This diagram shows plasma from interstellar space colliding with the heliosphere that surrounds the sun.(Credit: NASA)
Posted on 12/10/2007 7:59:55 PM PST by Ernest_at_the_Beach
Posted by Stephen Shankland
This diagram shows plasma from interstellar space colliding with the heliosphere that surrounds the sun.(Credit: NASA)
SAN FRANCISCO--Thirty years after launch but earlier than expected, Voyager 2 has left the cozy realm of our solar system, where the stream of particles from the sun dominates space.
You might think that space billions of miles from the sun is a placid, empty domain. In fact, Voyager 2 has been heading outward in the same direction as the solar wind, charged particles streaming from the sun, but things started to get a lot more complicated on August 30, when the spacecraft was 7.8 billion miles from the sun.
There, the spacecraft passed into a new region, where the solar wind suddenly slams into the prevailing breeze and magnetic field left from a series of massive supernovas from 20 million to 30 million years ago, said Voyager project scientist Edward Stone of the California Institute of Technology during a news conference at the American Geophysical Union conference here Monday.
In this area, called the termination shock, the speed of the solar wind drops abruptly from about 250 miles per second to about 60, said John Richardson, a Massachusetts Institute of Technology researcher who's the principal investigator for the Voyager's plasma science work.
Voyager 1, which is traveling faster than Voyager 2 and in a different direction, already crossed the termination shock boundary in December 2004, though some of its elderly instruments are defunct and it crossed during a gap when data wasn't recorded. But Voyager 2 crossed the boundary while significantly closer to the sun, indicating that this region where the solar wind dominates, called the heliosphere, is not in fact a sphere but rather is squashed.
"The termination shock is 1 billion miles closer to the sun in the southern hemisphere than in the northern hemisphere," Stone said, referring to regions of space on either side of plane in which the planets orbit the sun. "There's something outside pushing in on the field of the heliosphere. We believe it's a magnetic field distorting an otherwise spherical surface."
It'll be a while--probably 7 to 10 years--before the Voyager spacecraft leave the solar system altogether and cross into interstellar space itself, Stone said. The researchers hope that will be before the Voyagers' radioactively powered batteries are estimated to run out of juice--sometime between 2020 and 2025, he added.
A Voyager spacecraft(Credit: NASA)
If you're disgruntled that your own batteries seem to expire much sooner, bear in mind that NASA shuts down most of the spacecrafts' instruments and that they transmit data back to Earth with a 20-watt transmitter. That's much less than most conventional light bulbs.
Their distance from the sun in 2020 will be about 14 billion miles for Voyager 1 and 122 billion miles for Voyager 2. For perspective, that's 148 and 122 times as far away from the sun as the Earth is, respectively. Voyager 1 is traveling about 10.6 miles per second and Voyager 2 at about 9.3 miles per second.
That's remarkable longevity. NASA bet on an initially modest mission to Jupiter and Saturn but planned for the spacecraft to lead much longer lives. With a gradually lengthening series of three-year budget extensions, the spacecraft have made it to Uranus and Neptune, and Stone and his colleagues are now writing the next three-year funding proposal.
The Voyager spacecraft cost $865 million to build and launch and $120 million so far to operate.
Others likely will follow in the Voyagers' footsteps. First will be the New Horizons mission, now launched and scheduled to visit Pluto in 2015. The next planned is Ibex, short for Interstellar Boundary Explorer, a spacecraft dedicated to investigate these outer reaches of the solar system that's scheduled for a June 2008 launch.
Ibex in particular is geared to investigate one mystery that Voyager 2 uncovered. The researchers expected the solar wind particles to be a toasty 1 million degrees in temperature, but in fact they are a relatively cool 200,000 or so, Stone said. "The thermal energy that was missing most likely went into the acceleration of ionic particles," he said.
Also to be studied are the particulars of the termination shock, a fast-changing region. Voyager 2 actually crossed the boundary at least 5 times on its way out from the sun, Stone said, as it traversed the turbulent region.
NASA,
“Voyagers’ radioactively powered batteries are estimated to run out of juice—sometime between 2020 and 2025,”
Man I need some double AA’s that will last that long!!!<==<<
Once they leave the solar system, can’t they just switch from impulse to warp drive?
Maybe they will show up in cars....some day.
That’s a later technology...these are Model T’s.
How long yeh think until we have to start buying Bow Wave Shock Offsets from Al Gore?
OK - which one of you sat on it?
Yea, that idiot Algored selling those stupid carbon credits is the most ridiculous thing I have ever heard of or imagined.
Remember those old 40’s and 50’s western movies where the snake oil salesman had a sneaky untrustworthy personality ?
That is Algored to a T.
Trust him as far as I could throw him, as with his hulking tedkennedy girth, that would not be very far......
Amazing. I can’t believe the voyager is still operating. I remember when they launched it. It must’ve been 30 to 35 years ago. The last time I heard anything about the voyager, I think it was passing the rings of saturn, or somethign like that.
Remember the movie 2001 space odessy, when the machine’s name was v ger? Because the o and the y got wiped off?
I’ve probably paid Cosco enough for D cells in the past 15 years that I could have bought a couple of the radioactive batteries and still have money left over for a case of wine!
The funniest part is, idiots buy them. Iirc, there’s even airline companies that are starting to sell them to customers that want to “offset” their carbon expenses acquired from traveling.
To me, this smells more like the holy relic salesmen of the old medieval europe.
Knuckle bone of a saint! Guaranteed to absolve at least 3 mortal sins!
I thought that was the first Star Trek movie.
They have 14 billion miles for one and 122 billion for the other in 2020—there must be a typo (I think it should be 12 billion, not 122 billion), since the latter one is traveling more slowly.
Space Ping
As for the thread itself, it’s some really really cool stuff.
I know a woman that has a toy that is run by "D" batteries that seems to run all night every night. I'd love to be those batteries.
This stuff is fascinating as heck, but over my head.
Voyager 1 travels at about 11 miles per second.
How does it stay on course when hit with solar winds that can be from 60 miles per second to 250 miles per second ?
what or how is voyager propelled ? I read about the nuclear fuel and converting heat to electicity, but what propels it ?
Was it? I can’t remember. THat was a long long time ago in a galaxy far far away. That came from “the last starfighter”, I think.
ping
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