Never Fear, an Oceanic Asteroid Impact Wouldn’t Cause Apocalyptic Tidal Waves
But it could have long-term effects on the climate
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Fans of apocalyptic disaster movies are probably familiar with the scene: a rogue asteroid spiraling in from outer space lands in the middle of the ocean, triggering massive tidal waves and throwing the world into chaos. But when a group of scientists decided to put this scenario to the test, they found that a real life Deep Impact would have very different results, Maddie Stone reports for Gizmodo.
A team of data scientists at the Los Alamos National Laboratory (LANL) modeled what would happen if an asteroid struck Earth's vast oceans. They found that while one might expect a giant hunk of space rock to trigger enormous, Hollywood-worthy tsunamis, big waves aren’t the problem to fear.
The waves themselves would likely quickly dissipate out in the ocean. Imagine dropping a rock into a lake—the first ripples might be large, but as they spread out they get smaller and smaller. The same thing would happen in the case of an asteroid or comet impact, Stone reports, but it would still have a larger effect than dropping a pebble into a pond.
But while waves may not be the biggest threat from an asteroid impact, that doesn’t mean it wouldn’t affect our planet.
“The most significant effect of an impact into the ocean is the injection of water vapor into the stratosphere, with possible climate effects,” study leader Galen Gisler said while presenting his results at the American Geophysical Union meeting this week, Stone reports.
An asteroid impact in the ocean could vaporize hundreds of megatons of water, much of which would end up in the atmosphere. While a fair amount of that water vapor would likely turn into rain, some of it could linger slightly higher in what is known as the stratosphere. "And because it’s a potent greenhouse gas, this could have a major effect on our climate," writes Stone.
Of course, this isn’t the only scenario possible. Many asteroids never make it to the ground, and the water would absorb much of the blast from even a fairly large asteroid exploding, Robinson Meyer reports for The Atlantic.
While that wouldn’t harm human civilization too much, an explosion over a coastal city would be a very different thing. Either way, it might not be a bad idea to figure out ways to stop space rocks before they get too close.