Dinosaur-killing space rock 'was a comet'

[The Straight Story]

The space rock that hit Earth 65m years ago and is widely implicated in the end of the dinosaurs was probably a speeding comet, US scientists say.

Researchers in New Hampshire suggest the 180km-wide Chicxulub crater in Mexico was carved out by a smaller object than previously thought.

Many scientists consider a large and relatively slow moving asteroid to have been the likely culprit.

Details were outlined at the 44th Lunar and Planetary Science Conference.

But other researchers were more cautious about the results.

"The overall aim of our project is to better characterise the impactor that produced the crater in the Yucatan peninsula [in Mexico]," Jason Moore, from Dartmouth College in New Hampshire, told BBC News.

http://www.bbc.co.uk/news/science-environment-21709229

Not to worry, bloomberg has a plan to ban comets

[rrneck]

1. But only the really big ones. nt

[The Straight Story]

2. True, two smallers ones might hit in the same place

Making an even bigger one. Maybe we should let him know

[NutmegYankee]

3. I think the hard part to overcome is Iridium.

The KT boundary has a high concentration of iridium, which is more common in asteroids.

[The Straight Story]

4. According to the article though Iridium quantity is less than previously thought

Maybe.

However, in the first part of their work, the team suggests that frequently quoted iridium values are incorrect. Using a comparison with another extraterrestrial element deposited in the impact - osmium - they were able to deduce that the collision deposited less debris than has previously been supposed.

The recalculated iridium value suggests a smaller body hit the Earth. So for the second part of their work, the researchers took the new figure and attempted to reconcile it with the known physical properties of the Chicxulub impact

[longship]

5. Apparently this is not yet a done deal.

The scientific community seems to be divided on meteor/comet. There's even a small minority that advocates against a single event.

Science usually sorts these things out eventually.

I find this to be very interesting claim which should be testable, so we may find out. But as others here have written, and what I've heard from people in this field, the single meteor is in the majority.

Now this is a new wrinkle.

[exboyfil]

6. 1/2 m*v^2

Lucifer's Hammer instead of The Hammer of God