[JoeProBono]

[KoRn]

.

[beefree]

Aster risk

[PeterPrinciple]

because the comet fragment packed its own explosives—in the form of hydrogen

---

Interesting thought, good as some of the others............

[stormer]

[KarlInOhio]

Edward Drobyshevski, a research physicist at the Russian Academy of Sciences in St. Petersburg, thinks that instead, Tunguska is such a mystery because the comet fragment packed its own explosives—in the form of hydrogen, the gas that turned the Hindenburg airship into a blazing inferno in seconds......

The hydrogen is unlikely to have much effect. The kinetic energy of just about any interplanetary impact will be much greater than the chemical energy available from the impactor. A quick lookup showed that at 3 km/s closing velocity the kinetic energy of an object is the same as the chemical energy of the same mass of TNT - and 3 km/s is pretty slow when dealing with orbital velocities.

[Islander7]

[joethedrummer]

“A fireball powerful as hundreds of Hiroshima atomic blasts scorched through the upper atmosphere...”

OK... This was in 1908. How come the rest of the planet didn’t suffer? Why didn’t we as a species go extinct? Why weren’t our skies darkened for months, killing the ozone layer and bringing on global warming?

Yet, this is the type of scenario they teach us is what killed off the dinosaurs...

[PapaBear3625]

Comets mainly seem to be dirty snowballs. Consider a big ( say a hundred yards diameter) snowball entering the atmosphere at over 7 miles/sec straight down. It is in significant atmosphere for only about the last 10 seconds. It’s energy gets expended in vaporizing itself.

[SunkenCiv]

http://news.nationalgeographic.com/news/pf/15220271.html