Today’s exercise in bad science reporting…

[UPDATE] Or I could be an idiot, myself.  The theory has been advanced, from time to time.  Via Matt in comments.

…will be brought to you by the BBC.  While reporting the welcome news that we’re getting better and better at detecting extrasolar planets, this gem made it past the editors:

The scientists saw evidence of three of these “low-mass planets” orbiting a star called 61 Virginis, which is just 28 light-years from Earth and is visible with the naked eye in the constellation of Virgo.

The smallest of the three was five times the mass of Earth, and orbited the star once every four days.

Every four days. I’ll leave the actual math on that one to somebody who is capable of doing it, but that’s not an orbit: that’s a centrifuge.  To give you an idea: Mercury (the planet with the shortest year in our solar system) needs 88 days to orbit the sun, and that’s at .46 AU. I’m trying to imagine the sweet spot of a planet larger than Earth being able to spin around a star that quickly, and I’m failing.

Put another way: when an English major can see the oddity in your reporting right away, you might be having a problem with your reporting.

Moe Lane


  • Matt says:

    Hmmm…..I’ve found a pre-printed version of the paper that was accepted to the “Astrophysical Journal” for this. It says “Our 12.8 years of Keck High Resolution Echelle Spectrometer precision RVs indicate the presence of a 7.4M planet on a 5.77-day orbit.”
    It could be bad science, bad tech, or bad math, but it doesn’t appear to be bad science reporting.

  • Astro101 says:

    Actually, large mass objects in close orbits do have very fast orbits. There are binary stars that orbit each other in minutes. It’s basic orbital dynamics as defined by Johannes Kepler about 400 years ago. If you want to play with masses and orbital axes vs. orbital periods, this is a handy little site:

    The science is good, the reporting is good – except the reporting by the English major 🙂

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