None of the alien planets we know of could sustain life as we know it, study finds

[Admin]

Conditions for the emergence of more complex forms of life as we know it on Earth on exoplanets orbiting stars in the Milky Way seem to be rare, a new study has found.

None of the alien planets we know of could sustain life as we know it, study finds : Read more

 

[rod]

A good report here in my view I note from the report, "Even though the study was done only on a very small sample of planets, astronomers know enough about the nature of stars in the Milky Way to assume that the right conditions for photosynthesis-driven life might be rare. Most of the stars in the galaxy are the so-called red dwarfs, dim stars about a third of the sun's temperature, too cool to generate any photosynthetic activity on the planets in their vicinity."

The host star light and photosynthesis is an issue based upon this study. I use these exoplanets sites for study. http://exoplanet.eu/, 4776 exoplanets listed as confirmed. https://exoplanetarchive.ipac.caltech.edu/index.html, list 4422 exoplanets.

Using MS SQL query and descriptive stat review for exoplanets <=2 earth radii size is very revealing. More than 1300 exoplanets (1311 and 1305 for the nasa site) are found that meet this criteria in both databases and the orbital periods, semi-major axis distances, etc. show most if not all orbit very close to their parent stars. This selection criteria includes exoplanet systems like TRAPPIST-1. The average orbital period is 13 earth days in my query stats. We do not have planets like this orbiting our Sun. We do not know for the more than 1300 exoplanets <=2 earth radii size that there is any life *forms* on them

 

[sam85geo]

Perhaps now with this study we have the answer to the Fermi paradox? But just maybe on the far side of some galaxy, ours or Andromeda possibly, there is some alien scientist(s) posing the same paradox. Statistically such is a reasonable expectation. Sadly, the cynic in me says that we, (our species), will never know. However, I admit that there may be microbial life in our solar system.

 

[Helio]

Without reading the paper, I suspect there are some shortcomings in their estimates for potential life-sustaining planets.

They restrict useful radiation to the 400nm to 700 nm range, assuming photosynthesis needs about the same SED (Spectral Energy Distribution) in this range from any star.

There are, however, 32 known exoplanets that are in the HZ from G-class stars, which is the Sun's class that produces almost 1/3 or more of its radiation in this visible light range of 400nm to 700nm. There are 6 F-class stars with HZ planets, and these stars are even stronger in the visible band.

Also, with the discovery of life under the ocean that is in total darkness, it may be underestimating how powerful life can be. [Did they not watch Jurassic Park? ]

Also, this range is also our eye's vision range. It may be no coincidence that the evolutionary track for vision and photosynthesis favors the near optimal use of the Sun's radiation. It would be plausible that both of these might be different for slightly dissimilar suns.

So perhaps I'm missing some other criteria that cuts this way down, such as the mass of the exoplanets. [I will take more time reading it, to be fair, but wanted to jump in anyway.

 

[rod]

Concerning Helio's post #4 reference to 32 exoplanets around G class stars in HZ, I found 629 exoplanets orbiting class G stars, http://exoplanet.eu/catalog/

The 629 exhibit a very large range of property differences in the database. Min earth radii 0.86, max 21.29. Orbital period min 0.36 days, max 44296 days. Class G star mass ranges much too. Min 0.05 solar mass, max 3.9 solar masses. When it comes to radius where radius <=2 earth radii, only 26 show up. Those 26 all have more mass than Earth. Min 1.91, max 19.07 earth masses. Radius min 0.8631 earth radii, max 21.297.

Simple SQL queries like this support the report in post #1.

 

[Helio]

Concerning Helio's post #4 reference to 32 exoplanets around G class stars in HZ, I found 649 exoplanets orbiting class G stars, http://exoplanet.eu/catalog/

The 649 exhibit a very large range of property differences in the database. Min earth radii 0.86, max 21.29. Orbital period min 0.36 days, max 44296 days. Class G star mass ranges much too. Min 0.05 solar mass, max 3.9 solar masses. When it comes to radius where radius <=2 earth radii, only 26 show up. Those 26 all have more mass than Earth. Min 1.91, max 19.07 earth masses. Radius min 0.8631 earth radii, max 21.297.

Yes, which is why I only referenced 32 that fit the criteria to be considered in the habitable zone. The other 600+ are likely not in a habitable zone, though certain atmospheres may bump that total.

 

[rod]

Yes, which is why I only referenced 32 that fit the criteria to be considered in the habitable zone. The other 600+ are likely not in a habitable zone, though certain atmospheres may bump that total.

However, your selection for HZ narrows when you look at radii, mass range. None of those exoplanets look like habitable exoplanets. At the present, I do not know if they have life

 

[Helio]

However, your selection for HZ narrows when you look at radii, mass range. None of those exoplanets look like habitable exoplanets. At the present, I do not know if they have life

Oops, I meant to get back to you on this.

Yep. My program reveals only two exoplanets that are promising, apparently. [I limited planet mass to 3 Earth masses.]

TOI-700d --- 2.3 Earth masses; orbiting a K-class star
GJ273b --- 2.9 Earth masses; orbiting a K-class star

There are, however, a total of about 71 exoplanets in the HZ, 36 of which are orbiting G-class stars.

 

[Helio]

There is some interesting news in the current issue of S&T....

Red dwarfs, though they are known to be very feisty (i.e. flares), may be tossing flares from their polar regions, not their equator. Thus, those flares may not be a problem for orbiting exoplanets.

This would be very big news if their study contained a lot more than a data set of four (4). They were able to determine from only these four that their observed flares happened above 55 deg. latitude.

One scientist argues that the odds are 1 in 1000 that their results doesn't suggest flares are mainly from their poles, I think it was stated.

But, that seems very high. It would be better than the odds of flipping four coins and getting all heads (1:16) but nothing near 1000, IMO.

But there is certainly hope.

Red dwarfs are most likely the most numerous stars in the galaxy. 30 out of the closest 50 stars to us are red dwarfs. [see Space.com article .] If they can support exoplanets in the HZ, and not have big issues with planetary tidal lock inhibiting life, then perhaps this will be big news after all.

 

[sam85geo]

I recommend as a follow on to this discussion, the site: "worldscienceu.com" and the course on extraterrestrial life by Sara Walker.

 

[rod]

Oops, I meant to get back to you on this.

Yep. My program reveals only two exoplanets that are promising, apparently. [I limited planet mass to 3 Earth masses.]

TOI-700d --- 2.3 Earth masses; orbiting a K-class star
GJ273b --- 2.9 Earth masses; orbiting a K-class star

There are, however, a total of about 71 exoplanets in the HZ, 36 of which are orbiting G-class stars.

Very good here Helio on your MS Excel query I used this site, The Extrasolar Planet Encyclopaedia — Catalog Listing (exoplanet.eu) , now reporting 4858 exoplanets confirmed with temperature calculated and temperature measured columns. When I run my MS SQL query selecting temperature calculated, I get 56 exoplanets with temperature range 273 K to 373 K reported. There is a wide range of mass too from 0.4 earth masses to 11 Jupiter masses. Using temperature measured, I see only one exoplanet with temperature measured reported as 335 K. CWISEP J1935-1546, 11 Jupiter masses.

Unlike the 4 Galilean moons that are observed today and used well against the geocentric astronomers, do we have as yet a confirmed, well measured exoplanet showing it has liquid water on the surface and life there? I would like to see the report if you have it

 

[Helio]

Unlike the 4 Galilean moons that are observed today and used well against the geocentric astronomers, do we have as yet a confirmed, well measured exoplanet showing it has liquid water on the surface and life there? I would like to see the report if you have it

It doesn’t hurt to point out that the HZ is, so far, so labeled because they are determined to have temps. for liquid water on the planet, not verification of liquid water. Given the abundance of water found in the solar system — IIRC, one exo was found to have water vapor (or was it O2)— and in space, it’s strongly inferred. Bigger scopes will help.

 

[Catastrophe]

Helio, you do (iirc)

Scientists have found more water in space than they ever knew possible

We’ve known for a long time that there is water in space. But an international team of scientists has found a cloud of water vapor 12 billion light-years away – and it’s bigger than you could possi…

roboticsandautomationnews.com

"scientists have found an enormous cloud of water vapor floating in space."

Cat

 

[rod]

Cat, your post #13 link says "Though well below freezing, it is comparatively warmer than most water in space, and 300 trillion times less dense than our own atmosphere. However, what it lacks in density it makes up for in size. The cloud of water in space covers hundreds of light years, accounting for its remarkable size."

Question. How much below freezing is this cloud of *water*? What is the Kelvin temperature? My thinking, the report reads more like *yellow journalism*.

 

[Catastrophe]

Cat, your post #13 link says "Though well below freezing, it is comparatively warmer than most water in space, and 300 trillion times less dense than our own atmosphere. However, what it lacks in density it makes up for in size. The cloud of water in space covers hundreds of light years, accounting for its remarkable size."

Question. How much below freezing is this cloud of *water*? What is the Kelvin temperature? My thinking, the report reads more like *yellow journalism*.

Rod, this was a quote. It was in response to Helio's "iirc".
"scientists have found an enormous cloud of water vapor floating in space."
This may have been where he saw it. That is all.

Cat

 

[Catastrophe]

Rod, I don't know whether this helps. Must be around the triple point. Lowest anywhere seems about 273 K.

Imgur: The magic of the Internet

Cat

 

[rod]

Rod, I don't know whether this helps. Must be around the triple point. Lowest anywhere seems about 273 K.

Imgur: The magic of the Internet

Cat

The graph does show relationship to gas pressure and I like that. Standard atmosphere pressure at sea level at 15C or 288K is 1 bar or about 1013 millibar. I note your post reference #13 report link and some follows up, the report stated about the giant water cloud in space "300 trillion times less dense than our own atmosphere." This looks like a density some 3 x 10^14 times less dense than 1 bar on Earth using the graph. Could I really enjoy swimming in this *space water* or do some bogy boarding on the waves there?

For all the reports of water in space it seems claimed today, so far Earth has the obvious abundant supply of liquid water today. Accepting the postulate that early Mars contained much liquid water on its surface, 4 billion years ago, Mars today is essentially *bone dry*. Do we have liquid water on the surface of Venus, Io, Europa? Showing some 4800 or more exoplanets confirmed today have liquid water on their surfaces or even a small number from this population - is a work in progress.

A term I find used in some groups, *heliocentric certainty*. So far, the science of demonstrating liquid water on the surfaces of exoplanets or other planets and moons in our solar system, does not meet this standard of verification. There is one place known today with an abundance of liquid water. I can assign heliocentric certainty to the Earth meeting this condition.

 

[Helio]

I'm more concerned with the article's statement that..
"And now, scientists have found an enormous cloud of water vapor floating in space. Located 30 billion miles away in a quasar." [my bold] That's just outside the asteroid belt. I would worry that we would all soon drown, but having a quasar that close is even more disturbing.

[Ok, they meant lyrs., no doubt. ]

Being in an active galaxy like a quasar, it's reasonable to expect any gas (e.g. water vapor) will be warmer than normal. Of course, it can't be in liquid form.