When was the last time an asteroid hit Earth? Today! But it was almost definitely very small. Small asteroids and other tiny dust and particles bombard our planet daily. It’s the big ones we need to worry about. Scientists like Marina Brozovic are keeping their eyes to the sky.
Well, the answer depends on whether you’re asking about small or large impacts. Because Earth gets hit all the time. But luckily for us, the vast majority of these impactors are small and they just burn in the atmosphere.
The most significant fireball event in over 100 years occurred over Russia in 2013. We actually got hit by an asteroid that was the size of a small building and that one disintegrated about 20 kilometers above the city of Chelyabinsk. And it deposited a fair number of meteorites in the ground and I happen to have a piece of the Chelyabinsk impactor right here in my hand.
But what about big impacts, the ones that leave craters tens of kilometers wide and cause huge amounts of devastation?
We have to go far back in time for such an event and those old craters are not easy to spot because by now they’re heavily eroded, they’re filled with sediments, or they can be at the bottom of the ocean.
But to keep the long story short, small impacts, they happen all the time, especially given that about 15,000 tons of space dust hit Earth every year. And large impacts are rare, and we’re talking millions of years rare.
So, when was the last time an asteroid hit Earth? Probably today, but the odds are it was very small and just burned in the atmosphere. Explore more: https://www.nasa.gov/planetarydefense
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