Voyager still going strong

[Noah]

Just got this press release in the e-mail, thought it was interesting, and I believe the system for posting articles is still down. Enjoy!

 

VOYAGER APPROACHING SOLAR SYSTEM'S FINAL FRONTIER

 

NASA's Voyager 1 spacecraft is about to make history

again. It is the first spacecraft to enter the solar system's

final frontier, a vast expanse where wind from the sun blows

hot against thin gas between the stars: interstellar space.

 

However, before it reaches this region, Voyager 1 must pass

through the termination shock, a violent zone that is the

source of beams of high-energy particles. Voyager's journey

through this turbulent zone will give scientists the first

direct measurements of our solar system's unexplored final

frontier, the heliosheath. Scientists are debating if this

passage has already begun. Two papers about this research are

being published in Nature today.

 

The first paper, by Dr. Stamatios Krimigis of the Johns

Hopkins University Applied Physics Laboratory, Laurel, Md.,

and his team, supports the claim Voyager 1 passed beyond the

termination shock. The second paper, by Dr. Frank McDonald of

the University of Maryland, College Park, Md., and his team,

disputes the claim. A third paper, published October 30 in

Geophysical Research Letters by GSFC's Dr. Leonard Burlaga,

and collaborators, states Voyager 1 did not pass beyond the

termination shock.

 

"Voyager 1 has seen striking signs of the region deep in

space where a giant shock wave forms, as the wind from the

sun abruptly slows and presses outward against the

interstellar wind. The observations surprised and puzzled us,

so there is much to be discovered as it begins exploring this

new region at the outer edge of the solar system," said Dr.

Edward Stone, Voyager Project Scientist, California Institute

of Technology, Pasadena, Calif.

 

Launched on September 5, 1977, Voyager explored the giant

planets Jupiter and Saturn before being tossed out toward

deep space by Saturn's gravity. It is approaching, and may

have temporarily entered, the region beyond termination

shock. At more than eight billion miles from the sun, Voyager

1 is the most distant object from Earth built by humanity.

 

The termination shock is where the solar wind, a thin stream

of electrically charged gas blown constantly from the sun, is

slowed by pressure from gas between the stars. At the

termination shock, the solar wind slows abruptly from its

average speed of 700,000 to 1,500,000 mph.

 

Estimating the location of the termination shock is hard,

because we don't know the precise conditions in interstellar

space. We do know speed and pressure of the solar wind

changes, which causes the termination shock to expand,

contract and ripple.

 

From about August 1, 2002, to February 5, 2003, scientists

noticed unusual readings from the two energetic-particle

instruments on Voyager 1, indicating it had entered a region

of the solar system unlike any previously encountered. This

led some to claim Voyager 1 may have entered a transitory

feature of the termination shock.

 

The controversy would be resolved if Voyager could measure

the speed of the solar wind, because the solar wind slows

abruptly at the termination shock. However, the instrument

that measured solar wind speed no longer functions on the

venerable spacecraft. Scientists must use data from

instruments still working to infer if Voyager pierced the

termination shock.

 

"We have used an indirect technique to show the solar wind

slowed down from about 700,000 mph to much less than 100,000

mph. We used this same technique when the instrument

measuring the solar wind speed was still working. The

agreement between the two measurements was better than 20

percent in most cases," Krimigis said.

 

"T

[deamonstar]

kinda puts the energizer bunny to shame...