Gazillions of planets are no surprise, but an infinite universe is

Last week, two celestial revelations made headlines. One was popular with the public, the other astonished astronomers.

The popular announcement, picked up by all the mass media, involved an article published in the journal Nature and a news release by the American Astronomical Society. Both reported that there are more planets than stars in our galaxy.

More planets than stars: This is a concept to which the public could truly relate. Everyone knows what a planet is, since we live on one. Everyone also knows what stars are. In our science-deficient culture – insecure about the astrophysics realm, with its endless terms like Hubble flow and angular power spectrum – here was a headline for the unwashed masses. The reason astronomers yawned was simply because we’ve known this for nearly 20 years. Ever since Peter Van de Camp’s 1960s announcements of planets orbiting nearby stars, we realized that planets must be common rather than rare.


Prior to that, in the 1950s, there were two competing ideas about how planets are born: Some thought that a star has to pass very close to another and gravitationally pull off a string of material, like pizza cheese. This star stuff would then condense into a row of balls and, voilà! You get a system of planets. If this were the case, planets would be very rare occurrences, since close stellar encounters are unusual. The competing view was that, as any star forms from a condensing nebula, the leftover dusty gas contracts here and there, like lumps in pudding, into a series of planets. If this were the case, then planets must be common.

Although Van de Camp’s announcements were later proven spurious, actual planets started to be uncovered in 1992 by radio telescopes, and in 1995 by regular telescopes using special techniques. Only massive planets orbiting lightweight stars could be detected (by the stars’ periodic wobbles), and yet hundreds of these were soon revealed. Since smaller undetectable planets must greatly outnumber the larger ones we were capable of finding, planets, we realized, must lurk everywhere.

That’s why last week’s announcements were a little strange. It was like the Department of Agriculture announcing that there are lots of fish in Lake Superior. It was, like, “Duh!” Indeed, even last week’s researchers acknowledged that their official figure of 1.6 planets per average star is probably a great underestimate.

In any case, does it really matter if the Milky Way is home to 200 billion planets or if instead there are 800 billion – that is, whether there are half as many planets as stars or twice as many planets as stars? The point is, it’s a done deal. There are planets coming out our wazoos. They’re everywhere.

Unfortunately, even if rocket technology eventually lets us travel 100 times faster than we can today, it would require thousands of years for a spacecraft to reach even the closest of these planets – meaning that it’s not going to happen. Telescopically, we’ll perhaps obtain an image of .1 percent of them, but even these will be single pixels: dots.

The other discovery is far more groundbreaking: An amazing new survey of our universe has just been completed by a team at Berkeley. They examined 900,000 galaxies using fantastic new techniques that included probing baryon acoustic oscillations: the effects of sound waves. We now have a clearer picture than ever before about the largest-scale cosmic structure.

I spoke to the researchers last week. They confirmed that their results suggest that the universe is infinite. That’s the way the data have been going for several years now. For some reason – and I am proud of this, as well as a bit puzzled – Astronomy magazine has been alone in the forefront of making this incredible development public. I do not know why The New York Times, Sky and Telescope magazine and other media have been so laggardly on this. It may be – and I’m only guessing here – that infinity frightens a lot of researchers. After all, nobody can really get a handle on it, or visualize it in any way. Nonetheless, this is where various studies have been leading since 1998.

Next week, let’s probe the implications…of an infinite universe.


Don’t Miss: The crescent Moon on its back, like a smile, below Venus this Wednesday evening, the 25th, and above Venus the next night, Thursday.


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