In 2012, Voyager 1 turned the primary human-made object to enterprise past our photo voltaic system. The house probe is now not alone in that distinction. At the moment—November 4, 2019—researchers on the College of Iowa confirmed that Voyager 2 has entered interstellar house after beginning its journey from Earth 42 years in the past.
Voyager 2 has made historical past many instances since its 1977 launch. It has been to Saturn and Jupiter, and it stays solely spacecraft that has explored Uranus and Neptune. After exhausting the outer reaches of our photo voltaic system, Voyager 2’s subsequent vacation spot turned the mysterious areas of house that lie past it.
A brand new research from the College of Iowa printed within the journal Nature Astronomy confirms that Voyager 2 left the realm of our solar on November 5, 2018. The purpose the place our photo voltaic system ends and interstellar house begins could seem onerous to outline, however the Voyager crafts have supplied scientists with a transparent reply.
Relatively than steadily transitioning from one kind of house to a different, our photo voltaic system has a bodily boundary. The solar offers off a “photo voltaic wind” that is sizzling and low in plasma. This photo voltaic wind creates a bubble, referred to as the heliosphere, that stretches billions of miles from the solar. On the opposite aspect of this bubble, house is way cooler and extra dense in plasma. There is a clear level the place the bubble ends, like what you’d see with a bubble of oil in a glass of water.
A few yr in the past, a plasma-wave instrument aboard Voyager 2 recorded a dramatic bounce in plasma density, indicating that it had crossed over from the heliosphere into interstellar house. It made the transition about 11.1 billion miles from the solar, which is roughly the identical distance Voyager 1 clocked when it entered interstellar house from a distinct level within the photo voltaic system.
“It implies that the heliosphere is symmetric, at the very least on the two factors the place the Voyager spacecraft crossed,” research co-author Invoice Kurth stated in a information launch. “That claims that these two factors on the floor are nearly on the similar distance.”
Co-author Don Gurnett added, “There’s nearly a spherical entrance to this. It is like a blunt bullet.”
Now that each Voyagers are within the a part of house that lies between the celebrities, they’ll orbit the galaxy for five billion years or longer. Scientists predict they’ll outlast Earth.