Dear Friends,
That "weirdness" is because it's not going aywhere outside...
Be Well.
David
Voyager 1 Detects Weirdness at Solar System Edge
-
- Analysis by Ian O'NeillTue Oct 30, 2012 06:02 PM ET
Voyager 1 is the most distant man-made object
and is thought to have recently escaped the sun's sphere of influence.
The probe, launched 35 years ago, is therefore mankind's first
interstellar vehicle careening into the vast expanse of space between
the stars.
Needless to say, as one of two deep space probes launched in 1977,
Voyager 1 has explored previously unknown regions of the solar system,
making groundbreaking discoveries as it went. Now, in a new paper
published in the Journal of Geophysical Research, scientists analyzing
data streaming from the spacecraft have uncovered a small mystery right
at the solar system's magnetic boundary with the interstellar medium. She may be old, but you can't keep a good probe down.
As the sun travels through the galaxy, it carries its magnetic field
with it, creating a magnetic "bubble" -- the heliosphere -- that all
planets, spacecraft and people live inside. Until recently, Voyager 1
(and her sister probe Voyager 2) have also existed completely inside the
sun's environment. Both probes could detect the high energy particles
streaming from the sun and they 'felt' the solar magnetic field. At time
of writing, Voyager 1 is nearly 122 AU from the sun (over three times
the average Pluto-sun distance) and it takes over 17 hours for a signal
to travel from the probe to Earth.
So, in an effort to detect when the Voyager probes might exit the
heliosphere, scientists have kept a watchful eye on two key pieces of
data -- particle energy counts and magnetic field strength (and
orientation).
In 2004, scientists realized that Voyager 1 had traveled through the
"termination shock" -- a region where the solar wind begins to interact
with the interstellar medium. Then, in 2010, the probe crossed into a
stagnation region just beyond the termination shock known as the
"heliosheath" -- this is where the solar wind slows to zero and the
magnetic field becomes compressed and begins to fluctuate.
According to theory, as the magnetic field begins to fluctuate, the number of high-energy cosmic rays should decrease
inside the heliosheath -- charged cosmic rays entering the solar system
should become scattered by the magnetic fluctuations, decreasing the
number of detections by Voyager 1. Looking at data through 2010, the
researchers actually found the opposite to be true -- as the magnetic
field became more chaotic, the number of high-energy particles increased.
What's the reason for this weirdness? According to an AGU press release,
the researchers suspect that these magnetic fluctuations are somehow
energizing charged particles within the heliosheath, boosting the number
of high-energy particle detections.
This research comes during a very important year for Voyager 1. 2012 particle data from the probe suggest a profound change in its surroundings.
The number of high-energy particle detections (from interstellar space)
have increased, whereas the number of lower-energy particle detections
(from the solar wind) have dropped off a cliff (see graphs below). So now everyone is asking the question: has Voyager 1 officially entered interstellar space? We probably won't have to wait too long to find out.
Charts exhibiting the rapid increase in high-energy particles
(upper) and the rapid decrease in low-energy particles (lower) -- both
occurred late-August, 2012:
Image credit: NASA
No comments:
Post a Comment