Research suggests that the clouds of interstellar space caused the ice age

The Pleistocene epoch—with its ice ages, woolly mammoths, and Neanderthals—still looms large in Earth’s rearview mirror, having ended just 12,000 years ago. Now, a team of researchers claim that those hundreds of thousands of years of our planet’s history may have been cold because of a cloud in space that briefly removed Earth from the safety of the Sun’s warm glow.

Researchers suggest that, about two million years ago, an interstellar cloud interfered with the solar system in such a way that Earth and the other planets were briefly outside the Sun. heliosphere, the bubble of charged particles from our host star that today forms an amorphous envelope around the system. Their research was published today in Nature Astronomy.

“This paper is the first to quantitatively show that there was an encounter between the sun and something outside the solar system that would have affected Earth’s climate,” said Merav Opher, an astrophysicist at Boston University and lead author of the study. in an email. at Gizmodo. Opher added that the team is “still trying to quantify it with modern climate models,” but with an increase in hydrogen and dust “Earth would have entered an ice age.”

The Opher team modeled data from HI4PI survey and found that our solar system may have passed through the Local Cold Cloud Belt in the constellation Lynx between 2 and 3 million years ago. The Pleistocene began about 2.6 million years ago. It’s not possible to say for sure whether such cold clouds could have catalyzed an ice age, the release noted, but more evidence of cloud interference with the heliosphere could shed light on the kind of impacts it would have on Earth.

The team’s model found that, in such a passage, the heliosphere surrounding Earth and its neighboring planets would shrink to about 0.22 AU, or less than a quarter the size of Earth’s distance from the Sun. To put it into perspective, ESA Assessments that the closest boundary of the heliosphere today is about 100 AU from the Sun, about twice as far as the Kuiper Belt.

Outside the heliosphere, Earth would have been exposed to iron and plutonium in the interstellar medium, the team posited. Their timeline coincides with an increase in the amount of plutonium-244 and iron-60, two isotopes of the respective elements known to occur from events in space, in Antarctic snow, deep sea sediments and samples from the Moon. And as Opher added, samples from Mars, if tested in the same way as lunar and terrestrial samples, could reveal a similar spike in the iron isotope around 2 to 3 million years ago.

The heliosphere could have been trapped for anywhere from just a few hundred years to a million years, said Opher at a Boston university. RELEASE. As the Earth and other planets left the cloud, the heliosphere returned.

To verify their results, the team is now trying to understand the position of the Sun around seven million years ago, where there is evidence for another peak in the ratios of plutonium-244 and iron-60 in terrestrial ice and sediments. They’re trying to create a digital twin — essentially, a high-tech model — of the heliosphere to better model the kinds of conditions our solar system might have been subject to. Finally, additional data from ESA’s Gaia mission may further help the team to establish the exact position of the Sun at that moment in the ancient past.

According to the Utah Geological Survey, at least five major ice ages have occurred on Earth. The first occurred over 2 billion years ago and the most recent began about 3 million years ago. According to NASA, the ice age may have started due to a combination of factors, including changes in the Earth’s orbit, low amounts of energy from the Sun, the composition of the atmosphere, changes in ocean currents and even volcanoes, which were responsible for year without summer. In other words, we don’t want theories explaining Earth’s various cold moments, and the jury is out on how Earth outside the heliosphere could have catalyzed such a cold period.

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