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  1. #11

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    Well, this was an interesting article!! I have always been fascinated with the Tunguska blast from the early part of the 20th Century and the mystery surrounding it. Granted, there have been some far-flung ideas of it being a crashed spacecraft, but there have also been theories of it being a piece of comet or even a meteor. I ran across this on my Yahoo page today!

    Crater Could Solve 1908 Tunguska Meteor Mystery

    Dave Mosher
    Staff Writer
    SPACE.com Tue Jun 26, 6:46 AM ET

    In late June of 1908, a fireball exploded above the remote Russian forests of Tunguska, Siberia, flattening more than 800 square miles of trees. Researchers think a meteor was responsible for the devastation, but neither its fragments nor any impact craters have been discovered.

    Astronomers have been left to guess whether the object was an asteroid or a comet, and figuring out what it was would allow better modeling of potential future calamities.

    Italian researchers now think they've found a smoking gun: The 164-foot-deep Lake Cheko, located just 5 miles northwest of the epicenter of destruction.

    "When we looked at the bottom of the lake, we measured seismic waves reflecting off of something," said Giuseppe Longo, a physicist at the University of Bologna in Italy and co-author of the study. "Nobody has found this before. We can only explain that and the shape of the lake as a low-velocity impact crater."

    Should the team turn up conclusive evidence of an asteroid or comet on a later expedition, when they obtain a deeper core sample beneath the lake, remaining mysteries surrounding the Tunguska event may be solved.
    The findings are detailed in this month's online version of the journal Terra Nova.


    Submerged evidence
    During a 1999 expedition, Longo's team didn't plan to investigate Lake Cheko as an impact crater, but rather to look for meteoroid dust in its submerged sediments. While sonar-scanning the lake's topography, they were struck by its cone-like features.

    "Expeditions in the 1960s concluded the lake was not an impact crater, but their technologies were limited," Longo said. With the advent of better sonar and computer technologies, he explained, the lake took shape.
    Going a step further, Longo's team dove to the bottom and took 6-foot core samples, revealing fresh mud-like sediment on top of "chaotic deposits" beneath. Still, Longo explained the samples are inconclusive of a meteorite impact.

    "To really find out if this is an impact crater," Long said, "we need a core sample 10 meters (33 feet) into the bottom" in order to investigate a spot where the team detected a "reflecting" anomaly with their seismic instruments. They think this could be where the ground was compacted by an impact or where part of the meteorite itself lays: The object, if found, could be more than 30 feet in diameter and weigh almost 1,700 tons-the weight of about 42 fully-loaded semi-trailers.


    Caution for now
    From a UFO crash to a wandering black hole, wild (and wildly unsupported) explanations for the Tunguska event have been proposed. Alan Harris, a planetary scientist at the Space Science Institute in Boulder, Colorado, said the proposal by Longo's team isn't one of them.

    "I was impressed by their work and I don't think it's something you can wave off," said Harris, who was not involved in the research.
    Longo and his team "are among the recognized authorities on Tunguska" in the world, Harris told SPACE.com. "It would be thrilling to dig up chunks of the meteor body, if they can manage to. It would lay the question to rest whether or not Tunguska was a comet or asteroid."

    Some researchers, however, are less confident in the team's conclusions.
    "We know from the entry physics that the largest and most energetic objects penetrate deepest," said David Morrison, an astronomer with NASA's Ames Research Center. That only a fragment of the main explosion reached the ground and made a relatively small crater, without creating a larger main crater, seems contradictory to Morrison.

    Harris agreed that physics could work against Longo's explanation, but did note that similar events-with impact craters-have been documented all over the world.

    "In 1947, the Russian Sikhote-Alin meteorite created 100 small craters. Some were 20 meters (66 feet) across," Harris said. A site in Poland also exists, he explained, where a large meteor exploded and created a series of small lakes. "If the fragment was traveling slowly enough, there's actually a good chance (Longo's team) will unearth some meteorite material," Harris said.

    Longo's team plans to return to Lake Cheko next summer, close to the 100th anniversary of the Tunguska Event. "This is important work because we can make better conclusions about how cosmic bodies impact the Earth, and what they're made of," Longo said. "And it could help us find ways to protect our planet from future impacts of this kind."
    SOURCE
    OK... I BLOG. YOU READ. at http://jedipartner1967.livejournal.com
    **Steven Sterlekar (1969-2001)**

  2. #12
    My one problem with the debate on where the Tunguska event was caused by a comet or an asteroid is that we really don't know that much about either. Comets can look a lot like asteroids if they have run out of gas or have turned off. And asteroids can look like comets if they start venting gas. I personally think NASA's explanation is the best right now. A C class asteroid came in over Tunguska and exploded leaving little to no remnants. C class asteroid are very likely comets that have turned off.

    Quick note on names. Meteoroids are small chucks of rock in space. Meteor is an event where a small space rock enters the Earth atmosphere and burns up leaving a bright, but brief fiery trail. And a meteorite a piece of rock from space that survived it's trip through the atmosphere and landed on Earth.
    "I'm sick and tried of these motherfrakkking Sith on this motherfrakkker plane!"
    Mace Windu - Episode 2.5: Sith on a Plane

  3. #13
    Quote Originally Posted by LusiferSam View Post
    Quick note on names. Meteoroids are small chucks of rock in space. Meteor is an event where a small space rock enters the Earth atmosphere and burns up leaving a bright, but brief fiery trail. And a meteorite a piece of rock from space that survived it's trip through the atmosphere and landed on Earth.
    And a meteorette is a rock with a little pink bow on top.

    I earned my Boy Scout astronomy merit badge (many have said it's one of the hardest to get) when I went to a camping trip to Catalina Island. That was great, seeing the stars without city lights. I've also been to a few star parties over the years, but sady I seem to be unable to identify celestial objects well.
    "That's what Sheev said."

  4. #14
    I saw a huge meteor last night. I was at a friend's for a little party and we were watching other people's fireworks when I saw this. It must have traveled a fourth of the way across the sky, was twice the size of a pencil eraser held at arms length, lasted a good 5 or 6 seconds and you could see it brake up. It was easily the brightest one I've ever seen.
    "I'm sick and tried of these motherfrakkking Sith on this motherfrakkker plane!"
    Mace Windu - Episode 2.5: Sith on a Plane

  5. #15
    Quote Originally Posted by LusiferSam View Post
    I saw a huge meteor last night. I was at a friend's for a little party and we were watching other people's fireworks when I saw this. It must have traveled a fourth of the way across the sky, was twice the size of a pencil eraser held at arms length, lasted a good 5 or 6 seconds and you could see it brake up. It was easily the brightest one I've ever seen.
    I've worked the graveyard shift for 13 years and counting now. Seeing celestial displays like that is one of the benefits of being a night creature. It is soooo cool watching meteors! I've seen colors ranging from pure white, to yellow, to green. And just like LS says, they can get really bright. I've seen one so bright that it actually cast our shadows on the ground!
    ¡Que la fuerza te acompañe!

  6. #16

    Can trees grow on Mars?

    Here's a fascinating article about how scientists are contemplating terra-forming the Martian surface to produce oxygen for the atmosphere!

    [FONT=Century Gothic]Can trees grow on Mars?[/FONT]
    Scientists seek an answer by studying forests on a Mexican volcano

    MEXICO CITY - Scientists are using the pine-forested slopes of a Mexican volcano as a test bed to see if trees could grow on a heated-up Mars, part of a vision of making the chilly and barren red planet habitable for humans one day.

    Planetary scientists at NASA and Mexican universities believe if they can warm Mars using heat-trapping gases, raise the air pressure and start photosynthesis, they could create an atmosphere that would support oxygen-breathing life forms.

    Getting trees growing would be a crucial step. The scientists' quest has taken them to the snow-capped Pico de Orizaba — a dormant volcano and Mexico's tallest mountain — to examine trees growing at a higher altitude than anywhere else on Earth.

    "It sounds like science fiction, but we think it's feasible," said research professor Rafael Navarro-Gonzalez, who has spent nine years examining Pico de Orizaba's pine forests.

    "We have experienced warming our planet with greenhouse gases, but on Mars we could do it faster with more powerful gases," he said in his lab at Mexico City's UNAM university.

    The first human mission to Mars is seen 10 to 15 years away, and the warming-up process could start 50 years later, NASA scientist Chris McKay said. There will also be ethical issues to overcome.

    "It's playing gardener more than playing God, but the ethical questions are important," McKay said.

    By pumping in highly insulating gases like methane or nitrous oxide, the scientists think they could heat Mars to 41 degrees Fahrenheit from minus 67 F now. That would match temperatures where trees grow at 13,780 feet on Pico de Orizaba.

    Having trees on Mars, as opposed to only simple plant forms like algae or lichens, would open the possibility of humans one day being able to breathe Martian air.

    The scientists are studying what makes trees refuse to grow above a certain point, where temperatures drop and the air becomes thinner, to see how easily they could grow on Mars.

    "Things don't really start cooking from a biological point of view until trees start growing. Trees are the engines of the biosphere," McKay said.

    "It's possible Mars could have trees in 100 years. (But first) we need to understand what sets the tree line on Earth," McKay said by telephone from NASA's Ames center in California.

    No calls to earthlings
    Despite Mars' lifeless rocky surface, burning ultra-violet radiation and its extremely thin, carbon dioxide-loaded air, humans have for long been obsessed with finding life there.

    Scientists believe Mars has ice at its polar caps that could melt into seas and that its subsoil contains the key elements needed for life.

    Even though none will live to see the fruit of their work, the scientists on the Pico de Orizaba project believe it would be fairly straightforward to pump greenhouse gases into Mars' atmosphere, introduce bacteria to start photosynthesis and finally send up tree seeds with a human mission.

    "Nothing that we know rules it out. There's still a lot of uncertainty, but nothing that's a showstopper," McKay said.

    The project would be called off if life was found to already exist on Mars.

    "The idea is to explore the possibility of colonizing Mars. If there is life, we have no right to destroy it. But if Mars is barren we could take life from Earth to Mars," said Navarro-Gonzalez, spinning a Mars globe that shows ravines 6 miles deep and dizzying 10 mile high mountains.

    His "before" and "after" images show the arid planet transformed into a new world of lush green plains, lakes and mineral-rich mountains that could one day supply earth.

    Still, that vision is centuries away. For now, anyone braving the six-month flight to Mars would have to live in a pressurized dome, suffer violent dust storms and be cut off from earthlings too far away to easily speak to.

    In the long term, Mars's low gravity could also have odd effects on would-be settlers, causing people to grow alarmingly tall, and cosmic radiation could cause cancers and mutations.

    McKay ruled out anything more permanent than short-term research bases for the next century. "I don't have this vision of people moving to Mars the way people settled the New World, setting up homes and bringing their families."
    OK... I BLOG. YOU READ. at http://jedipartner1967.livejournal.com
    **Steven Sterlekar (1969-2001)**

  7. #17
    Sure, its getting harder and harder finding ways to screw up our planet so lets f*ck with the next one over.
    [FONT=Book Antiqua]He passes to Moses - He shoots, he scores![/FONT]
    Mummy of the raincoat is a gigantic trollop.
    DOMINATE!


  8. #18
    Ahem. If you don't wish to participate in a constructive way...
    OK... I BLOG. YOU READ. at http://jedipartner1967.livejournal.com
    **Steven Sterlekar (1969-2001)**

  9. #19
    I guess I should elaborate...
    Its f*cking retarded to attempt something this asinine and far-fetched on a complete and total waste of time. Far too much money would be wasted when it could be spent on something worthwhile and useful.
    [FONT=Book Antiqua]He passes to Moses - He shoots, he scores![/FONT]
    Mummy of the raincoat is a gigantic trollop.
    DOMINATE!


  10. #20
    All right, I really like this week's High Energy Astrophysics Picture of the Week. It's a Chandra image of a supernova remnant. While it's not the best image (which makes me think it's a short observation) it's still pretty cool. Other good Chandra images of SNR's are Cas A (a source I worked on for a couple of years), The Crab, and Tycho's.
    "I'm sick and tried of these motherfrakkking Sith on this motherfrakkker plane!"
    Mace Windu - Episode 2.5: Sith on a Plane

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