sábado, 18 de agosto de 2012
Expert rejects meteor claim
An astronomer from the Manitoba Museum has discounted the claim of a woman who said she found pieces of a meteorite on her property near Riding Mountain National Park.
Nicole Nixon said she experienced a bright light and loud noise Tuesday morning, then found two rocks she believed to be meteorites the following day.
Scott Young, astronomer at the Manitoba Museum and Planetarium, said Nixon "contacted us at the museum several times before, including last week, before Tuesday's alleged sighting.
"Interestingly, she sent us pictures of different rocks with the same story, which look nothing like the rock pictures that ran in the article, and aren't meteorites either."
On Friday, Nixon said the rocks she called Young about the previous week were from Portugal, and that Young is angry with her because she wouldn't give him some of her other meteorites.
"We've had a lot of problems with Scott Young. We had a huge meteor fall in 2009 here and Scott Young wanted some of the meteorites from that fall for free," Nixon said.
Young said it is difficult to tell from pictures alone, but the rocks in the pictures Nixon provided don't have the features normally found on meteorites.
Meteorites are usually dark, not porous (there aren't any air bubbles in them because their isn't any air in space), they don't have any crystals in them (quartz is very common on Earth but not found in meteorites), they are often magnetic, and very heavy for their size.
Nixon's description of the what happened doesn't add up, Young said.
"If you see a flash in the sky, the rock isn't falling where you are because this happens when the meteor's still 50 kilometres up and still moving at a couple hundred kilometres an hour," Young said.
"Once it slows down and stops burning it falls on a ballistic trajectory and it usually lands dozens or a hundred kilometres from where people saw it."
Such a large event is usually seen and heard for more than 100 kilometres, but Nixon has so far been the only person to have reported it.
Nixon said there are 10 other witnesses, but refused to provide their names or contact information for verification.
When meteorites as large as the rock Nixon found (70 kg) hit the Earth, their sonic boom and impact register on seismographs that are monitored in Manitoba.
Young said his office is contacted when this occurs but wasn't contacted about any recent activity.
Even though the Perseids meteor shower occurred recently, Young said there has never been a meteorite associated with a meteor shower.
A meteor shower occurs when the Earth passes through the trail of dust left behind by a comet, which is composed of tiny bits of sand and ice.
On average, the Earth is hit about once a day from meteors, but they usually come down in an ocean or in remote areas.
Publicado por Jorge M. Gonçalves às 10:12 da tarde