Scientists underestimated the risk of giant asteroids colliding with Earth
(ORDO NEWS) — James Garvin, chief scientist at NASA‘s Goddard Space Flight Center, believes we have most likely misinterpreted the signatures of some of the more serious asteroid impacts that have occurred over the past million years.
If the scientist is right, then the chances of being hit by a large asteroid could be higher than scientists predict.
The most famous of all the collisions that wiped out the dinosaurs took place 66 million years ago. Then a cosmic body 10 kilometers in size punched a hole in the earth’s crust near the modern Yucatan Peninsula.
It should be understood that much smaller impacts could still kick up enough dust to cover the planet and potentially lead to years of starvation.
According to some estimates, kilometer-wide asteroids hit the Earth‘s surface about every 600,000 years.
Unfortunately, over time, it is more difficult to assess the consequences of an ancient collision, thanks to the dynamic winds, water and tectonics of the Earth, which change its surface.
Even later events can be difficult to interpret due to dust accumulation and biology.
Garvin and his team studied recent high-resolution satellite imagery to get a closer look at the weathered remains of some of the largest impact craters that have formed over the past million years.
Based on their analysis, a number of these craters have faint rings outside of what is generally thought to be their outer edges, effectively making them larger than previously thought.
For example, a trough approximately 12-14 kilometers wide in Kazakhstan, called the Zhaminshin, is believed to have been formed by a meteorite 200 to 400 meters in diameter that hit Earth about 90,000 years ago – the most recent impact that potentially triggered a “nuclear winter”.
However, based on the new analysis, this already massive event could have been even more catastrophic, creating a crater that is actually closer to 30 kilometers in diameter.
The rim diameters of three other large craters have also been recalculated, and they have all doubled or tripled in size.
The consequences are serious, suggesting that kilometer-sized objects fall from above every few tens of thousands of years.
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