[meteorite-list] What's Hitting Earth?
From: John Hendry <pict_at_meteoritecentral.com>
Date: Wed, 02 Mar 2011 03:43:21 -0700 Message-ID: <C9936D2D.F17F%pict_at_pict.co.uk> >Are there papers supporting the 100 tons per day figure hitting the >atmosphere? Of that mass what proportion hits the surface? How are these >figures arrived at? >Can anyone point me to relevant references please? >Thx, >John > > > >On 01/03/2011 19:40, "meteoritefinder at yahoo.com" ><meteoritefinder at yahoo.com> wrote: > >>Yeah, Ron, like you, I thought this was newsworthy and I posted this to >>the List about 20 hrs ago. But no discussion here at all since then. >>Strange. >>Robert Woolard >> >>Sent from my iPhone >> >>On Mar 1, 2011, at 7:21 PM, Ron Baalke <baalke at zagami.jpl.nasa.gov> >>wrote: >> >>> >>> >>>http://science.nasa.gov/science-news/science-at-nasa/2011/01mar_meteorne >>>t >>>work/ >>> >>> What's Hitting Earth? >>> NASA Science News >>> >>> March 1, 2011: Every day about 100 tons of meteoroids -- fragments of >>> dust and gravel and sometimes even big rocks - enter the Earth's >>> atmosphere. Stand out under the stars for more than a half an hour on a >>> clear night and you'll likely see a few of the meteors produced by the >>> onslaught. But where does all this stuff come from? Surprisingly, the >>> answer is not well known. >>> >>> Now NASA is deploying a network of smart cameras across the United >>> States to answer the question, 'What's Hitting Earth?' >>> >>> Did that meteor you saw blazing through the sky last night come from >>>the >>> asteroid belt? Was it created in a comet's death throes? Or was it a >>> piece of space junk meeting a fiery demise? >>> >>> "When I get to work each morning and power up my computer, there's an >>> email waiting with answers," says William Cooke, head of NASA's >>> Meteoroid Environment Office. "And I don't have to lift a finger, >>>except >>> to click my mouse button." >>> >>> Groups of smart cameras in the new meteor network triangulate the >>> fireballs' paths, and special software^1 uses the data to compute their >>> orbits and email Cooke his morning message. >>> >>> "If someone calls me and asks 'What was that?' I'll be able to tell >>> them. We'll have a record of every big meteoroid that enters the >>> atmosphere over the certain parts of the U.S. Nothing will burn up in >>> those skies without me knowing about it!" >>> >>> In other U.S. meteor networks, someone has to manually look at all the >>> cameras' data and calculate the orbits - a painstaking process. >>> >>> "With our network, our computers do it for us - and fast," says Cooke. >>> >>> The network's first three cameras, each about the size of a gumball >>> machine, are already up and running. Cooke's team will soon have 15 >>> cameras deployed east of the Mississippi River, with plans to expand >>> nationwide^2 . Cooke is actively seeking schools, science centers, and >>> planetaria willing to host his cameras. Criteria are listed in the >>>notes >>> at the end of this story. >>> >>> In addition to tracking fireballs and their orbits, Cooke's system >>>gives >>> him other valuable information. >>> >>> "It provides data on meteor speed as a function of size - and this is >>> critical to calibrating the models we use in designing spacecraft." >>> >>> Meteorite hunters will reap benefits too. By determining a bright >>> fireball's trajectory through the atmosphere, the network's software >>>can >>> calculate whether it will plunge to Earth and pinpoint the impact >>> location fairly precisely. >>> >>> "And when we collect the meteorite chunks, we'll know their source. I >>> could be holding a piece of Vesta in my hand.^3 It would be like a free >>> sample return mission!" >>> >>> Opportunities like that, however, will be rare. "Most meteorites fall >>>in >>> the ocean, lakes, forests, farmer's fields, or the Antarctic," says >>> Rhiannon Blaauw, who assists Cooke. "And the majority of those >>> meteorites will never be found. But our system will help us track down >>> more of them." >>> >>> All cameras in the network send their fireball information to Cooke and >>> to a public website, fireballs.ndc.nasa.gov. Teachers can contact Cooke >>> at William.J.Cooke at nasa.gov to request teacher workshop slides >>> containing suggestions for classroom use of the data. Students can >>>learn >>> to plot fireball orbits and speeds, where the objects hit the ground, >>> how high in the atmosphere the fireballs burn up, etc. >>> >>> Cooke gives this advice to students and others who want to try meteor >>> watching on their own: >>> >>> "Go out on a clear night, lie flat on your back, and look straight up. >>> It will take 30 to 40 minutes for your eyes to become light adapted, so >>> be patient. By looking straight up, you may catch meteor streaks with >>> your peripheral vision too. You don't need any special equipment -- >>>just >>> your eyes." >>> >>> One more thing -- don't forget to check the website >>> <http://fireballs.ndc.nasa.gov/> to find out what you saw! >>> >>> >>> Author: Dauna Coulter >>> Editor: Dr. Tony Phillips >>> Credit: Science at NASA >>> >>> *More Information* >>> >>> (1) The smart meteor network uses ASGARD (All Sky and Guided Automatic >>> Realtime Detection) software, developed at the University of Western >>> Ontario with both NASA and Canadian funding, to process the information >>> and perform the triangulation needed to determine the orbits and >>>origins >>> of the fireballs. The Southern Ontario Meteor Network, or SOMN, >>>composed >>> of seven cameras, also uses the ASGARD system. >>> >>> (2) The cameras will be deployed in clusters of 5. One group will be >>> spread over the Southeast US, another in the Ohio and Kentucky area (to >>> overlap with the Southern Ontario Meteor Network, or SOMN), and another >>> along the Atlantic coast in the NorthEast. "Our hope is that at least >>> one of the three regions will have clear skies at any given time." >>> >>> *Here are the criteria* that must be met for a location to be >>>considered >>> as a camera site: >>> >>> 1. Location east of the Mississippi River >>> 2. Clear horizon (few trees) >>> 3. Few bright lights (none close to camera) >>> 4. Fast internet connection >>> >>> (3) The meteorite will have been altered by its journey, so it is not a >>> pristine sample, but, says Cooke, it is a good enough sample to give >>>you >>> basic characteristics of the non-volatiles. >>> >>> ______________________________________________ >>> Visit the Archives at >>>http://www.meteoritecentral.com/mailing-list-archives.html >>> Meteorite-list mailing list >>> Meteorite-list at meteoritecentral.com >>> http://six.pairlist.net/mailman/listinfo/meteorite-list >>______________________________________________ >>Visit the Archives at >>http://www.meteoritecentral.com/mailing-list-archives.html >>Meteorite-list mailing list >>Meteorite-list at meteoritecentral.com >>http://six.pairlist.net/mailman/listinfo/meteorite-list Received on Wed 02 Mar 2011 05:43:21 AM PST |
StumbleUpon del.icio.us Yahoo MyWeb |