
The Tunguska Event - jackgavigan
http://www.bbc.com/earth/story/20160706-in-siberia-in-1908-a-huge-explosion-came-out-of-nowhere
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alexholehouse
So I've always had this (entirely crackpot) idea that the Tunguska Event is
actually the place and time in space/history that you'd want to test the first
time-travel device to. From a 'test system' design perspective:

\- You'd want it to be somewhere isolated to avoid casualties, especially if
there was a radiation risk (which you wouldn't know).

\- You wouldn't want people to be able to analyze the immediate wreckage with
any kind of high fidelity because there might be signatures of whatever you
sent back (or however you sent it) that might change the course of
history/technology.

\- You'd want there to be fairly detailed recordings (ideally photos), and for
it to persist into modern history, not just be a weird anomaly of 'the past'.

\- You wouldn't want it be interpreted as some kind of military action.

To be very clear, I don't actually believe this is what happened, but I quite
like the idea...

~~~
rmsaksida
Another event that took place in Russia and led to a variety of crackpot
theories: the Dyatlov Pass incident. [0]

> The incident involved a group of nine experienced ski hikers from the Ural
> Polytechnical Institute who had set up camp for the night on the slopes of
> Kholat Syakhl. Investigators later determined that the skiers had torn their
> tents from the inside out. They fled the campsite inadequately dressed, some
> of them barefoot, under heavy snowfall and at temperatures below freezing.
> Six victims were determined to have died from hypothermia, while others
> showed signs of trauma. One victim had a fractured skull and another was
> found with brain damage without any sign of distress to the skull.
> Additionally, one woman's tongue was missing.

> Soviet authorities determined that an "unknown compelling force" had caused
> the deaths. Access to the region was consequently blocked for hikers and
> adventurers for three years after the incident. Due to the lack of
> survivors, the chronology of events remains uncertain.

> Several explanations have been put forward, including an avalanche,
> infrasound-induced panic, and a military accident. Sensationalist hypotheses
> include a hostile encounter with a yeti or other unknown creature.

[0]
[https://en.wikipedia.org/wiki/Dyatlov_Pass_incident](https://en.wikipedia.org/wiki/Dyatlov_Pass_incident)

~~~
Houshalter
The missing tongue is the weirdest part. Otherwise it could be explained by
hypothermia. Or, possibly, drugs.

~~~
imaginenore
The missing tongue is not the weirdest part. Animals could have eaten it.

Every hypothesis about this event that made any sense involves a physical
attack by a group of people, likely armed. The only two groups that would mass
murder people just not to be found out are 1) foreign military or 2) escaped
murderers.

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sandworm101
Bad news: It wasn't a very big rock.

[https://share.sandia.gov/news/resources/releases/2007/astero...](https://share.sandia.gov/news/resources/releases/2007/asteroid.html)

Most descriptions speak of a single explosion, something comparable to a
nuclear weapon. That isn't an appropriate model. It wasn't a single event at a
fixed spot, nor was it a series of events. It was more of a continuous release
of energy over a great distance. The rock exploded not at a particular
altitude, but dissipated its energy into the atmosphere over a period of
time/distance, a line rather than a point. Square-area/volume principals
therefore do not apply directly. With that understanding it turns out it was
probably a much smaller rock than previously though.

The trees were not knocked over all at once. I think of it more as them being
blown down in series as if by the wake of a passing boat, that boat being an
exploding rock. So you cannot take the total damage area and calculate a
single point for the explosion.

Old model:
[http://www.sandia.gov/videos2007/2007-6514Pfire.hv1.2.mpg](http://www.sandia.gov/videos2007/2007-6514Pfire.hv1.2.mpg)

New model:
[http://www.sandia.gov/videos2007/2007-6514Pfire.hv1.1.mpg](http://www.sandia.gov/videos2007/2007-6514Pfire.hv1.1.mpg)

~~~
plusfour
The new model is a lot more badass than the old one.

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bpicolo
You have to wonder when a large piece of space rock will hit somewhere
inhabited. That said, with 3% of earth's land being urban (3% of 29% of
Earth), and reasonably infrequent falling rocks, it's really not that likely
to happen in any given lifetime. I suspect we're keen enough these days to be
able to predict and evacuate the right areas, though. This paper references
another that suggests a "Tunguska Event" is a once in 200-300 year deal:
[http://articles.adsabs.harvard.edu//full/1994Metic..29..864Y...](http://articles.adsabs.harvard.edu//full/1994Metic..29..864Y/0000868.000.html)
(Man I am so far into the rabbit hole now)

Looks like 15th century China had an event that probably had a number of
casualties (though apparently modern researchers dispute the details). Wasn't
aware of that. [https://en.wikipedia.org/wiki/1490_Ch%27ing-
yang_event](https://en.wikipedia.org/wiki/1490_Ch%27ing-yang_event)

~~~
cryptoz
In 2013 in Russia, a meteor exploded over a city and injured thousands of
people.

[https://en.wikipedia.org/wiki/Chelyabinsk_meteor](https://en.wikipedia.org/wiki/Chelyabinsk_meteor)

Something extra interesting about this is the number of videos that recorded
it due to the prevalence of car dash cams. This helped scientists quickly
reconstruct what happened and is amazing footage to have of such a rare event.

~~~
foobarian
Speaking of, what is it with the Russians and the dash cams? There seems to be
a subculture of recording while driving and posting videos of road rage,
fistfights, etc.

~~~
D-Coder
I have heard it's due to the corrupt traffic police. Everyone wants their own
record of what happened.

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dmix
This article sounds almost like a word-for-word reworking of the Wikipedia
article, which I just read yesterday.

I recommend reading that as it includes some great quotes from witnesses and a
better overall structure:
[https://en.wikipedia.org/wiki/Tunguska_event](https://en.wikipedia.org/wiki/Tunguska_event)

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xg15
Summing up this article:

When people were first investigating the Tunguska event, they believed it to
be caused by an asteroid...

They were probably right.

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mutagen
Couple of papers from the Italian team that did bathymetry / seismics in Lake
Cheko:

[http://sci-hub.cc/10.1007/s12210-015-0403-8](http://sci-
hub.cc/10.1007/s12210-015-0403-8)

[https://www.researchgate.net/publication/229759371_Lake_Chek...](https://www.researchgate.net/publication/229759371_Lake_Cheko_and_the_Tunguska_Event_Impact_or_non-
impact)

Some argument against Cheko being an impact crater, referenced in the above
work:

[http://www.univie.ac.at/geochemistry/koeberl/publikation_lis...](http://www.univie.ac.at/geochemistry/koeberl/publikation_list/312-Lake-
Cheko-not-impact-crater-Terra-Nova-2008.pdf)

Data from the Italian team that investigated Cheko:

[http://www-th.bo.infn.it/tunguska/](http://www-th.bo.infn.it/tunguska/)

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lostlogin
The theory that the lake which is a distance from the proposed centre of the
blast is an impact crater may be born out by accounts from the time which
describe multiple hits at varying distances.

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autokad
I dont believe Lake Cheko is the impact site. its connected to a long river in
both directions

[https://www.google.com/maps/place/60%C2%B055'00.0%22N+101%C2...](https://www.google.com/maps/place/60%C2%B055'00.0%22N+101%C2%B057'00.0%22E/@60.945417,101.839777,17648m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d60.9166667!4d101.95)

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ivan_gammel
In sci-fi book "Monday begins on Saturday" by Arkady and Boris Strugatsky
there was cool, but rather unrealistic theory, according to which Tunguska
event was a landing of an alien spaceship, which had reverse time arrow. They
landed and then have gone to our past, finding themselves in the untouched
ancient taiga, and leaving no traces in our future.

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firebones
What are the economics (and physics) of creating a football-field-sized (and
proportionately-weighted) synthetic meteor and studying a controlled re-entry
into some part of the ocean? Would that be a useful experiment in terms of
learning how to deal with potential future threats, or too risky?

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mirimir
There's a great description of hypervelocity atmospheric impact in _The
Killing Star_ by Charles R. Pellegrino and George Zebrowski.

