(MENAFN- AzerNews)
New research suggests the Earth's climate might have been
dramatically influenced by the sun's passage through a dense
interstellar cloud millions of years ago, Azernews
reports.
The study published Monday in Nature Astronomy provides fresh
insights into how our solar system's movement through the Milky Way
could affect the Earth's climatic history.
The sun, as it travels around the center of the Milky Way,
oscillates relative to the galactic plane.
The motion might have led the solar system through regions of
space dense enough to interfere with the solar wind, potentially
cooling the Earth, according to the study.
"The Sun sends out a constant flow of charged particles called
the solar wind, which ultimately travels past all the planets to
some three times the distance to Pluto before being impeded by the
interstellar medium," NASA said on its official website. "This
forms a giant bubble around the Sun and its planets, known as the
heliosphere.”
NASA said that currently, the solar system resides within the
1,000-light-year-wide "Local Bubble," a region with a sparse
particle density; however, the solar system will exit the bubble
and reenter the denser ISM (interstellar medium) in a few thousand
years.
Researchers have found evidence suggesting we have traversed
denser regions in the past, the study revealed.
"In the ISM that the Sun has traversed for the last couple of
million years, there are cold, compact clouds that could have
drastically affected the heliosphere," the team explained in the
study.
"We explore a scenario whereby the Solar System went through a
cold gas cloud a few million years ago," it stated.
The research reported that such an encounter could have
contracted the heliosphere, allowing more ISM material to reach
Earth's atmosphere and that could alter atmospheric chemistry and
potentially cool the planet.
The study said the presence of specific isotopes, such as
iron-60 (60Fe) and plutonium-244 (244Pu), in geological records
supports the theory.
The research report highlighted that the isotopes, typically
associated with supernovas and neutron star mergers, might have
been delivered by interstellar dust during such an encounter, thus
previous attributions to nearby supernovas are now being
reconsidered.
Lead author Merav Opher, a space physicist and expert on the
heliosphere at Boston University, said in a statement: "This paper
is the first to quantitatively show there was an encounter between
the Sun and something outside of the solar system that would have
affected Earth's climate.
"But as soon as the Earth was away from the cold cloud, the
heliosphere engulfed all the planets, including Earth."
The study indicated that the heliosphere's contraction during
such events could last from hundreds of years to a million years,
and we might face another similar encounter within the next million
years.
"This work should be revisited with modern atmospheric
modelling," the team suggested in the paper, noting: "It has been
suggested that climate changes around this time could have affected
human evolution. The hypothesis is that the emergence of our
species Homo sapiens was shaped by the need to adapt to climate
change. With the shrinkage of the heliosphere, the Earth was
exposed directly to the ISM."
The study has sparked renewed interest in understanding how
interstellar phenomena influence our planet, emphasizing the need
for further research.
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