Fermi Bubbles: Cosmic Ice Cubes Found in Milky Way's Fiery Heart
Okay, so scientists have been poking around the center of our galaxy, the Milky Way, and they've stumbled upon something pretty wild. Imagine these gigantic, balloon-like structures, called Fermi bubbles, sticking out thousands of light-years from the galactic plane. They're made of high-energy radiation, and researchers think they might've been caused by some kind of crazy outburst way back when.
What's got everyone scratching their heads now is the discovery of cold hydrogen clouds chilling inside these bubbles. It's like finding ice cubes in a volcano, according to Andrew Fox, an astronomer at the Space Telescope Science Institute. Seriously, how do these cold clouds survive in such a super-heated environment? It just doesn't make sense!
The Fermi bubbles themselves were spotted back in 2010, and they look like a giant hourglass with each lobe stretching about 25,000 light-years. Rongmon Bordoloi, a physics professor at North Carolina State University, described the event that created them as a sudden and violent event, "like a volcanic eruption but on a massive scale.” When the team was observing the bubbles, they weren't expecting to find these cold gas clouds. The clouds are about 10,000 degrees Kelvin, way cooler than the surrounding million-degree gas.
Because of the extreme conditions, these hydrogen clouds should've been toast a long time ago, like, within a few million years. So, the fact that they're still around suggests the Fermi bubbles are actually way younger than anyone thought. If the bubbles were, say, 10 million years old, these clouds wouldn't even exist anymore.
The theory is that these clouds were somehow swept up from the Milky Way's center and dragged along by the hot wind that created the Fermi bubbles in the first place. Jay Lockman, an astronomer at the Green Bank Observatory, uses a neat analogy: "Just as you can't see the motion of the wind on Earth unless there are clouds to track it, we can't see the hot wind from the Milky Way but can detect radio emission from the cold clouds it carries along."
It's pretty amazing to think about these cosmic mysteries happening right in our own galactic backyard. Discoveries like these remind me how much we still have to learn about the universe, and how even the most extreme environments can surprise us.
Source: Gizmodo