Wednesday, 24 July 2013

The Exoplanet Blues: Why We Love and Hate Astronomers

Humans are on the cusp of what will prove to be the most frustrating scientific discovery in history.

Telescope technology has improved drastically over the past 100 years. We have gone from looking though wooden tubes with glass lenses, to building-sized telescopes powered by computers, to space-based telescopes that can read your T-shirt from their geosynchronous orbits.

At the same time, astronomers have gotten more and more clever. They have figured out that if you watch a star very closely and see it wobble a little on its axis, you can be reasonably sure that there is something orbiting it. Pretty frequently that something turns out to be a planet. From there, scientists have developed calculations that tell you how big the planet is, how far away it is from its home star, and even what it is made of.

The partnership of better ideas with more advanced technology came to a head in earlier this month when researchers from NASA in North America and ESA  in Europe published the first paper describing the colour of a planet outside of our own solar system. Even more exciting, the planet they studied turned out to be blue.

The researchers determined the colour of the planet by looking at the light signature from its parent-star and paying close attention to the wavelengths it was emitting. Using some of the outrageously clever and incomprehensible equations that astronomers are known for, they determined when the planet they were interested in would move behind its star and out of view. When it did, they compared the light they could see while the planet was visible with what they saw when it was eclipsed. Punch that data into a computer, and bingo! Blue planet.

Now before you get too excited, blue probably doesn’t mean water. The planet in question (HD 189733b) is a gas giant, meaning it isn’t much like Earth. A couple other planets in our own solar system – Neptune and Uranus – are also blue and definitively hostile to life. Adding insult to injury, HD 189733b (they really need to work on that name) orbits really closely to its parent star and is probably around 1000 Celcius. What scientists call a "Hot Jupiter."

The real boon to astronomy that this research signals is in the implications of the new planet-colour-coding technique used by the researchers. In the past couple years astronomers have discovered literally thousands of planets outside of our solar system (dubbed exoplanets). It is now only a matter of time before they find one that is rocky, blue, and in the habitable “Goldilocks Zone” around its parent-star.

Things might even get more specific than that. One day in the not-too-distant future scientists may be able to detect the chemical composition of atmospheres. Basically they will be able to look toward an exoplanet and say “Yeah that thing is pumping out a lot of oxygen and we’re pretty sure we can see an Arby’s.”

The frustrating part of all of this is that when it happens – and “when” is most assuredly the correct word – there won’t be anything more we can do about it. We will basically have confirmation that there is a planet covered in water and trees x-amount of light years away and we will have absolutely no hope of getting there or contacting whoever it was that opened the extraterrestrial Arby’s.

Don’t get me wrong. I will be thrilled when that day comes. It will be ground-breaking and life-affirming and I will stand in awe of the geniuses that pulled it off. But it will add an eagerness to stargazing that is at odds with the usual relaxation.

It will be like filling a room with adorable puppies and locking some kids in an adjacent  room, behind some two-way glass where they are forced to stare at something they want but can never have. Astronomers are the cruelest, cleverest bastards this side of the Andromeda Galaxy...