Some great news from the planet front has just arrived. As was expected Kepler has found lots of new planets. These planets are really planetary candidates and have to be positively confirmed but a high percentage definitely will be planets.
The recent findings increase the number of planets found by Kepler to 1235. 68 of these are Earth size, 288 are super Earth size, 662 are Neptune size, 165 are around the size of Jupiter and 19 are larger than Jupiter. 54 planets have been found in the habitable zone with five that are near Earth sized and the remaining 49 range from super Earth size up to twice the size of Earth with the remainder larger than Jupiter.
The habitable zone or Goldilocks zone is an area in which it is neither too hot nor too cold for liquid water to form. as 54 planets have been found in the habitable zone this could point to these having human like life although it is important to remember that life may not only exist where there is water.
These results show that planets are extremely common throughout the galaxy. This means that the stars that are nearby to our solar system must contain planets as well. This is not such a far out assumption as Kepler can only find a small fraction of the planets around a star as most of their orbits are not aligned in a way that Kepler can find them. Also Kepler is only halfway through its scheduled mission which means that a lot more planets will be found.
To make these planets even closer in appearance to the solar system 170 of the planetary systems show evidence of multiple planets including one which is called Kepler-11 that has been confirmed to have more than six planets. The planets have very varied structures with some having extremely low density and others denser than Iron. Earth’s density is somewhere in between these two extremes.
Kepler finds planets by measuring the decrease in light as a planet passes in front of its star. This is why the method that Kepler uses to find planets is called the transit method. Kepler requires three transits to positively identify a planet. Therefore if planets are close to their parent star they can be identified quicker as they have faster orbits but further out the orbit takes a longer. Planets in the habitable zone are expected to take three years to locate and verify.
These findings will make the Drake equation more accurate but increase the confusion about our lack of signals from alien civilisations.If there are so many planets why haven’t we heard anything yet? One reason could be that the radio era lasts a small-time so the radio telescopes only transmit and receive in a small window and you have to be listening at the correct time to intercept any single that passes Earth.
I expect in the future an exploratory probe will be sent to a suitable habitable planet and eventually we will go for a visit. We would need better spacecraft drives than we have today so the rocket scientists better start thinking.