Close Encounbters in Siberia (TUNGUSKA with VIDEO Link)

Originally posted by gallifreyan medic
reply to post by Arbitrageur

 

Good information you gave.
Though try to give people some credit of having some intelligence.

I did say pictures and not photos.

I'm glad you thought the information was good, though you'll have to explain the difference between pictures and photos to me, I thought they were two different words for the same thing?

Originally posted by C.H.U.D.

Anything will explode if heated rapidly and forcefully enough.

Meteoroids explode in the atmosphere every day. There is no doubt about that. The vast majority are totally vaporised since they are small. Even relatively large meteoroids are completely destroyed.

True. Some meteorites make it to the ground without exploding though so not sure about "anything". I thought most of them just vaporised instead of exploded but yes, they do record explosions.

Originally posted by C.H.U.D.The issue of weather something as large as the object that exploded over Tunguska was able to detonate without producing a crater has been hotly debated and I don't think anyone really knows for sure. There may well be a crater, and we just haven't found it... or perhaps we have: Team makes Tunguska crater claim

I don't think that's a very hot debate, though it may have been hotly debated. One obvious epicenter (there could be more than one since some witnesses heard up to 3 main explosions) left trees standing directly under the blast just like a nuclear bomb test, neither left a crater so there really shouldn't be any debate at all about that. The closer to the ground, the more likely a crater is, the higher up, the less likely.

reply to post by Arbitrageur

I thought they were two different words for the same thing?

One would assume that when referring to pictures of that event and taking into account the date it occurred,its meaning would refer to sketches and drawings.don't you think?

Of course your misunderstanding could be down to age or location.

Originally posted by gallifreyan medic

I thought they were two different words for the same thing?

One would assume that when referring to pictures of that event and taking into account the date it occurred,its meaning would refer to sketches and drawings.don't you think?

Of course your misunderstanding could be down to age or location.

There were cameras in 1908, but yes you have a point, could be geographical bias on the context, in fact read this article and you will see I'm not the only one who never had even a thought of drawings or sketches in the context of the word "picture":
difference-between-pictures- and-photographs

In fact I googled 1908 pictures and it seems like the vast majority of the results are photographs instead of drawings or sketches.
I've never heard pictures used in the context of drawings or sketches before (though I see it can be a valid use), though if you had used the words sketches or drawings they may have been less ambiguous. In any case, I really thought you meant photographs and didn't mean any insult in any way so I apologize if I came across that way. Sorry about that.

By the way there was one known sketch by an eyewitness referenced in that article, did you see it?

reply to post by Arbitrageur


I'm still going through the articles on world mysteries and haven't come across it yet.
Thank you for the heads up.

reply to post by gallifreyan medic


Come to think of it, not sure if that links directly to it so let me post a better link here:

only known drawing by eyewitness of so-called 'Tunguska meteorite' in flight

It's the #1 link on that site.


[edit on 2-7-2009 by Arbitrageur]

reply to post by Arbitrageur


Arbitrageur, you seem pretty clued up and have brought quite a lot of information to this thread....

many thanks - havent gone through everything yet but will do during the course of the day...

thanks

Originally posted by booda
reply to post by Arbitrageur

 

Arbitrageur, you seem pretty clued up and have brought quite a lot of information to this thread....

many thanks - havent gone through everything yet but will do during the course of the day...

thanks

You're welcome and thanks for starting this thread, I've watched every documentary I could find on this event (including Leonard Nimoy's "In Search Of" suggesting it could have been an exploding UFO or an atomic bomb which really got me interested) but I hadn't seen these. so I thank you for starting this thread so I could see these too.

Just one more thing to add that some people seem to think is unexplainable...the possibility of a change in direction. When an explosion occurs of an incoming object, it could explode the entire object or just part of it (especially if the object has an irregular shape, which the drawing would seem to suggest it did, or a non-homogeneous composition). If only part of it explodes, the force of that explosion can change the direction of the remaining mass, sort of like one billiard ball glancing or bouncing off on another billiard ball. So as you read all these explanations and theories, keep in mind that people seeing an object moving in different directions could have been looking at looking at remnants of the same original object that had changed direction. Based on eyewitness accounts of up to 3 main explosions, saying the object changed directions three times wouldn't violate any known laws of physics.

You know whenever I hear an eyewitness say "The object changed direction" so "it couldn't have been a meteor" or "it had to be intelligently controlled", I can understand why they might think that, and in fact the majority of objects entering our atmosphere do NOT change suddenly change direction, but, it can and does happen contrary to popular belief, for reasons that don't defy the laws of physics (like partial explosions causing sudden changes, or outgassing causing more gradual changes in direction). The Odd Flying Objects of E. L. Trouvelot is an interesting read for anyone who doubts this, see especially figure 1.

Originally posted by Wasco
... I advise you to read the book. It's out of print now but copies are still available. Compare it to the several modern documentaries. IF all of what Baxter and Atkins say is true it's hard to come to any other conclusion than a nuclear powered craft. I just don't know how much of "The Fire Came By" is true.

Ahh, Baxter and Atkins -- now THERE's a name I haven't heard for a long, long time... [cue theme]

See www.jamesoberg.com... for my involvement with them way, way back then...

Originally posted by JimOberg
See www.jamesoberg.com... for my involvement with them way, way back then...

I read that! Fascinating, thanks for posting it!

A friend of Isaac Asimov's, eh? I'm impressed! Is it fair to infer that you don't endorse their book as heartily as Isaac Asimov since you thought he was being too generous with his endorsement?

I guess my enjoyment of such a book would depend on whether I was reading it as science fiction or science fact, and Asimov was known for writing both. I can enjoy either, though I can get annoyed reading fiction presented as fact.

reply to post by Arbitrageur


Heating "some rocks" is not going to tell you much about how a meteoroid will behave in real life, is the point I was trying to make.

Quite simply, it does not take into account all the variables involved, such as angle of entry, and composition/structural integrity. Also, we know very little about the types of material that meteoroids are composed of, especially the less dense kinds which never make it to the ground, so meaningful research is hard to do.

We do know a bit about what happens through observations and falls though, such as velocity, composition and angle of entry all play key parts in what a meteoroid will do. Angle of entry has to be within certain narrow limits. A few degrees either way and a fall can not occur, except in exceptional cases where large objects are involved.

Too fast/small, and the meteoroid, even if it's made out of quite hard material, will either be completely vaporised or explode.

How big the explosion is, and how high up it is will both decide weather or not a crater is left behind (as well as if any large remaining chunks of the object survive). Can a meteoroid/comet/asteroid explode and not leave a crater? Yes!

Bearing in mind that our best guesses (in the case at hand) about the objects altitude, trajectory, and the size of the explosion produced are just that; "guesses" (investigations took place and statements were taken many years after the event - recollection after so may years is bound to be "colorful" at best in most cases), it's impossible to say with any certainty.

So without a crater, we are stuck with two possibilities. That there is a crater somewhere that has not been found, or that it was completely destroyed at high altitude, or some mixture in between the two may also be a possibility.

In a high altitude detonation, any surviving fragments will still be traveling at extremely high velocity, and would in most cases continue to be luminous afterwards for some time, although that time may be very short, as the surviving fragments may themselves be completely destroyed though ablation, which is the process by which material is stripped away from the meteoroid.

Observations of cometary material entering our atmosphere have shown us that it is particularly weak, and unless the angle and speed are both very low, it usually disintegrates almost immediately. This is something I've personally witnessed on many occasions, and the bigger the meteoroid, the more chance there is of it making it through the uppermost layers of the atmosphere, only to detonate when it hits the lower and thicker layers.



There are some great examples in this meteor compilation although most of these appear to be asteroidal in origin, especially the clip around 42 seconds, where you can clearly see a few pieces continuing to be luminous after the detonation!



In much the same way, the Perseids, which is a well known cometary meteor shower, shows just how fragile cometary material is. One explodes just off the screen in this clip.





More examples of cometary meteors, from the legendary Leonids.

[edit on 3-7-2009 by C.H.U.D.]

Originally posted by C.H.U.D.
reply to post by Arbitrageur

 

So without a crater, we are stuck with two possibilities. That there is a crater somewhere that has not been found, or that it was completely destroyed at high altitude, or some mixture in between the two may also be a possibility.

Thanks for the clarification and the cool videos, everything you're saying makes sense.
Regarding the known epicenter, I was pretty convinced by the trees standing in the middle, with the surrounding trees being flattened in a radial pattern from that epicenter, so it seems pretty clear to me at least that at least one blast/shockwave originated somewhere above that point and clearly left evidence of an epicenter with no crater.

However, I wouldn't rule out that other fragments could have exploded elsewhere closer to the ground, leaving some craters that weren't observed in the original expeditions. So of your 3 scenarios I think we can rule out (or rule as extremely unlikely if you prefer) the the idea that the entire thing exploded and left a crater we didn't find, but either of the other two scenarios are possible.

Those were great videos, they really show a lot of interesting effects. Too bad that one explosion is just off camera but I get the idea.

Great post, thanks!

Originally posted by Arbitrageur
A friend of Isaac Asimov's, eh? I'm impressed! Is it fair to infer that you don't endorse their book as heartily as Isaac Asimov since you thought he was being too generous with his endorsement?

You infer correctly.

Yeah, working with Isaac on some of these kinds of stories was pretty cool...

Jim and Isaac in New York City, 1982

reply to post by Arbitrageur



You're welcome Arbitrageur.

Agreed that the radial pattern of felled trees point to the area above, where the blast (or at least one of them ) occurred.

Also agreed that there is a possibility that surviving fragments from the initial blast may have continued on to form craters that have not been found (that's actually what I was trying to say when I said "or some mixture in between the two may also be a possibility", but it came out wrong!), but I think it would be highly unlikely that any more detonations at altitude from these hypothetical surviving fragments would be capable of causing craters, seeing as the primary blast failed to do so, and remaining fragments would be a good deal smaller. If they did produce craters, it would probably be because they impacted the ground.

If that was the case, surviving fragments could easily have impacted many 10's of miles away from the where the epicenter of the main blast was, making them even harder to find in what is already an extremely hard to search area.

Also, as you say, if the object completely disintegrated, and failed to produce a crater from the initial blast, there is no way a crater could be produced after that - that I know of anyway.

The above reasoning is why many think that it was a comet rather than an asteroid that detonated. As I mentioned before, cometary material is not as dense/hard as asteroidal material, and it also impacts our atmosphere at higher velocities, so logic dictates that if no crater was found, it was probably cometary in origin.

An asteroid would likely be hard enough (we think anyway), that in a large detonation, at least some fragments would be big enough to make it to the ground.

The area is so vast, we may never know for sure if there are any craters/surviving meteorites out there, and therefore what was responsible.

Re the videos: Glad you enjoyed them. If you haven't seen any of those effects before with your own eyes, you need to try meteor observing! There are a few showers every year that I'd recommend.

If you want to give it a try, I usually post a thread with observing tips and info in the space exploration forum a week or two in advance of any major event, unless someone beats me to it! The next big shower, the Perseids, is a few weeks away now.