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  • #91
    Originally posted by Mountain Man View Post
    Since underground nuclear explosions are conducted in specially constructed deep chambers, and thus representing the collapse of not only the chamber itself but the strata surrounding the chamber, can they be validly compared to craters created by surface impacts of non-explosive solid objects?
    Judging by the total lack of any response, apparently they cannot be validly compared.

    Thank you.
    Quis Custodiet Ipsos Custodes? Who is watching the watchers?

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    • #92
      Originally posted by Mountain Man View Post
      Judging by the total lack of any response, apparently they cannot be validly compared.

      Thank you.
      Speaking for myself, rather busy of late and limited time for all the threads, I remember seeing this and intending to respond.

      For the most part, impacts of solid objects usually tend to throw out material, ejecta, and/or produce raised rims. There's also materials at or just below the surface reflecting alteration from the heat of impact, something that seldom transfers up from underground nuke detonation. Also could be fracturing and shattering of strata layers evidence force and heat from above rather than below.

      But I'm not a geologists, so perhaps The Doctor would be better at chiming in.

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      • #93
        Comet ISON shaping up to be a spectacular display

        http://phys.org/news/2013-01-comet-i...ectacular.html

        Comet ISON is expected to be at its brightest in late November of this year, leading some to link it with the Star of Bethlehem which the Bible says led the three wise men to the newborn baby Jesus. Its perihelion – closest approach to the sun – is expected to occur on November 28 and the comet will likely be best viewed in the northern hemisphere.

        Read more at: http://phys.org/news/2013-01-comet-i...cular.html#jCp
        Excitement is mounting for astronomers and star gazers the world over as word spreads that Comet ISON may go down in the history books as one of the flashiest ever. First discovered in September of last year by Russian astronomers, Vitali Nevski and Artyom Novichonok, Comet ISON (C/2012 S1) has been drawing attention ever since.

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        • #94
          Talk about close! Asteroid to give Earth record-setting shave

          Close flyby comes on Feb. 15 — but NASA says it won't smash into our planet

          "" An asteroid half the size of a football field will give Earth the ultimate close shave this month, passing closer than many satellites when it whizzes by. But it won't hit the planet, NASA scientists say.
          The asteroid 2012 DA14 will fly by Earth on Feb. 15 and zip within 17,200 miles (27, 680 kilometers) of the planet during the cosmic close encounter. The asteroid will approach much closer to Earth than the moon, and well inside the paths of navigation and communications satellites.
          "This is a record-setting close approach," Don Yeomans, the head of NASA's asteroid-tracking program, said in a statement.
          ... ""
          http://www.nbcnews.com/id/50672151/n.../#.UQ6swfLheKw


          If it does hit, would be about like the Tunguska Blast of 1905.

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          • #95
            Originally posted by Mountain Man View Post
            Since underground nuclear explosions are conducted in specially constructed deep chambers, and thus representing the collapse of not only the chamber itself but the strata surrounding the chamber, can they be validly compared to craters created by surface impacts of non-explosive solid objects?
            Of course you can. A crater is a crater no matter how it is formed.




            Another interesting thing about the Barringer crater is the lack of debris field or "splotch" of ejecta around it. In the desert there is no vegetation to and little water to obscure such marks and this is a young impact.
            Attached Files
            Battles are dangerous affairs... Wang Hsi

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            • #96
              I've been there. It's amazingly flat surrounding that crater. A stark reminder of just what can happen to our planet.
              The First Amendment applies to SMS, Emails, Blogs, online news, the Fourth applies to your cell phone, computer, and your car, but the Second only applies to muskets?

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              • #97
                Originally posted by Pirate-Drakk View Post
                ... Another interesting thing about the Barringer crater is the lack of debris field or "splotch" of ejecta around it. In the desert there is no vegetation to and little water to obscure such marks and this is a young impact.
                That is interesting. Any theories you like as to why that is?
                Any metaphor will tear if stretched over too much reality.

                Questions about our site? See the FAQ.

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                • #98
                  Actually, at least in this article, there is a debris field:

                  "Limestone blocks as massive as thirty tons were tossed outside the crater’s rim, and debris from the impact has been found over an area of 100 square miles."

                  "Relatively large chunks of nickel-iron fragments, ranging from gravel size to blocks weighing up to 640 kilograms have been recovered from the debris field surrounding the crater."

                  http://www.philipcoppens.com/meteorcrater.html

                  It does look like there is no debris field, especially from simply looking at the pictures. I have never heard before that the area lacked a debris field.
                  The First Amendment applies to SMS, Emails, Blogs, online news, the Fourth applies to your cell phone, computer, and your car, but the Second only applies to muskets?

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                  • #99
                    Originally posted by Hida Akechi View Post
                    "Limestone blocks as massive as thirty tons were tossed outside the crater’s rim, and debris from the impact has been found over an area of 100 square miles."

                    ....

                    It does look like there is no debris field, especially from simply looking at the pictures. I have never heard before that the area lacked a debris field.
                    100 square miles sounds like a lot but when you do the math, the furthest debris is only 5 miles from the crater and amounts to a few pebbles.

                    When I think debris fields, they look like the fresh craters in the pics below. The first two are from Luna, the other two are from Mercury.
                    Attached Files
                    Battles are dangerous affairs... Wang Hsi

                    Comment


                    • Originally posted by Pirate-Drakk View Post
                      100 square miles sounds like a lot but when you do the math, the furthest debris is only 5 miles from the crater and amounts to a few pebbles.

                      When I think debris fields, they look like the fresh craters in the pics below. The first two are from Luna, the other two are from Mercury.
                      Ok, I understand then. But those are on worlds that don't have erosion or new soil laid down. Granted Meteor Crater is in the middle of a desolate nowhere, but those processes do happen in that area anyway.


                      The article did mention much larger boulders thrown up from the impact. So it's more than just a few pebbles.


                      But I'm not quibbling, I understand by what you mean now when you say "debris field". Utter ejection devastation. Like I said, I have been to the crater, I have seen ejecta laying about, but not on the scale of the pictures you present.


                      And if it is an actual mystery as to why there isn't, at least, more debris, then I'm inclined to wonder why as well.


                      Thanks for the brain-excercise!
                      The First Amendment applies to SMS, Emails, Blogs, online news, the Fourth applies to your cell phone, computer, and your car, but the Second only applies to muskets?

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                      • Originally posted by Hida Akechi View Post
                        ...
                        Thanks for the brain-excercise!
                        Your welcome, I also enjoy oddities I can't explain. Recall from this thread of mine:
                        http://www.armchairgeneral.com/forum...d.php?t=131466

                        "Simple craters generally have depth / diameter ratios of between 1/5 (0.2) and 1/3 (0.33) (Melosh, 1989)."
                        http://www.geologyrocks.co.uk/tutorials/meteor_craters

                        If we take the numbers from the wiki:
                        http://en.wikipedia.org/wiki/Meteor_Crater

                        We get: 170m/1186m = 0.143

                        This does not fall into the range of a "normal" simple crater which this appears to be.

                        So, we have a "crater" that does not fit the depth to diameter ratio, it lacks a significant debris field, and it is square instead of round.

                        I would say this is not much of an impact crater based on the actual evidence and science behind cratering. However, it is indeed a crater.
                        Battles are dangerous affairs... Wang Hsi

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                        • Here's a way to make craters of various types.



                          From page 234 of this interesting document:
                          http://www.osti.gov/bridge/servlets/...852629-81nrD8/

                          As you can see, all manner of ratios of diameter to depth ratios can be generated depending on the specifics of the blast parameters.

                          The explosions don't require nukes. You will get the same result for the same amount of bang out of any explosive.

                          All of the "mysteries" of the Barringer crater can be explained by an underground blast. The lack of radioactive debris in the area indicates it was not a nuclear explosion.

                          This underground blast theory can explain the crater, but not the "who", "when", and "why" questions that would be related if it were true...
                          Attached Files
                          Battles are dangerous affairs... Wang Hsi

                          Comment


                          • New proof that asteroid impact dealt the dinosaurs a quick death blow

                            ....
                            Timing of an impact
                            New findings using high-precision radiometric dating analysis of debris kicked up by the impact now suggest the K-T event and the Chicxulub collision happened no more than 33,000 years apart. In radiometric dating, scientists estimate the ages of samples based on the relative proportions of specific radioactive materials within them. [Wipe Out: History's Most Mysterious Mass Extinctions]
                            "We've shown the impact and the mass extinction coincided as much as one can possibly demonstrate with existing dating techniques," researcher Paul Renne, a geochronologist and director of the Berkeley Geochronology Center in California, told LiveScience.
                            ...
                            http://science.nbcnews.com/_news/201...eath-blow?lite

                            Comment


                            • Some more on 2012 DA14, this article was handy for the link it provided;
                              http://news.cnet.com/8301-11386_3-57...coming-friday/
                              which is this asteroid impact calculator;
                              http://www.purdue.edu/impactearth
                              And a more informative article (as to be expected) from space.com;
                              http://www.space.com/19759-asteroid-...ving-tips.html

                              Another addition:
                              Asteroid 2012 DA14: 5 Surprising Facts About Friday's Earth Flyby

                              http://www.foxnews.com/science/2013/...intcmp=related
                              Last edited by G David Bock; 14 Feb 13, 21:05.

                              Comment


                              • Maybe that large asteroid is bringing along some baby companions.

                                From: http://www.reuters.com/article/2013/...91E05Z20130215

                                Reuters) - A powerful blast rocked the Russian region of the Urals early on Friday with bright objects, identified as possible meteorites, falling from the sky, emergency officials said.

                                "It was definitely not a plane," an emergency official told Reuters, without elaborating. "We are gathering the bits of information and have no data on the casualties so far."

                                No one was hurt in a meteor shower, an emergency official told RIA-Novosti. Local residents said they witnessed burning objects in the sky of the Chelyabinsk and Sverdlovsk regions.

                                A Reuters witness in Chelyabinsk reported hearing a huge blast early in the morning and feeling a shockwave in a 19-storey building in the town center.

                                The sounds of car alarms and breaking windows could be heard in the area, the witness said, and mobile phones were working intermittently.
                                "Preliminary indications are that it was a meteorite rain," an emergency official told RIA-Novosti. "We have information about a blast at 10,000-meter (32,800-foot) altitude. It is being verified."

                                The trace from a falling object could be seen in Yekaterinburg, some 200 kilometers (125 miles) southeast of Chelyabinsk, another Reuters witness said.
                                "The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts."— Bertrand Russell

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