Double meteorite strike 'caused dinosaur extinction'

The dinosaurs were wiped out 65 million years ago by at least two meteorite impacts, rather than a single strike, a new study suggests.

Previously, scientists had identified a huge impact crater in the Gulf of Mexico as the event that spelled doom for the dinosaurs.

Now evidence for a second impact in the Ukraine has been uncovered.

This raises the possibility that the Earth may have been bombarded by a whole shower of meteorites.

Well if one didn't do it, there's always room for another. We all know about the Chicxulub Crater in the Gulf of Mexico is the site of the originally documented impact.

But now apparently a second crater has been confirmed to be the site of a second meteor strike. From soil core samples and sediment analysis it would appear that ferns colonised the area immediately after impact.

Ferns apparently have the amazing ability to regroup and 'rise from the ashes' so to speak, which of course suggests that there was a large impact event around this time, allowing them to flourish.

This of course results in fern pollen dominating the surrounding sediment, which is known as a "fern spike." In the case of the newly discovered Boltysh Crater in the Ukraine there were two separate incidences of "fern spikes" within one meter of each other. Which of course gives the impression of two devastating hits. The latter belonging to that of the Chicxulub impact.

Rather than being wiped out by a single hit, the researchers think that dinosaurs may have fallen victim to a meteorite shower raining down over thousands of years.

Well IMO the dinosaurs had a good run. But does this mean we can likely expect a similar situation should we ever be faced with an incoming object?

Like buses you wait for one then two come at once!

The original article;

www.bbc.co.uk...

Apologies if already posted but I didn't find anything in the search.

[edit on 27-8-2010 by Big Raging Loner]
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[edit on 28/8/2010 by ArMaP]

Interesting find, thanks. I wasn't aware of the Ukraine impact.

Originally posted by Big Raging Loner
Well IMO the dinosaurs had a good run. But does this mean we can likely expect a similar situation should we ever be faced with an incoming object?

It's not a question of "IF" there will be another big impact, it's only a question of "WHEN". Astronomers are searching the skies for Earth crossing objects but right now there aren't any known extinction impacts pending within the next century or so. But:

www.tulane.edu...

In 1993 and 1998 the U.S. Congress held hearings to study the hazards associated with NEOs. In 1997 NASA formulated a plan to find 90% of the NEOs larger than 1 km in diameter within the next 10 years. Still, at the current rate at which these objects are discovered and tracked, it will take over 100 years to achieve the 90% objective. Currently NASA spends about $3 million per year on this survey of space objects. How does this compare with funding for mitigation of less likely, but more local hazards in the Table of odds shown above?

That's a little dated, if anyone has more updated information, please post it.

But I suspect what can happen is, say, a collision of some asteroids in the asteroid belt could send one or both objects outside the belt, then we could have a couple of new objects to deal with and one of those might hit Earth, eventually. So those wouldn't even show up in our sky survey until after the collision takes place.

Large impacts are rare events, but they kill so many creatures when they happen, that the odds of getting killed by a meteor are larger than we might guess. According to this source it's about the same as the odds of dying in a plane crash, which sounds about right (though some of their other figures may be off):

Risk - It is estimated that in any given year the odds that you will die from an impact of an asteroid or comet are about 1 in 20,000. The table below shows the odds of dying in the U.S. from various other causes. Although 1 in 20,000 seem like long odds, you have about the same odds of dying in an airplane crash, and somewhat less risk of dying from other natural disasters likes floods and tornadoes. In fact the odds of dying from an impact event are much better than the odds of winning the lottery.

[edit on 28-8-2010 by Arbitrageur]

reply to post by Arbitrageur


Thanks for the awesome reply! I had heard they can only check a small percentage of the sky and actively monitor it.

So I suppose it's entirely possible for something to get a little too close for comfort. Depending on the size the asteroid wouldn't necessarily need to connect just pass by to create havoc.

Astronomers are searching the skies for Earth crossing objects but right now there aren't any known extinction impacts pending within the next century or so.

This is good to know

I've heard it said that the number of people who track NEOs could basically just about staff a small McDonalds....so not exactly a lot of people...

I sure hope they are good at what they do.

Even still though, if something WAS on the way, not so sure there is much we could do about it...except hunker down and try to live in the aftermath (if we survive the impact)...