No - not another news headline about Britney but a real hole in Russia. So big that helicopters have been sucked into it. What causes the suction? http://www.sreedhara.com/2006/07/25/the-biggest-hole-in-the-world-great-photos/ Wang King
OT:The worlds biggest hole
Started by ●June 6, 2007
Reply by ●June 6, 20072007-06-06
No - not another news headline about Britney but a real hole in Russia. So big that helicopters have been sucked into it. What causes the suction? http://www.sreedhara.com/2006/07/25/the-biggest-hole-in-the-world-great-photos/ Wang King
Reply by ●June 7, 20072007-06-07
could make a nice sattelite dish out of it (aka, Arecibo II)... On Jun 5, 11:13 pm, John Monro <johnmo...@optusnet.com.au> wrote:> gyansor...@gmail.com wrote: > > No - not another news headline about Britney but a real hole in > > Russia. So big that helicopters have been sucked into it. What causes > > the suction? > > >http://www.sreedhara.com/2006/07/25/the-biggest-hole-in-the-world-gre... > > > Wang King > > Dear King, > > Impressive photos. All that work for a few kilograms of carbon crystals! > > I imagine the 'suction' would be caused by thermal air currents rising > from the sunlit side of the hole. As that air rises, cold air would > flow down the cold side, creating a downdraft. > > Regards, > John
Reply by ●June 7, 20072007-06-07
Ikaro wrote:> could make a nice sattelite dish out of it (aka, Arecibo II)...I don't think it would have a good "field of view" (for want of a better term). IIRC from my days wandering Phillips Hall and looking at pictures, Arecibo's ratio of depth/diameter was much smaller. Then again they did try to graduate me for decades ;0> > > On Jun 5, 11:13 pm, John Monro <johnmo...@optusnet.com.au> wrote: > >>gyansor...@gmail.com wrote: >> >>>No - not another news headline about Britney but a real hole in >>>Russia. So big that helicopters have been sucked into it. What causes >>>the suction? >> >>>http://www.sreedhara.com/2006/07/25/the-biggest-hole-in-the-world-gre... >> >>>Wang King >> >>Dear King, >> >>Impressive photos. All that work for a few kilograms of carbon crystals! >> >>I imagine the 'suction' would be caused by thermal air currents rising >>from the sunlit side of the hole. As that air rises, cold air would >>flow down the cold side, creating a downdraft. >> >>Regards, >>John > > >
Reply by ●June 7, 20072007-06-07
On Thu, 07 Jun 2007 11:59:31 -0500, Richard Owlett <rowlett@atlascomm.net> wrote:>Ikaro wrote: >> could make a nice sattelite dish out of it (aka, Arecibo II)... > >I don't think it would have a good "field of view" (for want of a better >term). IIRC from my days wandering Phillips Hall and looking at >pictures, Arecibo's ratio of depth/diameter was much smaller. Then again >they did try to graduate me for decades ;0In general any antenna with a lot of gain is going to have a small "field of view" or main lobe width. That's pretty much how the gain is obtained, by narrowing the beam width...sorta like filter processing gain; you can get a narrow filter with lots of gain or you can get a wide one without so much gain. So an antenna made in that hole would have really high gain, but a very narrow beam. Might be good to look for distant quasars and stuff like that. Eric Jacobsen Minister of Algorithms Abineau Communications http://www.ericjacobsen.org
Reply by ●June 7, 20072007-06-07
Or, another idea, create a windfarm on it's edge.... There is gotta be a cool way to exploit the energy from this draft besides knocking out helicopters.> I imagine the 'suction' would be caused by thermal air currents rising > from the sunlit side of the hole. As that air rises, cold air would > flow down the cold side, creating a downdraft.
Reply by ●June 7, 20072007-06-07
Eric Jacobsen wrote:> On Thu, 07 Jun 2007 11:59:31 -0500, Richard Owlett > <rowlett@atlascomm.net> wrote: > >> Ikaro wrote: >>> could make a nice sattelite dish out of it (aka, Arecibo II)... >> I don't think it would have a good "field of view" (for want of a better >> term). IIRC from my days wandering Phillips Hall and looking at >> pictures, Arecibo's ratio of depth/diameter was much smaller. Then again >> they did try to graduate me for decades ;0 > > In general any antenna with a lot of gain is going to have a small > "field of view" or main lobe width. That's pretty much how the gain > is obtained, by narrowing the beam width...sorta like filter > processing gain; you can get a narrow filter with lots of gain or you > can get a wide one without so much gain. > > So an antenna made in that hole would have really high gain, but a > very narrow beam. Might be good to look for distant quasars and > stuff like that.There's a bit more to it. The basic reflector shape is a parabola, but there's not much difference between a sphere and a parabola with only modest depth, so images obtained with the sphere can be modestly sharp. When the reflector is spheric, its beam can be steered simply by shifting the receiver at its focus. Arecibo has a broader coverage area -- celestial latitude; longitude is steered by Earth's rotation -- than its beamwidth would suggest. Maybe the hole at Mirna could be used as a horn? Jerry -- Engineering is the art of making what you want from things you can get. ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Reply by ●June 7, 20072007-06-07
gyansorova@gmail.com wrote:> No - not another news headline about Britney but a real hole in > Russia. So big that helicopters have been sucked into it. What causes > the suction? > > > http://www.sreedhara.com/2006/07/25/the-biggest-hole-in-the-world-great-photos/If the airflow is that violent above the hole, I guess it is far worse inside. I wonder how the miners survived digging the hole? I'm not clear if this is an active or abandoned mine. If abandoned, then maybe they dug until the violence of the wind made it impractical to go further (Of course "practical" is relative, and diamonds are a strong driver). If the mine is actually exhausted, isn't it strange how small a spot contained the diamonds. Steve
Reply by ●June 8, 20072007-06-08
On Thu, 07 Jun 2007 20:28:39 -0400, Jerry Avins <jya@ieee.org> wrote:>Eric Jacobsen wrote: >> On Thu, 07 Jun 2007 11:59:31 -0500, Richard Owlett >> <rowlett@atlascomm.net> wrote: >> >>> Ikaro wrote: >>>> could make a nice sattelite dish out of it (aka, Arecibo II)... >>> I don't think it would have a good "field of view" (for want of a better >>> term). IIRC from my days wandering Phillips Hall and looking at >>> pictures, Arecibo's ratio of depth/diameter was much smaller. Then again >>> they did try to graduate me for decades ;0 >> >> In general any antenna with a lot of gain is going to have a small >> "field of view" or main lobe width. That's pretty much how the gain >> is obtained, by narrowing the beam width...sorta like filter >> processing gain; you can get a narrow filter with lots of gain or you >> can get a wide one without so much gain. >> >> So an antenna made in that hole would have really high gain, but a >> very narrow beam. Might be good to look for distant quasars and >> stuff like that. > >There's a bit more to it. The basic reflector shape is a parabola, but >there's not much difference between a sphere and a parabola with only >modest depth, so images obtained with the sphere can be modestly sharp. >When the reflector is spheric, its beam can be steered simply by >shifting the receiver at its focus. Arecibo has a broader coverage area >-- celestial latitude; longitude is steered by Earth's rotation -- than >its beamwidth would suggest. Maybe the hole at Mirna could be used as a >horn? > >JerryThat's a thought. It can definitely be steerable, and adjustable to some degree, but would still be very high gain in general...elsewise what would be the advantage of using so much area? Eric Jacobsen Minister of Algorithms Abineau Communications http://www.ericjacobsen.org
Reply by ●June 8, 20072007-06-08
Steve Underwood <steveu@dis.org> writes:> gyansorova@gmail.com wrote: > > No - not another news headline about Britney but a real hole in > > Russia. So big that helicopters have been sucked into it. What causes > > the suction? > > http://www.sreedhara.com/2006/07/25/the-biggest-hole-in-the-world-great-photos/ > > If the airflow is that violent above the hole, I guess it is far worse > inside. I wonder how the miners survived digging the hole? I'm not > clear if this is an active or abandoned mine. If abandoned, then maybe > they dug until the violence of the wind made it impractical to go > further (Of course "practical" is relative, and diamonds are a strong > driver). > > If the mine is actually exhausted, isn't it strange how small a spot > contained the diamonds.Not really. Kimberlite pipes aren't all that wide. See: http://en.wikipedia.org/wiki/Kimberlite Scott -- Scott Hemphill hemphill@alumni.caltech.edu "This isn't flying. This is falling, with style." -- Buzz Lightyear
