Voyager Makes an Interstellar Discovery

Science@NASA ^ | 12.23.2009 | Dr. Tony Phillips

[PeaceBeWithYou]

December 23, 2009: The solar system is passing through an interstellar cloud that physics says should not exist. In the Dec. 24th issue of Nature, a team of scientists reveal how NASA's Voyager spacecraft have solved the mystery.

"Using data from Voyager, we have discovered a strong magnetic field just outside the solar system," explains lead author Merav Opher, a NASA Heliophysics Guest Investigator from George Mason University. "This magnetic field holds the interstellar cloud together and solves the long-standing puzzle of how it can exist at all."

The discovery has implications for the future when the solar system will eventually bump into other, similar clouds in our arm of the Milky Way galaxy.

Astronomers call the cloud we're running into now the Local Interstellar Cloud or "Local Fluff" for short. It's about 30 light years wide and contains a wispy mixture of hydrogen and helium atoms at a temperature of 6000 C. The existential mystery of the Fluff has to do with its surroundings. About 10 million years ago, a cluster of supernovas exploded nearby, creating a giant bubble of million-degree gas. The Fluff is completely surrounded by this high-pressure supernova exhaust and should be crushed or dispersed by it.

"The observed temperature and density of the local cloud do not provide enough pressure to resist the 'crushing action' of the hot gas around it," says Opher.

So how does the Fluff survive? The Voyagers have found an answer.

"Voyager data show that the Fluff is much more strongly magnetized than anyone had previously suspected—between 4 and 5 microgauss*," says Opher. "This magnetic field can provide the extra pressure required to resist destruction."

NASA's two Voyager probes have been racing out of the solar system for more than 30 years. They are now beyond the orbit of Pluto and on the verge of entering interstellar space—but they are not there yet.

"The Voyagers are not actually inside the Local Fluff," says Opher. "But they are getting close and can sense what the cloud is like as they approach it."

The Fluff is held at bay just beyond the edge of the solar system by the sun's magnetic field, which is inflated by solar wind into a magnetic bubble more than 10 billion km wide. Called the "heliosphere," this bubble acts as a shield that helps protect the inner solar system from galactic cosmic rays and interstellar clouds. The two Voyagers are located in the outermost layer of the heliosphere, or "heliosheath," where the solar wind is slowed by the pressure of interstellar gas.

Voyager 1 entered the heliosheath in Dec. 2004; Voyager 2 followed almost 3 years later in Aug. 2007. These crossings were key to Opher et al's discovery.

The size of the heliosphere is determined by a balance of forces: Solar wind inflates the bubble from the inside while the Local Fluff compresses it from the outside. Voyager's crossings into the heliosheath revealed the approximate size of the heliosphere and, thus, how much pressure the Local Fluff exerts. A portion of that pressure is magnetic and corresponds to the ~5 microgauss Opher's team has reported in Nature.

The fact that the Fluff is strongly magnetized means that other clouds in the galactic neighborhood could be, too. Eventually, the solar system will run into some of them, and their strong magnetic fields could compress the heliosphere even more than it is compressed now. Additional compression could allow more cosmic rays to reach the inner solar system, possibly affecting terrestrial climate and the ability of astronauts to travel safely through space. On the other hand, astronauts wouldn't have to travel so far because interstellar space would be closer than ever. These events would play out on time scales of tens to hundreds of thousands of years, which is how long it takes for the solar system to move from one cloud to the next.

"There could be interesting times ahead!" says Opher.

To read the original research, look in the Dec. 24, 2009, issue of Nature for Opher et al's article, "A strong, highly-tilted interstellar magnetic field near the Solar System."

[PeaceBeWithYou]

Right out of Roddenberry's Star Trek.

Clickable pics open in a new window

Voyager flies through the outer bounds
of the heliosphere en route to interstellar
space. A strong magnetic field reported by
Opher et al in the Dec. 24, 2009, issue of
Nature is delineated in yellow.

An artist's concept of the Local Interstellar Cloud,
also known as the "Local Fluff."

The anatomy of the heliosphere. Since
this illustration was made, Voyager 2
has joined Voyager 1 inside the heliosheath,
a thick outer layer where the solar wind is
slowed by the pressure of interstellar gas.

[allmost]

Archaic tech. Let’s try again :)

[The Drowning Witch]

My God....We’re motes of sand a-drift in a river the size of the Mississippi.

[DesertSapper]

"an interstellar cloud that physics says should not exist"

Then it must not be there because physicists know everything!

[Frantzie]

VeeGer is still sending back data? Didn’t another one leave the solar system?

[GeronL]

cool!!

Solar Systems are like bubbles in the fluff!

[Skooz]

bfl

[Blood of Tyrants]

We are less than that.

[SaxxonWoods]

“There could be interesting times ahead!” says Opher.

There should be elaboration upon such a statement. This isn’t the Perils of Pauline. Or is it?

[dog breath]

Massive amounts of hot air and fluff, at first I thought this was another article about Obama.

[ProtectOurFreedom]

Thanks for posting. This really hits home for me as my Dad lead the program to develop and manufacture the powerplants that power Voyager 1 and 2. I really enjoy reading about these amazing spacecraft.

[buccaneer81]

Space ping!

[colinhester]

How cool!

[The Magical Mischief Tour]

Then it must not be there because physicists know everything!

No... that would be Algore.

[jonrick46]

Does this mean that we have to traverse a 4000 degree “fluff” zone on our way out of the solar system? That appears like this is an impenetrable zone that keeps man trapped inside the solar system.

[El Sordo]

If only we were that big.

[Centurion2000]

Best $$ ever spent on a space probe ... 30+ years and STILL working ... paid in full.

[Nik Naym]

“Then it must not be there because physicists know everything! “

That’s funny, physicists will be the first to tell you that they do not.

[Centurion2000]

My God....We’re motes of sand a-drift in a river the size of the Mississippi.

Less than that. If the sun were a basketball in New Orleans, the nearest star would be a basketball ..... in Moscow, Russia.

[Pan_Yan]

* 11

[ProtectOurFreedom]

It really was. I remember his showing me the plutonium canisters being destructively tested to make sure they wouldn’t crack open upon launch. Some amazing engineering feats in that project!

[Bean Counter]

Just amazing! There are a lot of guys who are retiring now, who cut their professional teeth on the Voyager program, and the spacecraft are still out there doing meaningful science./

Wow. Just wow!!

[opbuzz]

6000c = 10832f

Cool. How long will Voyager last in that?

[jdege]

I ran across a book, a few years back, called “The Big Bang Never Happened.” It’s premise was that cosmologists assumptions that only gravity mattered on a cosmic scale, because positive and negative electromagnetic forces canceled each other out, was unfounded. And that the observations were consistent with a universe filled with massive electromagnetic flux.

Interesting that we should have found some.

Of course, the consequence of having electromagnetism matter is that the past and the future of the universe is no longer predictable. If gravity is everything, we can know the end state. If it is not, we cannot.

http://bigbangneverhappened.org/

[ErnstStavroBlofeld]

Voyager is still sending data.It probably has enough power until another decade

[dragnet2]

NASA’s two Voyager probes have been racing out of the solar system for more than 30 years.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

The spacecraft are moving at approximately 12 miles per second......And they still haven’t left the solar system...lol..

[ErnstStavroBlofeld]

Family Portrait done by Voyager 1 in February 1990

[ErnstStavroBlofeld]

Close Ups

[PeaceBeWithYou]

A Breeze from the Thirteenth House - Interesting, Related.

[ErnstStavroBlofeld]

Where does the Solar System “end” or where interstellar space “begin”?

[Captain Beyond]

bump

[PeaceBeWithYou]

Voyager will most likely be OK, as the density of the cloud is much less than the Heliosphere and Heliosheath. (See link in post 29)

[38special]

Hey Hey, You You get off of my cloud...

[grey_whiskers]

Like, *PING*, dudes.

[grey_whiskers]

Artist's conception of Milky Way and Fluff:.

Milky Way is center just below the top with Fluff to its left:

Cheers!

[MediaMole]

Pretty sure only climatologists know everything.

[grey_whiskers]

Can anyone say "V'Ger" and "Heavenly Bodies"?

Cheers!

[dragnet2]

Where does the Solar System “end” or where interstellar space “begin”?

Well, there is no sign or solar system border line, but it's generally thought to be beyond the orbit of Pluto...It's up for debate...lol

That being said, the gravitational influence of the sun is estimated to reach approximately two light years out. Give or take.

[Gene Eric]

That’s cool. I’m amazed the Voyagers are still cruising some thirty years later.

[Spktyr]

No, it just means that we just enter and exit the system through the sun’s ‘wake’ or come up with a subspace drive that bypasses it entirely. Same reason you don’t jump off the front of a moving boat when diving.

[sig226]

Nah, physicists don’t matter. Now if climate scientists had said that it wasn’t there . . .

[americanophile]

Isn’t this where Lando Calrissian lives?

[ErnstStavroBlofeld]

You can say the Solar System ends at the Heliopause.Initial data from Interstellar Boundary Explorer (IBEX), launched in October 2008, revealed a previously unpredicted "very narrow ribbon that is two to three times brighter than anything else in the sky." Initial interpretations suggest that "the interstellar environment has far more influence on structuring the heliosphere than anyone previously believed. You can also say that the Solar System ends at the Oort Cloud.The Oort Cloud is a hypothesized spherical cloud of comets which may lie roughly 50,000 AU, or nearly a light-year, from the Sun.This places the cloud at nearly a quarter of the distance to Proxima Centauri, the nearest star to the Sun.

[PeaceBeWithYou]

No.

....A long time ago, in a Galaxy far, far, away....

[shibumi]

There is a secret stone, hidden in a deep well,

worthless and rejected, concealed in dung or filth.

It is a thing which is found everywhere,

which is a stone and no stone,

contemptible and precious,

hidden, concealed, and yet known to everyone.

(Certain "heavenly bodies" not withstanding.)

[stevie_d_64]

Too bad, she passed away back in 1998...

[grey_whiskers]

Yikes! I didn't know that.

Apologies for lack of decorum.

Cheers!

[stevie_d_64]

Ehhhh, don’t worry, You didn’t know, no apologies necessary...