Reader Jeane Schneider points out that the PlanetQuest exoplanet tally of extrasolar planets is a little behind. A more up-to-date count can be found at exoplanet.eu, where they are currently showing a grand total of 268.

The site lists planets by what technique was used to identify them, and also provides a list of controversial and retracted planets. Cool!

And in the little western Kentucky public library that I frequented when I was a boy, you could still find books that only listed eight. From a strictly local perspective, those formerly long-outdated books are once again up-to-date. Our solar system has only eight planets; the ninth got demoted a while back.

But back in those days, the number of planets in our solar system was equal to the number of known planets. That is no longer the case — not by a long shot. According to NASA’s PlanetQuest site, there are now some 264 known planets out there in the ‘verse, though none have been declared officially earth-like. There are 227 stars that have been identified as having planets orbiting them. One of these, 55 Cancri, has five confirmed planets.

We’ve certainly come a long way. Uranus was discovered in 1781. Neptune was first spotted in 1846. Then Pluto came along in 1930, and was eventually de-planeted primarily because we were finding too many other objects that we would also have to count as planets if we continued to count Pluto. (Eris, for example, which is more massive than Pluto.)

So we had thousands of years of knowing only about the planets that can be seen with the naked eye, then along comes the telescope and we’re finding a new one every 70-90 years. Pretty good progress, but it’s nothing compared to what happened once astronomers started looking for evidence of extrasolar planets in the tell-tale wobble that a star displays when a planet orbiting the star tugs on it with its own mass.

The NASA site lists PSR 1257 as the first extrasolar planet to be discovered, in 1991. So while thousands of years of naked-eye observation followed by hundreds of years of peering through telescopes never even got us to double digits, a little over a decade and a half has us more than a quarter of the way to quadruple digits. And it’s no understatement to say that we’re barely scratching the surface. Look at what a limited space (relative to the rest of the galalxy) in which we are currently looking.

And don’t forget, there may well be additional planets orbiting the stars around which we’ve already confirmed the presence of planets. The great age of planetary discovery is not yet even in its infancy, but perhaps we’ll be there soon. We may well look back on the time when there were “only” 264 as not terribly different from the time when there were only nine.

Let’s have no more of this nonsensical talk about banning astronomy:

Evidence for a parallel universe?

Last August, astronomers working on the analysis of data being acquired by NASA’s WMAP (Wilkinson Microwave Anisotropy Probe) satellite announced that they found a huge void in the universe. A void is a region of space that has much less material (stars, nebulae, dust and other material) than the average. Since our universe is relatively heterogeneous, empty spaces are not rare, but in this case the enormous magnitude of the hole is way outside the expected range. The hole found in the constellation of Eridanus is about a billion light years across, which is roughly 10,000 times as large as our galaxy or 400 times the distance to Andromeda, the closest “large” galaxy.

The dimension of the hole is so big that at first glance, it results impossible to explain under the current cosmological theories, although scientists put forward some explanations based on certain theoretical models that might predict the existence of “giant knots” in space known as topological defects.

However, University of North Carolina at Chapel Hill physics Professor Laura Mersini-Houghton made a staggering claim. She says, “Standard cosmology cannot explain such a giant cosmic hole” and goes further with the ground-breaking hypothesis that the huge void is “… the unmistakable imprint of another universe beyond the edge of our own“.

I’m not astrophysicist, so I will take it as a given that there can be something remarkable about a large piece of open space out in…space. I mean, isn’t that what we expect to find out there? But okay, granted.

Mersini-Houghton is a proponent of a theory of entangled universes. Her ideas about parallel universes are testable, so we should know in time whether this hole is just a big hole or evidence of something more. According to the theory, there should be a second void like this one in another section of the universe.

If such a void is, in fact, found, it still won’t be proof positive that we have discovered a parallel universe, but it will certainly add credibility to the argument.

To me, there’s something very odd about the idea of evidence of parallel universes in this universe. If we have some common context with another universe, isn’t that context the real universe? How can two parallel things be connected to each other? Similarly, Max Tegmark talks about the great physical distance one would have to travel to get from this universe to another universe. (I can’t find the exact reference; somebody help me out if you know what I’m looking for.)

Maybe I’m just playing word games, but it seems to me that if you can get there from here, then it’s not a different universe.

Before it, you know, wipes out the universe?

Could humanity’s observation of dark energy have shortened the life span of the universe? The answer is “yes” according to the author of a new scientific paper that has recently come to light. Featured in the latest edition of New Scientist magazine, the subscriber-only story, “Has observing the universe hastened its end?”, discusses the paper and its claims.

It’s the old principle that you can’t observe a phenomenon without affecting it. But can it really be dangerous, existentially dangerous, for us to observe some the building blocks of the universe in action?

Maybe.

Once again, this is territory ably covered by Greg Egan in his novel Quarantine, wherein aliens essentially wall off the solar system so that we can’t make any more universe-limiting observations of quantum phenomena.

Anyhow, if we really are at risk, this might be a job for the Lifeboat Foundation.

Also, I wonder if MDarling will consider this proof that there really is a God? And an angry, vengeful one at that…