21.   Annis counters that gamma-ray bursts are likely to have many indirect effects, such as wrecking ozone layers that protect planets from deadly levels of ultraviolet radiation.

22.   And though one genetic variation predominates, more work must be done to determine which mutations are involved in hair color and susceptibility to ultraviolet radiation.

23.   Any bacteria aboard a spaceship leaving Earth would almost certainly be killed from exposure to ultraviolet radiation during the trip through space, says Barengoltz.

24.   At high altitudes, Freons are broken down by ultraviolet radiation from the sun, producing chlorine compounds that react with ozone.

25.   At this temperature, the compressed gas radiates both visible light and high-energy ultraviolet radiation.

26.   A popular theory is that the extra melanin in darker skin protects against cancer and sunburn from ultraviolet radiation.

27.   According to Californian researchers, increased ultraviolet radiation from the ozone hole above Antarctica is scarcely having any effect on the growth of marine plankton in the ocean below.

28.   But critics of their work said that cosmic rays and ultraviolet radiation from the Sun would kill unprotected spores.

29.   But ultraviolet radiation also causes immune suppression.

30.   By blocking ultraviolet radiation produced by the sun, ozone protects human beings from damage to the immune system and increased risk of cataracts and skin cancer.