A massive asteroid shower hit Earth and the moon 800 million years ago, study says

Over the course of Earth’s ancient history, our planet has been blitzed with a variety of foreign objects, some of which may have triggered major events shaping this place we now call home.

One such incident was a massive asteroid shower that bombarded both the Earth and the moon 800 million years ago, according to a new study.

During this monstrous shower, the asteroids that collided with Earth were much larger than the asteroid responsible for the extinction of the dinosaurs 66 million years ago, the researchers believe.

There is also evidence that an asteroid shower that impacted Earth 470 million years ago could have triggered a fall in sea level, icy conditions and contributed to biodiversity.

Fast-forward to 66 million years ago, and the Chicxulub impact crater, beneath the Yucatán Peninsula in Mexico and located offshore near the town of Chicxulub, formed when a large meteorite between 6.8 and 50.3 miles in diameter hit the Earth.

This newly discovered event, however, that occurred 800 million years ago involved an asteroid shower with a total mass between 30 to 60 times that of the asteroid that created Chicxulub.

This impact occurred prior to the Cryogenien period between 635 million and 720 million years ago, when Earth was covered in icy deserts. This was an era of great environmental and biological changes, the researchers said.

The study published Tuesday in the journal Nature Communications.

This suggests “that it is not strange that an asteroid shower 800 million years ago might have triggered the ice age, because a total mass flux 800 million years ago is 10 -100 times larger than those of Chicxulub impact and/or a meteoroid shower 470 million years ago,” said Kentaro Terada, lead study author and professor at Osaka University in Japan, in an email.

Lunar craters tell a tale

Due to erosion and resurfacing that occurs on Earth caused by volcanoes and other geologic processes, it’s hard for scientists to study how our planet was impacted in the past by asteroids and date when they occurred. Any impact craters to Earth prior to 600 million years ago, researchers believe, have been erased.

That’s why the moon, which is largely unchanged by erosion and weathering, has provided a fruitful alternate path for scientists to study craters and piece together the shared history of Earth and the moon.

In this new study, researchers used data collected by the Japanese Space Agency’s lunar orbiter Kaguya. Of the 59 craters on the moon that the researchers observed that had diameters larger than 12.4 miles or 20 kilometers in diameter, eight of the craters appear to have formed at the same time. This includes the Copernicus crater, which is 57.8 miles in diameter.

Apollo 12 astronauts, the second manned mission to land on the moon, sampled what they believed to be material ejected from the Copernicus crater when it was created. The samples, which they collected after landing on November 19, 1969, were dated to 800 million years old, according to NASA.

These eight craters likely formed simultaneously when an asteroid 62 miles or 100 kilometers in diameter was disrupted, impacting both Earth and the moon.

The setup for life on Earth?

During the asteroid shower, a large amount of phosphorus was delivered to Earth and “huge amounts of volatile elements such as carbon, nitrogen and water were supplied on the surface of the dry moon,” Terada said.

Phosphorus could have acted as a nutritional element to promote more algae growth on Earth, Terada said. It’s also possible that the arrival of elements via asteroids on Earth could have “influenced marine biogeochemical cycles, severe perturbations to Earth’s climate system and the emergence of animals,” the authors wrote in the study.

The asteroid Eulalia, a C-type asteroid in the asteroid belt between Mars and Jupiter, may have caused the asteroid shower, the researchers theorized. C-type asteroids contain carbon and are the most common asteroids in our solar system.

Eulalia may be the parent body of Ryugu, an asteroid explored and sampled by the Japanese Hayabusa2 mission. Samples from the asteroid are currently on their way back to Earth. Ryugu is a rubble pile asteroid shaped like a spinning top. A rubble pile asteroid is a grouping of rocks held together by gravity rather than single objects.

There are similarities between Eulalia and Ryugu’s surface that have suggested Ryugu may have once been part of Eulalia.

If something caused Eulalia to be disrupted, with fragments breaking off and forming separate asteroids, it’s possible that this created an asteroid shower that impacted Earth and the moon, while also creating near-Earth asteroids.

Terada, a member of first characterization team of Ryugu sample, will help date the samples returned from Ryugu, which could confirm its “parent” and determine if it was created during this asteroid disruption event.

“If we get the age of 800 million years from the Ryugu sample, I will be so excited,” Terada said.