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NASA researchers studying meteorites have found that they contain several of the components needed to make DNA on Earth. The discovery provides support for the idea that the building blocks for DNA were likely created in space, and carried to Earth on objects, like meteorites, that crashed into the planet’s surface. According to the theory, the ready-made DNA parts could have then assembled under Earth’s early conditions to create the first DNA.
The researchers, from NASA’s Goddard Space Flight Center, found adenine and guanine — two of the nucleobases needed to make DNA (the other two are thymine and cytosine, which were not found) — on meteorite samples. Additionally, the samples showed the presence of three molecules that are similar to nucleobases, but do not have a biological role on Earth: Purine, 2.6-diaminopurine, and 6.8-diaminopurine.
Tag Archives | Meteors
Seems like NASA scientists have lately been making huge announcements (recall the claim a new form of Earth-bound life in December. While the potential of alien bacterial life may seem unglamorous to many, it may put Stephen Hawking’s mind at ease. CBS News:
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In what’s sure to rekindle the debate over the question of life beyond Earth, a scientist at NASA’s Marshall Space Flight Center says he has fossil evidence of bacterial life inside of a rare class of meteorites.
Writing in the March edition of the Journal of Cosmology, Richard B. Hoover argues that an examination of a collection of 9 meteorites — called CI1 carbonaceous meteorites mdash; contain “indigenous fossils” of bacterial life.
“The complex filaments found embedded in the CI1 carbonaceous meteorites represent the remains of indigenous microfossils of cyanobacteria, ” according to Hoover. That matter-of-fact sentence also underscores the shout-out-loud implication that the detection of fossils of cyanobacteria in the CI1 meteorites raises the possibility of life on comets.
One of the more credible of the various 2012 “end is nigh” scares is the prospect of a massive “Near Earth Object” (NEO), most likely a meteor or asteroid, smashing through the Earth’s atmosphere, causing damage locally on impact and potentially causing such great meteorological disruption that our way of life is changed forever, possibly to an extinction level. Frighteningly there is usually hardly any warning that they are coming. MIT’s Technology Review reports on an astronomer’s plans for a network of telescopes that could give up to three weeks’ warning of a city-destroying impact, on its Physics arXiv Blog:
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At about 3am on 8 October last year, an asteroid the size of a small house smashed into the Earth’s atmosphere over an isolated part of Indonesia. The asteroid disintegrated in the atmosphere causing a 50 kiloton explosion, about four times the size of the atomic bomb used to destroy Hiroshima.
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There is one near-extinction event that is fairly well-known, although it remains controversial. Roughly 70,000 years ago, give or take a few thousand years, an enormous eruption occurred in what is now Sumatra, leaving behind Lake Toba. The eruption coincides with a population bottleneck that is often cited as the reason for the relatively low genetic diversity across Homo sapiens sapiens. Research suggests as few as 2,000 humans were left alive by the eruption and its aftereffects.
A recent paper in the Proceedings of the National Academy of Sciences found another population bottleneck much farther back in human history. Genetic studies found that 1.2 million years ago there were as few as 55,000 members of genus Homo, including pre-human hominids like Homo erectus and Homo ergaster.
Scientists say they have confirmed that a meteorite that crashed into earth 40 years ago contains millions of different organic compounds. It is thought the Murchison meteorite could be even older than the Sun."Having this information means you can tell what was happening during the birth of the Solar System," said lead researcher Dr Philippe Schmitt-Kopplin. The results of the meteorite study are published in the Proceedings of the National Academy of Sciences.
"We are really excited. When I first studied it and saw the complexity I was so amazed," said Dr Schmitt-Kopplin, who works at the Institute for Ecological Chemistry in Neuherberg, Germany. Meteorites are like some kind of fossil. When you try to understand them you are looking back in time," he explained. The researchers says the identification of many different chemicals shows the primordial Solar System probably had a higher molecular diversity than Earth.
A METEOR has crashed in a blaze of colour in South Africa, but experts are unable to find where the out-of-space visitor landed. The rare astronomical phenomenon was captured by a local traffic camera and witnessed by locals, British tabloid the Sun reports. The footage initially shows cars on a busy road, near the city of Johannesburg, when the meteor suddenly streaks across the night sky. The meteor appears as a brilliant green light before it explodes on the horizon, transforming into an orange ball of flame. One witness told the Sun: “We saw this big green ball of fire. It kind of came out of the sky, out of the blue. “There was a sudden flash, like an orange stripe in the sky, followed by a very bright explosion where the sky lit up as if it was daytime.”
By Robert Roy Britt for Space.com:
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One of the best annual meteor showers will peak in the pre-dawn hours Tuesday, and for some skywatchers the show could be quite impressive.
The best seats are in Asia, but North American observers should be treated to an above average performance of the Leonid meteor shower, weather permitting. The trick for all observers is to head outside in the wee hours of the morning – between 1 a.m. and dawn – regardless where you live.
The Leonids put on a solid show every year, if skies are clear and moonlight does not interfere. This year the moon is near its new phase, and not a factor. For anyone in the Northern Hemisphere with dark skies, away from urban and suburban lighting, the show should be worth getting up early to see.
“We’re predicting 20 to 30 meteors per hour over the Americas, and as many as 200 to 300 per hour over Asia,” said Bill Cooke of NASA’s Meteoroid Environment Office.