Jun 12, 2024 03:11 AM
The solar system may have passed through dense interstellar clouds 2 million years ago, altering Earth’s climate
https://www.eurekalert.org/news-releases/1047528
EXCERPTS: Around two million years ago, Earth was a very different place, with our early human ancestors living alongside saber-toothed tigers, mastodons, and enormous rodents. And they may have been cold: Earth had fallen into a deep freeze, with multiple ice ages coming and going until about 12,000 years ago. Scientists theorize that ice ages occur for a number of reasons, including the planet’s tilt and rotation, shifting plate tectonics, volcanic eruptions, and carbon dioxide levels in the atmosphere. But what if drastic changes like these are not only a result of Earth’s environment, but also the sun’s location in the galaxy?
In a new paper published in Nature Astronomy, BU-led researchers find evidence that some two million years ago, the solar system encountered an interstellar cloud so dense that it could have interfered with the sun’s solar wind. They believe it shows that the sun’s location in space might shape Earth’s history more than previously considered.
[...] It’s impossible to know the exact effect the cold cloud had on Earth—like if it could have spurred an ice age. But there are a couple of other cold clouds in the interstellar medium that the sun has likely encountered in the billions of years since it was born, Opher says. And it will probably stumble across more in another million years or so.
Opher and her collaborators are now working to trace where the sun was seven million years ago, and even further back. Pinpointing the location of the sun millions of years in the past, as well as the cold cloud system, is possible with data collected by the European Space Agency’s Gaia mission, which is building the largest 3D map of the galaxy and giving an unprecedented look at the speed stars move.
“This cloud was indeed in our past, and if we crossed something that massive, we were exposed to the interstellar medium,” Opher says. The effect of crossing paths with so much hydrogen and radioactive material is unclear, so Opher and her team at BU’s NASA-funded SHIELD (Solar wind with Hydrogen Ion Exchange and Large-scale Dynamics) DRIVE Science Center are now exploring the effect it could have had on Earth’s radiation, as well as the atmosphere and climate.
“This is only the beginning,” Opher says. She hopes that this paper will open the door to much more exploration of how the solar system was influenced by outside forces in the deep past... (MORE - missing details, no ads)
https://www.eurekalert.org/news-releases/1047528
EXCERPTS: Around two million years ago, Earth was a very different place, with our early human ancestors living alongside saber-toothed tigers, mastodons, and enormous rodents. And they may have been cold: Earth had fallen into a deep freeze, with multiple ice ages coming and going until about 12,000 years ago. Scientists theorize that ice ages occur for a number of reasons, including the planet’s tilt and rotation, shifting plate tectonics, volcanic eruptions, and carbon dioxide levels in the atmosphere. But what if drastic changes like these are not only a result of Earth’s environment, but also the sun’s location in the galaxy?
In a new paper published in Nature Astronomy, BU-led researchers find evidence that some two million years ago, the solar system encountered an interstellar cloud so dense that it could have interfered with the sun’s solar wind. They believe it shows that the sun’s location in space might shape Earth’s history more than previously considered.
[...] It’s impossible to know the exact effect the cold cloud had on Earth—like if it could have spurred an ice age. But there are a couple of other cold clouds in the interstellar medium that the sun has likely encountered in the billions of years since it was born, Opher says. And it will probably stumble across more in another million years or so.
Opher and her collaborators are now working to trace where the sun was seven million years ago, and even further back. Pinpointing the location of the sun millions of years in the past, as well as the cold cloud system, is possible with data collected by the European Space Agency’s Gaia mission, which is building the largest 3D map of the galaxy and giving an unprecedented look at the speed stars move.
“This cloud was indeed in our past, and if we crossed something that massive, we were exposed to the interstellar medium,” Opher says. The effect of crossing paths with so much hydrogen and radioactive material is unclear, so Opher and her team at BU’s NASA-funded SHIELD (Solar wind with Hydrogen Ion Exchange and Large-scale Dynamics) DRIVE Science Center are now exploring the effect it could have had on Earth’s radiation, as well as the atmosphere and climate.
“This is only the beginning,” Opher says. She hopes that this paper will open the door to much more exploration of how the solar system was influenced by outside forces in the deep past... (MORE - missing details, no ads)