X-rays were discovered in 1895 by Wilhelm Conrad Röntgen. Since then, it has been an indispensable means of medicine. However, X-rays can lead to damage to the genetic material: In this video, we show how the body defends itself against it and what measures are taken by radiation protection. More i
The cosmic ray detector known as CREAM is headed for the International Space Station, with a goal of measuring the highest energy possible for direct measurement of high-energy cosmic rays. Visit http://science.nasa.gov/ for more. New Mission Going to the Space Station to Explore Mysteries of 'Cos
In the late 1960s, scientists accidentally discovered gamma-ray bursts — intense flashes of energy that typically last no more than a few minutes and are often as short as a fraction of a second. For decades after the discovery of these powerful bursts, they remained one of the greatest mysteries in
After Joe kills a man in self-defense who tried to set fire to the Ponderosa to clear himself some land, he has to take his lively, feisty, wild, daughter home, and she, and her relatives, are now determined to kill Joe. Joe tries to stop a homesteader he finds starting a fire on the Ponderosa and
Adam, Hoss, and new friend Sam Board act as escorts for a wagon train of Quakers who are heading to California to purchase land for their settlement. While Adam falls for the group leader's daughter, Reginia, Board plots to rob the group of its life savings. A wagon train of Quakers from Ohio are p
About to set out on a cattle drive, Ben hires a young drifter named Sam Jackson as one of his drovers. What he doesn't know is that Jackson is really outlaw Johnny Logan, who signed on to the drive because he knew it was going to pass near the town of Waycross, and Logan is determined to kill the Wa
Joe and Hoss take their dates to a bizarre traveling carnival and Joe's girlfriend Jennifer disappears. She's abducted by the evil owner, Phillip Reed, and held for one million dollars ransom. Reed's girlfriend Della is jealous of the attractive hostage and spills the beans to Joe. He and Hoss tear
Hoss falls prey to the wiles of a beautiful woman with a gambling addiction and refuses to believe she's only interested in his money in spite of Adam's proof to the contrary. Hoss and Little Joe travel to Sacramento to help the widow of an old friend of the Cartwrights. Hoss discovers that the wid
When 16-year-old Todd Grayson arrives from Boston to Virginia City, he is told that his father has been killed by Ben Cartwright. Ben shot Luke Grayson in self-defense, but Todd won't listen to this. The boy has only one thing in his head: to avenge his father by killing Ben Cartwright. The son of
Dolly Kincaid so feed up with her extremely dominant, controlling, sheriff father, that she runs away with her boyfriend. She later finds out he is the leader of some murderous bank robbers and when they kidnap Hoss and Joe, she still sticks with him. Joe's friend Dolly Kincaid rebels against her a
Hoss and Joe get themselves involved in a family feud in a small Texas town when they are mistaken for bloodthirsty hired killers. Ellen Corby, Henry Hull, and George Mitchell guest star. On a cattle buying trip to Texas, Hoss and Little Joe are mistaken for a pair of hired killers recruited by a f
Adam rides up on some Indians wanting to harm a white woman they believed was a mountain spirit. He kills them but not before they wound him. The woman nurses him back to health but the rest of the tribe is still out there looking for her. While traveling, Adam is wounded by Indians and left for de
