Tuesday, December 14, 2010

Voyager Is Near Solar System's edge

BBC News reports.  A distinct change in the general velocity of charged solar-wind particles measured by Voyager 1 indicate is close to crossing the heliopause, by one definition, the edge of the solar system.

Now 17.4 [billion] km (10.8 [billion] miles) from home, the veteran probe has detected a distinct change in the flow of particles that surround it.
It means Voyager must be very close to making the jump to interstellar space - the space between the stars.
The newly reported observation comes from Voyager 1's Low-Energy Charged Particle Instrument, which has been monitoring the velocity of the solar wind.

This stream of charged particles forms a bubble around our Solar System known as the heliosphere. The wind travels at “supersonic” speed until it crosses a shockwave called the termination shock.

At this point, the wind then slows dramatically and heats up in a region termed the heliosheath. Voyager has determined the velocity of the wind at its location has now slowed to zero.

Story by By Jonathan Amos,
Science correspondent, BBC News, San Francisco