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twoeleventhe kepler planet-hunting mission, that is. or rather the people who want to popularize its discoveries make me crazy, because they seem too willing to mix fiction with their science.
the ugly first:
a few months ago, the folks on the kepler team published a picture of what kepler found around the star now called kepler-62. that image seems to have disappeared into the memory hole, but they have published this new and improved version:
from NASA's Kepler Discovers Its Smallest 'Habitable Zone' Planets to Date
there's just one problem with this image. this is a simulation of sort of data kepler actually recorded about that star:
from Transit Detection
right: it's just a measurement of how much light it saw; it didn't actually see any planets, much less determine if they had atmospheres, continents, or liquid water. getting from the light measurements to "there's planets around them thar stars" is just math, as is figuring out how far away from the star they are. from that, estimating how much light they get is easy. that's the end of the actual facts we know.
getting surface temperatures requires some notion of the planets' atmospheres, about which we know nothing. even estimating how hot/cold the planets would be as airless rocks takes a guess as to how reflective they are, which we also don't know. and yet, the kepler team make these pretty pictures showing clouds, land, water, ice-caps, and other goodies. the obvious question is why.
they're apparently just following orders. i have a Highly Placed Source -- a moderately big-name astronomer -- who recently went to a conference about said results. said Source presented my objections to the image to both one of the people who runs the kepler team and one of the NASA bigwigs who controls their money. the actual scientist is, in fact, concerned about over-selling "earth-like planets", since we don't actually know of any... and won't until the james west telescope starts measuring their atmospheres some time after 2018.
the bigwig, OTOH, apparently believes that hyperbole is good and science be damned. pretty pictures get attention, even if they are wrong. *sigh* they do so well with the (local) planetary missions and the other telescopes...
in any case, the bad:
i'm not quite sure of where this image comes from originally:
immediately from Tau Ceti Probably Does Not Have a habitable World (click for much bigger)
chester harman, the creator, appears to be a researcher at u. puerto rico (associated with the arecibo radio telescope), but i can't find an original of their image on with their other press releases, tho there are other similar images there. (i didn't look too hard, tho, since it doesn't specifically matter where it is on their site.)
i like this image better because it gives some idea of what astronomers mean by "earthlike", even if the planets and their surface conditions are bogus. by "earthlike" they mean "there's at least a dim chance of liquid water", even tho we would probably consider nearly all the worlds far too hot or far too cold.
also, i'm happy that whoever made the picture of kepler 62f in this image (all the way on the left in the "ugly" picture) has partially corrected it to being a snowball world, which is much more likely given its orbit. (but, of course, we don't actually know.)
the good:
i really like this image showing the worlds kepler has discovered transiting their suns:
from Kepler's Planet Candidates: A Family Portrait (larger image and explanation available there).
kepler hasn't actually *seen* the transits as depicted -- it can't resolve the stars, much less the shadows of the planets -- but the data it gathers makes calculating the sizes of the stars and the planets transiting them trivial, given what we know about stars, their color, brightness, and size. so, the image is correct, informative, and visually interesting. this is how kepler's science should be shown.
the ugly first:
a few months ago, the folks on the kepler team published a picture of what kepler found around the star now called kepler-62. that image seems to have disappeared into the memory hole, but they have published this new and improved version:
from NASA's Kepler Discovers Its Smallest 'Habitable Zone' Planets to Date
there's just one problem with this image. this is a simulation of sort of data kepler actually recorded about that star:
from Transit Detection
right: it's just a measurement of how much light it saw; it didn't actually see any planets, much less determine if they had atmospheres, continents, or liquid water. getting from the light measurements to "there's planets around them thar stars" is just math, as is figuring out how far away from the star they are. from that, estimating how much light they get is easy. that's the end of the actual facts we know.
getting surface temperatures requires some notion of the planets' atmospheres, about which we know nothing. even estimating how hot/cold the planets would be as airless rocks takes a guess as to how reflective they are, which we also don't know. and yet, the kepler team make these pretty pictures showing clouds, land, water, ice-caps, and other goodies. the obvious question is why.
they're apparently just following orders. i have a Highly Placed Source -- a moderately big-name astronomer -- who recently went to a conference about said results. said Source presented my objections to the image to both one of the people who runs the kepler team and one of the NASA bigwigs who controls their money. the actual scientist is, in fact, concerned about over-selling "earth-like planets", since we don't actually know of any... and won't until the james west telescope starts measuring their atmospheres some time after 2018.
the bigwig, OTOH, apparently believes that hyperbole is good and science be damned. pretty pictures get attention, even if they are wrong. *sigh* they do so well with the (local) planetary missions and the other telescopes...
in any case, the bad:
i'm not quite sure of where this image comes from originally:
immediately from Tau Ceti Probably Does Not Have a habitable World (click for much bigger)
chester harman, the creator, appears to be a researcher at u. puerto rico (associated with the arecibo radio telescope), but i can't find an original of their image on with their other press releases, tho there are other similar images there. (i didn't look too hard, tho, since it doesn't specifically matter where it is on their site.)
i like this image better because it gives some idea of what astronomers mean by "earthlike", even if the planets and their surface conditions are bogus. by "earthlike" they mean "there's at least a dim chance of liquid water", even tho we would probably consider nearly all the worlds far too hot or far too cold.
also, i'm happy that whoever made the picture of kepler 62f in this image (all the way on the left in the "ugly" picture) has partially corrected it to being a snowball world, which is much more likely given its orbit. (but, of course, we don't actually know.)
the good:
i really like this image showing the worlds kepler has discovered transiting their suns:
from Kepler's Planet Candidates: A Family Portrait (larger image and explanation available there).
kepler hasn't actually *seen* the transits as depicted -- it can't resolve the stars, much less the shadows of the planets -- but the data it gathers makes calculating the sizes of the stars and the planets transiting them trivial, given what we know about stars, their color, brightness, and size. so, the image is correct, informative, and visually interesting. this is how kepler's science should be shown.