What if I told you that “instability fingers” were a thing?
They appear all across the universe, in fact, and in your salad dressing, too, as you start to mix the ingredients properly.
Imagine vinegar on olive oil – water on fat that is. Then you take a chop stick and pierce through the water into the oil fast enough. Essentially, what you are doing is to make the lighter fluid (water) push into the heavier fluid (oil). If you were to film the whole thing in slow-motion you would more likely than not even see what is called “instability fingers”:
The underlying physical process is called Rayleigh-Taylor instability. It’s difficult maths, but an important thing to get right. See, instabilities like this can happen, too, in mushroom clouds (volcanoes and bombs) or supernova explosions like the one photographed by the Hubble telescope at the very top of this article. Understanding these instabilities helps us understand both technology and nature.
Still, it’s very difficult to handle properly and we give it a silly name. Aren’t we awesome?