Knowledge Capsule: Large asteroid heading to Earth? Pray,says NASA

Large asteroid heading to Earth? Pray,says NASA

NASA chief Charles Bolden has advice on how to handle a large asteroid headed toward New York City: Pray. Thats about all anybody can do at this point about unknown asteroids and meteors that may be on a collision course with Earth. An asteroid estimated to have been about 55 feet in diameter exploded on February 15 over Chelyabinsk,Russia,leaving more than 1,500 people injured. Later that day,a larger asteroid passed about 27,681 km from Earth,closer than the satellites that ring the planet.

NASA is tracking about 95 per cent of the largest objects flying near Earth,those that are 1 km or bigger. But only about 10 per cent of an estimated 10,000 potential city-killer asteroids,those with a diameter of about 50 metres,have been found. On an average,objects of that size hit Earth about once every 1,000 years. We dont know of an asteroid that will threaten the population of the US, Bolden said. But if its coming in three weeks,pray. Reuters

Dollos evolution theory bites dust (mites)

DOLLOS law states that evolution always moves forwardthat an organism cannot redevelop an organ or attribute discarded by its ancestors. But new research on humble dust mites,the arachnids that live in cushions and carpets everywhere,is challenging the law. Two University of Michigan biologists have shown that the miteswhich are not parasites but free-living organismsevolved from parasites,that in turn evolved from other free-living organisms. That would seem to contradict Dollos law. The closest living relatives to the mites are all able to digest tough materials like skin and keratin. The researchers think this helped the mites break free from birds and mammals to live off material found in nests and homes. NYT

New autism numbers for US,1 million children affected

A survey of parents says 1 in 50 US schoolchildren has autism,surpassing other estimates for the disorder. Health officials suggest that doctors are diagnosing autism more frequently,especially in children with milder problems. For decades,autism meant kids with severe language,intellectual and social impairments. But the definition has gradually expanded and now includes milder conditions. The estimate released by the Centers for Disease Control and Prevention would mean at least 1 million children have autism,and comes from a national phone survey of more than 95,000 parents. Less than a quarter of the parents contacted agreed to answer,and its likely that those with autistic kids were more interested than others in the survey. AP