I found this on the homepage of Sky & Telescope Magazine. I just have to quote the beginning of the article:
You may think you have a hard job, but imagine this item on your to-do list: saving Earth from nonexistence. It sounds like a task worthy of Superman, but it has fallen instead to computational astrophysicists like Mordecai-Mark Mac Low of the American Museum of Natural History to make sure our planet is spared oblivion — or at least virtual oblivion in numerical simulations.
Okay, it appears that many, perhaps most, planets end up being swallowed by their suns before they even get a chance to start their "lives"! Astronomers agree that planets are born in the rotating disk of matter that is left over when a sun is born. Various condensations and dense knots in the disk may give rise to planets. However, this rotating disk of gas tends to drag the newborn planets ever closer to their sun, where they may eventually be swallowed. Goodness!
A rotating disk giving rise to star and planets Well, according to the article in Sky & Telescope, gas clouds in the disk may sometimes halt the natural inward drag on the planets. Eventually the disk will disperse, and then the doomsday plunge of the planets to the fiery hell of the Sun will cease! But if the disk doesn't disperse soon enough, many planets may be swallowed, and other may end up too close to their Sun, so that they will be fried. (Why am I thinking about the Lord of the Rings, and that fiery hellish chasm where Frodo was supposed to throw down his ring?)
In case you are still worried about what might have happened to the Earth in its youth, let me quote some more from Sky & Telescope:
Instead of maintaining a safe and steady orbit, the equations suggest the young Earth should have been locked in a death spiral that sent it plunging into the Sun.
There is, of course, some compelling evidence to the contrary. "We're still here!" says Mac Low.
Well! That's good to know! And the S&T article suggests that we can actually sleep easy, because we do indeed exist!
(That's what I love about astronomy... the wonderful weirdness of it all.)
Here is the full article. And perhaps the support club (or, a more direct translation, the "interest club", the club for those who are interested) may have taken notes!
Ann
