The Dinosaur-Killing Asteroid Was Worse Than We Thought

If you’re still on the fence about NASA, some other space agency or a coalition of governments banding together to develop a plan to destroy or deflect giant asteroids heading towards Earth … what’s wrong with you? How can you be against saving us from the fate of the dinosaurs? Maybe this will knock you over to the “whack those ‘roids back to the Kuiper Belt” side. A new study found that the impact of the Chicxulub asteroid some 66 million years ago stretched far beyond the Yucatan Peninsula in the Gulf of Mexico and its force was felt far longer than first thought.

"Our study picks up the story after the initial effects—after the earthquakes and the tsunamis and the broiling. We wanted to look at the long-term consequences of the amount of soot we think was created and what those consequences might have meant for the animals that were left."

The study, published in the Proceedings of the National Academy of Sciences, was led by National Center for Atmospheric Research (NCAR) scientist Charles Bardeen. He first points out what we already know – the Chicxulub asteroid’s impact sent huge tsunamis across the oceans, created earthquakes and volcanoes and vaporized rock that fell around the planet, sparking fires that cooked plants and animals far from the impact zone.

As bad as that sounds – along with all of the dinosaurs that were killed immediately – this was just the beginning. Using the Community Earth System Model (CESM), Bardeen and his team simulated the effect of the soot from those fires. They found that solar heat lifted the fine particle far higher into the atmosphere than first suspected, and the amount was enough to create a global barrier that completely blocked out the Sun … think eclipse with the moon stuck in the full blackout position for up to 18 months.

It gets worse. The fires killed most plant life and the darkness killed photosynthesis for the rest, so the next step down on the scale of life was phytoplankton, the microalgae that fill the oceans and feed so much of marine life. Unfortunately, phytoplankton themselves feed on … you guessed it … sunlight. Without it, most of the phytoplankton died off, upsetting the ecological balance of the oceans.

We’re here, so obviously, as bad as this sounds, it eventually ended. Surprisingly, the simulation showed that the clearing of the soot happened faster than expected. While the temperature at the planet’s surface dropped substantially -- 50 degrees Fahrenheit (28 degrees Celsius) over land and 20 degrees Fahrenheit (11 degrees Celsius) over water – the upper atmosphere got hot as the soot absorbed sunlight. That destroyed the ozone layer, which was replaced by water vapor. This huge reservoir of water eventually cooled, falling to Earth and washing the soot quickly from the atmosphere. Eventually, surviving seeds and phytoplankton revived and the planet came back to life.

Does this sound like a nuclear winter? Bardeen thinks so too.

"The amount of soot created by nuclear warfare would be much less than we saw during the K-Pg extinction. But the soot would still alter the climate in similar ways, cooling the surface and heating the upper atmosphere, with potentially devastating effects."

Wait a minute … I thought we were talking about killer asteroids, not killer nuclear wars. The devastation would be the same. Which do you think has a higher chance of occurring in your lifetime?