Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Pseudoscience-is-malarkey on 26/06/2021 04:17:38

Title: If Tunguska was "2,000 times stronger" than the a-bombs, how did Earth survive?
Post by: Pseudoscience-is-malarkey on 26/06/2021 04:17:38
Even if the Tunguska event was 200x, let alone 2,000x more powerful than the bombs my country dropped on Hiroshima and Nagasaki, how did it not wipe out life on Earth, and how come only a few people noticed the event actually happen? I know it was in the desolate Siberian wilderness, populated by some farmers and Tsarists political prisoners, but still...
Title: Re: If Tunguska was "2,000 times stronger" than the a-bombs, how did Earth survive?
Post by: alancalverd on 26/06/2021 11:17:16
The atom bombs were in the 20 kiloton range. People have exploded 10-megaton bombs since then, with almost nobody else noticing.

Humanity at its worst is puny compared with a decent hurricane or tsunami.
Title: Re: If Tunguska was "2,000 times stronger" than the a-bombs, how did Earth survive?
Post by: Bored chemist on 26/06/2021 12:03:52
Also the Tunguska event didn't produce radioactive fallout.
Title: Re: If Tunguska was "2,000 times stronger" than the a-bombs, how did Earth survive?
Post by: evan_au on 26/06/2021 13:05:38
The blast radius increases as the cube root of the energy exploded (all other things being the same)...
- So if you had an explosion 1,000 times larger, the blast radius would only increase by a factor of 10
- This is because the blast energy expands outwards in 3 dimensions

This is also why research into very large nuclear bombs was not pursued - you can do a lot more damage with 10 "little" bombs than one big one with 10 times the explosive power.
See: https://en.wikipedia.org/wiki/Multiple_independently_targetable_reentry_vehicle
Title: Re: If Tunguska was "2,000 times stronger" than the a-bombs, how did Earth survive?
Post by: yor_on on 27/06/2021 13:01:18
Quite interesting comment Evan, and one that I'm sure was considered when this new doctrine was introduced, of 'low yield' limited nuclear wars. The one we're gearing up to today.
Title: Re: If Tunguska was "2,000 times stronger" than the a-bombs, how did Earth survive?
Post by: Just thinking on 20/07/2021 18:10:11
It is believed that the entire nuclear arsenal on the earth could destroy almost all human life many times over but that is the calculation taking into account direct hits on populated sites around the earth. But if all the nuclear weapons were detonated let's say in the middle of the south pole only penguins and other creatures would be bothered. The sound my travel quite some distance many thousands of kilometres and radiation would be a very big problem may be killing people some years down the track but the planet would barely feel it.
Title: Re: If Tunguska was "2,000 times stronger" than the a-bombs, how did Earth survive?
Post by: Petrochemicals on 20/07/2021 22:07:30
The kt didn't affect the earth catastrophically unless you where a boiligical life form.

Quote
The Chicxulub impactor had an estimated diameter of 11–81 kilometers (6.8–50.3 mi), and delivered an estimated energy of 21–921 billion Hiroshima A-bombs (between 1.3×1024 and 5.8×1025 joules, or 1.3–58 yottajoules).
Title: Re: If Tunguska was "2,000 times stronger" than the a-bombs, how did Earth survive?
Post by: Europa on 21/07/2021 16:19:27
Even if the Tunguska event was 200x, let alone 2,000x more powerful than the bombs my country dropped on Hiroshima and Nagasaki, how did it not wipe out life on Earth, and how come only a few people noticed the event actually happen? I know it was in the desolate Siberian wilderness, populated by some farmers and Tsarists political prisoners, but still...
The Tunguska explosion is estimated to be 33 times the blast at Hiroshima or 500 kilotons.
https://en.wikipedia.org/wiki/Tunguska_event#:~:text=The%20exploding%20meteoroid%20was%20determined,release%20of%20approximately%20500%20kilotons.

Title: Re: If Tunguska was "2,000 times stronger" than the a-bombs, how did Earth survive?
Post by: Bored chemist on 21/07/2021 17:39:08
boiligical life form.
Life forms which are not biological are seldom troubled by anything...
Title: Re: If Tunguska was "2,000 times stronger" than the a-bombs, how did Earth survive?
Post by: Bored chemist on 21/07/2021 17:43:05
Even if the Tunguska event was 200x, let alone 2,000x more powerful than the bombs my country dropped on Hiroshima and Nagasaki, how did it not wipe out life on Earth, and how come only a few people noticed the event actually happen? I know it was in the desolate Siberian wilderness, populated by some farmers and Tsarists political prisoners, but still...
The Tunguska explosion is estimated to be 33 times the blast at Hiroshima or 500 kilotons.
https://en.wikipedia.org/wiki/Tunguska_event#:~:text=The%20exploding%20meteoroid%20was%20determined,release%20of%20approximately%20500%20kilotons.


It's also estimated as up to 30 MTons
"The 30 Mt (130 PJ) estimated upper limit blast power of the Tunguska event could power the same average home for more than 3,100,000 years."
from
https://en.wikipedia.org/wiki/TNT_equivalent

But the detail doesn't matter.
Most of Hiroshima survived the blast.
Almost all the damage was confined to sticky out bits that people had put there.
The flat bits were generally  fine.

That wiki page lists plenty of earthquakes etc that were much bigger than a thousand times the upper bound to the estimated energy from Tunguska.
A notable example is an hour's worth of sunshine: 104000 megatons.