Which rock killed the dinosaurs? The plot thickens
Scientists blame huge clashing asteroids for wiping out Earth's dinosaurs 65 million years ago.
September 20th, 2011
10:20 AM ET

Which rock killed the dinosaurs? The plot thickens

(CNN) - A 65-million-year-old murder mystery just got a bit more mysterious.

Which "family" of asteroids killed earth's dinosaurs?

New data from NASA's orbiting Wide-field Infrared Survey Explorer (WISE) throws doubt on a 2007 theory that blamed the death of the dinosaurs on fragments from an asteroid family called Baptistina, located between Mars and Jupiter.

Baptistina was a huge asteroid which crashed into another space rock millions of years ago, sending mountain-sized pieces flying in various directions.

Scientists had theorized one of those Baptistina fragments slammed into the Gulf of Mexico, triggering the end of Earth's reptile dynasty.

The earlier Baptistina estimates were off, says Lindley Johnson, program executive for the Near Earth Object (NEO) Observation Program at NASA Headquarters in Washington. "With infrared light, WISE was able to get a more accurate estimate."

Infrared light is electromagnetic radiation which humans sense as heat.

Reconstructing what really happened so many millions of years ago sounds very much like a script from a detective show.

Baptistina broke up into chunks about 15 million years before the dino-killing event, according to WISE data - which doesn't fit scientists' timeline.

In this crime of epoch proportions, that gives Baptistina a pretty good alibi.

Baptistina asteroids apparently were nowhere near the scene of the crime because it likely would have taken millions of years longer for them to drift into regions of space called resonances.

Resonances have gravitational forces created by Saturn and Jupiter which can shoot asteroids toward Earth - sort of like a pinball machine.

"It doesn’t completely rule it out as the source of the dino-killing culprit," says Amy Mainzer, who co-authored the WISE study. "But it does give theorists something new to think about."

What damaged the Baptistina theory?

Mainzer's team measured the size and amount of sunlight reflected from 120,000 asteroids, including 1,056 members of the Baptistina Family. From that data, they calculated how much time it took these asteroids to reach their current locations.

When Mainzer talks about the project, the conversation is sprinkled with vocabulary you might hear in a gangster flick or an episode of "Law & Order."

There are no "major suspects"  in the case, she says - now that Baptistina is in the clear. She plans to create "family trees," for thousands of asteroids - conjuring up images of FBI bulletin boards with photos of Mafia crime bosses connected by pieces of string.

"The first thing we want to do is look at the whole asteroid belt and really kind of go back to Square One and say, 'OK, what are the major families that we know about in the asteroid belt and which are the most likely culprits?'" she says.

Ironically, Mainzer's position in the project is labeled "principal investigator."

The asteroids in our solar system's main asteroid belt range in size from about 0.6 miles wide to 583 miles across. In fact, about once a year a car-sized asteroid strays toward earth and burns up while entering the earth's atmosphere, according to NASA.gov.

By the way, astronomers recently surprised Mainzer by naming an asteroid after her called "234750 Amymainzer."

"We did indeed observe it with WISE," she says. "It is a bit funny to have your namesake be a seven kilometer chunk of charcoal-dark rock!"

Fortunately, she jokes, asteroid Amymainzer poses no hazard to the Earth or its inhabitants.

What's next? Just like any good police investigation, you need to establish a credible timeline.

"We've got to go back in time as it were to reconstruct what happened using the huge amount of new information we now have thanks to WISE," says Mainzer.

"That's going to help point us in the right direction, I hope."

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Filed under: Dinosaurs • Discoveries • Hardware in Orbit • In Space • News
soundoff (806 Responses)
  1. Tammera Borders

    Effective suggestions. I'm going to write about this rather quickly.

    December 8, 2011 at 7:03 pm |
  2. Laronda Klimaszewski

    Thanks a bunch for sharing this with all folks you actually understand what you're speaking about! Bookmarked. Please also talk over with my web site =). We may have a link change arrangement among us!

    December 2, 2011 at 7:39 am |
  3. 2011 2011

    My brother recommended me to this blog. He was absolutely right. This post really meets my expectations. It's hard to imagine how much time I spent on that information. Thanks Amelia

    November 17, 2011 at 7:22 am |
  4. steveinmo

    What killed the dinosaurs? The flood.

    October 11, 2011 at 12:40 am |
    • fimeilleur

      Ummmm no...

      October 11, 2011 at 4:44 am |
  5. Peter

    Amy Mainzer is the prettiest PhD scientist I've ever seen.

    OK sorry guys, I'm off topic. Carry on with your religious war.

    October 5, 2011 at 4:34 pm |
  6. What The????

    Is this article about some god called asteroid? or the death penalty of an asteroid? or is this about a flood somewhere in the universe caused by an asteroid. Why do people always confuse their comments and bring gods in science news. If religion is their call, fine, go to church and be a good worshiper.
    I love science, it is always open for discusion and it is very enlightning.

    September 26, 2011 at 3:08 pm |
  7. What The????

    In the island of Sodor, the great flood, Muhamed Ali, and all those have nothing to do with this article

    September 26, 2011 at 2:57 pm |
  8. Miguel Alonzo

    I am confused, The article was about asteroids, or was it about a god called asteroid, or the death penalty of an asteroid, or the Bible or the Koran have a god called asteroid??????
    I really do not understand how religion, death penalty or anyother subject is being mixed in this article.
    Somebody help me understand why people do not understand the article.

    September 26, 2011 at 2:53 pm |
    • Bucko G

      It's called a "rambling conversation", Miguel. Which is good because it opens viewpoints we ourselves may have not considered! Now if we were discussing mathematical equations, it might be an entirely more rigid conversation.

      September 27, 2011 at 12:32 am |
  9. Ron

    While there is increasing evidence of a large asteroid impact 65 million years ago, this had absolutely nothing to do with dinosaur extinction.

    First of all, there is a very clear geologic layer associated with the asteroid strike, called the iridium layer. There are no signs whatsoever of mass extinction in or near this layer.

    Second, all of the large dinosaurs were already extinct long before this asteroid impact. T. rex, triceratops, stegosaurus and the brontosaurus had already been extinct for many millions of years, died off from gigantism and over specialization.

    Third, the dinosaur isn’t extinct. Not only did mammals flourish during the 15 million year period after the asteroid strike, but so did many species of reptile and dinosaur. Modern turtles, snakes and birds are the descendents from these post-asteroid evolutionary success stories. And if you don’t think a bird is a dinosaur, just take a good look at their feet.

    September 26, 2011 at 6:08 am |
  10. yahmez

    I am sick of godtards spamming the forums of every science article. This article was about Asteriods.

    September 23, 2011 at 4:54 am |
  11. Cool

    This is cool. A great topic for my current events assignment

    September 22, 2011 at 4:27 pm |
    • Cool

      How old are you???

      September 22, 2011 at 4:28 pm |
  12. Muhammad


    September 22, 2011 at 10:31 am |
  13. Muhammad

    Prophet Muhammad.

    September 22, 2011 at 10:31 am |
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