Uncommon Descent Serving The Intelligent Design Community

Rob Sheldon: Don’t give up all ET hope due to recent exoplanet disappointment

arroba Email
An illustration of a number of the different kinds of planets found by Kepler all lined up in a row.
types of planets Kepler found/NAA

Even in our own solar system, he says, there are reasons for believing that the picture is more complicated. Yesterday, we mentioned a recent finding that rocky alien planets orbiting red dwarfs (the favored sites for exoplanet life) might in fact feature too extreme temperatures, based on recent research on one of them (–273 degrees Celsius on the night side and 767 degrees C on the day side, which implies little or no atmosphere to moderate it.).

Anyway, our physics color commentator offers some thoughts:

This report is about the Holy Grail of exoplanets–finding a planet with liquid water on it. So far, the thinking goes, a planet has to orbit its host star at just the right distance so that the temperature is between the freezing and boiling point of water. This “Goldilocks Zone” is further away for big hot stars, and close in for small cool stars. Most stars in our galaxy are smaller/cooler than our Sun, so there are better chances of finding a planet in the GZ for these “red dwarf” stars. Indeed, this is exactly what the planet finder mission is discovering.

The Long Ascent: Genesis 1â  11 in Science & Myth, Volume 1 by [Sheldon, Robert]

But the kicker is that when a planet is very close to its host star, the tidal forces are also much greater. It is tidal forces that lock our Moon’s rotation so that only one side ever faces the Earth. The same thing happens to planets orbiting a red dwarf–only one side ever faces the star, and that side gets hot, too hot for water, whereas the dark side gets too cold for liquid water.

Some optimists had theorized that if such a planet had a thick atmosphere with strong winds, then the heat could be distributed to the cold/dark side, and perhaps liquid water could still exist. So this paper takes a hard look at one such planet as it orbits its star, and tries to measure the temperature. As far as they can tell, the planet’s dark side is the temperature of space (4K), while the hot side is 1000K (or 750C). It doesn’t look promising for water.

What I find odd, is that in our own solar system, Saturn is far outside the “Goldilocks Zone” yet it has a moon, Enceladus, that is emitting steam jets filled with hydrocarbons. So this fixation on GZ seems overrated. Or to say it differently, life can live in far more extreme environments than the astrobiology community want to consider. It is almost as if this fixation with the GZ is intended to turn a qualitative observation into a quantitative field worthy of funding. The danger of being overly-quantitative is not just the overreliance on models, or the higher risk of failure, but rather the real probability that “certainty” blinds one from observing the actual phenomenon.

It’s not what you don’t know that hurts you, it’s what you do know that ain’t so.

Rob Sheldon is the author of Genesis: The Long Ascent

See also: Bad news about life on rocky alien planets.
Kreidberg’s team estimated that the promising planet had temperatures of –273 degrees Celsius on the night side and 767 degrees C on the day side, which implies little or no atmosphere to moderate it.

LoL! @ Vmahuna- Yeah, I guess that I am so unedumacted cuz the very next verse has:
So God created man in his own image, in the image of God created he him; male and female created he them.
God said one thing and man said the other. ET
ET at 9. I guess you're not educated enough to know that male plurals were used as Honorifics: Queen Victoria, "WE are not amused..." This continued well into the 20th century. So Jehovah is always cast as a male, although He/It was clearly sexless. Jehovah is called "Father" for the same reason. The languages simply lacked honorifics for wimmen. What would make more sense is for there to be 3 genders with the 3rd being "REALLY important individual regardless of gender". But it's too late to fix that in writings more than 2,000 years old. vmahuna
Drc466- The Bible seems like a good resource for extraterrestrial visitation. Image of God? You mean: "Let US make man in OUR image, after OUR likeness" ET
ET - just out of curiosity, why do you think that? It kind of depends on whether you consider humankind a unique "in the image of God" creation, doesn't it? Are you a priori assuming a non-Biblical ID source? drc466
If Intelligent Design is true then we would expect there to be more than just us. More than just one habitable and inhabited planet. Just sayin'... ET
LoL! Brother Brian's other persona- acartia bogart- is allegedly a marine biologist and yet it did not know that a whale's fluke is a tail! Talk about giving up hope on a person who is clearly incapable of thought... ET
I gave up all hope for ET a long time ago. :) Brother Brian
Excellent advice. Take off the theory goggles. Considering all the wildly unexpected places where bacteria and small invertebrates live on earth, no situation can be totally dismissed as barren. polistra
Fasteddious, The telescopes couldn't get the temperature within 100 degrees, so the dark side was consistent with space, which is 4K or four degrees above absolute zero. Given the error in measurement, that is anywhere between 0K and 100K, but likely not colder than space. Likewise the hot side was 1000K, give or take a few, which when converted to Celsius by the journalist, comes out 727C. It looks precise, but it probably should have been rounded to 700C where zeroes indicate the lack of precision. One of the pitfalls of reading popsci journalism rather than the original paper. Robert Sheldon
The coldest spot (that we know of) on our Moon is -247 C. And that, believe it or not, is colder than Pluto. ET
One has to wonder how they estimated -273C for the dark side. That is very close to absolute zero, and seems highly unlikely, given that even the radiative temperature of deep space is a couple of degrees warmer (~2.7K if I recall correctly). If the planet is +767C on the hot side, then some heat must be conducted through the planet, to be radiated at some temperature well above -273C. I expect the back side temperature is much higher than suggested, but still well below the freezing point of water. Fasteddious

Leave a Reply