… 995, 996, 997, 998…





Icy Exoplanet (artist's impression)
Source: ESO (


We’ve already touched on the subject of exoplanets, but it is such a rich and exciting topic, with something new popping up every day. It all started two decades ago, when astronomers first discovered a world beyond the boundaries of our solar system. Right now, as we speak, the number of discovered planets outside our Solar System is nearing 1000. The number skyrocketed since 1992, when researchers were able to detect two planets that were orbiting around a rotating neutron star, approximately 1000 light years from Earth. The first official confirmation of a planet circling around a star, somewhat similar to our Sun, didn’t come until 1995.

As scientists continue to refine their equipment and techniques and sift through vast amounts of data captured by the instruments on Earth and in space, new information just keeps piling on. It is estimated that the most information in the near future should come from Kepler space telescope, launched by NASA, which was already the main source of many fantastic finds, until it was damaged when the second of its four orientation-maintaining reaction wheels malfunctioned. So far, Kepler has been able to detect 3,588 space objects that are potential planet candidates. Although only 151 of them have been officially confirmed as planets, astronomers expect that over 90 percent of the candidates will end up being the real deal.

Source: NASA/JPL-Caltech (

These numbers, even though they are pretty impressive, are barely scratching the surface of our galaxy, the Milky Way. Take into account the fact that Kepler telescope studied only a small patch of the sky, and it could only spot a planet that happened to cross the face of the star it was orbiting around, from the telescope point of view. That’s why there is reason to believe that there are many more out there going undetected by us. As a matter of fact, researchers have made an estimate that every star in the Milky Way galaxy, and there’s 100 billion of them as we mentioned in one of our articles, hosts 1.6 worlds. If you do the numbers, that potentially 160 billion planets in our galaxy alone.

Source: NASA’s Goddard Space Flight Center/S. Wiessinger (

And that’s only the tip of the iceberg. If you take into account “rogue” planets, whose orbit isn’t bound to a specific star, but they rather wander through space, the number is even larger, since rogue planets outnumber “normal” planets by about 50 percent. Having the correct numbers is important, obviously, but what is of even more interest to astronomers is the nature and characteristics of those far away planets. Their diversity has been incredible, with some being as light as Styrofoam, and some of them being denser than iron. However, the most interesting planets are those which orbit their stars inside the inhabitable zone, at just the right distance from the star, which makes it possible for the planet to have water in liquid form, which means that the planet could possibly support life as we know it. The evidence of a planet similar to Earth existing is maybe already in the data gathered by Kepler, it’s just waiting to be pulled out.

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