Earth-like exoplanets may be common, study says.

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Profile William Rothamel
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Message 2017976 - Posted: 6 Nov 2019, 13:21:32 UTC - in response to Message 2017972.  
Last modified: 6 Nov 2019, 13:29:44 UTC

So the chance that there is intelligent life -- lots of intelligent life -- out there is probable.


That is right. The question is how probable and therefore how densely spaced are they expected to be. Most would believe that given certain conditions (and there may be quite a few of these conditions) life would arise, evolve and achieve a sentience, reasoning power and intelligence similar to ours here on Earth. Only those who think that "our God" was required to have created us would be able to deny this . In order to discover them, they would almost certainly need to have developed high power transmissions of some kind.

The task then is to be reasonably certain of those dozen or so situations that must exist for this to happen. After that we need to refine further --as we are doing now--our ability to detect which planets have these requirements.
If as I expect these planets are extremely distant from us then we need to develop a message and blast it at high power in the direction of those planets. Perhaps such a message may inspire a civilization to build a similar capability and attempt to answer back. Many lifetimes may elapse before we ever get a signal. If we do this now perhaps a 1000 years from today the earth will receive the answer to the most profound question ever asked. Let's all hope we are still here to detect and de-code it.
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Message 2017995 - Posted: 6 Nov 2019, 18:48:01 UTC - in response to Message 2017972.  
Last modified: 6 Nov 2019, 18:54:31 UTC

Perhaps there are intelligent life out there.
Or perhaps not.
The weak anthropic principle https://www.youtube.com/watch?v=8wa1l7M5gU8
https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
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Message 2018005 - Posted: 6 Nov 2019, 21:48:20 UTC - in response to Message 2017995.  
Last modified: 6 Nov 2019, 22:02:50 UTC

He doesn't give any evidence to support the "weak anthropic principle". He simply says that because we can only observe one instance of intelligent life (us), then the various factors causing it MAY be rare.

They probably are, for the various reasons he has also given, but the mere fact that we are the only intelligent life we know about is not a convincing argument, or even an argument at all.
It depends on what you mean by "exceedingly rare". The so-called "principle" fudges that issue.
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Message 2018014 - Posted: 6 Nov 2019, 23:02:50 UTC - in response to Message 2018005.  
Last modified: 6 Nov 2019, 23:11:16 UTC

You cannot give evidence of anything of something that we don't even know exist.
Saying "exceedingly rare" is of course also wrong since you cannot compare to anything.
When finding some exoplanet with at least bio-signatures then we can tell something how rare it is.
Or we might be lucky finding an exoplanet with techno-signatures.
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Message 2018015 - Posted: 6 Nov 2019, 23:14:54 UTC

The rare Earth hypothesis makes a number of rather simplistic, unwarranted assumptions, which could very well make the chances for life in the universe appear much poorer than they actually are.

The requirement for a planet with a relatively large moon, like our own situation, is somewhat debatable, but suppose we let it stand. We have two examples of this situation in our solar system: Earth and its Moon and Pluto and Charon. On what basis is such planetary configuration assumed to be rare?

It is also averred that red dwarf stars must be unsuitable for planets with life. Habitable Zone planets of red dwarfs are expected to be tidally locked; the same side always facing the star, the other, always facing away from it; a too hot side, and a too cold side, it is claimed. This neglects a body of thought that supports a livable zone between these two extremes, where the star's heat is received at a very low angle.

Then, too, the rare Earth hypothesis neglects the quite reasonable possibility of a thick atmosphere and/or large oceans moderating the extremes of heat and cold over an even wider area of the planet's surface.

It is also objected that red dwarf stars are flare stars, which would vary their output to such an extent as to inhibit life. In fact, red dwarfs often become much steadier in their output, as they mature. And since these are very long-lived stars there should be ample time for life to emerge, and evolve, once these stars settles down.
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Message 2018028 - Posted: 7 Nov 2019, 2:01:04 UTC - in response to Message 2018014.  

You cannot give evidence of anything of something that we don't even know exist.
Saying "exceedingly rare" is of course also wrong since you cannot compare to anything.
When finding some exoplanet with at least bio-signatures then we can tell something how rare it is.
Or we might be lucky finding an exoplanet with techno-signatures.

You miss the point. He is trying to elevate his lack of knowledge to a "principle".
He should just say what evidence he has (or lacks) and leave it at that.
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Message 2018754 - Posted: 13 Nov 2019, 4:34:26 UTC

How Many "Earth-Like" Planets Are There Really?
https://www.youtube.com/watch?v=xEt941k2GAg
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Profile William Rothamel
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Message 2018790 - Posted: 13 Nov 2019, 13:49:09 UTC - in response to Message 2018754.  

It's time to clean up this mess. I demand definitions of:

    "Earth-like" Planets
    Habitable planets
    Planets that have all the requirements for sentient beings such as ourselves to exist spatially and time-wise with us.


The only one that matters and the only one that deserves headlines and wild speculation is the last one of these on the above list.

I claim a handful, at best, in the Galaxy. In time better probes may prove me wrong. For now the range of stupid estimates is much more than what is claimed in the video.

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Message 2018803 - Posted: 13 Nov 2019, 15:35:24 UTC

Not forgetting of course we are looking back in time - in many thousands of years into those planets past. We have no way of knowing how any intelligent life form, or indeed non-intelligent life form, has changed since since the light from their parent star set off on its inter-stellar journey to us. The best we can hope for is to identify a life form that had at the "light departure date" reached a level of technology that allowed it to use radio communications as their general means of communicating over long distances. Look at our own planet - 200 years ago there was no radio, but ~100 years ago Earth became an "active radio source". So an observer 200 light years away would not see anything of interest, but one 100 light years away would see the start of radio as a communications tool, one 50 light years ago would see a massive jump in signal strength as TV took its wings (All this presupposes that these "people" have the technology to detect RF that is only just above the noise floor)
Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?
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Message boards : SETI@home Science : Earth-like exoplanets may be common, study says.


 
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