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asteroid 2012 DA14 next week
If I go out on Valentine's day next week with binoculars and clear sky at
the Plough and manage to see this object going zenithwards across the handle of the pan-handle 21:00 to 22:00 or so, will it be varying brightness from tumbling. ? If it is tumbling before near earth encounter would that gravitational encounter stop the the tumbling of an asymetric object? |
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asteroid 2012 DA14 next week
"N_Cook" wrote in :
If I go out on Valentine's day next week with binoculars and clear sky at the Plough and manage to see this object going zenithwards across the handle of the pan-handle 21:00 to 22:00 or so, will it be varying brightness from tumbling. ? If it is tumbling before near earth encounter would that gravitational encounter stop the the tumbling of an asymetric object? Yes. No. |
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asteroid 2012 DA14 next week
Sjouke Burry s@b wrote in message
2.10... "N_Cook" wrote in : If I go out on Valentine's day next week with binoculars and clear sky at the Plough and manage to see this object going zenithwards across the handle of the pan-handle 21:00 to 22:00 or so, will it be varying brightness from tumbling. ? If it is tumbling before near earth encounter would that gravitational encounter stop the the tumbling of an asymetric object? Yes. No. Would the brightness variability be perceivable by simple looking through binoculars (if seen at all) and over what sort of periodicity? |
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asteroid 2012 DA14 next week
For the UK it is the 15 Feb
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asteroid 2012 DA14 next week
"N_Cook" wrote in :
Sjouke Burry s@b wrote in message 2.10... "N_Cook" wrote in : If I go out on Valentine's day next week with binoculars and clear sky at the Plough and manage to see this object going zenithwards across the handle of the pan-handle 21:00 to 22:00 or so, will it be varying brightness from tumbling. ? If it is tumbling before near earth encounter would that gravitational encounter stop the the tumbling of an asymetric object? Yes. No. Would the brightness variability be perceivable by simple looking through binoculars (if seen at all) and over what sort of periodicity? Depends on how fast it is tumbling, and how irregular the surface is. |
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asteroid 2012 DA14 next week
In uk.sci.astronomy message
..12.10, Thu, 7 Feb 2013 20:15:55, Sjouke Burry posted: "N_Cook" wrote in : If I go out on Valentine's day next week with binoculars and clear sky at the Plough and manage to see this object going zenithwards across the handle of the pan-handle 21:00 to 22:00 or so, will it be varying brightness from tumbling. ? If it is tumbling before near earth encounter would that gravitational encounter stop the the tumbling of an asymetric object? Yes. No. I would expect that a non-tumbling asymmetric asteroid approaching from infinity would be tumbling after the encounter. Gravitational motion is time-reversal symmetric. Therefore an asteroid approaching from infinity with just the right tumble would not be tumbling when it finally reached infinity again. So only rather probably No. IIRC : Consider not Niven's "Neutron Star" itself, but comments made after its publication, such as in http://en.wikipedia.org/wiki/Neutron_Star_%28short_story%29#Notes blob 2. -- (c) John Stockton, nr London, UK. Mail via homepage. Turnpike v6.05 MIME. Web http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms and links; Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc. No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News. |
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asteroid 2012 DA14 next week
Dr J R Stockton wrote in message
nvalid... In uk.sci.astronomy message .12.10, Thu, 7 Feb 2013 20:15:55, Sjouke Burry posted: "N_Cook" wrote in : If I go out on Valentine's day next week with binoculars and clear sky at the Plough and manage to see this object going zenithwards across the handle of the pan-handle 21:00 to 22:00 or so, will it be varying brightness from tumbling. ? If it is tumbling before near earth encounter would that gravitational encounter stop the the tumbling of an asymetric object? Yes. No. I would expect that a non-tumbling asymmetric asteroid approaching from infinity would be tumbling after the encounter. Gravitational motion is time-reversal symmetric. Therefore an asteroid approaching from infinity with just the right tumble would not be tumbling when it finally reached infinity again. So only rather probably No. IIRC : Consider not Niven's "Neutron Star" itself, but comments made after its publication, such as in http://en.wikipedia.org/wiki/Neutron_Star_%28short_story%29#Notes blob 2. -- (c) John Stockton, nr London, UK. Mail via homepage. Turnpike v6.05 MIME. Web http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms and links; Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc. No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News. I'll try looking ESE about 20:00, when brightest, but whether I can make out Denebola is another matter, I hope these path charts are still valid http://www.britastro.org/~rmiles/Ima...950-2100UT.png Path 20:00 to 21:00 http://www.britastro.org/~rmiles/Ima...100-0100UT.png Path 21:00 to 01:00 |
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asteroid 2012 DA14 next week
Too much mist at horizon level for me to see with binos at the Leo level ,
and returned to it for the Plough crossing but had clouded over by then, so did not see it. I wonder what traumatised state that Russian was who took that image of that meteor/ite coming straight for him, an amazing piece of phone-cam imagery |
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