During its history, the Earth has faced several ice ages during which temperatures dropped drastically, and the last of those ages ended about 12,<> years ago, and we are now living in what scientists call an "interglacial" period with moderate temperatures.

Snowball hypothesis

But the most striking of these ice ages occurred about 635 million years ago, and scientists describe it as one of the harshest cold waves in the history of the Earth, during which temperatures in some areas reached less than 100 below zero, to the point that ice covered the entire globe from the North Pole to the South Pole.

This phenomenon was called the "snowball earth hypothesis", a term coined by the geologist from the Caltech Institute in the United States of America Joseph Kirschvink in the eighties of the last century, and in that period scientists doubted the validity of that hypothesis, but with time and the meeting of evidence from earth and climate sciences found the interest of the majority of scientists.

With time and the combination of evidence from earth and climate sciences, the "snowball hypothesis" found the interest of the majority of scientists (Getty Images)

In this regard, the researchers believe that the Earth's entry into an ice bout of such cruelty was related to the low level of greenhouse gases in the atmosphere (such as carbon dioxide), to the extent that it caused temperatures to drop drastically.

But the drop in temperatures led to the formation of large areas of ice sheets that reflected sunlight and did not absorb it as the planet normally does, causing more temperature drops, and consequently more ice.

Was it really an ice ball?

Scientists agree that this period saw the largest accumulation of ice in the history of the Earth, but it may not have been a complete sphere, but almost complete.

According to a study recently published in the journal Nature Communications, new evidence collected in the eastern Xinongjia forest area of China's Hubei province suggests that the land was not completely frozen, but there were patches of open water in some shallow seas in mid-latitudes.

The mid-latitudes are located between the Tropic of Cancer and the Arctic Circle and between the Tropic of Capricorn and the Antarctic Circle.

A previous NASA study in 2015 suggested that Earth may not have been a completely snowball (Shutterstock)

According to the study, which was published on the fourth of April, scientists reached these results based on geological samples dating back to that period of Earth's history, where this team found that species of algae that lived at the bottom of those seas 600 million years ago were of the type that needs sunlight to convert water and carbon dioxide into energy through photosynthesis, otherwise they would have become extinct, and consequently they lived in the bottom of open seas Not covered with ice.

This is consistent with the findings of an earlier study involving NASA in 2015 that also suggested that Earth may not have been a complete snowball, but some areas of it contained swathes of water with masses of ice in the middle.

Will the snowball come back?

Until now, scientists believe that the wave of the "snowball" has not hit the Earth only once, but twice or 3 times, and there is nothing to prevent this phenomenon from happening again, especially as it is also related to disturbances in the orbit and inclination of the planet Earth that are still occurring until now.

However, the researchers believe it won't happen in the next several tens of thousands of years.

If the Earth were to enter the snowball phase one day, life would collapse drastically, as there would be widespread extinctions and very little life would be left to adapt to those changes.

For humans, advanced technologies may help protect them, but if that were to happen now, it could lead to the extinction of the human race or at least reduce our numbers to very small proportions.