Worried that we wouldn’t find a second Earth in your lifetime? Well, your fears look misplaced. A new report indicates that rocky planets are probably everywhere, around most of the stars out there. And the more rocky planets there are, the more likely it is that they will be in the star’s habitable zone.
The claim is based around the spectrographic analysis of over 150 stars that are planet candidates. The team from the University of Copenhagen was looking at the levels of various metals in the star. Previously it had been assumed that rocky planets could only form around metalline-rich stars, which would make them more uncommon.
But while gas giants are still more common around metalline-rich stars, rocky planets don’t seem to care. If there’s a star, then they will form around it.
Of course, that doesn’t mean finding the rocky planets will be any easier. Small planets are still devilishly difficult to spot thanks to their low mass and small circumferences. We will still need a combination of more advanced search techniques and better optics to spot any planets that could theoretically support us. But at least we know the planets will be there when we go looking.
Of course, high metal stars are still more likely to host gas giants than those with less metal. And that explains why we believed that high metal stars would have more rocky planets in the first place. Gas giants are the easiest type of planet to spot by far: regardless of the spotting technique, gas giants stand out. It goes without questioning that planetary formation models would be based on the evidence we have seen, which in this case was planets orbiting stars with high levels of metal.