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Tunguska

Cochise said:
i visualise that as a bit like the way you have to start a ramjet? Some external force / reaction is necessary to get the body up to the speed where the ramjet ignites - could the friction with the Earth's atmosphere have caused the meteorite to 'ignite' as it were and fire off in a different direction?
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If the object had been a mixed material mass (e.g., a chondritic / stony object; perhaps even an asteroid) it's plausible that uneven intense heating could have caused a 'blow-out' of sufficient force to alter the object's trajectory.

I suspect this is less likely for an iron meteorite.

The main problem I see with the skipping-iron-meteor hypothesis is that it seems to be framed with regard to having caused a single dramatic blast and shock wave. The eyewitness reports (such as they are ... ) are pretty consistent in mentioning a series of multiple such 'blasts' / 'shocks' / 'thunderclaps' during the incident.
 
EnolaGaia said:
If the object had been a mixed material mass (e.g., a chondritic / stony object; perhaps even an asteroid) it's plausible that uneven intense heating could have caused a 'blow-out' of sufficient force to alter the object's trajectory.

I suspect this is less likely for an iron meteorite.

The main problem I see with the skipping-iron-meteor hypothesis is that it seems to be framed with regard to having caused a single dramatic blast and shock wave. The eyewitness reports (such as they are ... ) are pretty consistent in mentioning a series of multiple such 'blasts' / 'shocks' / 'thunderclaps' during the incident.
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I forget where I saw it, but speculation about the composition of the object has been interesting. things that are mixes of rock and ice apparently do weird stuff on entry to the atmosphere.
kamalktk said:
It wouldn't need to be accelerating to escape velocity, rather it wouldn't drop below escape velocity as it travelled a path that doesnt intersect the ground.
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I dunno, it'd still have a lot of atmospheric friction to deal with. It'd also have to get close enough to nearly hit the ground
 
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marhawkman said:
... It'd also have to get close enough to nearly hit the ground
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No, it wouldn't ... Eyewitness accounts only mention seeing a fiery object, fiery phenomena, and / or bright flashes aloft. Even though some of the eyewitness accounts mention shocks or vibrations akin to an earthquake, none (that I've ever seen) clearly indicate there was a ground impact.

Consider this ... The damage and injuries from the 2013 Chelyabinsk meteor resulted from an explosion at an altitude of circa 29 - 30 km. Even though fragments of this meteorite were found, its primary effects didn't directly involve the ground impact. This was believed to have been an asteroidal object only some 20 m in breadth.

Still ... To have generated a much bigger series of shock waves at an altitude sufficient to allow skipping back out of the atmosphere the Tunguska object would have had to be bigger, faster, or both.

Some eyewitnesses reported small 'stones' raining from the sky in 1908. FWIW I still think a catastrophic disintegration of a stony meteor or asteroidal object remains the best hypothesis for what came down (but not all the way ... ) over the Tunguska area.
 
I'd think the angle is very important; I'd imagine there wasn't much of a "bounce" with Tunguska --it must have just come in at a very shallow angle and continued on, causing destruction as it passed through and compressed and heated the atmosphere. Smaller objects skip more, perhaps. I just saw a bunch of posts that just materialized after I posted this. So it has been said already methinks.
https://www.sciencealert.com/satellite-filmed-meteoroid-bounce-off-earth-s-atmosphere-like-a-stone-skimming-a-pond#:~:text=On September 22, 2020, a,and bounced back into space.&text=The most common effect that,reach the ground as meteorites.
 
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I noted on Twitter that today is Tunguska Day and the British Newspaper Archive retweeted my comment, complete with the screenshot! (Derby Daily Telegraph 2/7/1908)
 

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Just wondered - are there any contemporary eyewitness reports of the immediate atmospheric effects of the Tunguska event in sources other than newspaper reports (actually - are there many newspaper reports)? It's said that it was possible to read print, as if in daylight, at midnight in Western Europe for a week or so afterwards (various plausible explanations advanced for this, which I'm not interested in disputing).
Are there any published diaries, letters, memoirs, whatever to support this? Did George Bernard Shaw, to choose at random someone who was around at the time, write to a friend "Isn't it odd how light the nights have been recently - I can hardly get to sleep for it"?
And, I suppose, if not, why not?
 
ghughesarch said:
It's said that it was possible to read print, as if in daylight, at midnight in Western Europe for a week or so afterwards (various plausible explanations advanced for this, which I'm not interested in disputing).
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I can't think of anything that might do that - unless there was some trace of the explosion left high up in the upper atmosphere, perhaps as some glowing particulate matter raining down very slowly.
 
Or particulate matter hurled into the atmosphere which was scattering sunlight from sunlit areas to the darkened areas of the planet?
 
DrPaulLee said:
Or particulate matter hurled into the atmosphere which was scattering sunlight from sunlit areas to the darkened areas of the planet?
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Maybe. Which might indicate a high concentration of metal, perhaps?
 
ghughesarch said:
Just wondered - are there any contemporary eyewitness reports of the immediate atmospheric effects of the Tunguska event in sources other than newspaper reports (actually - are there many newspaper reports)? It's said that it was possible to read print, as if in daylight, at midnight in Western Europe for a week or so afterwards ...
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Some basic notes on the nocturnal lighting effects in the wake of the Tunguska event ...

The reported "bright nights" phenomenon was limited to a swath of Eurasian territory extending from some distance west of the incoming object's estimated path westward to the British Isles.

Here is a diagram attributed to Russian researchers I. T. Zotkin and A. L. Tchijevsky that illustrates the geographic range for the "bright nights" phenomenon. I can't find any specific citation of a published source for this diagram, but Tchijevsky was studying Tunguska in the early 1920s. My guess is that it comes from a Russian publication during the 1920s - 1930s.


This diagram's caption (via Google Translate) describes it as:
... trace of the evolution of the reddish atmospheric halo which appeared in the European sky between June 30 and July 1, 1908. ...​
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I mention the caption because it illustrates two things.

First, the nocturnal 'glow' was often, but not universally, cited as having a color or tint ranging from yellowish to reddish (i.e., 'warm' colored).

Second, the phenomenon didn't last as long as a week. Those accounts that describe the phenomenon and note its duration most commonly cite the first post-event evening (June 30 / July 1) alone. This evening's scanning hasn't surfaced any specific duration claim exceeding 3 nights.

Finally ... It's worth noting that the Tunguska event occurred only about a week after the summer solstice. At least within the northern reaches of the 'glow zone' illustrated above, it doesn't get fully dark at night during that time of year. My point is that the "bright nights" phenomenon didn't need to supply much additional light to afford readability outdoors at the time.
 
ghughesarch said:
Just wondered - are there any contemporary eyewitness reports of the immediate atmospheric effects of the Tunguska event in sources other than newspaper reports (actually - are there many newspaper reports)? ...
Are there any published diaries, letters, memoirs, whatever to support this? ...
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The closest thing to such a first-person report I've been able to find comes from the French article cited above. It's a letter quoted / published in a UK newspaper some days after the event. No date or publication or letter's author name is given. Here's the relevant passage (again, via Google Translate from the French):

 
EnolaGaia said:
Yep - same item ...
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Letter signed by, 'Holcombe Ingleby, Brancaster', whom a Google search reveals was a somewhat eccentric character and aapparently designed the layout for the Royal West Norfolk Golf Club, Brancaster.

That seems to explain the background to his experience?

Brancaster is on the Norfolk coast and only 38 miles from Cromer. :)

I wonder if there might be similar reports in local newspapers?
 
Many years back I was looking into creating an interactive map (like my ghost and Titanic efforts) to show what people around the globe described of the after effects of the impact - I may still do this BTW! What struck me is the number of people who attributed the glow to a large fire, a warehouse or whatever, with some people thinking that it was fairly close by. This made me think that the nocturnal lights were far brighter than anything that the last vestiges of a midsummer sun-set could produce.
 
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@Comfortably Numb
I honestly don't know! When I did my newspaper trawl years ago, some people attributed the light sky to the aurora but I thought people wouldn't have been so easily misled (of course, there may have been an aurora which may have contributed).

Hmm... I wonder if anything is in the easily accessible US and Australian newspapers in line? A job for another time (more sleep beckons )
 
I'm glad that Krakatoa was mentioned above too. I was fumbling for other examples of airglow and this slipped my mind. Blame fatigue!
 
Mythopoeika said:
I can't think of anything that might do that - unless there was some trace of the explosion left high up in the upper atmosphere, perhaps as some glowing particulate matter raining down very slowly.
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DrPaulLee said:
Or particulate matter hurled into the atmosphere which was scattering sunlight from sunlit areas to the darkened areas of the planet?
Click to expand...
Mythopoeika said:
Maybe. Which might indicate a high concentration of metal, perhaps?
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Long story short ...

Given the timing and the planet's orientation, it's almost universally presumed the Tunguska afterglow was reflected sunlight from 'way over the horizon.

Earlier hypotheses emphasized the notion that the airburst near the Siberian surface blew considerable debris high into the stratosphere (analogous to what happened during the Krakatoa explosion). This approach sounds straightforward, but there are problems validating it using (e.g.) simulations. Most particularly, there's been no convincing explanation for how dust blown upward off the surface could result in a cloud layer high enough (at or beyond the edge of space) and fast enough to reflect sunlight as far and in as widespread a manner as was reported in 1908.

The most recent analyses and simulations point to two more probable conclusions:

- the Tunguska afterglow was caused by a radical instance of a noctilucent cloud (NLC); and ...
- the material comprising the NLC mainly, if not wholly, originated from aloft rather than from the ground.

It wasn't until the 1990s that data and observations from space shuttle re-entries demonstrated NLCs could be generated by objects incoming from outside the atmosphere without any interaction with the earth's surface (e.g. kicking up dust) or troposphere.

The latest hypothesis is that the explosions during the Tunguska object's descent / incursion, combined with the huge final airburst, blew atmospheric moisture and the object's own or affiliated dust clear out into space as a plume which slowly settled back into the atmosphere. As the plume settled back into the atmosphere it created huge NLCs floating at the very edge of space.

See, for example, this presentation by a scientist specializing in near-earth objects, earth defense, and impacts / impactors:

https://asteroidday.org/resources/asteroid-learning/meteor-marvelling-noctilucent-clouds-and-us/
 
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If it may be of interest, researching the newspaper.com archives, under a simple search for two words, 'tunguska comet', there seems to be no newspaper report (within their archives) of a comet connection until an article in 'The Brooklyn Daily Eagle', on 11 January, 1929.

There are no other, related publications showing on that day and the next associated article doesn't appear elsewhere until 23 January.

The article has been uploaded to :

Page 1
www.forteanmedia.com/Brooklyn_01.pdf

Page 2
www.forteanmedia.com/Brooklyn_02.pdf
 
Paul_Exeter said:
*bump*

This blog post contains photographs of alleged engravings on Tunguska debris:

https://ufoconjectures.blogspot.com/2022/12/tunguska-actual-ufo-disaster.html

It is certainly new to me that such artefacts existed, how about anyone else...?
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These look like metallic meteorites that have had a slice removed, the flat face has been polished up and then soaked in etchant acid to reveal the crystalline structure. The crystalline structure of many meteorites can be quite elaborate (example below).

Muonionalusta-Widmanstatten.jpg
 
Mythopoeika said:
These look like metallic meteorites that have had a slice removed, the flat face has been polished up and then soaked in etchant acid to reveal the crystalline structure. The crystalline structure of many meteorites can be quite elaborate (example below).

Muonionalusta-Widmanstatten.jpg
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Thanks, think you have nailed it. Had my doubts, the whole hieroglyphics on crashed alien spacecraft remnants is getting a bit old hat tbh
 
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