A group of American scientists has discovered traces of an explosion caused by a large asteroid on the ocean floor, with debris drifting to Earth that may have cooled the planet’s climate 8.3 million years ago.
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Asteroid Toutatis (Photo: Astrosurf) |
Researchers at the California Institute of Technology (Caltech) noted that at the end of the Miocene epoch, sediment layers on the ocean floor exhibited helium-3 concentrations four times higher than normal.
Helium-3 is an isotope of helium, a gas that is very common in the universe and is often used to inflate balloons at fairs. The helium-3 atom consists of two protons and one neutron, while normal helium (He-4) only contains one proton and one neutron.
Helium-3 is extremely rare on Earth, but cosmic dust that falls to our planet has been supplemented with He-3 during its journey by solar winds. Consequently, this isotope serves as a reliable marker for the intensity of interplanetary dust showers that fall on Earth.
Studies of sediment layers in the Indian and Atlantic Oceans demonstrate that helium-3 concentrations peaked twice, 35 million years ago and 8.3 million years ago. While the first peak was attributed to impacts from celestial bodies, the second aligns with the explosion of a large asteroid measuring over 150 kilometers in diameter. The largest debris now forms the Veritas asteroid group, located about 300 million kilometers from Earth.
Nearly half of the mass of this asteroid may have been ejected as dust, with a portion landing on our planet. Currently, 5 tons of this dust continues to fall to Earth each year.
Periods of cooling climate are often explained by the presence of dust particles in the atmosphere—originating from volcanic eruptions, meteorite impacts, or even pollution—that darken the atmosphere and reflect solar radiation.
