300 Sextillion Stars

The universe is a whole lot bigger than we thought.

Generally scientists believe there are 100 billion to a trillion galaxies in the universe. And each galaxy — the Milky Way included — was thought to have 100 billion to a trillion stars. Sagan, the Cornell University scientist and best-selling author who was often impersonated by comedians as saying “billions and billions,” usually said there were 100 billion galaxies, each with 100 billion stars.

Van Dokkum’s work takes these numbers and adjusts them. That’s because some of those galaxies — the elliptical ones, which account for about a third of all galaxies — have as many as 1 trillion to 10 trillion stars, not a measly 100 billion. When van Dokkum and Conroy crunched the incredibly big numbers, they found that it tripled the estimate of stars in the universe from 100 sextillion to 300 sextillion.

That’s a huge number to grasp, even for astronomers who are used to dealing in light years and trillions, Conroy said.

“It’s fun because it gets you thinking about these large numbers,” Conroy said. Conroy looked up how many cells are in the average human body — 50 trillion or so — and multiplied that by the 6 billion people on Earth. And he came up with about 300 sextillion.

So the number of stars in the universe “is equal to all the cells in the humans on Earth — a kind of funny coincidence,” Conroy said.

Wrap your head around those numbers, and the notion of a sextillion, which sounds kind of funny.  A funny coincidence.

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