Friday, 19 April 2013

Kepler continues

The big announcement in astronomy circles this week was the discovery of three more Earth-like planets by the Kepler spacecraft. There's a ton of coverage out there, but the New York Times is a good place to go for straightforward rundown of the finds.

Kepler-62e and 62f have 1.6 and 1.4 times the radius of the Earth, and lie comfortably within their stars theoretical habitable zone. Kepler-69c has a radius about 1.7 times that of the Earth. System K-62 lies around 1200 light years away, K-69 about 2700 ly.

Here's a nice artist's impression of all four Earth-like planets next to the Earth itself.

From left to right, we have the previously discovered K-22b, K-69c, K-62e, K-62f and Earth. The planets are shown to scale, but the look of the four new worlds is down to artistic licence.

Many of the articles turning up feature pretty rampant speculation as to how wonderfully hospitable for life these planets will be, with thick moist atmospheres and rolling oceans. However, these claims make a hell of a lot of assumptions as to the makeup of the planets and their systems. With only our own solar system to go on, we have little knowledge that is useful in predicting just how planets in other systems are likely to develop. Remember, also, that planetary scientists use 'Earth-like' in this context to mean any planet of size similar to Earth with a likely rocky makeup. This doesn't necessarily mean that the planet will have oceans and rolling green hills; Venus and Mars are Earth-like under these criteria.

A more illuminating look at the nature of our system compared to Kepler's discoveries can be seen here, at New York Times once again. It's a fascinating inforgraphic comparing the Kepler star systems.

Additionally, the good folk at Planet Hunters have had their own planetary discovery, provisionally named PH1b, accepted by the Kepler team and officially designated as Kepler-64b. The Planet Hunters website is open to all, allowing anyone to review the data and see if they can spot a previously unknown planet.

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