Cosmology Gets Real

An astrobiologist comes to grips with the new cosmology results.



So they found ripples from the origin of the universe: gravitational waves from tiny quantum fluctuations in the instant after the Big Bang (S&T: July 2014, page 18). It’s clearly an incredibly important discovery, and my friends all want to know what I think. Even worse, they want me to explain it.

But dammit Jim, I’m an astrobiologist, not a cosmologist. People think that I know all about this stuff because it’s out there in space, just like those stars, planets, and moons I’m always going on about. I follow cosmology and particle physics on the level of reading S&T and Scientific American, and if I were a 19th-century natural philosopher, I might be able to know all of science, or at least make a better stab of it. But now science has grown to a sprawling, branching tree of knowledge, and we rely on the authority of those in other fields to tell us what’s important, what’s believable, and what it means.

When I tell people that I study other planets, sometimes they look at me like I’m from Neptune. I suppose what I do is abstract and esoteric compared to selling cars, fixing bridges, or running a frozen yogurt company. But compared to cosmology or particle physics, it feels so concrete. At least I can picture planets as cratered, rocky plains or wave-tossed seas under an alien sun.

But what about the worlds of subatomic particles and baby universes ballooning out of nothingness? There are good reasons to believe. The math is elegant and, most importantly, predicts other patterns and phenomena that we then observe. I’ve taken university courses in general relativity and quantum mechanics, and though I couldn’t reproduce the logic or math in any depth now, having been through it once gave me an appreciation for their depth and veracity. I’ve taught the cosmic microwave background in intro astronomy courses and planetarium shows. I dutifully report on how tiny quantum bumps became frozen into the distribution of matter as the cosmos expanded from unimaginable tininess to inconceivable vastness, and miniscule vacillations evolved into massive superclusters of trillions of stars. I know the drill, but I also have a voice in my head saying “Really? It’s a good story, but do we really know this?”

I must confess to having doubts about the Big Bang. Not that I have any better ideas, it’s just that ideas about the early universe seem to rest on so many layers of abstraction. I get that it fits an impressive amount of data, but I can imagine that it might all somehow be wrong, a beautiful and complex edifice that may someday come crashing down in a paradigm-shifting upheaval of reality.

We’ll never visit the early universe. But that’s also true of Earth’s early Archean era, and perhaps the exoplanets, and yet planetary scientists study these times and places. We do, at least, have rocks from the Moon and mineral grains from the Archean (S&T: June 2014, page x16). And now, it seems, we have the equivalent for the primordial universe. Detecting these gravitational waves, closely conforming to predictions, makes it a lot more real to me. Maybe these folks really are on to something! I’m very glad people are studying these things, and I’m glad that someone keeps the yogurt machines running too.

This Cosmic Relief article first appeared in print in the August 2014 issue of Sky & Telescope.

Astronomy Blogs, Cosmic Relief with David Grinspoon
David Grinspoon

About David Grinspoon

David Grinspoon, Senior Scientist at Planetary Science Institute, is an astrobiologist who studies the possible conditions for life on other planets. He is also an award-winning science communicator and writer and writes the Cosmic Relief column for Sky & Telescope. His new book Earth In Human Hands will be published in December 2016.
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