Tunguska Event~1908

Incidentally, We human beings have created an explosion 10 times more powerful than the Tunguska event of 1908:

en.wikipedia.org/wiki/Tsar_Bomba

Only VERY recently has it been realised that a LAKE just offset from the epicentre of Tunguska DID NOT EXIST prior to 1908 .

I thought this area hadn't really been explored or mapped out fully prior to expeditions in the 1920's, so wouldn't it be hard to prove that the lake wasn't there before 1908?

Hey PJ,
there is a fine line yet a distinction between a comet and meteor. Meteor was used in a broad sense for many years as the cause of the Tunguska event because it was believed that if a comet was to hit Earth, we'd be obliterated. The difference between a meteor and a comet is the size (comet is bigger), and a comet expels matter when raised above a certain temperature. Prior to that, it is no more unlike an asteroid.

The comet idea was proposed because it would most likely have the properties to have exploded unlike a meteor: stored up gases and ice due to its size meant that upon hitting our atmosphere, it heated up very quickly coming from cold outer space, thus causing the ice, most of it in the form of dry ice (frozen carbon dioxide) to thaw. Dry ice sublimes directly from a solid to a gas when the temperature is raised, expanding in volume greatly and quickly, thus would have caused the comet to explode before impact on the ground.

The comet itself would have been quite small in comparison to those periodic ones we already know about.

Seanie.

My thoughts as well, lake was probably there to start with. The first expedition was nearly 19 years after the event. The environment is hostile and it's hard to reach. Asteroid or comet? almost certanly one of them......but exploding space craft. Black holes or micro galaxies, hhhhhmmmm.... if there are any micro galaxies and they have intellegent life, then, they must be very small minded people :roll:

signed:
very perturbed

Co Laois

A secondary crater can be caused by a "soft landing"...therefore not deep.

But Gasperini's team argues that the older deposits found by the Russians were already there when the explosion took place.

"We found evidence that only the topmost, one-meter-deep [three-foot-deep] layer of debris actually came from the inflowing river," Gasperini said.

"[The] deeper sediments are deposits that predate 1908. They were the target over which the impact took place, so Lake Cheko is only one century old."

Hey PJ,
there is a fine line yet a distinction between a comet and meteor. Meteor was used in a broad sense for many years as the cause of the Tunguska event because it was believed that if a comet was to hit Earth, we'd be obliterated. The difference between a meteor and a comet is the size (comet is bigger), and a comet expels matter when raised above a certain temperature. Prior to that, it is no more unlike an asteroid.

The comet idea was proposed because it would most likely have the properties to have exploded unlike a meteor: stored up gases and ice due to its size meant that upon hitting our atmosphere, it heated up very quickly coming from cold outer space, thus causing the ice, most of it in the form of dry ice (frozen carbon dioxide) to thaw. Dry ice sublimes directly from a solid to a gas when the temperature is raised, expanding in volume greatly and quickly, thus would have caused the comet to explode before impact on the ground.

The comet itself would have been quite small in comparison to those periodic ones we already know about.

Seanie.

Evidence points to the Tunguska impactor being part of the Beta Taurid meteor stream - fragments of Comet Encke (2P) which underwent a major split several thousand years ago. The Beta Taurids are a daytime stream, peaking on June 30 - we re-encounter the stream later in the year as the Taurids in October/November.