New research from Boston University and the Harvard Radcliffe Institute suggests that the sun passed through a massive hydrogen cloud two million years ago, directly impacting the protective heliosphere and possibly permanently altering all life on Earth. Evidence for this event and its effects on Earth’s climate also shows that the Sun’s location in the Milky Way can have a direct effect on the plants and animals that live on Earth.
“This paper is the first to quantitatively demonstrate that an encounter occurred between the Sun and something outside the solar system that could have influenced Earth’s climate,” said astrophysicist Merav Opher, professor of astronomy at Boston University and fellow at Harvard Radcliffe Institute. press release announcing the team’s research.
Although climate change is currently a politically charged topic, plants and animals living on Earth have experienced repeated and dramatic fluctuations in their environments for millions of years. Historically, events such as volcanic eruptions, shifting plate tectonics, shifts in atmospheric carbon dioxide levels, and even the Earth’s tilt and rotation have all likely contributed to these extreme climatic shifts.
As an astrophysicist who specializes in studying the Sun’s heliosphere, a halo of stellar wind composed of highly charged particles that encompasses the rest of the solar system and protects it from harmful interstellar and galactic radiation, Opher speculated that if the Sun were to coming into contact with one of the large hydrogen bubbles floating around our Milky Way could also have a direct and dramatic effect on the planet’s climate. Now she believes her team’s study supports this theory. This adds another factor to the ever-evolving picture of Earth’s climate.
“Stars move,” Opher said, “and now this paper not only shows that they move, but that they undergo drastic changes.”
Astrophysics ‘Time Travel’ reveals the position of the sun two million years ago
To test the team’s theory, Opher, whose previous work suggesting that the heliosphere is shaped like a puffy croissant reportedly “shook up the space physics community,” decided to use computer models to track the Sun’s movement through the Milky Way. to follow. By turning the astronomical clock back in time, Opher came across an event that occurred about two million years ago.
In their study published in the journal Nature AstronomyOpher and colleagues explain how a series of large, dense interstellar clouds composed of extremely cold hydrogen atoms, called the Local Ribbon of Cold Clouds system, was rather precariously positioned. Upon closer inspection, the simulator’s ‘astrophysical backtracking engine’ showed that one of the clouds, the Local Lynx of Cold Cloud, may have collided with the heliosphere due to its position near the end of a particular ribbon of the Local Ribbon of Cold . Clouds.
According to Opher, the team’s simulations indicate that if such a collision were to occur, the heliosphere could have changed enough to temporarily deprive Earth of its critical protection. This means that all life on Earth would not only have been exposed to incredibly powerful levels of interstellar radiation and cosmic rays (which can alter DNA), but would also have been exposed to dangerous amounts of iron and plutonium atoms left over from exploded stars living in measurable quantities exist. concentrations in the interstellar medium.
“This cloud was indeed in our past, and crossing something that big exposed us to the interstellar medium,” Opher says.
This idea is supported by geological evidence showing unusually high concentrations of 60Fe (iron 60) and 244Pu (plutonium 244) isotopes in the ocean, on the moon, buried in Antarctic snow and collected from ice cores from the same period two million years ago. . Although no direct research has been done to determine what the collective effects of a long-term removal of heliosphere protection and all this exposure might be, the authors of the paper outlining this possibility believe that this could be a direct effect have had on everything that lives on earth. Soil.
“Only rarely does our cosmic environment outside the solar system impact life on Earth,” said Avi Loeb, director of Harvard University’s Institute for Theory and Computation and co-author of the paper. “It is exciting to discover that our passage through dense clouds a few million years ago could have exposed Earth to a much greater flow of cosmic rays and hydrogen atoms.” Loeb is also a regular contributor to The debriefing.
Next steps and other potential cosmic collisions
While there is no direct way to travel back in time to see how the sun colliding with an interstellar cloud of cold hydrogen atoms might have affected our ancient human ancestors or the plants and animals that lived alongside them, suggests one theory that a large enough event would have caused one of the many ice ages the Earth experienced during its lifetime. Given the more than four billion years since the creation of our solar system, Opher thinks it is likely that the Sun has experienced many similar events in the past, all of which could have affected life in a number of different and unpredictable ways.
“And it will likely encounter more in another million years,” explains the press release announcing the research.
Next, Opher and her team at the university’s NASA-funded SHIELD (Solar Wind with Hydrogen Ion Exchange and Large-scale Dynamics) DRIVE Science Center will investigate how such a massive collision between the Sun and an interstellar cloud of hydrogen atoms could cause the De atmosphere and climate of the earth, but also radiation.
The researchers then want to trace the position of the sun back to seven million years ago. If their assumptions are correct, data collected by the European Space Agency’s Gaia mission, which is building the largest three-dimensional map of the Milky Way ever and also mapping how fast stars are moving, should not only help them pinpoint the location of the Milky Way sun in the Milky Way, but also indicate where the ribbons of the cold cloud system were located. If the two coincide with known climatic events in Earth’s past, it could add even more evidence to the team’s theory.
“This is just the beginning,” says Opher.
Looking ahead, the astrophysicist says she hopes this paper will open the door for much more research into how the solar system was affected by outside forces in the deep past and how these forces in turn shaped life on our planet. Loeb agrees.
“Our results open a new window on the relationship between the evolution of life on Earth and our cosmic environment,” he said.
Christopher Plain is a science fiction and fantasy novelist and chief science writer at The Debrief. Follow him and connect with him X, Learn more about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.