Planet-spotting

(Courtesy: Randall Munroe/Creative Commons)

By Tushna Commissariat

At first glance, the image above might remind you of a colour-perception test. But what one-time physicist and comic-designer Randall Munroe has done is to create a to-scale visualization of all the known 786 planets that we have discovered over the years – including the eight of our own system.

He has been particular enough to note that the size of some of these planets has been determined simply on the basis of their mass – meaning that they might, in actuality, be smaller and denser. Interestingly, this is not the first time that Munroe, who is behind the hugely popular xkcd.com webcomic, has had something to say about the billions and billions of exoplanets that we now know exist. In fact, in a previous comic, he talks about travelling in interstellar space, with one particular character agonizing about his partner’s apparent apathy over the wonder of all the worlds.

While Munroe’s newest comic is excellent, unfortunately, he is already out with the count. As of yesterday, the team behind NASA’s planet-finding Kepler telescope announced that it has found another two planets in its data. However, these two planets are caught in quite a clinch – they are closer to each other than any planetary system we’ve found to date.

The cosy system, mundanely called Kepler-36, contains two planets circling a subgiant Sun-like star that is several billion years older than the Sun. The inner world, Kepler-36b, is a rocky planet with a 14-day orbit. It is about 1.5 times the size of Earth and is 4.5 times as massive. The outer world, Kepler-36c, is a “hot Neptune” planet with a 16-day orbit that is 3.7 times the size of Earth and 8 times as massive.

The researchers point out that as the planets are so close to each other, from the surface of the smaller planet one would see the partner-planet as we see the Moon, only 4–5 times bigger, filling up its sky and presenting quite a spectacular view.

If Munroe’s first exoplanet comic does prove to be correct, I vote we point our spaceships towards this rather interesting system.