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
Adam is bushwhacked by three deserters from the Army who are hiding out on the Ponderosa. When Ben pursues them, he is hindered by a Captain Bolton, the arrogant commander of a military posse who is also after the men. Three army prisoners have escaped Ft Dayton. Mertz still has chains around his w
The Cartwrights take young Billy Allen to the Ponderosa following the death of his mother. Hoss is the only one that is able to penetrate the boy's hostility and bitterness. As the two begin to get close, Billy's father Vance breaks out of prison and comes for the boy. A young boy named Billy Allen
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
Angry with the way a beautiful deaf girl is treated by her father, a sheepherder living in a remote mountain cabin, Little Joe takes it upon himself to teach her sign language, so they can communicate better. His plan backfires when the young woman falls in love with him and the girl's brutish neigh
The Cartwrights try to disprove the validity of a Spanish land grant to stop the De La Cuesta family from seizing part of the Ponderosa and all of the Carson Valley settlers' homestead lands. The episode opens with a settler being evicted from his land by some Spanish vacqueros. When the couple ins
The Cartwrights construct a grist mill to help neighbor Tom Edwards, a disabled man who bitterly blames Ben for his condition. Tom is being manipulated by hired hand Ezekiel, who's not only cheating him out of his money, but also intends to steal his wife. The Cartwrights' neighbor Tom Edwards has
Jeb Drummond is a murderous sheep herder that has Adam taken hostage to try and force Ben to sign over a large section of Ponderosa land to him. Jeb Drummond is driving his herd of sheep across the Ponderosa when the Cartwrights ride up. Ben politely tells him to leave. Jeb asks for permission, he'
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
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
