The NASA Voyager 2 probe left our solar system almost a year ago and was the second spaceship ever to enter interstellar space.
It followed six years behind its sister spacecraft Voyager 1, which reached the limits of the solar system in 2012. However, a plasma gage on Voyager 1 had been damaged, leaving the probe with no crucial data on the transition from our solar system to interstellar space could collect.
Voyager 2, who left the solar system intact with his instruments, completed the record. The researchers shared their findings for the first time on Monday with over five articles published in the journal Nature Astronomy.
The analyzes show that there are mysterious additional layers between the bubble of our solar system and the interstellar space. Voyager 2 discovered solar winds ̵
"Material from the solar bubble licked outward, up the galaxy at distances of up to a billion miles," said Tom Krimigis, a physicist who authored one of the publications, in a call with reporters.
The new boundary layers indicate that there are stages in the transition from our solar bubble into space. Scientists have not understood that yet.
The place where sun and interstellar winds interact.
On November 5, 2018, Voyager 2 left the so-called "heliosphere," a huge bubble of charged particles that flows out of the sun and surrounds our solar system. The probe crossed a border area called the "heliopause". In this area, the edge of the bubble of our solar system, solar winds meet interstellar winds and fold back on themselves.
Both spaceships took less than a day to cross the entire Heliopause. The twin probes are now racing through a region known as the "bow shock," in which the plasma of interstellar space flows around the heliosphere, much like water flowing around the bow of a moving ship.
Both Voyager probes have measured changes in the intensity of cosmic rays during transition through the heliopause as well as the transition between magnetic fields inside and outside the bubble.
But so much of the transition from our solar system The damaged instrument of Voyager 1 was marked in space by changes in the plasma (a hot ionized gas, which is the most abundant matter in the universe).
Now the new measurements from Voyager 2 point to the boundaries between our solar system and interstellar space may not be as easy as scientists once thought.
The data suggest that there is a previously unknown boundary layer just behind the heliopause. In this area, solar winds invade space and interact with interstellar winds. The intensity of the cosmic radiation there was only 90% of its intensity farther out.
"There seems to be a region outside the Heliopause we are still connected to – there is still an inward connection," Edward Stone, a physicist who has been working on the Voyager missions since 1972, said in the call.
Other results of the new analyzes also show that the relationship between the interstellar space and our solar system at its edges is complicated.
The scientists discovered that beyond the mysterious, newly identified layer there is another, much thicker boundary layer in which interstellar plasma flows over the heliopause. There, the density of plasma increases by a factor of 20 or more for a region that includes billions of miles. This suggests that something compresses the plasma outside the heliosphere, but scientists do not know what.
"This is currently a mystery," said Don Gurnett, an astrophysicist who wrote one of the five papers in the call. 19659002] In addition, the new results showed that Voyager 2 experienced a much quieter transition from the heliopause to a strong new magnetic field outside the solar system compared to Voyager 1.
"That remains a mystery," said Krimigis.
Scientists hope to continue exploring these boundaries over the next five years, before the Voyager probes have run out of fuel.
"The heliopause is a barrier to the interstellar system flow," added Stone. "We want to understand this complex interaction to the greatest possible extent."
5 more years of Voyager data
NASA launched the Voyager Probes in 1977. Voyager 2 launched a special course two weeks ahead of Voyager 1 to explore Uranus and Neptune. It is still the only spaceship that has visited these planets.
The detour meant that Voyager 2 reached interstellar space six years after Voyager 1. It is now NASA's longest running mission.
"When the two Voyagers were launched, the space age was only 20 years old, and it was hard to say at that point that anything could take over 40 years," said Krimigis.
Well, he said, scientists spend another five years computing data from the probe as they move into interstellar space. The team hopes the Voyager will reach the distant point where the heliosphere will not disturb space before they run out of fuel.
After the spaceship dies, they continue to drive through space. If aliens ever find them, each Voyager probe contains a golden record encoded with sounds, images, and other information about life on Earth.
In the future, researchers would like to send more probes in different directions to the edges of our probes solar system to study these boundary layers more closely.
"We definitely need more data, here's a whole bubble, and we've just crossed two points," said Krimigis. "Two examples are not enough."