This is Not a Simulation

When someone tries to explain the concept of planet transits, you often see simulated graphics like the one below:

Well James Gilbert from the University of Oxford took the video of the transit of Venus he captured in 2012 (which was a real example of the transit technique in our backyard) and made the simulation into a reality. He measured the Sun’s brightness throughout the duration of the transit video, and  the result is the below:

That’s no simulation! It’s truly amazing. You can find out more about how James made the video and took the footage at his blog: LabJG: James Gilbert.


3 responses to “This is Not a Simulation”

  1. Brian Warren says :

    Hi Meg,
    thanks for that: truly illuminating! So does this mean the original simulations that we were shown in the training aren’t correct. They had a smooth ‘U’ shape for a transit light curve. That’s the standard I’ve tried to follow closely, but admit to accepting ‘V’ shapes & very deep ‘U’s. But the main base of my selections has been the SMOOTHNESS of the curve (with some exceptions that were too big to ignore!).
    I’ll continue assessing possible transits the same, but will open my scope to include ‘bumpy bottomed’ curves also. I’ll stop including short dips, especially ‘V’ shapes: they’re out.
    Please correct me if I’ve got this wrong. I’d appreciate your directions.
    Brian Warren,
    aka hiwayman.

    • Meg says :

      Well V-shaped could mean it’s a grazing transit where the planet only goes over the limb. Most times the v-shape suggests its an eclipsing binary instead, but the shape of the transit alone shouldn’t be used to reject the hypothesis that the transiting body is a planet. This transit has more a U if you zoomed out more. It has a flat bottom and we do see that for other planets transits, depends on whether on where the track of the planet is across the star and timing resolution I would say. So U-shaped more flattish bottom U’s are all possibles and even in the V’s though much more suspicious.



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  1. Esto no es una simulación [eng] - March 30, 2014

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