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solar flare - can it erase hard drives?
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#12
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solar flare - can it erase hard drives?
In article ,
John Savage wrote: Also - those X-rays can't reach the ground - Earth's atmosphere is equivalent of roughly 10 meters of water... Curious. So if I sunbaked on the bottom of a 1 metre deep swimming pool, (with a suitable snorkle) I should expect to get sunburnt almost as severely as when lying on the deck (if we can disregard for the moment the not insignificant reflection at the air-water interface)? No, these are two different issues. To stop X-rays, you basically need mass. Most any kind of mass is as good as any other kind; essentially nothing is transparent to X-rays. So that extra 1m of water does not add very much more shielding against X-rays. But solar X-rays aren't what give you sunburn. Sunburn comes from short-wavelength ultraviolet. Stopping short UV is a different problem. Things that are opaque to it are very very opaque to it; you need only quite a small thickness of such a material. Normal air is quite transparent to it, so almost all of that 10t/m^2 of air makes no useful contribution here. Ozone is quite opaque to it, so the traces of ozone found in the lower stratosphere cut out a lot of it, even though they are a negligible fraction of the atmosphere's mass. Small thicknesses of water, glass, or even light clothing will block the remainder completely. -- MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer pointing, 10 Sept; first science, early Oct; all well. | |
#13
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solar flare - can it erase hard drives?
Henry Spencer wrote:
In article , John Savage wrote: Also - those X-rays can't reach the ground - Earth's atmosphere is equivalent of roughly 10 meters of water... Curious. So if I sunbaked on the bottom of a 1 metre deep swimming pool, (with a suitable snorkle) I should expect to get sunburnt almost as severely as when lying on the deck (if we can disregard for the moment the not insignificant reflection at the air-water interface)? No, these are two different issues. To stop X-rays, you basically need mass. Most any kind of mass is as good as any other kind; essentially nothing is transparent to X-rays. So that extra 1m of water does not add very much more shielding against X-rays. Actually - 1 meter of water roughly reduces hard x-rays by a factor of 5 to 10 depending on energy. Of course, since virtually no solar x-rays reach ground level it doesn't make a lot of a difference on those ... But OTOH as you mention, sunbaking is about UV, not x-rays ... |
#14
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solar flare - can it erase hard drives?
"Mad Scientist" wrote in message om... | I was wondering if someone could put to rest this question: | | Can the electromagnetic radiation from this solar flare erase hard | disks or other magnetic media? Only if your system unit happens to be a couple of million miles nearer the sun, in space, I'd imagine. Of course, if the power surge due to the magnetic storm wrecks your puter, then yes....:-) Brian -- Brian Gaff.... graphics are great, but the blind can't hear them Email: __________________________________________________ __________________________ __________________________________ --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.537 / Virus Database: 332 - Release Date: 06/11/03 |
#15
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solar flare - can it erase hard drives?
In article ,
=?ISO-8859-1?Q?Anders_Ekl=F6f?= wrote: To stop X-rays, you basically need mass. Most any kind of mass is as good as any other kind; essentially nothing is transparent to X-rays. So that extra 1m of water does not add very much more shielding against X-rays. Actually - 1 meter of water roughly reduces hard x-rays by a factor of 5 to 10 depending on energy. Notice the word "more" in my statement. :-) Yes, 1m of water will cut X-rays down a lot... but compared to an atmosphere equivalent to 10m of water, the improvement from an extra 1m of water is slight. -- MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer pointing, 10 Sept; first science, early Oct; all well. | |
#16
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solar flare - can it erase hard drives?
Henry Spencer wrote:
To stop X-rays, you basically need mass. Most any kind of mass is as good as any other kind; essentially nothing is transparent to X-rays. No. There's a strong dependency on atomic number. Lead blocks x-rays much better than the same mass of water does. (That's why I was working with beryllium many years ago. It makes a good airtight x-ray window.) -- Keith F. Lynch - - http://keithlynch.net/ I always welcome replies to my e-mail, postings, and web pages, but unsolicited bulk e-mail (spam) is not acceptable. Please do not send me HTML, "rich text," or attachments, as all such email is discarded unread. |
#17
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solar flare - can it erase hard drives?
Henry Spencer wrote:
While it is possible, "easily" is a vast overstatement. Motors usually don't produce strong external magnetic fields, and magnetic media are much more robust than people commonly think -- to have any effect at all, a magnet must be either very strong or very close (practically touching the media). I've had diskettes and tapes erased by taking them on the DC Metro. They remain ok if I'm careful to keep them off the floor of the trains, and if I pack them surrounded with a few inches of anything. -- Keith F. Lynch - - http://keithlynch.net/ I always welcome replies to my e-mail, postings, and web pages, but unsolicited bulk e-mail (spam) is not acceptable. Please do not send me HTML, "rich text," or attachments, as all such email is discarded unread. |
#18
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solar flare - can it erase hard drives?
Keith F. Lynch wrote:
Henry Spencer wrote: To stop X-rays, you basically need mass. Most any kind of mass is as good as any other kind; essentially nothing is transparent to X-rays. No. There's a strong dependency on atomic number. Lead blocks x-rays much better than the same mass of water does. There is also a strong dependancy on photon energy, especially for high atomic numbers. What you say is true for x-ray tube x-rays, that are usually in the 20-200 keV range. You possibly worked with even lower energies if you used beryllium for windows. Solar x-rays extend into the MeV range, and there the dependency on atomic number is next to nothing (within a factor of 2). |
#19
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solar flare - can it erase hard drives?
In article ,
Keith F. Lynch wrote: While it is possible, "easily" is a vast overstatement. Motors usually don't produce strong external magnetic fields, and magnetic media are much more robust than people commonly think... I've had diskettes and tapes erased by taking them on the DC Metro. I've never had any trouble with the Toronto subway. Subway cars do have a *lot* of current running around -- it's amusing to take a compass along on a subway ride, and watch it spin back and forth as things switch under the floor. -- MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer pointing, 10 Sept; first science, early Oct; all well. | |
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