Wednesday, December 4, 2013

That's Hot

Back in October, the Curiosity rover found... well, technically it found moist dirt, but that counted as finding water for scientific purposes. It'd be great to find bodies of water like we have on Earth, but you take what you can get.

Such as what NASA has found via the Hubble Telescope: water, or at least signs of water, on five distant planets which for now all still have those nigh-meaningless alphanumeric-soup placeholder names. The actual makeup of the water on each of them is uncertain, as the Hubble isn't quite that powerful, but we can at least analyze the atmospheres, as was done by aiming Hubble at each of them when they were passing in front of their respective suns.

Don't get too excited about those planets, as none of them are going to be remotely livable. All five are known as 'hot Jupiter' planets, which means they're big (and thereby easy to detect); they orbit very close to their parent sun with years as short as a couple days; and a lot of the time they're tidally locked, which means the same side of the planet is always facing its sun (our moon, for example, is tidally locked to Earth, thus the phrase 'dark side of the moon'). When a planet is tidally locked, it gets unbearably hot on the near side and unbearably cold on the far side, with only a narrow band in between that might be at a decent temperature.

However, there is one more thing to note. In the case of all five planets, the water signal was weaker than NASA was expecting, as there was dust obscuring the signal. Which means two things: first, hot Jupiters might have that dust as a common feature, and second, just because water can't be detected doesn't necessarily mean it's not there. The problem could well be with the tools or the signal and not with the planet.

And part of it is in fact the tool. Hubble is only strong enough to pick up water signals in gas-giant planets. Smaller, rockier planets like ours, planets in the habitable zone, need a more powerful telescope, and NASA isn't projected to have one of those up in the sky, the James Webb Telescope, until 2018. But the gas giants are taken as useful test cases, comparatively easy planets to monitor so the procedure can be fine-tuned for when the more difficult 'Earthlike' planets are ready to be looked at.

Until then, we can only fantasize at the ways in which those planets will be proven to be hilariously uninhabitable as well.

No comments: