From the UK Telegraph – source link
The protective bubble around the sun that helps to shield the Earth from harmful interstellar radiation is shrinking and getting weaker, NASA scientists have warned.
By Richard Gray, Science Correspondent
Last Updated: 9:23AM BST 19 Oct 2008
New data has revealed that the heliosphere, the protective shield of energy that surrounds our solar system, has weakened by 25 per cent over the past decade and is now at it lowest level since the space race began 50 years ago.
Scientists are baffled at what could be causing the barrier to shrink in this way and are to launch mission to study the heliosphere.
The Interstellar Boundary Explorer, or IBEX, will be launched from an aircraft on Sunday on a Pegasus rocket into an orbit 150,000 miles above the Earth where it will “listen” for the shock wave that forms as our solar system meets the interstellar radiation.
Dr Nathan Schwadron, co-investigator on the IBEX mission at Boston University, said: “The interstellar medium, which is part of the galaxy as a whole, is actually quite a harsh environment. There is a very high energy galactic radiation that is dangerous to living things.
“Around 90 per cent of the galactic cosmic radiation is deflected by our heliosphere, so the boundary protects us from this harsh galactic environment.”
The heliosphere is created by the solar wind, a combination of electrically charged particles and magnetic fields that emanate a more than a million miles an hour from the sun, meet the intergalactic gas that fills the gaps in space between solar systems.
At the boundary where they meet a shock wave is formed that deflects interstellar radiation around the solar system as it travels through the galaxy.
The scientists hope the IBEX mission will allow them to gain a better understanding of what happens at this boundary and help them predict what protection it will offer in the future.
Without the heliosphere the harmful intergalactic cosmic radiation would make life on Earth almost impossible by destroying DNA and making the climate uninhabitable.
Measurements made by the Ulysses deep space probe, which was launched in 1990 to orbit the sun, have shown that the pressure created inside the heliosphere by the solar wind has been decreasing.
Dr David McComas, principal investigator on the IBEX mission, said: “It is a fascinating interaction that our sun has with the galaxy surrounding us. This million mile an hour wind inflates this protective bubble that keeps us safe from intergalactic cosmic rays.
“With less pressure on the inside, the interaction at the boundaries becomes weaker and the heliosphere as a whole gets smaller.”
If the heliosphere continues to weaken, scientists fear that the amount of cosmic radiation reaching the inner parts of our solar system, including Earth, will increase.
This could result in growing levels of disruption to electrical equipment, damage satellites and potentially even harm life on Earth.
But Dr McComas added that it was still unclear exactly what would happen if the heliosphere continued to weaken or what even what the timescale for changes in the heliosphere are.
He said: “There is no imminent danger, but it is hard to know what the future holds. Certainly if the solar wind pressure was to continue to go down and the heliosphere were to almost evaporate then we would be in this sea of galactic cosmic rays. That could have some large effects.
“It is likely that there are natural variations in solar wind pressure and over time it will either stabilise or start going back up.”
(hat tip to Dvid Gladstone)
kim (11:45:49) :
but I believe in Easterbrook’s thesis about the PDO.
I’m kinda a believer myself. Of course, the next question is what causes the PDO…
Leif
Does that mean you agree 0 AD to 1930 is no ‘threat’ to the GCR theory?
Post-1930 is ok. No warming between 30 and the climate shift in 77, (which there is no reason to believe is man-made). Taking the two large volcanoes into account there was no warming between early 80s and 97, and the warming after 97 has disappeared again. No need for anthropogenic causes.
Leif (12:07:05) Why, it’s the sun, but how, even kim doesn’t know.
Not yet, anyway.
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lgl (13:13:53) :
Does that mean you agree 0 AD to 1930 is no ‘threat’ to the GCR theory?
GCR is completely dominated by the Earth’s dipole. Solar activity is just small wiggles. Climate is completely dominated by the orbital changes, all the rest are just small wiggles. The orbital effects have been linear the past 10,000 year so should just give a linear trend in T [downwards]. CGRs have been increasing the past 2000 years because the dipole has been decreasing, thus also a linear down trend in T. Added together there should have been a linear trend. There is not, there are warmings, and LIA’s and lots of variation. All of these show that there are internal oscillations in the system not related to the external drivers and that these variations are the dominant ones. On top of that, there is no doubt that all kinds of effects are in play, TSI, volcanoes, land-use, etc. So, to ‘agree’ the GCR effects should have been quantified [also in relation to all of the other effect], so much for insolation, so much for GCRs, so much for volcanoes, so much for clouds, land-use, etc. Only when these thing are accounted for and compared with [almost non-existing good T data] can one even begin to discuss how well things fit. My point all along is that it is not correct to claim that there is strong, exceedingly good, exceptional, etc., evidence for any of these mechanisms [besides insolation and dipole effects].
Leif
http://geo.oregonstate.edu/people/faculty/publications/clarkp/Clark-AGU-2007.pdf This is showing a 7-kyr cycle. Do you have more records of the dipole, a few 10000 years back?
lgl (15:03:00) :
Do you have more records of the dipole, a few 10000 years back?
I think so. Will take me a little while to find it in my notes. Patience.
Leif
Evidence?
http://www.uibk.ac.at/geologie/pdf/christl.pdf
lgl (05:29:52) :
Evidence? http://www.uibk.ac.at/geologie/pdf/christl.pdf
I’ll look at it.
Of, course, for every claim, there is a counterclaim:
[another threas] Pierre Gosselin (06:19:42) :
I just happened to stumble onto this report in the German FAZ newspaper
http://www.faz.net/s/RubC5406E1142284FB6BB79CE581A20766E/Doc~EA76668E9105E490AAEE2DE0CE7CC317C~ATpl~Ecommon~Scontent.html
via a sceptic German site.
Summing the main points of the report in English:
1. Two researchers at the Ludwig-Maximilians-University in Munich have determined that the Earth’s magnetic field and earth climate are coupled.
2. Whenever the earth’s magnetic field was weak, average global temperatures increased slightly.
Weak field => more GCR => cooling, but they found warming…
Leif,
Found some other interesting stuff here:
http://www.eolss.net/ebooks/Sample%20Chapters/C01/E6-16-04-01.pdf
so I made this:
http://virakkraft.com/PDO-mag-dec.jpg
Must be the moon, last lunar minor standstill was in 1997.