Nasa’s Voyager 2 sends back first message from interstellar space, 42 years after it was launched
- Probe is second Nasa spacecraft to leave our solar system
- Scientists analyse treasure trove of data sent back
A probe launched by Nasa four days after Elvis died has delivered a treasure trove of data from beyond the “solar bubble” that envelops Earth and our neighbouring planets, scientists reported.
But for every mystery Voyager 2 has solved about the solar winds, magnetic fields and cosmic rays that buffet the boundary between interstellar space and the Sun’s sphere of influence, a new one has cropped up.
Voyager 2 left Earth’s orbit in 1977 a month before its twin Voyager 1, but took seven years longer to reach the heliosphere’s outer limit some 18 billion kilometres (more than 11 billion miles) away.
Shaped something like a windsock in a stiff breeze, the heliosphere is formed by the Sun’s magnetic field and solar winds that can reach speeds of three million kilometres per hour.
It can be compared to a cosmic supertanker ploughing through space, said Edward Stone, a professor at the California Institute of Technology and lead author of one of five articles published in Nature Astronomy.
“As it moves through the interstellar medium” – the vast expanses of space between stellar fiefdoms – “there’s a wave in front, just as with the bow of a ship,” Stone told journalists by phone.