Astronomers have in the past 20 years located several hundred planets orbiting distant stars, and they have only scratched the surface. In a small patch of stars—less than 1 percent of the sky—in the Northern Hemisphere, NASA's Kepler mission has already found more than 100 planets, along with strong hints of thousands more. Stars across the sky ought to be similarly laden with planets. A recent study indicated that each star hosts, on average, 1.6 planets. Exoplanets, as these strange worlds are called, are as plentiful as weeds—they crop up wherever they can. Whether any of them harbors life remains to be seen, but the odds of finding such a world are getting better.
Graphics and interactive by Jan Willem Tulp (Sources: the Exoplanet Data Explorer at exoplanets.org; planetquest.jpl.nasa.gov; “The Exoplanet Orbit Database,” by J. T. Wright et al., in Publications of the Astronomical Society of the Pacific, Vol. 123, no. 902; 2011)
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5 Comments
Add CommentI find the title to this article to be a gross understatement (unless you're talking a very, very big bucket).
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Reply | Report Abuse | Link to thisBefore the recent outpouring of exoplanet discoveries astrophysicists wondered about the exoplanet mass spectrum. This mass spectrum ranges at least from Mercury-mass to about 20 times Jupiter-mass. Prevalent opinion was that the peak of the exoplanet mass spectrum would probably be at the low-mass or high-masses ends of the spectrum.
Discrete Scale Relativity definitively predicted that the peak would instead come at 8 x 10^-5 solar mass, which equals 17 Earth/masses or about the mass of Neptune.
Here are the results so far:
There are not yet quite enough representative exoplanet mass data to fully test this prediction, but the Kepler mission has found that the thousands of candidate exoplanets it has identified so far have a radius function that is strongly peaked in the Neptune range. Also, the inferred mass spectrum for exoplanets with periods less than 100 days is strongly peaked at roughly the mass of Neptune [M. Mayor and D. Queloz, New Astronomy Reviews, 56(1), 19-24, 2012; Figure 7].
Discrete Scale Relativity appears to be spot-on, and conventional astrophysics got it quite wrong and does not understand this mass spectrum.
For 14 definitive predictions of Discrete Scale Relativity, see: http://www.academia.edu/2042222/Predictions_of_Discrete_Scale_Relativity
5 of the definitive predictions are already verified or strongly supported by observations.
Why does everyone talk about the old failing paradigms of particle physics and cosmology, while a new unified paradigm that can explain all of nature, like Discrete Scale Relativity, is totally ignored by the physics community and the science media.
Are they interested in science, or obsessed with fashions, funding and status?
Robert L. Oldershaw
http://www3.amherst.edu/~rloldershaw
More like a drop in an ocean.
Reply | Report Abuse | Link to thisAlthough it is just a cliche indicating a small part of a much larger amount, a drop is nominally 0.05 milliliter, and a bucket may be assumed to be around 20 liters, thus there are about 400,000 drops/bucket. At 1.6 planets per star, the Milky Way would be expected to have half a trillion planets. So the title is a severe understatement in numerical terms.
Reply | Report Abuse | Link to thisGiven what we know about our own Solar System, and the detection of gas and dust disks around other stars, we should not expect to find just one or two plants/star, but a size distribution that follows a power law. For example, asteroid number varies about the inverse square of size, so there are a large number of smaller objects for every large one.
We currently only find a few planets/star because they are the largest and easiest to find. As our methods improve, we should expect to find lots more smaller ones.
The methods used to discover exoplanets seem to favor large planets close to their primaries whose orbits are are in a plane roughly parallel to the line of sight from the Solar System. I would assume that planets not meeting those criteria would be less likely to be detected.
Reply | Report Abuse | Link to thisCalculations would also be affected by knowing whether planetary orbits have a tendency to be in line with the general plane of the galaxy, since if they were, that would make a greater number of planets 'visible'. I would like to know if the above assumptions ae correct (my degree is in ancient history) and if so, were they factored into the estimate of the number of planets per star.