Posted: 08 Feb 2010 10:11 PM PST
Scientists have unearthed an almost perfectly preserved spider fossil in China dating back to the middle Jurassic era, 165 million years ago. The fossilized spiders, Eoplectreurys gertschi, are older than the only two other specimens known by around 120 million years.
The level of detail preserved in the fossils is amazing, said paleontologist Paul Selden of the University of Kansas and lead author of the study appearing Feb. 6 in Naturwissenschaften. "You go in with a microscope, and bingo! It's fantastic."
The fossils were found at a site called Daohugou in Northern China that is filled with fossilized salamanders, small primitive mammals, insects, and water crustaceans. During the Jurassic era, the fossil bed was part of a lake in a volcanic region, Selden said.
Spider fossils from this period are rare, because the arachnids' soft bodies don't preserve well. The pristine fossil pictured in these photos was probably created when the spider was trapped in volcanic ash. The ultra-fine clay particles squashed the spider without breaking up the animals' delicate cuticle as more coarse sediment would, Selden said.
E. gertschi shows all the features of the modern members of the family, found in North America, suggesting it has evolved very little since the Jurassic period, Selden said. "The scimitar-shaped structure you notice out of the male is so distinctive," he said. "Looking at modern ones, you think, well, it's just a dead ringer."
The findings also suggest this family of spiders, the Plectreuridae, was once much more widespread than it is today. Currently, the family has only been found living in California, Arizona, Mexico and Cuba. Yet 165 million years ago, they lived on a small continent called the North China Block.
"At some point something caused their range to contract to this part of southern North America," Selden said. He speculates that changes in vegetation during an ice age or other climactic event wiped them out in other areas, "but they were still happy in these arid areas of the Southwest."
Images: Paul Selden
Citation: "The oldest haplogyne spider (Araneae: Plectreuridae), from the Middle Jurassic of China" Paul A. Selden and Diying Huang, Naturwissenschaften, 6 Feb. 2010.
Posted: 08 Feb 2010 12:20 PM PST
As the sun emerges from a long lull in activity, the star's emissions in the radio band of the spectrum have also picked up. And from a shed on three acres of land outside Santa Fe, New Mexico, amateur radio astronomer Thomas Ashcroft is making recordings of them available for download.
"The Sun has become hyper-dynamic the past few days," Ashcroft wrote on his website Sunday, along with links to four "specimens" of radio bursts, as he calls them.
The sun is crackling with solar flares now as a very large sunspot continues to circle our star. The recent solar activity almost assuredly signals the end of the solar minimum. Only 5 percent of the days in 2010 have seen a blank sun. In 2008 and 2009, more than 70 percent of the days had no sunspot activity.
Here is what one long burst sounded like on Sunday.
Not all bursts sound the same, though. Another kind, Type V, is generally shorter and sharper. They happen to be Ashcroft's favorites.
"I like that one because they are very strong and very fast," Ashcroft told Wired.com. "They are only short lived, only a minute or two minutes. You can get a rush out of it. You can get high off of it. You can trip on it a little bit."
Ashcroft recorded a decently powerful Type V on Sunday.
The wires running from the antennas on his property to his observatory are visible in the photo above.
The physics of solar radio emissions are quite complicated, but Ashcroft just likes to listen to the radio static out in the shed on his property. It gives him a feel for what the sun is doing, he said. He held up the phone to his speakers where the standard hiss of the radio, speckled by cosmic background radiation, constantly plays.
"I have that playing at a low level. I'm able to hear when there are sudden fluctuations," Ashcroft said. "That makes me hypersensitive to the sun. I consider my antennas, which are mostly dipole antennas, I consider them my hyperextended nervous systems, so I can feel subtle solar movements."
When he processes the recordings, Ashcroft likes to track one frequency (say, 21 megahertz) in one channel and another (say, 24 megahertz) in the other channel. It tends to give his specimens what he calls "spatiality" and a kind of pulsating effect. That's because he isn't just trying to record the sun, he's trying to make it into something with which people can connect.
"I sort of see it as a possible musical form of the future. You know? An energetic form," Ashcroft said. "Maybe the word isn't even art anymore, it's almost nutritional to the nervous system in a way that I don't know about, but I'm groping towards, kind of as an artist."
After almost 20 years of studying the sun, Ashcroft said his view of being a human has actually changed.
"I'm very conscious of myself as an organism, an electroreceptor sensing the sun," Ashcroft said. "It's human, but the human is a subset of being an organism."
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