Pressure runs high at edge of solar system

Pressure runs high at edge of solar system
Illustration depicting the layers of the heliosphere. Credit: NASA/IBEX/Adler Planetarium

Out at the boundary of our solar system, pressure runs high. This pressure, the force plasma, magnetic fields and particles like ions, cosmic rays and electrons exert on one another when they flow and collide, was recently measured by scientists in totality for the first time—and it was found to be greater than expected.

Using observations of galactic —a type of highly energetic particle—from NASA's Voyager spacecraft scientists calculated the total pressure from particles in the outer region of the solar system, known as the heliosheath. At nearly 9 billion miles away, this region is hard to study. But the unique positioning of the Voyager spacecraft and the opportune timing of a solar event made measurements of the heliosheath possible. And the results are helping scientists understand how the Sun interacts with its surroundings.

"In adding up the pieces known from previous studies, we found our new value is still larger than what's been measured so far," said Jamie Rankin, lead author on the new study and astronomer at Princeton University in New Jersey. "It says that there are some other parts to the pressure that aren't being considered right now that could contribute."

On Earth we have air pressure, created by air molecules drawn down by gravity. In space there's also a pressure created by particles like ions and electrons. These particles, heated and accelerated by the Sun create a giant balloon known as the heliosphere extending millions of miles out past Pluto. The edge of this region, where the Sun's influence is overcome by the pressures of particles from other stars and , is where the Sun's magnetic influence ends. (Its gravitational influence extends much farther, so the solar system itself extends farther, as well.)

In order to measure the pressure in the heliosheath, the scientists used the Voyager spacecraft, which have been travelling steadily out of the solar system since 1977. At the time of the observations, Voyager 1 was already outside of the heliosphere in interstellar space, while Voyager 2 still remained in the heliosheath.

"There was really unique timing for this event because we saw it right after Voyager 1 crossed into the local interstellar space," Rankin said. "And while this is the first event that Voyager saw, there are more in the data that we can continue to look at to see how things in the heliosheath and interstellar space are changing over time."

Pressure runs high at edge of solar system
The Voyager spacecraft, one in the heliosheath and the other just beyond in interstellar space, took measurements as a solar even known as a global merged interaction region passed by each spacecraft four months apart. These measurements allowed scientists to calculate the total pressure in the heliosheath, as well as the speed of sound in the region. Credit: NASA's Goddard Space Flight Center/Mary Pat Hrybyk-Keith

The scientists used an event known as a global merged interaction region, which is caused by activity on the Sun. The Sun periodically flares up and releases enormous bursts of particles, like in coronal mass ejections. As a series of these events travel out into space, they can merge into a giant front, creating a wave of plasma pushed by magnetic fields.

When one such wave reached the heliosheath in 2012, it was spotted by Voyager 2. The wave caused the number of galactic cosmic rays to temporarily decrease. Four months later, the scientists saw a similar decrease in observations from Voyager 1, just across the solar system's boundary in interstellar space.

Knowing the distance between the spacecraft allowed them to calculate the pressure in the heliosheath as well as the speed of sound. In the heliosheath sound travels at around 300 kilometers per second—a thousand times faster than it moves through air.

The scientists noted that the change in galactic cosmic rays wasn't exactly identical at both spacecraft. At Voyager 2 inside the heliosheath, the number of cosmic rays decreased in all directions around the spacecraft. But at Voyager 1, outside the solar system, only the that were traveling perpendicular to the in the region decreased. This asymmetry suggests that something happens as the wave transmits across the solar system's boundary.

"Trying to understand why the change in the cosmic rays is different inside and outside of the remains an open question," Rankin said.

Studying the pressure and sound speeds in this region at the boundary of the solar system can help scientists understand how the Sun influences interstellar . This not only informs us about our own solar system, but also about the dynamics around other stars and planetary systems.


Explore further

NASA Voyager 2 could be nearing interstellar space

Citation: Pressure runs high at edge of solar system (2019, October 8) retrieved 20 October 2019 from https://phys.org/news/2019-10-pressure-high-edge-solar.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
3192 shares

Feedback to editors

User comments

Oct 08, 2019
Out at the boundary of our solar system, pressure runs high. This pressure, the force plasma, magnetic fields and particles like ions, cosmic rays and electrons exert on one another when they flow and collide, was recently measured by scientists in totality for the first time—and it was found to be greater than expected.

It shouldn't be a surprise the plasma ignoramuses were wrong again.

Oct 08, 2019
@Cant

And not one person is surprised that you are wrong again.

Oct 08, 2019
Funny how they make that first statement so very nice, and then back it up with the:

"In adding up the pieces known from previous studies, we found our new value is still larger than what's been measured so far," said Jamie Rankin, lead author on the new study and astronomer at Princeton University in New Jersey. "It says that there are some other parts to the pressure that aren't being considered right now that could contribute."

Part it really makes it foolish to say this is not an electromagnetic effect, note they specifically denote it as a magnetic effect apart from gravitational.

If this were the program making the 1:1 comparisons of Cosmic vs Quantum level events, if used with lightspeed as a constant, the time it takes to cross an electron orbital-path length may end up being a fractal scaling size equivalent to a globular cluster's path across a galaxy, if you made those size-scale comparable, then we are looking deep into hydrogen and other ions, secs after BB, skyward.

Oct 08, 2019
@Cant

And not one person is surprised that you are wrong again.


I was so curious so I had to unhide the troll comment.

And yeah, it was the plasma experts that did the research. The plasma ignoramuses on the other hand confine themselves to troll drivel in comments - not even a number as support for the baseless claim. Trolls can't count, apparently. Or understand texts or science or plasma.

So what we learn from the article is not much, since there is no published research yet. But let's take the article claim of having measured the plasma+EM pressure at the heliopause. Then its still order of magnitude less than the gravity that drives the system (holds it together, cause the conditions for solar fusion), so: plasma is from now and to eternity known to be weak in comparison! Quite like the plasma ignoramuses trolls, by the way...

Oct 08, 2019
plasma is from now and to eternity known to be weak in comparison

LOL! Opposite world as usual. That plasma has a response 36 orders of magnitude stronger to EM than gravity is taken as weakness speaks volumes. And you should stop lying larsen, the opposite of what you claim is what was found. And none of their maths gymnastics can match what was measured.

Oct 08, 2019
woo-hoo!
gravity rules...
e/m drools

G Constant
still King of the hill. baby

while the eu thunderdolts
& plasmaoidspazz
skulk off to lick their ignorance

Oct 08, 2019
plasma is from now and to eternity known to be weak in comparison

LOL! Opposite world as usual. That plasma has a response 36 orders of magnitude stronger to EM than gravity is taken as weakness speaks volumes. And you should stop lying larsen, the opposite of what you claim is what was found. And none of their maths gymnastics can match what was measured.


Wrong. Again. Gravity dominates at those scales. You are getting confused with micro scales versus macro scales. Not surprising, since nobody in your cult has the foggiest about physics, astrophysics or plasma physics.

Oct 08, 2019
For f@ck say Willis, stop using your keyboard for your spittoon.

Oct 08, 2019
So what we learn from the article is not much, since there is no published research yet.


This would appear to be a preprint;

Heliosheath Properties Measured from a Voyager 2 to Voyager 1 Transient
Rankin, J. S. et al.
https://arxiv.org...0676.pdf


Oct 08, 2019
In adding up the pieces....

One wonders what jigsaw puzzles these guys made, growing up.
"Look mom, extra pieces."

Oct 08, 2019
What is the energy source for both Voyager 1 and 2 that allows them to continue to travel out of the Solar System since 1977? How far into interstellar space can they travel on that energy source?

Oct 08, 2019
What is the energy source for both Voyager 1 and 2 that allows them to continue to travel out of the Solar System since 1977? How far into interstellar space can they travel on that energy source?


Er, momentum?

Oct 08, 2019
No, I don't mean momentum, which is what happens once they get into 'high gear' beyond the initial 'push' due to the energy source. I have forgotten what it is.

Oct 08, 2019
OK found it at Wiki under Voyager 1
Power
Voyager 1 has three radioisotope thermoelectric generators (RTGs) mounted on a boom. Each MHW-RTG contains 24 pressed plutonium-238 oxide spheres.[21] The RTGs generated about 470 W of electric power at the time of launch, with the remainder being dissipated as waste heat.[22] The power output of the RTGs declines over time (due to the 87.7-year half-life of the fuel and degradation of the thermocouples), but the craft's RTGs will continue to support some of its operations until 2025.[17][21]

Oct 08, 2019
OK found it at Wiki under Voyager 1
Power
Voyager 1 has three radioisotope thermoelectric generators (RTGs) mounted on a boom. Each MHW-RTG contains 24 pressed plutonium-238 oxide spheres.[21] The RTGs generated about 470 W of electric power at the time of launch, with the remainder being dissipated as waste heat.[22] The power output of the RTGs declines over time (due to the 87.7-year half-life of the fuel and degradation of the thermocouples), but the craft's RTGs will continue to support some of its operations until 2025.[17][21]


But not its propulsion. These will be for powering systems on the spacecraft. It is heading out due to its own momentum, and lack of anything to slow it down. It will keep going forever. Unless it smacks into something. Propulsion would only be needed for course corrections. Those days have long gone.

Oct 08, 2019
So the propulsion source is no longer available and only the instruments are getting powered up?
Still, it's like the Energizer Bunny. lol

Thanks for the explanation, CV

Oct 09, 2019
thanks castro, iamvik
for correcting the 'silly' loon for me
i wasted too much time sorting through all his gibberish

by now, i should just automatically discount & disparage the sillyegghead's blather & incontinent out of context plagiarizing

i have noticed among popular altright fiction
(non-science, the twits insist on calling science fiction)

that, in addition to the complete lack of creative originality
they all keep copying one another's errors of fact

none of them realize that momentum is not acceleration
or why inertia matters

nor do they comprehend that in Space, stars neither twinkle nor show color

generally they are just poor quality clones of popular entertainment

they just cant get literature "right"

Oct 09, 2019
At Voyager 2 inside the heliosheath, the number of cosmic rays decreased in all directions around the spacecraft. But at Voyager 1, outside the solar system, only the galactic cosmic rays that were traveling perpendicular to the magnetic field in the region decreased. This asymmetry suggests that something happens as the wave transmits across the solar system's boundary.

In there lies the secrets to the Deflector Shields of the USS Enterprise.

Oct 09, 2019
- case in point -

Oct 14, 2019
There is so much we still don't know.
It could very much be that the speed of light is much faster or much slower in interstellar space.
This would mean that other galaxy's and solar systems could be much closer or much further apart than we might realize.
I have long theorized that it is the former.
We should never be too comfortable with what we believe to be scientific facts as it can change in the wink of an eye.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more