Showing posts with label asteroids. Show all posts
Showing posts with label asteroids. Show all posts

Monday, May 11, 2009

Icelandic Asteroid

I recently noted that another writer has recently mentioned Iceland as a prospective asteroid impact zone.

When I first investigated the conjecture several years ago that the crust had shifted thirty degrees, I went looking for a lever in the way of a significant asteroid impact. I had no reason to also postulate human intervention as I have since come to appreciate. That inevitably led me straight away to Iceland.

It was in the right location and was certainly big enough and perhaps even small enough. Importantly, there were no other recent geological events that came close to matching it. And a quick check of geological reports indicated an extraordinary youth to the rocks on Iceland. The closest estimate that I came across was well under 100,000 years. Anyone familiar with the travails of geological aging would immediately rewrite that figure as 100,000 plus or minus 500,000 or so. The island has no old rocks.

That is impossible in practice because older rocks will get themselves cut off and isolated and then exposed for investigation. So if older rocks fail to exist, then they never existed. Some will want to argue the point, but the evidence to date is lack of evidence and in geology lack of evidence really is evidence. I become a little deaf when a clear cut Triassic is been argued as part of a Precambrian suite for which there is no other evidence. In geology, you really do come from Missouri.

Iceland was formed yesterday in terms of geology.

What disturbed me at the time was that the structure was sitting dead center on the mid Atlantic rift and was surely generated by the rift. It would be an astounding coincidence for an errant asteroid to hit such a target like that and I had no reason five years ago to conjecture human intervention. In fact, it was clear negative evidence of an asteroid event. Needless to say I was hesitant in forwarding Iceland, but as the only available prospect, I still wrote it up. Sometimes you have to go with what you have and that we had something at all was compelling.

Accepting the human intervention postulate changes everything and also justifies the choice of impact zone. An impact centered on the mid Atlantic ridge is on a zone of weakness and derivative shock waves will propagate along the ridge. The crust will also bend easiest here and deliver maximum energy to the slip plane itself. (read my earlier work on this).

The incoming asteroid was on a flat shallow trajectory that likely sent ample debris into the ice cap and exploded a lot of the cap itself producing the telltales that do exist.

It makes a pretty picture and also suggests extreme tsunami events hitting the European coast. The sea level was 300 feet lower though, but the worst of it should still have left traces.

In the event if you ever wanted an energy source able to produce forty days of rain if not decades of rain this surely does the trick. Of course, it took centuries for sea levels to rise as a result. However we certainly have a package of events that sort of conform to the ancient legends.

The problem is that right now no one is looking for confirmation in the evidence and a lot of good evidence has been explained away as much as possible. Piecing a good geological support structure together is not a minor enterprise and wrong opinions hang around for many decades.

The best evidence would be to discover unambiguous multimillion year old rocks on Iceland that is not a remnant from underlying ridge geology. That would possibly eliminate this conjecture. Otherwise, it is time to catalog possible tsunami remnants throughout Western Europe and see if it all hangs together. Certainly supporting anomalies have already been noted and commented on.

Tuesday, March 10, 2009

A Close Shave

This is a few days old but it is a reminder of just how busy space is. That the odds for a seriously damaging impact are low means nothing if you are at ground zero.

We are fortunate that geological events are proving to have a history of repetition and preliminary activity. It has become possible to establish warning systems and rapid reaction response systems. That we have not done enough yet is a given, but the cost is dropping and the expertise is rising. At some point, I expect that a satellite will pick up all the preliminary noise and trigger warnings based on excellent modeling.

We are a long way from doing the same for incoming asteroids and comets. Certainly what we know of their history and energy, we ultimately will. Just not with our current level of knowledge and expertise.

What just blew by would have been a very big atomic bomb in terms of energy release. It is still quite smallish. Anyway, the bad ones can be expected to scour a region at least fifty miles across through shock.

Seriously bigger than that, and we start hammering the entire globe. The blast that hit us almost thirteen thousand years ago in the northern ice cap released energy that appears to have been fully felt throughout the rest of North America and must have been also felt more survivably everywhere else.

The only way we can protect ourselves from these events will be to disturb their orbits at aphelion, likely way out in the Kuiper belt. We are a long ways away from that.

Space rock gives Earth a close shave

by Staff Writers

Paris (AFP) March 3, 2009

An asteroid of a similar size to a rock that exploded above Siberia in 1908 with the force of a thousand atomic bombs whizzed close past Earth on Monday, astronomers said on Tuesday.

2009 DD45, estimated to be between 21 and 47 meters (68 and 152 feet) across, raced by at 1344 GMT on Monday, the Planetary Society (http://planetary.org/news/2009/0302_Space_Rock_Swoops_by_Earth.html) and astronomers' blogs reported.

The gap was just 72,000 kilometers (44,750 miles), or a fifth of the distance between Earth and the Moon and only twice the height of satellites in geosynchronous orbit, the website space.com said.

The estimated size is similar to that of an asteroid or comet that exploded above Tunguska, Siberia, on June 30 2008, flattening 80 million trees in a swathe of more than 2,000 square kilometres (800 square miles).2009 DD45 was spotted last Saturday by astronomers at the Siding Spring Survey in Australia, and was verified by the International Astronomical Union's Minor Planet Centre (MPC), which catalogues Solar System rocks