- NASA research links the Sun’s journey through space to Earth’s ancient climate changes
- The heliosphere shields Earth from galactic radiation and varies in size with space conditions
- Sun passed through dense interstellar clouds three times in the last 14 million years
NASA-funded research shows that the Sun's long journey through space played a major role in shaping Earth's ancient climate. When it comes to climate change, scientists usually point to internal planetary shifts like volcanic activity or greenhouse gases to explain past ice ages. But the new study suggests external space environments also caused major planetary changes.
Our solar system travels inside a giant, protective bubble of charged solar winds called the heliosphere. This bubble shields Earth from harsh galactic radiation.
To understand it in-depth, scientists at NASA's SHIELD (Solar Wind with Hydrogen Ion charge Exchange and Large-Scale Dynamics) centre studied the trajectory of the heliosphere.
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The computer simulations revealed that over the last 14 million years, the Sun passed through extremely dense, frigid interstellar clouds at least three times.
During these periods, the intense pressure from the cold space dust compressed the heliosphere to a fraction of its normal size. As a result, the protective bubble shrank, leaving our planet directly exposed to interstellar space.
Earth's upper-atmosphere moisture was increased after the atmosphere absorbed cold galactic hydrogen and cosmic rays. The global weather patterns were also altered.
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"In summary, our heliosphere's trips through colder regions in our galaxy may be a key factor in driving some of Earth's ancient changes in climate, including possible ice ages," NASA's report read.
The report further mentioned that this cosmic exposure matches physical evidence found on Earth. Scientists discovered traces of interstellar dust trapped in deep-sea ocean sediments, lunar core samples, and ancient Antarctic ice.
In conclusion, these findings show that Earth's climate history is not just an isolated story of local geology. Instead, our planet's deep freezes and warming cycles are linked to the Sun's continuous journey through the Milky Way galaxy.
