Earth Like Planet Found

rod

Oct 22, 2019
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Proxima Centuri b is an exoplanet that is studied more now. Here is another report from Nov-2020 this year. https://phys.org/news/2020-11-earth-like-stellar-proxima-centauri.html,

"...The comparatively low surface temperature means that its habitable zone lies very close to the star and Proxima b, with its mass of about 1.2 Earth-masses, lies about twenty times closer to the star than the Earth does to the Sun, orbiting in only 11.2 days. Being as close as it is to its star, Proxima b (like all habitable-zone exoplanets around M-dwarf stars) is susceptible to stellar flares, winds, X-rays, and other kinds of activity that could disrupt its atmosphere and possibilities for life. These activities are linked to the strong magnetic fields in M-dwarfs, and they remain active in dwarf stars over much longer timescales than in higher-mass stars like the Sun, so that the cumulative exposures are commensurately greater. All these issues have been investigated in some detail for Proxima b; one conclusion, for example, is that it is probably subject to wind pressures ten thousand times larger than those exerted by the Sun on the Earth."

[My observation. This suggest that any atmosphere could be quickly eroded, thus not a habitable exoplanet around the red dwarf host.]

I also notice some different properties reported too, example this site shows eccentricity is 0.10, http://exoplanet.eu/catalog/proxima_centauri_b/, potential surface temperature 216 K, very cold. This site shows eccentricity is 0.35, https://exoplanetarchive.ipac.caltech.edu/overview/alf Cen, https://exoplanetarchive.ipac.caltech.edu/overview/alf Cen#planet_Proxima-Cen-b_collapsible

234 K surface temperature shown. Eccentric orbit and surface could be very cold and possible red dwarf host star stellar winds 10,000 x stronger than Earth receives from our sun, possible atmosphere erosion too.

The exoplanet is an intriguing and interesting find---Rod
 
Oct 23, 2020
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That`s an interesting article but I guess that this planet is not completely like Earth. Scientists used to think that Venus is the second Earth but when we had got deeper, we found out that because of the temperature and pressure humans just can`t survive over there.
 
Dec 29, 2019
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I suspect that should we find a planet with life and a Nitrogen Oxygen atmosphere in proportions like Earth - that the presence of life will make it uninhabitable by humans. Even if the essential biochemistry is very similar it seems likely there will be incompatibilities, aka poisons and allergens. Infections, infestations, predations possible as well -and I think it would be a mistake to introduce any terrestrial life on such a world. It's greatest value would be scientific - and if it were possible for humans to reach such a planet they ought to be able to survive well enough in space habitats and not require on-planet colonisation for survival.
 
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Feb 17, 2021
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I suspect that should we find a planet with life and a Nitrogen Oxygen atmosphere in proportions like Earth - that the presence of life will make it uninhabitable by humans. Even if the essential biochemistry is very similar it seems likely there will be incompatibilities, aka poisons and allergens. Infections, infestations, predations possible as well -and I think it would be a mistake to introduce any terrestrial life on such a world. It's greatest value would be scientific - and if it were possible for humans to reach such a planet they ought to be able to survive well enough in space habitats and not require on-planet colonisation for survival.
We may not even survive the microbes there.
 

Catastrophe

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Should there not be a strict agreed definition of "Earthlike"?

As Serhiy pointed out:
"Scientists used to think that Venus is the second Earth but when we had got deeper, we found out that because of the temperature and pressure humans just can`t survive over there. "

At one point Venus certainly could have been described as "Earthlike", but opinions changed enormously with time.

Earth-life-like to describe a planet appearing to be possible of sustaining life (what sort of organism? Microbe/human?) and Earth-environment-like to describe physical similarity and location? Initials might help here: ELL and EEL or LL and EL or L-planet and E-planet? Maybe also G-planet for anything in the Goldilocks zone?
I am sure some of you will come up with better terminological refinements.

Cat :)
 
Oct 23, 2020
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This planet is far away. The best we can say is it the right size, the right composition and the right distance from its star, so likely the right temperature. We don't know a lot about this planet, but it is interesting to think about.
 

Catastrophe

Approaching asteroid? Is this THE one?
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S "We don't know a lot about this planet, but it is interesting to think about."

Doubtless more info will be obtained. I do, however, believe some classification is necessary.

Cat :)
 

IG2007

"Don't criticize what you can't understand..."
Apr 5, 2020
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You know, I am bored with so many "earthlike-planets". So many people say that there are so many "earthlike" planets, but where, have they got life? No life = not earthlike. Simple. It should be as simple as this. Mars was also called earthlike, same for Venus, but they are not "earthlike". Not at all.
 
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Dec 29, 2019
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No life = not earthlike. Simple.
I would go along with that. I was going to say that without an atmosphere like Earth's I would not call it Earthlike - and that Earth's atmosphere is like it is because of life. But even though an atmosphere of N2, O2 and H2O as cloud and vapor would catch attention, Earth, with life wasn't always like that. So atmospheres of various kinds, that could be explained by the presence of life - and difficult to explain without - would be the first thing to look for to find "Earthlike".
 
Oct 23, 2020
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We also know that it is tidally locked to its star with a high radiation environment from the frequent stellar flares so likely no atmosphere and no life.
So it seems to me that it has the familiar characteristscs like Venus. Some stuff can remind us Earth but environment is very harsh and makes living there impossible.
 
Feb 17, 2021
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If M-stars are not that life friendly, should we consider K-stars, perhaps?
K-stars last a little longer than G-stars, and the planets in question may not be tidally locked.
 
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Catastrophe

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IG: "I am reiterating my stance, any planet that does not have life cannot be called earthlike, and that's my final stance."

I respect your opinion, but do you not agree that there should be some nomenclature to cover planets similar to Earth (in dimensions, position, etc) which had or maybe will have life, or maybe will just share some non-life characteristics? What would you call them? Or define them?

Cat :)
 

IG2007

"Don't criticize what you can't understand..."
Apr 5, 2020
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I respect your opinion, but do you not agree that there should be some nomenclature to cover planets similar to Earth (in dimensions, position, etc) which had or maybe will have life, or maybe will just share some non-life characteristics? What would you call them? Or define them?

Cat :)
Look, planets that were once capable of life forming in them were earthlike at that time, not at the present time. And, in case of planets which might be able to have life in the future, it will be earthlike when it has life, not now. Yes, you can say that a planet is earthlike in dimension, or earthlike in position from its parent star. But, it's not perfectly earthlike. I hope you can understand my point, :)
 
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Catastrophe

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IG: "But, it's not perfectly earthlike. I hope you can understand my point,"

I totally understand your point. I hope you understand mine.

I accept you could use the description "perfectly Earthlike" - you might, perhaps, consider "biologically Earthlike" as covering any life form?

You, personally, may not need them, but there may be a necessity to describe non-biological earthlike planets for whatever purpose. I think you might agree that science is best served by the best nomenclature. "The map is not the territory" but the best description, allowing for semantic obfuscation, should be in the best interests of science, and therefore in the future of humanity (if any).

Cat :)
 

IG2007

"Don't criticize what you can't understand..."
Apr 5, 2020
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IG: "But, it's not perfectly earthlike. I hope you can understand my point,"

I totally understand your point. I hope you understand mine.

I accept you could use the description "perfectly Earthlike" - you might, perhaps, consider "biologically Earthlike" as covering any life form?

You, personally, may not need them, but there may be a necessity to describe non-biological earthlike planets for whatever purpose. I think you might agree that science is best served by the best nomenclature. "The map is not the territory" but the best description, allowing for semantic obfuscation, should be in the best interests of science, and therefore in the future of humanity (if any).

Cat :)
Cat, I have already told what I meant to say. My point is that, just stop saying that you have got earthlike planets, say how it is earthlike. Is it earthlike in dimensions? Is it earthlike in position from the sun? Is it earthlike in mass? Is it earthlike in terms of life? I am bored of the generalisation of the term of "earthlike." That's what my point is. To be more simple, my point is that, a planet can only be called perfectly earthlike if it matches the composition, the atmosphere, the shape, the mass of Earth and of course, it has got to have life. That is when a planet becomes perfectly earthlike, otherwise, it just remains earthlike in a specific category.
 
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Catastrophe

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IG Pease read my post on defining planets of certain dimensions etcetera.

"My point is that, just stop saying that you have got earthlike planets, say how it is earthlike. Is it earthlike in dimensions? Is it earthlike in position from the sun? Is it earthlike in mass? Is it earthlike in terms of life?" In what way is it not bio-earthlike (life-like-earth-like)?
How can these be defined/discussed?

I could not agree more. I said exactly the same myself.

If you are not interested in defining non-bio earthlike plannets, FINE.

We can just leave it at that. It is not interesting.

Sincere best wishes

Cat :)
 

Catastrophe

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Let us be quite clear about the semantics here. In the absence of any clear cut definition, we must examine the term carefully.
There is room for discretion here, so personal opinion can result in strong preference.

The difficulty is that there is room between totally like Earth, and a bit like Earth.
On the side of totally like Earth, strict adherence would be undesirable. Not even the strictest adherent is going to insist on same diameter to within 0.001% - likewise temperature or atmospheric pressure. Such correspondence is clearly impossible because of latitude, height above sea level and topographical features; unless Earthlike means identical, which it should not.
Totally Earthlike would have to include not only the presence of bacteria (or similar) but the presence of intelligent life with one head and four limbs. It is obviously ridiculous to insist on such identical forms, so a compromise must be struck. Possibly the presence of any life form - animal, vegetable or mineral - would be an acceptable guide.

At the other end of the scale, we must clearly avoid oversimplification. Whilst it is theoretically correct to say that an exoplanet is Earthlike if it is of similar size, but orbiting a totally unsuitable star, it is NOT going to be sufficiently Earthlike to please most people.

So even those with a relaxed view of what Earthlike means should exercise discretion. Generally, we probably find ourselves using the word Earthlike in the context of the possibility of life on exoplanets. Here, I feel that we should lean towards the definition of Earthlike which seeks evidence of extra terrestrial life. Otherwise there will be such a gap between debaters as to preclude sensible discussion.

The remaining question, therefore, is whether our definition must include evidence of life (on the exoplanet) or whether we are satisfied that conditions are sufficiently Earthlike (in a strict sense) to form a judgment that evidence of life should be found on searching.
There remains the historical perspective. How do we define a dead exoplanet with evidence of extinct life forms?. By definition, the exoplanet could have been Earthlike, but is no longer. Therefore a planet may now be dead but was Earthlike in the past. Such nomenclature might apply in our own Solar System, looking at Venus and Mars. Maybe moons of the outer planets will become Earthlike in the future. Why should a moon not be Earthlike? Orbiting a gas giant instead of a star strictly rules it out. But, wait a moment, Jupiter could have become a star under different circumstances.

Venus raises a particular problem. Whilst Earthlike in some respects (size, distance from Sun, etcetera) conditions on the surface seem to preclude almost all forms of life. But life may well be possible a few tens of miles up in the atmosphere. Resistance to sulphuric acid should not be that much of a problem, as we know here on Earth that life can be very determined to survive and propogate (just look at humans). So may Venus become Earthlike again? Or has it ever stopped being Earthlike.

I hope this little exegesis may provoke some thought, and help to heal any differences of the 'yes, it is' 'no, it isn't' variety. A little attention to semantics will help us all.

Cat :)
 
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