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The Voyager 1 spacecraft is poised to leave the solar system and reach interstellar space. In fact, it may already have.
Voyager 1 launched in 1977. It's now 17 billion kilometers from Earth. And it should be close to the heliopause, where the plasma flowing outward from the sun no longer holds back the interstellar winds.
The heliopause was expected to be a rather sharp boundary between the sun’s domain and interstellar space. But instead the spacecraft now finds itself in an unexpectedly tranquil zone. Voyager 1 no longer has the wind at its back, so to speak—since last year the velocity of the outward-flowing solar wind has been zero. And it has unexpectedly stayed that way for hundreds of millions of kilometers, according to a mission update in the journal Nature. [Stamatios Krimigis et al., Zero Outward Flow Velocity for Plasma in a Heliosheath Transition Layer"]
That could mean that Voyager 1 is drawing close to the heliopause, which just happens to be surrounded by a broad expanse of calm. Or it could mean that Voyager 1 has already crossed the heliopause. Either way, the spacecraft becomes the first object in interstellar space created by intelligent life. That we know about.
—John Matson
[The above text is an exact transcript of this podcast.]
[Scientific American is part of Nature Publishing Group.]
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2 Comments
Add CommentAs the energetic particles that constitute the Solar wind lose their momentum, their motion relative to a calm background medium would effectively cease. At that point I suspect that all motion would be gravitationally directed.
Reply | Report Abuse | Link to thisI suggest that that the specific flow velocity of the interstellar medium is locally, regionally and galactically determined local, regional and galactic mass distributions and its gravitational effects.
I further suggest that the interstellar medium is itself rotating around the galactic center, and that shock waves have only been observed for giant stars that happen to have peculiar velocities in relation to the interstellar medium because most stars in the galactic disc do not have such peculiar relative velocities.
Please see, especially:
http://en.wikipedia.org/wiki/Heliopause#Cassini_results
"first object in interstellar space created by intelligent life. That we know about."
Reply | Report Abuse | Link to thisintelligent life ? where ? you sure ? I think that is really pushing the description .Never mind quite self serving as what are you comparing this assumption too ?
Calling Humans who kill each other, are killing the planet that supports life for money that will be worthless as we run out of clean Air & Water and ask the blessing of a GOD ( I will skip that can of worms ) . I guess it depends on what you consider intelligence. Me I think not . I will consider the this is first piece of trash from Earth that far away.
We treat space as a dump as we do our planet That is far from intelligence . But , what do I know ?