PDA

View Full Version : Discussion: Book Review: The Tunguska Fireball



Fraser
2005-Aug-29, 06:31 PM
SUMMARY: Dream up an hypothesis and envelop it with supporting evidence and you're well on the way to contributing to the scientific process. Given that nature surrounds us with a veritable nirvana of wonders, this reasoning process serves us well. A case in point - many years ago, bright flashes in the sky, followed by powerful explosions, teased our imaginations and brain power then and today. Surendra Verma in his book The Tunguska Fireball plays part detective, part historian and part scientist in presenting some highly speculative yet nevertheless plausible reasons for this natural wonder. Scientific processes by their nature are based on fact, but read this and you can judge for yourself how close imagination is its parody.

View full article (http://www.universetoday.com/am/publish/book_review_tunguska_fireball.html)

What do you think about this story? Post your comments below.

antoniseb
2005-Aug-29, 06:53 PM
Here's a bit of trivia that I do not know the answer to.

The Tunguska event reported happened about 7 in the morning on June 30, 1908. But this happened in Russia where they were still using the Julian Calendar. So was the date June 30 Gregorian, or July 10 Gregorian?

Wikipedia seems to say it was June 30 Gregorian, so the locals must have thoght it was June 19th. Does anyone have some record of the event (like British seismic data) that would say which it was? If it were July 10 Gregorian, that would place it at the peak of the Pegasid meteor shower that year.

jhwegener
2005-Aug-29, 07:01 PM
Might there have been similar events, perhaps even in the last 100 years or so, which passed relatively unnoticed?
My reason for such a question, which may at first seem unfounded:
Though the event happened in a sparsely populated area, it was over land. We should expect most impacts over sea, since most of earths surface is sea. And a significant part is high arctic too. Would there be anything to see afterwards if something fell in such places? (In Tunguska and surroundings a lot of destruction visible after the event).

antoniseb
2005-Aug-29, 07:19 PM
Originally posted by jhwegener@Aug 29 2005, 07:01 PM
Might there have been similar events, perhaps even in the last 100 years or so, which passed relatively unnoticed?
Yes, there may have been, and there are some efforts in place to study such things, including some that have detected smaller such events on a regular basis through the detection of very low frequency sound waves and other such tools.

The likelyhood of an event of this size going unnoticed in the last twenty years is very small, since we increasingly have satellite observation covering most of the planet.

BillyJay
2005-Aug-30, 04:08 PM
:ph34r: The methane explosion sounds good to me, the area was a swamp.

jhwegener
2005-Aug-30, 06:28 PM
Is anybody searching for underwater meteorites, and perhaps other cosmic influence on earth (like supernovae eruptions etcetera)? I have heard that the Arctics are preferred, but perhaps one might find some different ones under water?
After all the physics of a big body hitting hard surface of earth, and hitting water may be different, so because it explode in the one case, does not necessarily imply the same in the second. And what about very high parts of the earth, like the tibetan plateau. Perhaps more meteorites will survive the thin atmosphere?

rocketblair
2005-Aug-31, 03:30 AM
Originally posted by antoniseb@Aug 29 2005, 06:53 PM
The Tunguska event reported happened about 7 in the morning on June 30, 1908. But this happened in Russia where they were still using the Julian Calendar. So was the date June 30 Gregorian, or July 10 Gregorian?


Several articles I have read about the event include pictures of the horizon with a "strange glow" that was seen from european countries who were no doubt using the Gregorian calander, and they give the date as June 30th, 1908. The locals, many years later told stories of being knocked off their feet by the blast wave. Even if the event didn't coincide with the peak of the meteor shower, it's possible a large fragment from that stream was the cause.

Fireball
2005-Aug-31, 04:33 AM
June 30 Gregorian