One of my most important responsibilities at COSI is to ensure the correctness of our presented science, from descriptions on exhibits to scripts for shows. Granted, a large fraction of the material COSI presents to the public is not in my specific domain - they don't typically hand out Ph.D.'s in "All the Science" - but that's where my connections back to OSU come in handy. If something crops up beyond my expertise, then a quick call to campus can easily resolve the issue.

So with all that in mind, I encourage all COSI team members to send me scripts. Develop a new show? Send the script. Create a new outreach demo? Send the script. Have a question about a floor cart activity? Send the script.

I hope you get the point by now: send the script!

Some weeks ago I was chatting with a couple members of COSI's floor faculty team about meteors (they were doing a tabletop meteorite demo, so this conversations wasn't totally unwarranted), when the subject of fire came up. Meteoroids that come screaming through the Earth's atmosphere are very bright, emitting a lot of heat and light, so it naturally leads to the question: are they on fire?

When a piece of space rock intersects the orbit of the Earth at the exact wrong time, it's typically traveling at a few tens of thousands of miles per hour, and that only increases in its final moments. And even though our upper atmosphere is only a tiny fraction of the density of our surface-level air, that speed is sufficient to cause a ton of pressure and friction.

Friction from the rubbing of air against the meteor, and pressure as the rock pushes on the air directly in front of it during its passage. Both of these processes generate a lot of heat; enough heat to ionize both the air and the meteor material, ripping electrons off molecules and causing them to glow.

The air will stay ionized for a few moments after the meteoric passage, forming the familiar trail. Bits and pieces of the meteor itself will get stripped away - a process called ablation - leaving a glowing aftermath in its wake as well.

But fire is not involved here. Fire is a chemical reaction between oxygen and a fuel source, and the physics on display in a meteor shower are based on different, and far more violent, processes.

An anonymous question appeared on my board recently: if most of the matter in the universe is "dark", why can't we detect it via other means, like gravitational lensing?

Indeed, we do! From our understanding of general relativity, the presence of matter and energy warp and flex spacetime like a (four dimensional) rubber sheet. And beams of light like to travel in straight lines, but the spacetime "underneath" them is warped, forcing the light to follow curving paths. This means that a massive object can bend light around it like a lens...hence, gravitational lensing.

The measurement of this effect around the sun was one of the first pieces of evidence that Einstein got it right, and now we use it routinely to study matter all around the universe, including the dark kind.

"Dark" matter is really invisible matter - it turns out that most of the matter in the universe simply doesn't interact with light. We're not exactly sure what it is yet, but tools like gravitational lensing are helping us to study it. Even when we can't see it directly, it bends the path of light around it, so we know it's there and we can learn more about it.