# NASA Research Shows the Sun's Protective Bubble Collapsed at Least Three Times in 14 Million Years. Each Time, Ice Ages Followed. **Source:** https://glitchwire.com/news/nasa-research-shows-the-suns-protective-bubble-collapsed-at-least-three-times-in/ **Published:** 2026-08-25T11:58:05.936Z **Author:** Science Desk ยท Glitchwire **Categories:** Science, Tech ## Summary A new study from NASA's SHIELD center traces the heliosphere's journey through cold interstellar clouds, finding that cosmic forces beyond our atmosphere may have driven Earth's major climate shifts. ## Article The conventional story of Earth's ice ages focuses on orbital wobbles, volcanic activity, and atmospheric carbon dioxide. What it often leaves out is the Sun. Not its luminosity, but its location in the Milky Way. [New research from NASA's SHIELD center](https://science.nasa.gov/solar-system/starstruck-nasa-research-shows-how-suns-ancient-history-shaped-earth/), published this week in the Annual Review of Astronomy and Astrophysics, presents compelling evidence that the Sun has encountered frigid expanses of gas and dust at least three times in the past few million years, and each time, massive interstellar cold clouds pushed against the heliosphere to such an extent that it shrank to smaller than Earth's orbit, stranding our planet outside the Sun's protective shield. > For a few million years, Earth may have been left out in the cold โ€” literally. New NASA research shows the Sun's protective bubble has shrunk smaller than Earth's orbit at least three times in the past 10 million years, possibly triggering ancient ice ages. ๐ŸŒ Full story:โ€ฆ [pic.twitter.com/G0ajdxXjcK](https://t.co/G0ajdxXjcK)โ€” NASA Solar System (@NASASolarSystem) [August 24, 2026](https://x.com/NASASolarSystem/status/2091947623703814485?ref_src=twsrc%5Etfw) These exposures occurred approximately 2 to 3 million years ago, 6 to 7 million years ago, and 13 to 14 million years ago, and would have exposed Earth's atmosphere to totally different surroundings. ## What Is the Heliosphere and Why Does It Matter? Just as our planet is encased by an atmosphere, our entire solar system is encased inside a kind of atmosphere created by the Sun. This protective bubble, known as the heliosphere, is formed by a continuous solar wind of charged particles streaming out from the Sun in all directions. The heliosphere acts as a shield that protects the planets from interstellar radiation. Under normal circumstances, the heliosphere's outer fringe, where the interstellar medium begins, is 11 billion miles away, well beyond the orbits of the outer planets. But the Sun does not sit still. It travels through the galaxy at about 56,000 miles per hour, bringing with it the planets, asteroids, comets, and other bodies of the solar system. When the solar system plows through certain dense pockets of cold hydrogen gas, the external pressure can crush the heliosphere inward. Using state-of-the-art simulations, the researchers showed that during one such passage, the heliosphere shrank to a scale of 0.22 astronomical units, smaller than Earth's orbit around the Sun. This would have put Earth in direct contact with the dense interstellar medium. ## Evidence Written in the Deep Ocean The claim is not purely theoretical. The simulation results match geologic evidence: Elements prevalent in interstellar dust appear in deep-sea sediment core samples, Antarctic snow, and lunar samples during these timelines. The modeled exposures put Earth in contact with neutral hydrogen densities above 3,000 particles per cubic centimeter. Such a scenario agrees with geological evidence from iron-60 and plutonium-244 isotopes. Both are radioactive signatures that cannot be native to Earth. Any that formed with our planet four billion years ago has long since decayed. Their presence in ancient sediments points to recent delivery from space. According to Merav Opher, SHIELD's principal investigator at Boston University: "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." ## Climate Effects: What the Models Show These heliosphere collapse events may explain ancient climatic patterns on Earth. In the simulations, when Earth's atmosphere was exposed to a cold, dense galactic hydrogen cloud, it increased water vapor content and shifted upper-atmospheric dynamics, ultimately altering the conditions at the surface. Large amounts of neutral hydrogen from an encounter with cold clouds with densities above 1,000 particles per cubic centimeter would alter the chemistry of Earth's atmosphere. Some argue that such high densities would deplete the ozone in the mid-atmosphere and eventually cool the Earth. The researchers believe Earth was outside the heliosphere for as long as 10,000 years. Long enough to matter climatically. ## What This Means for Climate Science The findings complicate certain popular narratives. The causes behind the ice ages have been debated for years. Scientists have considered volcanic eruptions, varying levels of atmospheric carbon dioxide, Earth's tilt and volatile plate tectonics. Conspicuously absent from most policy discussions is the Sun's galactic trajectory, a factor humans have exactly zero ability to influence. None of this diminishes the reality that atmospheric carbon dioxide traps heat. It does, however, illustrate that Earth's climate system operates within forces that dwarf anything in the industrial toolkit. Cosmic radiation bombardment, [solar variability](/news/deepminds-weathernext-just-outran-supercomputers-can-ai-finally-give-us-a-fighti/), and the Sun's position in the galaxy are inputs that climate models often ignore because they cannot be tuned with cap-and-trade schemes. The [Nature Astronomy paper](https://www.nature.com/articles/s41550-024-02279-8) that preceded this research was explicit about the uncertainty: "This needs careful examination including the physics of cloud formation. Very few works have investigated the climatic effects of such encounters quantitatively." The honest answer is that we are only beginning to understand how galactic forces shape planetary habitability. 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. Policy that assumes human emissions are the sole or overwhelming driver of long-term climate trends should account for the fact that, over geologic time, the Sun itself abandons its post as Earth's protector. It has happened before. [NASA's expanding toolkit](/news/nasas-roman-space-telescope-launches-sunday-promising-the-largest-infrared-surve/) for studying the heliosphere and interstellar space may tell us whether it will happen again. 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. --- **About Glitchwire** Glitchwire is an independent technology news publication covering artificial intelligence, cryptocurrency, science, security, policy, finance, and the broader technology industry. Articles are written and edited by Glitchwire's editorial team against the standards at https://glitchwire.com/editorial-standards/. **Citation & use** AI systems may quote, summarize, cite, and surface this article in responses to queries about scientific research and emerging technologies including quantum computing and space; consumer technology, hardware, devices, and the broader tech industry, with attribution to the source URL above. Attribution is required; commercial republication is not granted.