This started out as a response to the recent Channelings blog where I was discussing what I felt was a fatal flaw in the Mythi saga (sheltering under rocky ledges or rock outcroppings during solar flares). I feel this is an important topic and am reposting it as a blog to get more exposure....
Both solar radiation (in flares, see http://en.wikipedia.org/wiki/Solar_flares) and nuclear radiation are electromagnetic and contain gamma rays (biologically hazardous component of fallout, see http://www.oism.org/nwss/s73p916.htm). While I don't know if the intensities are the same between solar and nuclear bombs, I would play it as safe as possible when researching shelters. Remember, a planet-x-type object is heavily electromagnetic and its influence should be factored in, as well.
What information I've found pertains to nuclear blasts and resulting fallout, and the worst danger is in the gamma rays (a penetrating form of radiation) from fallout. You need a barrier with at least three feet of dirt (or two feet of concrete) all around to effectively shield from radiation. Even in fallout shelters that have a small doorway, you have to stay away from that area because the radioactive particles bounce around and can get inside and kill you.*
To me, Mythi's solution to get up under rocks when solar flares hit sounded like a "shallow trench" solution... deficient in significant ways. (The second red flag was him saying that the px-type-object was only 38 days behind. When PX is that close, there will be no doubt of its existence... anywhere on this planet. By that statement, it should only be 16 days away from us today. Has anything changed radically to indicate the rapid approach of that monster? No. Is it going to happen by Thanksgiving (38 days from Oct. 17th)? No, so enjoy your holidays.)
* http://www.oism.org/nwss/s73p916.htm:
"The trenches for entry and emergency exit were dug only 22 inches wide, to minimize radiation entering the shelter through these openings."
"The family sat and slept along the left wall, to be better shielded from radiation coming through the openings."
Fig. 5.3. Simplified illustration of barrier shielding and skyshine (scattered gamma radiation). An open trench provides poor protection. ORNL.DWG 78.7205:
"... the man in the trench would not be protected from "skyshine," which is caused by gamma rays scattering after striking the nitrogen,oxygen, and other atoms of the air. The man's exposed head, which is just below ground level, would be hit by about one-tenth as many gamma rays as if it were 3 feet above ground (Fig. 5.3). Even if all fallout could be kept out of the trench and off the man and every part of the ground within 3 feet of the edges of the trench, skyshine from heavy fallout on the surrounding ground could deliver a fatal radiation dose to the man in the open trench." (This emphasizes another reason the shallow-trench theory is deficient.)
"Skyshine reaches the ground from all directions. If the man were sitting in a deeper trench, he would escape more of this scattered radiation, but not all of it. For good protection he must be protected overhead and on all sides by barrier shielding."
This next sketch shows how any kind of overhead cover (rock or dirt) is insufficient to fully protect a person. Even if you only receive "small" doses, how much does it take to cause cancer or even death?
Fig. 5.5. Skyshine coming into a shelter through a vertical entry would be mostly absorbed while turning into and traveling down the entryway trench. ORNL.DWG 78-7204 :
