There are things you get used to, take for granted. When I was growing up I loved looking at National Geographic’s Our Universe book. It’s a stunningly illustrated compendium of the celestial bodies in our solar system and galaxy. It had an image of a space ship on the cover, but the book was only about the things we know. Things that we had seen with either our own eyes, in photos taken through telescopes or beamed back through space from probes we sent out. They were re-imagined by artists and information designers, but we knew they were real. Things like a planet that was home to a hyper logical, green blooded race, or a dry desert planet that orbits two suns on which travel droids that we aren’t looking for were just imagination.
In less than 20 years, astronomers have gone from not knowing if other planets exist in the universe, to our current Kepler catalog on almost 2000 planets. Our Milky Way galaxy may be home to at least two billion Earthlike planets, a recent study based on initial data from from Kepler space telescope shows — a number that is actually far lower than many scientists anticipated. (The Daily Galaxy)
Which is why I’m left wondering what it means that the predictions we make completely in the spirit of fiction are coming true in fact. The Kepler Spacecraft, who’s mission is to detect objects orbiting distant stars, has found a planet that could be habitable and another that may be emitting radio signals.
Tatooine Planet
One of the coolest images from the original Star Wars movie was a desert landscape with two setting suns. Here on earth, we only have one warmth and live giving star to power our climates harvests and imaginations. But Kepler has found a planet, a gas giant similar to Saturn, orbiting a twin star, or binary star. While we could never bullseye womprats (not much bigger than 2 meters) in a t-16 on Kepler-16b, it could well hold an Earth like moon where we could. Think about that! How cool would it be to live on a moon orbiting something like Saturn which orbits not one but TWO stars?!?!?
Alien radio waves
Recently, the Search for Extra Terrestrial Intilligence (SETI) detected radio signals coming from the area of a potentially habitable exoplanet, or a planet outside (exo) our own solar system. This is not confirmed, so we can’t start phoning home yet, but it makes you think. Who’s out there?
“These signals look similar to what we think might be produced from an extraterrestrial technology. They are narrow in frequency, much narrower than would be produced by any known astrophysical phenomena, and they drift in frequency with time, as we would expect because of the Doppler effect imposed by the relative motion of the transmitter and the receiving radio telescope,” according to the Berkeley team. (The Daily Galaxy)
How do we know all this?
There are two concepts here that are simple to grasp, but not obvious. 1) How Kepler figures out there is a planet, and 2) how we know they could be habitable.
The Kepler determines that there is a planet orbiting a distant star simply by waiting to see it. Planets can’t be seen from great distances because they do not emit any light, they only reflect the light of their own star. We can see the planets in our own solar system because they are so close. Kepler watches distant stars and waits for them to dim as a planet passes in front of them. If the observe the same dimming three times in predictable intervals, they know it’s a planet. If Kepler is watching a star whose planets orbit such that they never pass between Earth and the star, then we never see them. So there could be far more planets than we’ll ever know about.
We know exoplanets are potentially habitable because they are within a given distance from their sun called the “goldilocks zone.” If you’re sitting around a camp fire on a chilly evening you need to get close or you’ll get cold. But a fire is dangerous and if you get too close you’ll get too hot, maybe even burn your feet or choke on the smoke as the wind blows it in your face. So you have to be far enough away to be cool enough to survuve and close enough not to freeze. Since life as we understand it depents on liquid water, the distances are determined by the temeratures at which liquid water boils and freezes.
Kepler
The Kepler Space Craft is named for Johannes Kepler, a German mathmatician and astronomer who in the 1500’s figured out the laws of planetary motion. Basically, he figured out how planets move around the sun, and each other, making sense of the way things appear to move in strange ways about the night sky to an observer on Earth.
-Mike
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