这基本上是一篇物理学文章的题目，《Message in the Sky》，徐一鸿和另一个徐（Stephen Hsu）三个月前写的文章。Tony是个非常非常聪明的人，这一次不知道他真的收到了上帝的启示，还是认真地恶作剧一回？

他们说，如果上帝在创造世界的时候想留给我们一点关于他的启示，不会在大峡谷的岩石中留下什么痕迹，也不会在我们的基因中留下什么痕迹。最有可能的是，他在微波背景辐射涨落的功率谱上做了什么手脚，因为微波背景辐射是宇宙中任何角落的智慧动物都能够看到的。给定一个角“量子数”，角功率谱有个样本，扣掉不确定性，上帝在中能够给我们的信息量是。我们现在能够观测的上限是，这样，可以有大约bits原则上能够被我们读出。

这是一个相当大的信息量，两位徐先生说，上帝可以告诉我们大统一的群是什么，等等。

老实说，虽然大部分人会将这样的想法当着科幻来看，如果物理原理并不禁止我们在实验室中造出另一个宇宙，他们的想法也不能被看成纯粹的胡说八道，也许有一天，一个科学疯子会成为一个新宇宙的上帝。

Note added: 桑葚告诉我们Stephen Hsu讨论过他们的文章，我去看了一下，觉得他提到Linde给他写信的那个帖子有意思，就顺手转过来。Note added to note added: 这个转帖没有征得Steve的同意。

Message from Linde
Andre Linde (Stanford) sends some interesting comments on our paper Message in the Sky. He points to an earlier paper of his, and a nice interview in Slate, where he discusses the idea of creating a universe in the lab. In the comments section of the previous post I mentioned that one of the reasons I had been thinking about this topic is the work of Farhi and Guth (MIT) on the behavior of a false vacuum bubble created in the lab. I hadn’t known that Andrei had also worked out the solution (although I should have). A false vacuum bubble can expand in a non-Euclidean way, so that the observer in the lab sees the bubble shrink while an observer inside sees it expand (inflate).

Andrei also had the idea that the creator of the bubble universe might like to send a message to its future inhabitants. He discusses tuning the fundamental parameters so that physicists in the bubble universe would understand that their physical laws had been adjusted just-so. Our proposal allows a bit more information to be encoded (or rather, read out), but the idea is similar. The problem with having special values of the constants is that some nutty physicists might come up with anthropic reasons explaining those values, and not figure out it was done intentionally

But why bother making a universe if it’s going to run away from you? Wouldn’t you want to have some power over how your creation unfolded, some way of making sure the beings that evolved in it turned out well? Linde’s picture was as unsatisfying as Voltaire’s idea of a creator who established our universe but then took no further interest in it or its creatures.

“You’ve got a point,” Linde said. “At first I imagined that the creator might be able to send information into the new universe—to teach its creatures how to behave, to help them discover what the laws of nature are, and so forth. Then I started thinking. The inflation theory says that a baby universe blows up very quickly, like a balloon, in the tiniest fraction of a second. Suppose the creator tried to write something on it surface, like ‘Please remember I created you.’ The inflationary expansion would make this message exponentially huge. The creatures in the new universe, living in a little corner of one letter, would never be able to read the whole thing.”

But then Linde thought of another channel of communication between creator and creation—the only one possible, as far as he could tell. The creator, by manipulating the cosmic seed in the right way, has the power to ordain certain physical parameters of the universe he ushers into being. So says the theory. He can determine, for example, what the numerical ratio of the electron’s mass to the proton’s will be. Such ratios, called constants of nature, look like arbitrary numbers to us: There is no obvious reason they should take one value rather than another. (Why, for instance, is the strength of gravity in our universe determined by a number with the digits 6673?) But the creator, by fixing certain values for these dozens of constants, could write a subtle message into the very structure of the universe. And, as Linde hastened to point out, such a message would be legible only to physicists.

“You might take this all as a joke,” he said, “but perhaps it is not entirely absurd. It may be the explanation for why the world we live in is so weird. On the evidence, our universe was created not by a divine being, but by a physicist hacker.”

Linde’s theory gives scientific muscle to the notion of a universe created by an intelligent being. It might be congenial to Gnostics, who believe that the material world was fashioned not by a benevolent supreme being but by an evil demiurge. More orthodox believers, on the other hand, will seek refuge in the question, “But who created the physicist hacker?” Let’s hope it’s not hackers all the way up.