Billions of planets may be just right for life
For a planet to have liquid water – something necessary to support life as we know it – it has to be within a certain distance of its star. Too close, and the water burns up. Too far away, and it’s a frozen wasteland.
But according to new research, most stars in the galaxy have so-called ‘‘Goldilocks planets’’ which sit in the habitable zone, where temperatures are just right for life.
New calculations in a study published on Thursday in Monthly Notices of the Royal Astronomical Society indicate that billions of the Milky Way’s stars have one to three planets in the habitable zone, meaning that they potentially have liquid water as well.
The calculations, produced by a group of researchers from the Australian National University and the Niels Bohr Institute at the University of Copenhagen, are based on a method called the Titius-Bode law. This law, which was created about 1770, predicts how planets in a solar system will be spaced out. The researchers applied the law to the 1000 exoplanets (and 3000 possible exoplanets) found by Nasa’s Kepler satellite.
The researchers looked at 151 planetary systems – ones where Kepler had detected between three and six planets – and found that the TitiusBode law fitted well with the way 124 of them were spaced out.
‘‘Using T-B’s law, we tried to predict where there could be more planets further out in the planetary systems. But we only made calculations for planets where there is a good chance that you can see them with the Kepler satellite,’’ said Steffen Kjær Jacobsen, a PhD student in the research group Astrophysics and Planetary Science at the Niels Bohr Institute at the University of Copenhagen.
In the planetary systems where ratios were off, they were able to estimate where ‘‘missing’’ planets might be.
Once those planets were added, all 151 systems showed one to three planets in their habitable zone. The researchers believe this indicates that most systems do have planets orbiting at the proper distance to hold liquid water.
To help confirm their theory, they’ve flagged several supposed Goldilocks planets that Kepler should be able to see at some point. They hope that other scientists will spot them, adding weight to the ‘‘missing planets’’ they’ve calculated.
Unfortunately, being in the habitable zone doesn’t mean that liquid water is present, and the presence of liquid water does not necessarily mean that life ever can, will, or did exist. But here’s to hoping.