Science Made Simple is a Cardiff-based science outreach program, for those not aware of the pun. The Up Goer Five text editor isn't, but it could be. Sort of. It's a text editor that only lets you use the 1,000 words most often used. If you're too lazy to click the links, it's called Up Goer Five because the original xkcd comic described the Saturn 5 rocket in such a way.
Anyway. this begs the question : can I explain my job using only the ten hundred most used words ? I don't know, but I'll give it a go. Although the UG5 editor allows you to define words if they're not in its dictionary, I decided to do this in its purest form.
"In space, there are lots of stars in big groups which move around really really fast. Each star goes around and around the middle of all the stars in the group. Some stars are closer to the middle than others. The stars very close to the middle are okay, but the ones far away are going much too fast. In fact, they should all fly off into space without something really heavy to hold them all together.
We can't see what this really heavy thing is but it must be there. Sometimes we also find other stuff (which is a bit like smoke) that is moving even faster than the stars and is even further away from the middle of the stars. This 'smoke' is also moving much too fast so we can be quite sure there must be a really heavy thing we can't see holding the whole lot together. Maybe one day we'll find some fast-moving smoke without any stars inside. That would be really cool, and then we will have a party."
Someone then asked about microlensing :
"Really heavy things can make light turn. We can look at how much the light turns and work out how heavy the thing making it turn is. Sometimes we may not be able to see the things making it turn. These could be very large rocks or other things that are hard to see or maybe because of some interesting dark stuff we don't know anything about."
This is curiously addictive. I guess I got lucky that "stars" are in the dictionary. But what if it wasn't ? How to explain a star ?
"In space there are huge balls of stuff that's a lot like smoke. Sometimes they are so heavy that they start to get smaller, because really heavy things do that. This makes them get hotter. When they get really hot, something amazing happens.
Remember that everything is made of lots of really little things. When things get hot enough, these little things fly around very fast and hit each other. Sometimes they stick together. This sends out even more hot stuff, sort of like fire, only not really but close enough. The hot fire stuff makes everything even hotter, of course, and that makes it even easier for all the little things to hit each other, sending out more fire, and so on.
The big ball of smoke gets hotter and hotter as it gets smaller and all its little things hit each other faster and faster. When it gets really really really hot, there is so much fire stuff that it pushes out very hard. This makes the ball stop getting smaller. Then it just sits there for a very long time, making more of the fire stuff."
One day, someone's going to write an entire textbook like this. But not today.