NOVA scienceNOW: Dark Matter; Of Mice And Memory; Hany Farid; Wisdom Of The Crowds

Hosted by renowned astrophysicist, author and director of the Hayden Planetarium, Neil deGrasse Tyson, NOVA scienceNOW covers four timely science and technology stories per one-hour episode.

"Dark Matter" - Host Neil deGrasse Tyson reports from a half-mile underground in an abandoned mine, where scientists are using special detectors to look for evidence of a ghostly substance that they believe makes up most of the matter of the universe - a hypothetical entity called dark matter.

"Of Mice And Memory" - Researchers have found that mice with induced memory loss are able to retrieve memories after they spend time in enriched environments that stimulate mental activity.

What's more, these scientists have identified a drug that has a similar effect. It appears to promote gene activity in the brain that is important in memory. These insights may lead to a better understanding of dementia and memory-impairment disorders such as Alzheimer's.

While scientists are yet in the early stages of translating this research in mice into treatments for humans, it's striking that many Alzheimer's sufferers temporarily improve in an activity-rich environment, providing a tantalizing clue to further research and possible therapies.

"Hany Farid" - Is seeing believing? In this age of easy photo manipulation, sometimes only a digital detective can tell. Enter Hany Farid, professor of computer science at Dartmouth College. He developed a program that can unmask photo tampering by analyzing light sources and other subtle features in an image - a service that turns out to be in high demand, especially during political campaigns.

"Wisdom of the Crowds" - In the early 1900s, British scientist Sir Francis Galton thought he was proving the ignorance of the masses when he noted that no one got the right answer at a country-fair competition in which entrants were asked to guess the exact weight of an ox.

What Galton failed to realize was that the median of all the guesses produced close to the right answer—and showed the "wisdom of the crowd."

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