May 10, 2013

• Our Very Normal Solar System Isn’t Normal
  http://www.npr.org/blogs/krulwich/2013/05…solar-system-isn-t-normal07

  excerpted from an article by Robert Krulwich, 5/6/2013

  Some things you just count on. Like if we ever meet a space alien, it should have eyes (and maybe a head). Like somewhere out there, there are planets like ours. Like we have an ordinary solar system —”ordinary” because you know what it looks like …

  

  It’s got a sun in the middle, little planets on the inside,bigger ones farther out. That’s what most of them should look like, no?  We thought they should. In astronomy class(for any of us who took astronomy) they talked about a “frost line.”That’s a line, some distance from the sun, where it gets too cold to make rocky planets.

  

  They said when a planetary system forms, the dust that’s closer in, on the hot side of that line, melts into rocky minerals, forming solid balls, like Earth and Mars.  But farther out, on the frosty side, the dust stays gassy, mostly hydrogen compounds, swelling to gigantic size, like Jupiter, Saturn and Neptune.

  Distance from the sun sculpts the neighborhood. That’s why most planetary systems in the universe were supposed to look like us. Rocky planets in, gassy planets farther out.  Then we looked. And what did we discover?

  Big gassy planets not where they should be. Instead of keeping their distance, and staying past the frost line, there are dozens and dozens of Jupiter-sized balls (big! really big!) tucked incredibly close to their star, squeezing so close, their “year,” their orbit, lasts only a few Earth days. They are in tighter than Mercury.

  Which means these once-cold planets are now, puzzlingly, hot.Astronomers call them “hot Jupiters,” because temperatures at their cloud tops can sizzle at 1,000 degrees Celsius.

    Or — and here’s a pattern that shows up very often — you’ll get not one, but two biggish Neptune-sized planets, like hungry twins, nuzzling together near their star. Very near.

  Or we find a bunch of rocky planets — larger than Earth, but definitely rocky — gathered in tight formation around a star (with orbits that last 3.7 days! 10.9 days! Would you feel the whip, like a roller coaster?) and— large, then small, then large again, then small, then large … How odd.

  As of this month, we’ve discovered 884 planets, 692planetary systems, 132 of them with more than one planet and, strange to tell,almost none of them look like us.

  “We are now beginning to understand that nature seems to overwhelmingly prefer [planetary] systems that have multiple planets with orbits of less than100 days,” Steve Vogt, astronomer at the University of California, Santa Cruz. “This is quite unlike our own solar system, where there is nothing with an orbit inside that of Mercury. So our solar system is, in some sense, a bit of a freak and not the most typical kind of system that Nature cooks up.So our solar system is … a bit of a freak.” 

  All of sudden, we’re the abnormal ones.

  …Mike Brown, an astronomer at Caltech… is getting more and more uncomfortable. Though it will take a while to discover smaller planets, right now there’s only one planetary system that looks a lot like our own, he says. “…What I would desperately like to know is whether or not it has the small rocky bodies on the inside too. But it’ll be along time before we can find that.”

  Meantime, he is trying to get used to the idea that we live on an unusual planet in an unusual solar system. That’s two”unusuals.” One more than he’s used to. To live doubly-unusual, is to be luckier — and perhaps rarer — than we knew.

  “It really is something that I find deeply weird,”he writes. “What does it all mean? I don’t know.”

  aNNa’S NoTe:  I love astronomy articles like this… where science proves that where Yehovah set us is NOT found in the other solar systems.  It’s NOT normal.  It’s special – just for us.  This one is going in our nature notebooks (astronomy section)… right up front!

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