--------------- FIDO MESSAGE AREA==> TOPIC: 180 ASTRONOMY Ref: F5G00017 Date: 04/13/98 From: BARTON PAUL LEVENSON Time: 07:20pm \/To: STEVEN GRAY (Read 1 times) Subj: ASTEROID PASSING CLOS SG> Hello, Barton. Nice analysis, but if I may quibble a bit, I think you're SG> off by a factor of two. SG> Since E = (1/2)mv^2, (dE)/(dv) = mv SG> dE = mv^2(dv/v) = 2E(dv/v) SG> So the change in energy is twice the initial energy times the fractional SG> change in the speed. Doesn't change the conclusion, of course . Good call. I think you're right. --- Maximus 3.01 * Origin: SoundingBoard, Pittsburgh PA (1:129/26) --------------- FIDO MESSAGE AREA==> TOPIC: 180 ASTRONOMY Ref: F5G00018 Date: 04/15/98 From: Time: 10:34am \/To: (Read 1 times) Subj: --- FreeMail 1.10 alpha-3 * Origin: RainTree BBS - 804-741-5105 - 300-28.8 (1:264/323) --------------- FIDO MESSAGE AREA==> TOPIC: 180 ASTRONOMY Ref: F5G00019 Date: 04/15/98 From: KEITH KNAPP Time: 05:53pm \/To: TONY DUNLAP (Read 1 times) Subj: Tasco Buys Celestron TD>MK> Tasco is going to buy Celstron International. This is good news for al TD>MK>amateur astronomers as now all C8s through C14s will come shipped with TD>MK>three TD>MK>quality Huygens oculars and a 3X barlow! TD> KK> And don't forget, the eyepieces will be sized to the much TD> KK> more modern .965" form factor! TD>Hmmm... My Tasco takes 1.25 eyepieces. Sorry, we were being facetious. 1.25" is the preferred size. * SLMR 2.1a * Marriage is like a novel, except the hero dies right away --- PCBoard (R) v15.4/M 5 Beta * Origin: * Binary illusions BBS * Albuquerque, NM * 505.897.8282 * (1:301/45) --------------- FIDO MESSAGE AREA==> TOPIC: 180 ASTRONOMY Ref: F5G00020 Date: 04/14/98 From: VANESSA POLAND Time: 11:30am \/To: MIKE ROSS (Read 1 times) Subj: Asteroid passing close to MR> Earthquakes will be triggered on already primed tectonically fragile MR> areas. like the entire ring of the pacific ocean?? --- * Origin: Paradoxia BBS * Rio Linda, Ca * 916-991-8462 (1:203/448) --------------- FIDO MESSAGE AREA==> TOPIC: 180 ASTRONOMY Ref: F5G00021 Date: 04/15/98 From: BARTON PAUL LEVENSON Time: 05:30pm \/To: ADAM MAJER (Read 1 times) Subj: S of L. BPL> BK> Accepted. The only problem is you haven't answered the BPL> BK> question. Could you have another go please. BPL>Photons and probably neutrinos have energy but not AM> mass. One is convertibl BPL>into the other. Energy and mass are both "stuff" BPL>but of different types. AM> Incorrect. Einstain proved that energy and mass are one and the same AM> thing - E=mc2. Your analogy is the same as someone saying that ice and AM> liquid water are all "stuff" but of different types. Oh, get a life. --- Maximus 3.01 * Origin: SoundingBoard, Pittsburgh PA (1:129/26) --------------- FIDO MESSAGE AREA==> TOPIC: 180 ASTRONOMY Ref: F5G00022 Date: 04/15/98 From: BARTON PAUL LEVENSON Time: 05:31pm \/To: CURTIS JOHNSON (Read 1 times) Subj: Asteroid passing close to CJ> There would most definitely be effects on the other side CJ> of the globe at the anti-impact point, in the form of considerable CJ> earthquakes. A good example of this is the chaotic terrain on CJ> Mercury opposite the Caloris Basin. CJ> Just to add to the above, some of the scientists working CJ> with the K/T meteorite scenario have contended that the fireball's CJ> heat would creat significant quantities of nitrous and nitric CJ> acid--resulting in acid rain. 1. Mercury is 1/20 the mass of the Earth and whatever hit it was a lot larger than a 1-km. asteroid. 2. Acid rain will be local, it will not travel as far as the antipodes. --- Maximus 3.01 * Origin: SoundingBoard, Pittsburgh PA (1:129/26) --------------- FIDO MESSAGE AREA==> TOPIC: 180 ASTRONOMY Ref: F5G00023 Date: 04/15/98 From: BARTON PAUL LEVENSON Time: 05:34pm \/To: ADAM MAJER (Read 1 times) Subj: White dwarfs AM> You don't really have to worry about neutron stars or black holes. They AM> aren't that common as compared to the white dwarfs. Either of them would AM> run in the tenths if not a millionths of a percentage (the latter goes AM> especially for BHs) O, B and A-type stars are about 0.6%. --- Maximus 3.01 * Origin: SoundingBoard, Pittsburgh PA (1:129/26) --------------- FIDO MESSAGE AREA==> TOPIC: 180 ASTRONOMY Ref: F5G00024 Date: 04/15/98 From: BARTON PAUL LEVENSON Time: 05:38pm \/To: MARTYN HARRISON (Read 1 times) Subj: BB theory CJ> stars will appear dimmer with distance, but the increased number CJ> of stars will more than make up for this. MH> Assuming none of them are occulted by dead stars. MH> In reality, there is a lot more stuff up there than just stars, and MH> providing a certain degree of non-bright objects occulting some of the MH> stars, there wouldn't be a bright star (or cluster of dim stars just as MH> bright) in every direction. We can't eve see the centre of our own MH> galaxy due to dense clouds of (?) dust. With infinite amounts of time available, or even very large amounts of time, any dust or dead objects in the way would have heated up to the same temperature as the surface of a star. Dust in the way thus does not effectively answer Olbers's Paradox. This was investigated extensively in the 19th century. --- Maximus 3.01 * Origin: SoundingBoard, Pittsburgh PA (1:129/26) --------------- FIDO MESSAGE AREA==> TOPIC: 180 ASTRONOMY Ref: F5G00025 Date: 04/15/98 From: BARTON PAUL LEVENSON Time: 05:40pm \/To: MARTYN HARRISON (Read 1 times) Subj: A 5th force? MH> way, but at the moment it's another pointer away from the standard big MH> bang model. No it isn't. The Big Bang doesn't depend on the rate of increase being either increasing or decreasing. --- Maximus 3.01 * Origin: SoundingBoard, Pittsburgh PA (1:129/26) --------------- FIDO MESSAGE AREA==> TOPIC: 180 ASTRONOMY Ref: F5G00026 Date: 04/15/98 From: SID LEE Time: 10:35am \/To: BARTON PAUL LEVENSON (Read 1 times) Subj: Asteroid passing close to -=> Quoting Barton Paul Levenson to Sid Lee <=- BPL> The radiation given off by a collision follows a blackbody curve, and BPL> the more energy involved, the higher the fraction of energy released BPL> in the shortwave part of the spectrum. A large enough mechanical BPL> collision will give off not only radio and infrared (i.e., heat) but BPL> visual light, UV, X-rays and even gamma rays. The collision of a BPL> sufficiently large asteroid with the Earth will be _indistinguishable_ That is all "electromagnetic radiation" not nuclear radiation. YOu are in fact quite correct that a strike or any large explosion will generate an EMP. Nuclear explosions generate them as well of course however the use of the word "radiation" is commonly interpreted to mean nuclear radiation which only arises from nuclear reactions. There will be no nuclear reactions involved in such a strike and hence no nuclear radiation. BPL> from a very large nuclear explosion. Note that the Tunguska area was BPL> radioactive after the 1908 airburst of what was probably a comet. Sorry, that is incorrect. Even if it were correct the phenomena would not have been detected since nuclear processes were barely being discovered at that time in history. TTunguska was a pure mechanical explosion and no nuclear radiation was produced. BPL> Heck, the BOP shop here at the USX Edgar Thomson works gets up to BPL> higher temperatures than 500 C, and so does some of the exhaust it BPL> emits. I agree there will be a shockwave, but it will dissipate with BPL> distance. Air, unlike water, is compressible. Well I have no idea who or what "BOP" is or how this statement is related to the discussion ;-) A self cleaning oven reaches temperatures of the order of 500 deg C as well but does not cause a worldwide firestorm either. However if you place a stick of wood in one it will combust, the temperature being above the ignition point and oxygen being present. In a large strike an enormous volume of atmosphere will be heated to a very high temperature and that atmosphere will begin mixing with the worldwide atmosphere violently and rapidly (imagine the force of the winds driven by a temperature difference of thousands of degrees!) bringing the average temperature of the ENTIRE atmosphere well above the ignition temperature of combustibles like vegetation. The self cleaning oven or the "BOP shop" would start a worldwide conflageration if either could heat enough atmosphere fast enough but we are safe because they cannot. The strike of a largish object moving at tens of km/sec on the other hand can and would ;-) -- Regards -- Sid Lee (FIDO - 1:134/122, Internet - sidlee@agt.net) --- Blue Wave/Max v2.12 * Origin: RASCAL BBS [Calgary, Alberta - (403)686-2550] (1:134/122)