New estimate of 300 to 900 billion planets in habitable zone in the milky way galaxy is triple the old prediction

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With about 300 billion stars in our galaxy, researchers analyzing Kepler data and modified theory calculate there are 600 ± 300 billion planets in circumstellar habitable zones in our galaxy.

In the observable universe there are about 100 billion galaxies. Thus there are approximately 10^22 stars in the observable universe and twice that many planets in circumstellar habitable zones in the universe.

That’s a lot of real estate for alien development. Not all of these habitable zone planets will be wet and rocky like the Earth, but a fair fraction (about 30%) should be. Now we need some zippy interstellar spaceships to colonise and over-populate all these worlds before the aliens do.

The Goldilocks zone or habitable zone around a star is where the temperature is just right to have liquid water. Our new result suggests that there are, on average, two planets in the habitable zone. Aditya Chopra, ANU, adapted from NASA/JPL

Monthly Notices of the Royal Astronomical Society- Using the inclinations of Kepler systems to prioritize new Titius–Bode-based exoplanet predictions

Nextbigfuture covered this paper two weeks ago. This new look is applying the results of a prediction tripling the estimate of habitable zone exoplanets to galactic and universal estimations.

Abstract – Using the inclinations of Kepler systems to prioritize new Titius–Bode-based exoplanet predictions

We analyse a sample of multiple-exoplanet systems which contain at least three transiting planets detected by the Kepler mission (‘Kepler multiples’). We use a generalized Titius–Bode relation to predict the periods of 228 additional planets in 151 of these Kepler multiples. These Titius–Bode-based predictions suggest that there are, on average, 2 ± 1 planets in the habitable zone of each star. We estimate the inclination of the invariable plane for each system and prioritize our planet predictions by their geometric probability to transit. We highlight a short list of 77 predicted planets in 40 systems with a high geometric probability to transit, resulting in an expected detection rate of ∼15 per cent, ∼3 times higher than the detection rate of our previous Titius–Bode-based predictions.

SOURCES – The Conversation, Monthly Notices of the Royal Astronomical Society