Roberto Sanchis-Ojeda and Josh Winn of MIT co-authored a paper in “Nature” that reveals the details of the planetary system of Kepler-30. 10,000 light-years distant from Earth, the system has three planets that orbit around the star’s equator, and rotate in the same direction as their star. What’s important about this find is that the planets of our own star, Sol, orbit in exactly the same way.
Stars rotate, just as planets do. Therefore, our sun has an axis with poles. And it has an equator. All of the planets in our solar system go around that equator in roughly the same flat plane. Put another way, if the orbits of the planets could be drawn in space, they would go around the sun’s “waist” like the rings of Saturn. The planets also spin in the same direction as the star (with the exception of Venus, which is slowly rotating backward due to a probable collision, and Uranus, which has been knocked on its side). This arrangement suggests that the planets and the sun all formed from the same rotating disk. Kepler-30 appears to have also formed this way.
Since this basic similarity exists, we can surmise that our solar system is not unique. However, before we can say that all planets orbiting in the same plane also spin the same way as their star, more examples need to be found. That said, the planetary orbits are probably stable, which increases the possibility that they harbor life. The more star systems we find like our own, the greater the chance that we will find life as we know it.
The discovery was made in January with the Kepler telescope. Kepler’s mission is to find Earth-like planets. Larger planets, including gas giants, super-sized Earth-like ones and ice giants, have already been discovered. Smaller ones like our own have proved more elusive. For comparison, Jupiter is 11 times the diameter of Earth, and many of the gas giants that have been found are larger than that.
The Kepler team uses the transit method of discovering planets. In this method, the telescope watches the surface of a distant star, and waits to see the light from the star diminish as a planet moves in front of it. Another method used to discover some of the larger planets has been to record a “wobble” in the star’s motion, which is caused by the gravity of the nearby planets.
Of course, finding a planet like Earth and getting there are two different things. We may discover a great many worlds worth visiting long before we ever devise a way to get there. With the distances that must be covered, current ships would take thousands of years to reach even the nearest star. The recent discovery of the Higgs boson has led to speculation about new technologies that might make such things possible, but only time will tell.