Our ancestors once faced a brutal period when Earth was suddenly stripped of the protection of the heliosphere.
According to Sci-News, a new study reveals that a cold cloud between the stars once invaded the Solar System, causing Earth to be “cast out” from the protective embrace of its parent star.
This event occurred about 2 million years ago, or at most 3 million years ago, based on calculations by scientists from Boston University (UK), Harvard University, and Johns Hopkins University (USA).
Did Earth become a “lonely entity”, no longer protected by its parent star? – (AI Image: Anh Thu)
In recent years, several NASA spacecraft have achieved breakthroughs by escaping the Solar System and entering interstellar space, thus leaving behind the so-called heliosphere.
The heliosphere is a gigantic “bubble” that envelops the Sun and its planets, along with some outer structures including dwarf planets like Pluto and other celestial bodies beyond the orbit of Neptune.
The heliosphere is formed from plasma and the Sun’s magnetic field, acting as a cocoon that protects all objects within from the harsh cosmic radiation from outside.
This protection, combined with Earth’s own magnetic field, has been crucial in supporting the development of life and stabilizing planetary evolutionary processes over many years.
However, 2 million years ago, during the attack from the cold cloud identified by British and American scientists, Earth was stripped of its heliospheric protection.
According to a paper published in Nature Astronomy, the authors used complex computer models to visualize the position of the Sun 2 million years ago, the state of the heliosphere, and the objects within it.
They also mapped the trajectory of the Local Cold Cloud System, a series of large, dense, very cold clouds primarily composed of hydrogen atoms, drifting between the stars.
Their simulations indicate that one of the clouds near the end of this cloud chain, named the Local Lynx Cloud, may have collided with the heliosphere.
This collision compressed the heliosphere, reducing it from a vast structure beyond the orbit of Pluto to a tiny bubble surrounding the central region.
Unfortunately, Earth fell outside the radius of this tiny bubble.
This result aligns with geological evidence showing an increase in iron-60 and plutonium-244 isotopes in the oceans, on the Moon, in Antarctic snow, and in ice cores from that period.
These isotopes indicate that Earth was “bathed” in harsh radiation from the interstellar environment and may have experienced a severe ice age before the cloud drifted away and the heliosphere once again enveloped everything.
“Local Lynx may have continuously blocked the heliosphere for several hundred years to a million years, depending on the size of the cloud,” said Professor Avi Loeb from Harvard University, a member of the research team.
It is certain that life on Earth faced difficulties at that time, including our ancestral species. However, this harshness may also have driven evolution.
Two million years ago marked the emergence of the Homo erectus, or “upright man,” believed to be the first species to walk upright like we do today and to use tools, forming societal structures.
Professor Loeb also predicts that the event of “falling” out of the heliosphere could happen again in about a million years.
