Baptistina asteroid family didn’t kill the dinosaurs

NASA’s Wide-field Infrared Survey Explorer (WISE) was launched in December 2009 with the aim of surveying the entire sky for coolest and darkest regions of space in the infrared. Amongst the objects WISE is searching for include near-Earth asteroids and comets. WISE will determine  the orbits, size and number of asteroids and comets which will help determine the likelihood of the Earth being a target.

In 2007, William Bottke and collaborators published an article in Nature suggesting that the collisional break-up of the 170-m Baptistina asteroid approximately 160 million years ago produced the Baptistina asteroid family (BAF), and that over time dynamical processes involving the Yarkovsky/YORP effects put some of the BAFs on Earth crossing orbits. Bottke et al. (2007) argued that this shower of asteroids lead to the extinction of the dinosaurs 65 million years ago.

Scientist from the WISE team have now confirmed asteroids from the BAF were not responsible for the extinction.  The infrared observations of Near Earth Object WISE project (NEOWISE) are more accurate in determining sizes than previous optical estimates, since the infrared light comes from the asteroid itself while optical light is reflected sunlight and to determine sizes one needs to know about the reflectivity of the object. NEOWISE has already cataloged 157,000 asteroids, including  1,056 members of the BAF. Joseph Masiero and collaborators have determined the original Baptistina asteroid break-up occurred closer to 80 million years ago, which does not allow enough time for the BAF to reach the resonance spot required to fling them towards the Earth.  Combining the infrared data with optical data provides a much better estimate of the reflectivity, which  the NEOWISE team hopes will help them determine the composition of asteroid belt objects and hence better characterise asteroid family groups.

For more information, see

[Post by Catarina Ubach & Sarah Maddison]

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1 Response to Baptistina asteroid family didn’t kill the dinosaurs

  1. rob hunt says:

    Dr Heidi Hammel (Executive Vice President of AURA) recently gave a lecture at ANU about her involvement in three, once-in-a-lifetime events involving solar system collisions and Jupiter, as well as a summary of NEAs and Earth-collisions. She quite reasonably ends her talk with a “Should I be worried?” section, in which she concludes: “No, but buckle up in your car on the way home”. The science is as interesting as the sociological phenomenon of NEA-strike fear.

    Rob 😉


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