E is for . . .

Image source: Fanpop, glelsey's View of Saturn

Exoplanet. What is it? Simply a planet that orbits a star other than our sun. Over 2,000 have been discovered so far. The interesting ones in terms of finding life are those that exist in what’s called the habitable zone.

In this zone, the temperature allows water to exist as a liquid. If an exoplanet is too close to its star, water will evaporate. If it is too far away, water will freeze.

Notice that this definition assumes habitation by creatures like those found on earth. The habitable zone doesn’t account for creatures made primarily of something other than water, say liquid nitrogen for example.

Speaking of liquid nitrogen, its boiling point is frighteningly cold: -196 °C. A critter with a high degree of liquid nitrogen for blood would vaporize on Earth the second it slithered out of its spaceship. It would be much happier somewhere like Pluto with temps around -223 °C.

Of course, water-based beings would be miserable on Pluto.You want to see what happens to earthly things at such low temperatures? Check this out:

Image source: Gizmodo, photographer Martin Klimas

I’m seeing the potential for a seriously star-crossed lover’s tale here. And Bella/Edward thought they had problems!

Are you a Game of Thrones fan? Ever wonder how you might justify winters that last arbitrarily long? Snowball states might be the key. According to Wikipedia, an exoplanet in the habitable zone can periodically become frozen by orbital fluctuations (among other things).

Image source: Fanpop, Winter is coming by Invisible-Tears

Say what? Well, the build up of ice reflects sunlight away from the exoplanet causing more cooling which leads more ice which causes to more cooling which leads . . . you see where I’m going. This feedback loop can freeze a planet.

So how does winter end? Dragons? Nope, volcanoes! They emit carbon dioxide into the atmosphere creating a greenhouse effect to thaw the planet out. (Then again, if Daenerys' dragons emitted carbon dioxide with their fire breath instead of carbon monoxide, maybe they could reverse an ice age. Someone notify George R.R. Martin!)

Image source: Bitch Flicks

What do you call a planet that isn’t orbiting a star? A rogue planet. The movie Melancholia examines the life of two sisters (one about to marry) as a rogue planet prepares to collide with Earth. I started watching this on Netflix and loved the imagery (see above), but I got bored in the middle and gave up.

Anyone see Melancholia? Should I try to finish it? Anyone ever freeze things with liquid nitrogen?

Today's also an IWSG day, but my post is already too long. I'll whine about my sick kids and the pain of creating hyperlinks in Word next month. (Don't tell Alex.) But do visit his blog and those of this month's hardworking cohosts:  Megan Morgan, Chris Votey, Viola Fury, Christine Rains, Madeline Mora-Summonte, L.G. Keltner, Rachna Chhabria, and Patricia Lynne.