Voyager 2, the multi-planetary exploratory probe launched in 1977, has finally entered interstellar space, some six years after its twin, Voyager 1, did the same. It’s now about 11 billion miles from Earth, the second-farthest-out human-made object in space.
Interstellar space starts where the sun’s “heliosphere” ends — the big ball of radiation and plasma in which the planets bathe and by which they are protected. Both Voyagers have instruments on board that monitor all this stuff, and both have shown a major dropoff in electrical and plasma activity, suggesting they’ve crossed over.
The exact border of interstellar space is a matter of debate, a great deal of which occurred while Voyager 1 was on the very edge and scientists were arguing whether it was out or not. A consensus was reached, however, and most agree that both probes have now left the heliosphere.
They have not, however, left the solar system, defined more or less by the extent of …read more
Source:: TechCrunch Gadgets