Quick Questions, Short Answers - No Debate

In which case their Lagrange points would not start behaving like black holes. But could you have Lagrange points that did?

Yes, that's what I was asking. If it can't happen, then I guess the universe was weird enough already.Edited by Dr Adequate, : No reason given.

Unless I'm mistaken, your ranking depends on the rankings of other people, so that your rating might go up as a consequence of me being jeered. Also, I think Percy's formula only takes into account the last n days or posts or something, so your rating might go down as a result of one of your much-admired posts becoming superannuated. So while Percy might be able to implement the feature you describe quite easily, it would not (assuming I'm right) really tell you what you want to know.

I vaguely remember a story like this, possibly from one of Gould's essays: A sort of organism, I think a shellfish, was once widespread in the fossil record. Then it apparently went extinct --- at least, it went missing from the fossil record. Which was odd, because this variety of shell is still around today. The puzzle was resolved when a specimen was found in the strata from which it was thought to be missing, showing that it hadn't gone extinct, just become scarce and/or localized.Can anyone name the species and fill in the details for me? Thanks.

I'm having to write about this for my geology thread. A couple of questions.(1) Is it true that all radioactive decay involves a change in the atomic number? Is there no decay that just involves an atom spitting out a neutron or two but remaining the same element?(2) If so, is there a reason for this? My own guess is that the instability of nuclei is down to the difficulty of holding together the positively-charged protons, given that like charges repel, but I would be the first to admit that I know nothing about quantum chromodynamics.

Thanks.So would it be accurate for me to say that radioactive decay involves any change of the atomic number, the atomic weight, or both --- that by definition it involves a change in the composition of the nucleus?

Thanks.Really I don't know if I'd have started this course on geology if I'd known how hard it would be. I thought I'd be explaining to people: "Sandstone is lithified sand. You wanna guess what mudstone is?" But in fact it has gone on and on and on and on, and now I have to explain nuclear physics to people without myself being a nuclear physicist, and I've written about 80,000 words. I do feel very satisfied with my achievement, but looking back I should probably have tried to achieve something easier.

It's definitely underwater, I found it in an article on underwater photography in which the fnucking idjits who wrote it didn't caption any of the photographs.

Yes, that's me. What can I do for you?

You want to meet up?

Some while back I read a jolly if unprofound short sci-fi story. The basis of the plot was that a guy crash-lands on a tropical-island-paradise planet. He realizes that when the planet is "discovered" by the wider galactic civilization of which he is a citizen, they'll turn it into a tourist resort. He teaches the natives a plan to be passed down from generation to generation to be put into action in case of this eventuality.Can anyone tell me what it's called and who it's by? Thanks.

It is! Thank you! How could I forget the name of Lloyd Biggle Jr?What's more, the short story version is available free online. Happy day!

There are about 100 mitochondria in a human cell. Suppose they were all different (they won't be, that's what we're trying to explain, but suppose they were). They (approximately) double in number and then the cell divides. But there's no reason why each daughter cell should get one copy of each distinct mitochondrion. (Unlike chromosomes, where there's a mechanism for this.) Instead, there's a sort of founder effect every time a cell division takes place.The graph below shows the average behavior of the diversity if we started with 100 mitochondria all different. As you can see even given this starting point we expect the diversity to be completely eliminated after about 400 cell divisions.

Does it have a name? Thanks.