Scientists believe the Sun’s location in space may influence Earth’s history more than previously thought.
The authors of a new study published in the journal Nature Astronomy believe that a very long period of significant temperature drop occurred on Earth due to the solar system’s collision with an interstellar cloud. Phys.
About 2 million years ago, Earth began an era of long ice ages, which ended in about 12,000 years. Scientists believe these multiple ice ages may have been caused by changes in the planet’s tilt or rotation, shifting plates, volcanic eruptions and high levels of carbon dioxide in the atmosphere. The authors of the new study believe that the Earth did not freeze due to environmental changes on the planet, but due to an external factor.
Astrophysicists have found evidence that the solar system collided with a very dense interstellar cloud about 2 million years ago, affecting the heliosphere. So scientists say the Sun’s location in the Milky Way may influence Earth’s history more than previously thought.
The solar system is surrounded by a giant plasma bubble called the heliosphere. Its existence is constantly supported by streams of solar particles or the solar wind coming from the sun. The heliosphere protects the Earth and its inhabitants from harmful galactic radiation.
The authors believe that the collision with the interstellar cloud caused the heliosphere to contract and Earth and other planets of the solar system were briefly outside the heliosphere’s influence. That is, this event affected the Earth’s climate, leading to cooling. The way the sun moves through space could affect the chemical composition of our planet’s atmosphere, scientists say.
Using computer models, astrophysicists have discovered where the Sun and the heliosphere were 2 million years ago. Scientists also studied the movement of several large, cold, dense interstellar clouds, which are composed mainly of hydrogen.
As modeling shows, the collision of one of the interstellar clouds with the heliosphere could have resulted in Earth being exposed to the influence of the interstellar medium filled with various chemical elements, including iron and plutonium.
Due to the fact that the Earth was not protected, many radioactive elements easily reached the planet. These data are consistent with geological records showing elevated levels of iron-60 and plutonium-244 isotopes in Earth’s ocean and ice about 2 million years ago.
As soon as the interstellar cloud ceased to affect the heliosphere, it again surrounded all the planets of the solar system with its protection. Scientists suggest a similar collision could happen again in 1 to 2 million years.
