Science: New Planets

Attenion!  We are no alone in the universe!

No, we haven’t found ET, but we may be getting close.  The fine folks at SETI have been hard at work scanning a nearby star that goes by the name of Epsilon Eridani.  What they found is the first verifiable proof that our solar system may not be unique in the universe.  Essentially, this is what happened:The Hubble telespcope has spied upon Eridani, a bright star only 10.5 light years away (in astronomical terms, that’s about as close as the kid who dorms down the hall, blasting his obnoxious techno while you try to study), numerous times, and scientists have suspected that planets might orbit it for awhile.  The Hubble confirmed a large gas giant orbiting it a few years ago, the first concrete evidence of a planet outside of the 8 (or 9) that we’re accustomed to learning about in science class.

Just recently, however, there was some indirect evidence that there may be quite a few planets, not just the one scientists have predicted, and that it might be a pretty close approximation to what our solar system looked like a little over three and a half billion years ago (Epsilon Eridani is only 850 million years old, compared to our star, Sol, which is 4.5 billion years old).

The primary evidence for these claims are based upon two asteroid belts and an icy field of debris orbiting around the star.  The belts, visible with the Hubble’s massive telescopic power, are interesting, because they imply that there must be something in between them.

Here’s a fun and tasty project to teach you how they deduce this.

Spill some M&Ms or Skittles or something onto a table, and put something big in the middle of the pile to represent the star.  Now, account for gravity, which tends to pull things into a circular or spheroid shape, so round it out so it’s circular and evenly space them out.  Now, eat the leftovers.

The candy is essentially the dust cloud, and large and small chunks of rocks and ice, essentially a giant asteroid and dust cloud surrounding the star.  This is what it would look like it Epsilon Eridani had no planets.  Take your pinky finger and poke somewhere in the cloud, and ‘draw’ a circle around it.  Notice how you, by pushing the Skittles (or whatever) out of the way, that you’re essentially clearing an orbit out.  That’s the effect of a planet, it essentially works like a little mop, sweeping up asteroids and and dust into it’s gravitational field.  After a few million years, this clears out a swath around the star, and eventually, with a few inner planets, the ‘inside’ of the solar system is largely free of asteroid clutter.

There are two main asteroid belts around Epsilon Eridani, one more or less around the same distance as our own (between Mars and Jupiter), which implies at least one planet is inside of the resulting ring, probably a small, rocky one, like our own, orbiting within the habitable zone where life could presumably evolve.  Now take your thumb (larger space) and make another ring, further out.  That’s the second belt, and in between which, scientist assume that larger gas giants may reside, including the one previously discovered.

Those few Skittles that might be scattered around outside form the second ring, and presumably there might be planets in between that and the second.  That ring isn’t as much an asteroid belt as the others, but more of a loose conglomeration of ice shards and frozen rocks, akin to a similar belt that orbits outside of Pluto (remember the talk of a tenth planet?).  That field, in our system, is known as the Kuiper Belt, 

Scientists hope to be able to view the individual planets soon, as telescope technology improves.  I’m looking forward to it.  You can eat the rest of your Skittles by the way.  Now go brush your teeth, and if you decide to look up at the stars tonight, Epsilon Eridani is a very bright star near Orion’s Belt, in a constellation called Eridanus, which looks like a snake, or a deformed tape worm.

– Fernando Arrue

Tags: asteroid belts, asteroids, astronomy, Epsilon Eridani, Fernando Arrue, Hubble, Hubble Telescope, Kuiper Belt, life on other planets, new planets, planets, possible life, SETI