[url]http://blog.xkcd.com/2012/07/12/a-morbid-python-script/[/url]

Go NASA!

[url]http://www.youtube.com/watch?v=QFvNhsWMU0c[/url]

[url]http://www.youtube.com/watch?v=SP65V4AoFyA[/url]

I'm looking à ceux ici qui parlent français...

[URL="http://www.stumbleupon.com/su/4rMVAK/:1ES5J0y-t:44uGni!A/www.nailmaster.ru/fuck.html/"]LOL[/URL]

Should be hilarious for native and non- speakers of English alike. Warning: Seriously not safe for work.

Spanish fresco restoration botched by amateur
[URL]http://www.bbc.co.uk/news/world-europe-19349921[/URL]

[QUOTE=Brian-E;308950]Spanish fresco restoration botched by amateur
[URL]http://www.bbc.co.uk/news/world-europe-19349921[/URL][/QUOTE]
Looks disturbingly similar to the work of Mr.Bean (on the "Portrait of the Artist's Mother").

[QUOTE]Hello, I'm Dr. Bean. Apparently. And my job is to sit and look at paintings. So, what have I learned that I can say about this painting? Well, firstly, it's quite big, which is excellent. If it were very small, microscopic, then hardly anyone would be able to see it. Which would be a shame. Secondly, and I'm getting quite near the end of this... analysis, secondly, why was it worth this man spending fifty million of your American dollars? And the answer to that is, that it's a picture of Whistler's mother. And as I've learned, staying with my best friend David Langley and his family, families are very important. Even though Mr. Whistler was obviously aware that his mother was a hideous old bat who looked like she'd had a cactus lodged up her backside, he stuck with her, and even took the time to paint this amazing picture of her. And that's marvellous. It's not just a painting. It's a picture of a mad old cow who he thought the world of. Well that's what I think.[/QUOTE][COLOR=White].[/COLOR]

[QUOTE=Batalov;308959]Looks disturbingly similar to the work of Mr.Bean (on the "Portrait of the Artist's Mother").[/QUOTE]

I said the same comment to my girlfriend when she told me about that news yesterday evening. It's so funny.

[QUOTE=ewmayer;308958]
The explosion had a yield of 15 Mtons TNT, implying a mass-conversion efficiency ratio of around 1.5x10[sup]7[/sup]. That's in about the same ballpark (nyuk, nyuk), but about a factor 10x more off than I'd like."[/QUOTE]AIUI, a substantial fraction of the energy yield of many so-called fusion weapons comes from the tertiary fission of U-238 by fast neutrons produced by the secondary fusion component, itself ignited by the Pu-239 fission primary. Again AIUI, such devices were always called a "super" by those in the business of designing them rather than H-bombs. Once more AIUI, the largest such device detonated, the Tsar Bomba, had only half its design yield because the uranium casing was replaced with inert lead. Just as well, otherwise the aircraft dropping it would undoubtedly have been fried as opposed to merely getting rather warm.

Further consideration of the original thought experiment indicates that nuclear reactions, far from being a mechanism for converting kinetic energy to thermal energy would remove energy from the system. The KE per nucleon is well above the nuclear binding energy and so spallation would take place, in the baseball and in anything it hit, thereby absorbing energy.

It would be interesting, IMO, to model the physics more carefully. Useful conclusions would be the distribution of heat as a function of time and position, the expected trajectory, and how much matter and in what forms would leave the earth's gravitational well.

For instance, assume that the ball hit only air (not a terribly plausible hypothesis admittedly). Air pressure at sea-level is approximately 100 kg/m^2 and that is a good estimate for the air mass directly above one square metre of surface. A baseball has a diameter of 0.0737m apparently, and so a cross-sectional area of 4.3e-3 m^2. It's not heading straight up so to make the computation easier assume that it travels through 10/4.3 air masses; i.e. it has an effective area of 1e-2 m^2 heading upwards.. If the ball remains intact (big if!) it then collides with 1kg of air, larger than the rest mass of the baseball. If it breaks up its cross-sectional area will become greater and will collide with an even larger mass of atmosphere.

Even this grossly oversimplified model, assuming I haven't made any multiple orders of magnitude mis-estimates, leads me to believe that very little will escape the earth. It would be good to build a more realistic model.

[QUOTE=xilman;309008]Air pressure at sea-level is approximately 100 [B]kg/m^2[/B] and that is a good estimate for the air mass directly above one square metre of surface. [/QUOTE]

Pressure unit is wrong...maybe you meant kgf/m^2.

[QUOTE=pinhodecarlos;309010]Pressure unit is wrong...maybe you meant kgf/m^2.[/QUOTE]Yup, I was using air pressure in order to get a value for the air mass above an area.