simulated transits
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by
bethrobin
I feel kind of cheated. I was excited to find a transit, but then it said it was simulated. Is all of this data fake?
Posted
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by
dfischer123
scientist
Simulations are an important way to see what fraction of planets of different sizes are found. If users find 90% of simulated transits for Jupiter-size planets and 50% of simulated transits that are the size of Neptune, then we know that in the real data, the number of Neptune-size planets is about twice the number that were identified, while we would only add 10% to the number of Jupiter-size planets that were detected. Without simulations, we can't do the science of figuring out how often different types of planets form. Finding a simulated transit is every bit as "real science" as finding a transit. We need the collective 100,000 eyes of planet hunter volunteers to find transits and the unexpected. Hope that helps!
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DZM
admin
Thank you for the excellent explanation, @dfischer123 -- that's a useful thing to know.
In addition -- and this is useful for me to know as I'm still learning about all of the projects -- why are we/volunteers told after classifying if there was a simulated transit, whether or not they marked one?
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by
mschwamb
scientist
in response to DZM's comment.
Hi Darren,
So people don't think they found a new planet when it's a synthetic light curve. We always put up a message saying the light curve was a simulation after classifying and tag them in Talk, so it's clear to everyone. We can't say before because they might change how you or other classifiers might mark the light curve. If you knew there was a simulated transit in the light curve, you might me more likely to mark an iffy feature than you would if you didn't know that.
You can learn more about the importance of the simulations in this blog post and the science page.
Cheers,
~Meg
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DZM
admin
Sure, but what about when I miss one... so I don't think that I found anything... and then the thing pops up, essentially saying "there was a synthetic transit here, but you missed it, buddy?" 😃 (Happens more often than I'd like to admit!) That sometimes makes makes me feel like I'm going to miss a real transit on the off-chance I do stumble upon one.
But, yes, of course, you don't want to tell people in advance that it's not real data, and you don't want them to get the impression that they've found something when it's simulated.
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by
mschwamb
scientist
in response to DZM's comment.
Hi Darren,
We're very careful about how we worded the simulation message because we don't want to make it sound like we're testing a volunteer or judging your contribution. We're testing the project as a whole. And if you did miss a simulation, you might have missed a real transit. That's the exact point of the simulations, it will tell us what kinds of planets and orbits Planet Hunters is good at finding and what it is not good at finding. I encourage to read the blog and the science page I posted above for more context. Human beings are not going to spot all transits (especially ones with very shallow depths), so this is our way of figuring out where that limit is. The simulations are very important.
Also I think it's our responsibility to be open and honest about what we're showing volunteers. So if we've done something to the data that we're showing, and its not pure Kepler data we should tell the classifier.
Cheers,
~Meg
Posted