-running space mission in history, lasting in excess of 40 years and counting. It crossed over into the interstellar medium (ISM) on November 5, 2018, journeying more than 11 billion miles from the sun. However, it has taken until now for the first data sent back to be published. This Voyager 2 data sheds new light on the structure of the heliosphere, the edge of our solar system. The data provides valuable information about the bubble-like heliosphere, which is created by wind streaming out from the sun. Voyager 2 is so far away from Earth that it takes the information 19 hours to travel from the spacecraft back to Earth.
“In a historical sense, the old idea that the solar wind will just be gradually whittled away as you go further into interstellar space is simply not true,” University of Iowa research scientist Don Gurnett said in a statement. “We show with Voyager 2 — and previously with Voyager 1 — that there’s a distinct boundary out there. It’s just astonishing how fluids, including plasmas, form boundaries.”
The data sent back by Voyager 2 adds to the information about the heliosphere that had already been uncovered by Voyager 1. It describes a sharper, thinner boundary to the heliosphere than the one recorded by Voyager 1. Voyager 1’s data was gathered some 13.5 billion miles from the sun, compared to Voyager 2’s 11 billion. While the research doesn’t settle the question of the overall structure and shape of the heliosphere, it does add more data points that astronomers will be able to use to augment their knowledge of the topic.
“[This new information] implies that the heliosphere is symmetric, at least at the two points where the Voyager spacecraft crossed,” Bill Kurth, a University of Iowa research scientist, said in a statement. “That says that these two points on the surface are almost at the same distance.” Gurnett described the structure of the heliosphere as being “like a blunt bullet.”