July 11, 2003

New Old Planet

We can file some of our ponderings about this development under the "what might have been" heading. The actual find: a new planet about 8 billion (appropriate Saganesque emphasis applied) years older than the rest of the planets discovered so far outside of the solar system. It's not only old and huge — about twice the size of Jupiter — it's apparently seen some action.

...it is believed the planet formed about a sunlike star near the edge of the globular cluster. Over time, the star and its planet were gravitationally captured by the pulsar, which was then a neutron star with another star as a companion. As the sunlike star was sucked into the mix, the companion star was ejected from the group. This left the sunlike star and neutron star bound to each other while the planet orbited both.

Eventually, the sunlike star burned up its fuel, bloomed into a red giant and then collapsed into a white dwarf. The neutron star, with its greater density, sucked in material from the collapsing star. This caused the neutron star to start spinning at 100 times a second and emitting radio signals, turning into a pulsar. It was the clocklike pulsing of these radio signals, picked up by radio telescopes, that led to other observations and the discovery of the complex.

The article explains how this planet's very existence calls into question assumptions astronomers have made about when and how planets formed. The current thinking is that planets showed up only after the galaxy had cycled through a generation or two of stars. These later stars (like our sun) contained more heavy materials, such as carbon, that would make it possible for planets to form. So how did this planet manage to materialize so early? I think they'll be scratching their heads over that one for a while.

And while we're asking questions, let's turn to a few that have been raised by the all the other (more than 100) supersized planets that have been discovered outside the solar system. Are they all alone out there? Could they have smaller, earthlike moons or planetary companions? Is it possible that life has formed on any of these hundreds of smaller bodies?

These questions take on a certain poignancy when applied to our new old planet. Here's why:

But when the sunlike star was pulled into orbit of the neutron star, any planets near the sun would have been destroyed. Only the gaseous planet, orbiting some two billion miles out, would have survived.

If there was intelligent life on such a planet, he said, it was destroyed as the parent sun was pulled toward the neutron star.

"They would have seen it coming..."

But could they have done anything about it?

Let's say it was happening to us, at our current level of development. The only scenario that might work would be a desperate, swing-for-the-fences, When Worlds Collide kind of approach. Say we knew we had about ten years: we might be able to slap together a small fleet of manned "space arks" that could get a few thousand of us to the moons of the gas giant. I'm not sure if we'd be safe there, though. And of course, this assumes that the moons are there and that they would have sufficient resources to sustain us.

If we knew we had fifty or a hundred years, we might have a shot at building something that would carry us out of harm's way altogether and into interstellar space. Centuries later, our descendants could conceivably wash up on some hospitable shore. I'm not saying that's easy. How would we go looking for such a "shore?" There are none that we know of. We would just have to aim ourselves at a star that has big planets, and which therefore might have little, earthlike planets, and hope for the best.

I'm going on the assumption that we would want to land on a planet. That isn't necessarily the case. Putting oursleves on a permanent, renewable space station might make more sense in either the 10-year or 100-year scenario.

But what if we had been in that situation in the year 1800? If we were 100 years out from the big smash-up, I wonder whether our astronomy would have been sufficient even to tell us this fact? Presumably, one could just look at the night sky and know something was up. Under those circumstances, it doesn't seem possible that we could have done anything at all.

So here's to the hypotehtical inhabitants of a hypothetical planet that was once a neighbor of our newly discovered (very old) planet. I hope they were farther along than us technologically. I hope they found some way out of their predicament. And if not, I hope they went out with grace and dignity and (wouldn't it be nice) the biggest party their planet ever saw. They may have passed into oblivion, leaving behind no signpost or message in a bottle to declare that once they existed. So I'm glad I thought about them, and I hope anyone who reads this takes a moment to think about them.

There may be no way to remember them, but through us they are not entirely forgotten.

Posted by Phil at July 11, 2003 06:21 AM
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