On the Earth's surface, we are relatively shielded from ... "galactic radiation" by the atmosphere. However, during high-altitude commercial flights, people are at risk of increased exposure to primary and secondary galactic ionizing radiation and to solar ionizing radiation (see Box 1). The impact of acute and chronic exposure to such forms of radiation has been studied for 4 decades, and safe exposure limits have been recommended. (Friedberg 1989, another study in 2000)
The solar wind has actually almost stopped at one point already...
"On may 10, 1999. The Solar Wind from the sun stopped (actually dropped to 2% of it's normal density, that's 98% drop!). NASA sat on this story for 5 months because they could not explain it" - yh
One person writes:
I remember that night in 1999 - it was the first and only time I saw the northern lights from Seattle. A huge blue/green curtain to the north and a crazy warp tunnel effect overhead. One of the most beautiful sights I've ever seen. -dig
What happened with the galactic radiation on that day? (I'm guessing it didn't change much because the solar wind started up in time to shield the earth. We are inside quite a large protective bubble currently, but that bubble is shrinking. It is now 25% smaller.
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. 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. - telegraph
How much heliosphere do we need?
According to one post I found, the heliosphere has shrunk by 25% over the past 10 years. Even a 50% drop in range wouldn't get it close to pluto. So we're safe for now.
Would we be protected from galactic radiation by moving underground? Might work...
Life can not survive on the surface of Mars due to the galactic radiation. Mars has a thin atmosphere and so, not much protection from galactic radiation. Life could exist on Mars "several meters [yards]" below the surface (well out of reach of any drills the current Mars probes have). Perhaps the galactic radiation on the surface of Mars is only deadly in combination with the cold?
"There's actually less radiation on the surface of Mars than some natural locations on Earth." The problem is that the subzero temperatures on Mars' surface makes it extremely difficult for cells to repair radiation damages that do occur or to divide. The cells would be frozen solid and held in stasis and the radiation damages would accumulate, until the point where they're killed off, Dartnell said.- space
This from gizmodo about NASA's latest probe:
the IBEX (Interstellar Boundary Explorer) was conceived to study the farthest reaches of our solar system. At the very edge is the termination shock, where the system ends, and deep space begins. Studying the unknown will always be cool, but it turns out the IBEX mission could also lead to a better understanding of our future doom.
The termination shock is also the point at which the sun's solar wind begins to taper off, and eventually end. Much like our atmosphere here on Earth, the solar wind protects the solar system from the deadly radiation that saturates deep space. It does this by hurling ions in every direction, at 1 million miles per hour, all the time. Scientists believe the solar wind stops about 90% of the radiation from reaching the planets housed within the termination shock.
The trouble is these winds have fallen to their weakest levels in 50 years. In the past 10 years, the wind's intensity weakened by about 25%. Why? Who knows. Hence, IBEX.
Said David McComas, IBEX chief scientist, "We don't believe we're in imminent danger, but we've only measured the solar wind for about 50 years." - gizmodo
Firming up our understanding of what is happening to the Voyagers, the IBEX mission is designed to create global energetic neutral atom (ENA) images based on hydrogen ENAs generated in the inner heliosheath, thus telling us much about the properties of the solar wind flow in the regions now being crossed by the spacecraft. Another useful area of research: how the solar wind regulates galactic radiation, crucial data for future probes beyond the Solar System.
IBEX won’t itself travel to these regions. Its target is a highly elliptical orbit reaching 150,000 miles from Earth at apogee. A low-cost mission (first proposed by Southwest Research Institute and now part of NASA’s Explorer program), the spacecraft will be launched from Kwajalein on a Pegasus rocket dropped from an airplane. But it should pay off with big science dividends since the interaction between the Solar System and the interstellar medium has never been directly observed. “Everything we think we know about this region is from models, indirect observations and the recent single-point observations from Voyagers 1 and 2 that frankly have created as many questions as answers,” says principal investigator Dr. David J. McComas. Now comes the needed closer look. - cd
solar wind and what causes it?The solar wind is a stream of charged particles—a plasma—ejected from the upper atmosphere of the sun. It consists mostly of electrons and protons with energies of about 1 keV. These particles are able to escape the sun's gravity, in part because of the high temperature of the corona, but also because of high kinetic energy that particles gain through a process that is not well-understood at this time.
Is the solar wind uniform? No.
The Ulysses spacecraft has now completed one orbit through the solar system during which it passed over the Sun's south and north poles. Its measurements of the solar wind speed, magnetic field strength and direction, and composition have provided us with a new view of the solar wind.
Some people are already living underground successfully.
Is this responsible for global warming?
No. Global warming results from increasing amounts of greenhouse gases. Those who say the sun is involved use arguments based on solar luminosity not solar magnetic field or increased radiation from outside of our solar system.
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