Forget Tsunamis: Asteroids Will Really Kill Us With UV Rays [Spf100000]

If a medium-sized asteroid lands within the ocean, tsunamis won’t be the one worry. Water vapor and sea salt thrown up by the impact could damage the ozone layer , leading to record levels of ultraviolet radiation which can threaten humanity.

” This means new issues you’ve with ocean impacts that folk hadn’t considered before,” says Brian Toon of the University of Colorado at Boulder, who was not enthusiastic about the work.

Elisabetta Pierazzo of the Planetary Science Institute in Tucson, Arizona, and associates used a world climate model to check how water vapor and sea salt thrown up from an impact will affect ozone levels for years after the event.

They involved in medium-sized asteroids, either 500 meters or 1 kilometer wide. To this point, 818 asteroids which might be a minimum of 1 km wide were discovered on orbits that might take them near to Earth .

Olympic Splash

These objects are on orbits that give them a really small probability of hitting Earth within the near future. However, estimates of the asteroid population suggest dozens more haven’t begun to be found, with unknown orbits that may intersect with the Earth.

To get a sense of the way much water may well be jettisoned into the atmosphere if these asteroids hit the ocean, the team modeled what would happen if they reached Earth’s atmosphere at a clip of 18 kilometers per second, a typical speed expected for a near-Earth object, and hit the ocean inside the northern hemisphere at a 45-degree angle.

As expected, the simulations showed that the larger, 1-km asteroid created the bigger splash, throwing 42 trillion kilograms of water and vapor  – enough to fill 16 million Olympic-sized swimming pools  – across a local more than 1000 kilometers wide and up to hundreds of kilometers above the Earth’s surface.

Engulfing Earth

Once within the atmosphere, the water, along side compounds containing chlorine and bromine from vaporized sea salts, destroyed ozone above the Earth’s atmosphere at a miles faster rate than it’s miles naturally created.

Some simulated impacts created depletions that were still felt across the total Earth a year later. ” It’s going to produce an ozone hole if you want to engulf the total Earth,” Pierazzo says.

The longest enduring and most severe depletion – a cut of more than 70 per cent in ozone levels – occurred over much of the northern hemisphere.

That’s a much bigger hole than the one who was above the South Pole in 1993, when Earth’s ozone layer was at its thinnest. The resulting ultraviolet-radiation levels could be higher than anywhere on this planet today, the team writes, presenting a new hazard for human civilization.

Dry Hits

While people could possibly protect themselves from the increased threat of sunburn, the bright UV light may also affect our food supply by damaging plants and the phytoplankton that represent the bottom of the ocean’s food chain. ” It is enough to truly cause problems for our civilization,” Pierazzo says.

Better understanding these effects could help us prepare within the event of an impact. For instance people could plant crops more immune to UV radiation, she adds.

Toon notes that impacts on land or shallow water may ultimately do more damage by kicking up dust that may significantly darken skies and inhibit plant growth. Pierazzo is now working on a model to assess how asteroids that hit dry land would affect the atmosphere.

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This post is tagged: colorado at boulder, near earth object, northern hemisphere, planetary science institute, ultraviolet radiation, university of colorado at boulder