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  • When Worlds Collide (in Sci-Fi and Science)
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    Envoyée le mercredi 16 juin 2010 11:34:08
    par SpaceRip
    Vue 36152 fois
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    Watch this and other space videos at http://SpaceRip.com

    From Spitzer Space Telescope's acclaimed Hidden Universe series, NASA/JPL/Caltech.

    Nearly 60 years ago, audiences thrilled to the destruction of the Earth in George Pal's classic film, "When Worlds Collide." The idea of a planetary smash-up is a staple of science fiction, but can it really happen?

    Astronomers using NASA's Spitzer Space Telescope think they've actually seen the aftermath of such a collision around another star.

    The story unfolded as Dr. Casey Lisse and his team studied disks around young stars. Once planets have formed astronomers think there are a lot of left-over asteroids in the system. They occasionally slam together and produce dusty debris.

    Spitzer's Infrared Spectrograph was designed to detect the faint glow from this material. By spreading the light out into its component colors, astronomers can look for the spectral fingerprints of different minerals.

    Our dusty star of interest is a faint speck known as HD 172555. It's about 100 light years away and 12 million years old which, compared to our 4.5 billion year old Sun, is like a baby born a few days ago.

    Studying its spectrum, Dr. Lisse and his colleagues realized they had found something very peculiar that they had not seen around other stars. Aside from the usual indicators of rocky rubble, they found features corresponding to tektite, obsidian, and silicon monoxide gas.

    What's strange is that tektite and obsidian are formed from molten materials. Tektites are hardened chunks of lava found around meteor impacts on Earth, and obsidian is volcanic glass. Vaporized rocks can form silicon monoxide gas.

    You don't get this kind of material by just smashing a couple of asteroids together. The evidence suggests something much more... cataclysmic. Imagine what would happen if our moon slammed, at high velocity, into a Mercury-sized planet. The resulting impact would eject a massive amount of molten material into space. As it cooled it would likely form tektite, obsidian, and silicon monoxide gas, explaining the features seen in the HD 172555 spectrum.

    It's amazing to think Spitzer may have caught the aftermath of such an incredible collision. But, it's not the first time astronomers have speculated about world-shattering events. In fact, similar things may have happened right here in our own back yard.

    Mercury is a strangely dense planet compared to the other worlds in the solar system. Now if it formed from the same stuff as Venus and Earth, why would it be any different? A world-shattering impact could be the answer. When planets form the lighter materials rise and denser ones sink to the core. Remove the outer, lighter layers and you're left with a denser planet, once what's left cools off.

    Looking to our neighbor Mars we see a massive impact scar in its Southern hemisphere. This area, known as the Hellas Basin, must have formed from an asteroid impact long ago. The resulting plume of molten material would have been blasted into space, some of it eventually reaching the ancient Earth.

    Even closer to home, most astronomers believe that our own moon was formed in a similar cataclysm. The theory is that a Mars-sized body grazed the still- forming Earth, generating a massive amount of molten debris. The orbiting rubble would clump together over time, forming the moon.

    The tektite and obsidian debris from such massive impacts would not last long around our sun, or others. Solar winds and gravitational interactions tend to sweep away the dust over time, and in a few tens of thousands of years the evidence would be erased.

    In the long history of our solar system, that's hardly the blink of any eye. The evidence may be long gone here, but seeing what may happen when worlds collide around a nearby star shows us it's not just science fiction after all.



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  • AutumnKnightmare

    You call people nerdy and use the word "fail"...
    dimanche 25 mars 2012 18:31:31
  • bencinurts

    Densth
    samedi 15 octobre 2011 21:09:05
  • bencinurts

    That guysth cut!
    samedi 15 octobre 2011 21:07:05
  • rugmanbob

    the world is comming to an end and they are worried about THE COST of building another space ship lol
    mardi 04 octobre 2011 15:06:19
  • revrunnertech2772

    i got interested in science and space after my mom showed me a picture of the 9 (now 8) planets since then, i know 1000% more science than anyone else
    dimanche 17 juillet 2011 14:24:17
  • granddad2002

    Space is fascinating. I'm 47 and everything I knew as a child has been re-written. Between the probes we sent across the solar system, to vast technical improvements of telescopes... even our media and the public consciousness isn't the same as it was 50 years ago. I hope that people who know how to watch the skies and launch probes can get the NEOs tagged.... a rock the size of Witchita, Ks hitting the Earth at 30,000 kph would be a bad day for us.
    lundi 04 juillet 2011 11:44:40
  • Scytherene122190

    Funny thing is a huge portion of my latter life was devoted to getting fucked up; being outright lazy, drinking, smoking, snorting etc... now the past year and a half I've chosen to ascend myself in knowledge, personality and compassion. I understand I was confused, and it seemed there weren't many choices left for me anymore.. I dwarfed myself. I still smoke marijuana nowadays, but that's very minor compared to many other people's severe problems.
    samedi 05 mars 2011 19:28:11
  • lgarvey

    Most adults stay up talking with friends and having parties. I like to get naked and watch spacerip all night long
    dimanche 13 février 2011 14:28:37
  • MMaeidlilniAW

    I do the same but instead science it is usually politics for me.
    samedi 12 février 2011 03:15:25
  • KarbineKyle

    @WildWaffleWriter I don't throw stupid parties either. I think relaxing, and watching videos about science all night is actually way better! Besides, all people do now at parties is get f**ked up. I'm not perfect. I've gone to parties, but I just like socializing. I LOVE TO LEARN! It's funny, because the people I've been around with say I'm the smartest person in the group. Gee, I wonder why? =P 2 worlds colliding... Imagine the mass panic if it was Earth! The Universe is Beautiful, yet Chaotic!
    mercredi 15 décembre 2010 03:20:40
  • isakilla1

    :D same
    samedi 27 novembre 2010 19:33:46
  • funnyfootballs

    4:32 I was like "Dude Watch Out!" :)
    mardi 09 novembre 2010 14:11:46
  • davothebum2201

    whoa ! at 4:34 I thought that planet was gonna hit him ..
    mercredi 27 octobre 2010 05:59:08
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