Wednesday, May 20, 2015

Life on a Neutron Star

Imagine taking a star and squeezing it into a smaller and smaller space.  The pressure inside the star would fight against this crushing force, but eventually it could no longer resist, and the star would collapse into a gigantic atomic nucleus, called a neutron star.  The gravity on a neutron star is a billion times stronger than on the earth – on a neutron star, you’d weigh one hundred million tons.  Or at least you would until you were squished down into nuclear goo. 

In two novels, Dragon's Egg and Starquake, Robert Forward imagined what it would take for life to survive on a neutron star. I met Forward at the Texas Symposium on Relativistic Astrophysics in 1986 -- he told me that each of his two books had put one of his kids through college. The exchange rate between college tuition and science fiction book royalties has gotten a lot worse since then -- I doubt that a single novel would put anyone through  college these days.

Forward's aliens, the Cheela, aren’t composed of ordinary atoms (see reference to “squished down into nuclear goo,” above) – they would have to be made of pure neutrons, just like the neutron star itself. But this adaptation leads to a bizarre result.  Neutrons are held together by the “strong force,” which operates millions of times faster than the chemical reactions that power our own bodies. So Forward's aliens experience time a million times faster than us.  Their entire civilization advances from the Stone Age to space travel in the course of a few days. 

Dragon's Egg is an outstanding work of hard science fiction, and I highly recommend it. But it also raises an interesting question:  Is the universe filled with different civilizations living at extraordinarily different rates of time? What about the opposite possibility to Dragon's Egg – are there alien races that experience time so slowly that we would see them as no more than nonliving piles of stones? Even if we were able to contact such a race, communication would be tedious at best – imagine waiting years for the answer to a simple question. It would be a bit like raising a teenage boy.

Of course, scientists have shown extraordinary patience when necessary. For example, here's the famous pitch drop experiment, constructed in 1927 to measure the viscosity of pitch:
Makes "watching the grass grow" seem exciting in comparison!

Right now, scientists are watching the ninth droplet slowly take shape. You can watch it yourself at this link, if you have nothing better to do for a few decades. But it would be ironic indeed if we eventually did discover intelligent life in the universe, only to realize that it was simply too tedious to communicate with them.

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