People are constantly exposed to low levels of naturally occurring radiation called background radiation. Background radiation comes from cosmic radiation and from radioactive elements in the air, water, and ground. Cosmic radiation is concentrated at the poles by the earth’s magnetic field and is attenuated by the atmosphere. Thus, exposure is greater for people living at high latitudes, at high altitudes, or both and during airplane flights. Terrestrial sources of external radiation exposure are primarily due to the presence of radioactive elements with half-lives comparable to the age of the earth (~4.5 billion years). In particular, uranium (238U) and thorium (232Th) along with several dozen of their radioactive progeny and a radioactive isotope of potassium (40K) are present in many rocks and minerals. Small quantities of these radionuclides are in the food, water, and air and thus contribute to internal exposure as these radionuclides are invariably incorporated into the body. The majority of the dose from internally incorporated radionuclides is from radioisotopes of carbon (14C) and potassium (40K), and because these and other elements (stable and radioactive forms) are constantly replenished in the body by ingestion and inhalation, there are approximately 7,000 atoms undergoing radioactive decay each second.
Internal exposure from the inhalation of radioactive isotopes of the noble gas radon (222Rn and 220Rn), which are also formed from the Uranium (238U) decay series, accounts for the largest portion (73%) of the US population's average per capita naturally occurring radiation dose. Cosmic radiation accounts for 11%, radioactive elements in the body for 9%, and external terrestrial radiation for 7%. In the US, people receive an average effective dose of about 3 millisieverts (mSv)/yr from natural sources (range ~0.5 to 20 mSv/yr). However, in some parts of the world, people receive > 50 mSv/yr. The doses from natural background radiation are far too low
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A stop motion animated movie based on the game Space Hulk, set in the universe of Warhammer 40k.
Synopsis: A team of Space Marine Terminators investigate a strange distress call on a derelict ship. They encounter a horror unlike anything they've seen before...
Warhammer 40K: Space Marine - Behind the Scenes: The Universe
War Hammer 40K Space Marine is dropping their newest trailer at E3. Metacafe Video Games is your home for all E3 news and coverage so don't miss it as we are on the floor at the convention bringing you the latest info!
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Space Marine review part 2 of 2. Classic Game Room - WARHAMMER 40K SPACE MARINE review Pt2
Space Marine review part 1 of 2. Classic Game Room reviews WARHAMMER 40K SPACE MARINE from Relic and THQ. Based in the Warhammer 40,000 universe which takes place 40,000 years in the future, Space Marine has you playing as Captain Titus of the ULTRAMARINES!!! Produced in the "camera behind the Space Marine" perspective called third person shooter, Space Marine is jam packed with action and waves of attacking orcs. Shoot the baddies with a variety of weapons or melee them with your chain sword and axe! This Warhammer 40,000 Space Marine video review has gameplay from the Xbox 360 version of Warhammer 40K Space Marine. Warhammer videogame also available for PS3 Playstation 3 and PC.