Space is a dangerous place, not only because of meteors but also because of rays from the sun and other stars.The atmosphere acts as our protective blanket on earth.Lights get through , and this essential for plants to make the food which we eat .Heat,too,makes our environments tolerable and some ultraviolet rays penetrate the atmosphere .Cosmics rays of various kinds come through the air from outer space ,but enormouse quantities of radiation from the sun are screened off.Radiation is greatest known danger to explorers in space ,but their spacesuits or walls of their spacecraft do prevent a log of radiation damage.

We all receive radiation here on earth from the sun , from cosmic rays and from radioactive minerals .The trouble is that it is extreemly difficult to be sure about radiation damage a-person nay feel well,but the cells of his or sex organs may be damaged.and this will not discovered until the birth of (deformed) children or even grandchildren.There have been a lot
of miserable cases resulting from radiationor radioactive dust.