Voyager 1 findings continue to confound experts
By RBR Staff
December 05, 2012
Now about 10.8 billion miles from the sun, Voyager 1 will be the first human-made object to escape the solar system.
NEWSCIENTIST.COM: With all the excitement surrounding Curiosity’s first full chemical analysis of Martian soil this week, it’s easy to forget about another, much more distant robotic explorer. Voyager 1 could soon leave our solar system and cross over into interstellar space, the first time any human-made object has left the cosy confines of our planetary neighbourhood.
Exploring solar system for 35 years
Yesterday, NASA announced that on its way out, Voyager 1 – which has been travelling through our solar system since 1977 – has encountered a new region of the solar system. It has been dubbed a “magnetic highway”.
The solar wind blows charged particles from the sun’s upper atmosphere around the solar system, creating an enormous “bubble” known as the heliosphere.
Charged particles travel along magnetic field lines, and the magnetic highway is thought to be the result of the sun’s magnetic field connecting up with field lines in the clouds of gas and dust of interstellar space.
The highway allows particles with low energy from the heliosphere to jet into interstellar space at high speed and high energy particles from the outside to rush in, an interaction that has been observed around other stars by the Hubble Space Telescope.
The magnetic highway was identified when Voyager encountered intense cosmic radiation. The obvious interpretation would be that this happened because Voyager had finally reached interstellar space, yet its instruments did not detect any change in the direction of the magnetic field, which we would expect to see when leaving the heliosphere.
This led researchers to conclude that Voyager was in a hitherto unknown region representing a bridge between the solar system and interstellar space.
Cosmic rays routinely enter the heliosphere, but we are shielded from their potentially damaging effects by the Earth’s magnetic field. “The magnetic highway gives us an insight into how the cosmic rays get in,” says Timothy Horbury of Imperial College London.
“Everything we’ve seen [from Voyager] is not what we expected to see,” Horbury says. “People have been working on this for a long time. Just about every expectation we’ve had has been confounded so far.”
Voyager reached the termination shock – the region of the outer solar system where the solar wind starts to slow – in 2003, but it may be several months to a couple of years before the craft fully escapes the solar system.
NASA scientists now say the magnetic highway may be the “very last layer between us and interstellar space”.