What's so special about Earth?

Gawdzilla Sama said:
The planetary detection system wasn't "biased", it was what we had at the time.
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In the sense that the detection system was more likely to detect Jupiter-type gas giant planets than small rocky worlds, it was biased.

Do you think that using the word "biased" in this sort of context is a mistake?

I'm not saying that the astronomers who were looking for exoplanents only wanted to find gas giants, or anything like that. They were fully aware of the limitations of the equipment and methods that were using and they were the first to agree that they would expect to detect more gas giants than rocky planets, all else being equal.

No "detector" in science is capable of detecting everything. The Hubble space telescope isn't good at detecting infrared light. The James Webb telescope is great at detecting infrared light, but not as good as Hubble at visible light. We could say that the Hubble telescope is "biased" towards detecting visible light sources, whereas the Webb telescope is biased towards detecting infrared sources.

This isn't a moral judgment. It is just stating a fact about the limitations of the detectors.
 
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We do spot the elephants before the mice in most cases. I'll go with biased in that fashion. But I remember the old rule, "Never look down the barrel of a loaded word."
 
Gawdzilla Sama said:
We do spot the elephants before the mice in most cases. I'll go with biased in that fashion. But I remember the old rule, "Never look down the barrel of a loaded word."
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All words have multiple meanings and usages. Context generally implies which meaning is intended. In this case, James R was pretty explicit about his intended usage:

"Due to the detection mechanisms we have used, the exoplanets we are currently aware of make up a biased sample, in the sense that it is a lot easier to detect gas giant planets that are relatively close to their parent star than it is to detect small rocky planets like Earth."

It's pretty hard to misinterpret that.
 
I think what makes earth so “special” is that it’s the only place we know of as home. I guess we’re a little biased. Without earth, we wouldn’t be alive, but since we’re here, it’s because of earth’s atmosphere, water, climate stability (well, for now). There’s no plan B as far as we can tell. Or planet B. So, from this simplistic viewpoint, earth is pretty remarkable.
 
DaveC426913 said:
All words have multiple meanings and usages. Context generally implies which meaning is intended. In this case, James R was pretty explicit about his intended usage:

"Due to the detection mechanisms we have used, the exoplanets we are currently aware of make up a biased sample, in the sense that it is a lot easier to detect gas giant planets that are relatively close to their parent star than it is to detect small rocky planets like Earth."

It's pretty hard to misinterpret that.
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I don't think I did.
 
The earth is the only known planet in the universe where water can naturally exist as a liquid, a solid and a gas.

Were the amounts of liquid, solid and gas water changed by only a small margin - all life on earth cease to exist.
 
toocoolblue said:
Were the amounts of liquid, solid and gas water changed by only a small margin - all life on earth cease to exist.
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Well, considering the amounts of liquid solid and gaseous water change on a seasonal level - and even more so on a geological timescale (eg. ice ages) - and it hasn't ended all life on Earth - I'm sayin' that's not true.
 
toocoolblue said:
The earth is the only known planet in the universe where water can naturally exist as a liquid, a solid and a gas.

Were the amounts of liquid, solid and gas water changed by only a small margin - all life on earth cease to exist.
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You mean a liquid. Water will exist as a solid and/or a vapour at a very wide range of temperatures.

But liquid water is certainly a fundamental requirement for most biochemistries that can easily be envisaged. A further requirement is a temperature low enough to allow complex molecular structures to be maintained, in practice <80C or so, and a temperature high enough for a wide range of chemical reactions to proceed at significant rates, in practice > 0C or so. These limits happen to coincide pretty closely with the temperature range of liquid water, at the prevailing ambient pressures close to the Earth’s surface.

However there is absolutely no basis for thinking these conditions are unique to just one planet in the entire cosmos. We only know of a handful of planets, because they re so small and do not reflect much light into our telescopes. There will be billions of them out there, if our model for the formation of the solar system is anything close to being correct.
 
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