Possibility of life around Brown dwarfs? 3 possible planets found to be potentially Earthlike

[PB666]

Not to really engae here, but for some bacteria carbohydrates, sukfate, nitrate, nitrite can act as oxides for catabolism, some organisms can bypass the mitochondria and use a primative form of metabolism.

around a brown drawf photosynthesis is implausible, brown dwarfs do not produce visible light, the em they do produce is not of sufficient enough energy to drive activity on a proximal planet. 

Without photosynthesis the sulfate in sea water would be a smaller proportion, sulfate, nitrates and carbohydaters are the oxygen donors in anoxic, but these inevitably are driven by photsynthesis, if we release all the carbon stores, they become oxidized and these oxygen donors become rare in the benthic marine environment. Sulfate may still be present but it might be locked up in complex nitrogen carbons. As on mars you will see chlorates.

People think that the deep sea is devoid of oxygen, but in reality there is a large amount of oxidized sulfur in the form of sulfate. This does not doom life on non photosynthetic planets,, but the thermodynamic potential for life becomes smaller and in theory life would evolve much more slowly.. A brown dwarf would last a very long time, but i would say that planets orbiting would never have enough surface dynamic energy, the flux, to produce complex life. For themselves to be stable they need to orbit at a distance. Its not a good recipe for life. Innthat cicumstance they would have to be blessed with alot of long lived radioactive species, and be fairly large.

[todofwar]

As has been stated, you can't effectively run photosynthesis on IR light. There aren't many electronic transitions down there, I don't think there are any in fact, so no ability for charge seperation. Life would be most similar to whatever may be on Europa or Enceladus 

On Friday, April 29, 2016 at 8:46 AM, kerbiloid said:

Then you probably can explain how an oxygen atmosphere can co-exist with "energetical" amounts of H₂S.

This is the basis for life in general, to dissipate energy more effectively. Vents represent a transition from an environment where H2S is favored to one where it is not. These chemical gradients are the catalyst for life formation. 

[PB666]

47 minutes ago, todofwar said:

As has been stated, you can't effectively run photosynthesis on IR light. There aren't many electronic transitions down there, I don't think there are any in fact, so no ability for charge seperation. Life would be most similar to whatever may be on Europa or Enceladus 

This is the basis for life in general, to dissipate energy more effectively. Vents represent a transition from an environment where H2S is favored to one where it is not. These chemical gradients are the catalyst for life formation. 

Saying sulfide cant exist on a photosynthetic body is like saying strict anaerobes cant exist. Sulfides and anareobes MUST exist for photsynthetic world to be efficient. We can take a look at live rock as an example, while the growth of carbonates is dependent on photosynthesis, it sets the stage for the production of sulfide and a home for anaerobes. Why would a photosynthetic algae provide a home for anaerobes. The answer is quite simple, in an a completely aerobic world intractable matter degrades at a dependency of oxide in the water. The problem is that aerobic organisms hold the oxide potential just over 300 millivolts, in other words sea water tends to oxidize even at a pH around 8.0. Sea water rusts things, no surprise there, but the oxide content is actually much lower than the rate of release of dissolved organics and intractable reduced material, and this eventually spoils the system. These substrates are to difficult to degrade and too low of energy for aerobic life to use, so they accumulate, or not . . .  .

But there is a more serious problem because the rate of nitrogen fixation is much much lower than the rate of nitrogen accumulation in DOCs and intractable material, and as the material accumulate nitrogen and phosphate tend to flow into the deep ocean benthic layers. IOW something should release nitrogen, carbon and phosphate before these elements reach layers were photosynthesis cannot be conducted. You might say that cyanobacterium can fix nitrogen. Yes they can, but they require phosphate, they do this in a specialized cell, and the contents of that cell are toxic to photosynthesis, that process has to be partitioned from oxidative phosporylation and photosynthesis. If we fix all the nitrogen and dont clean up nitrogen in docs and intractable, eventually  you have a environment only facultative anaerobes and strict anaerobes can live in. 

This is where the anaerobes come in, in the stills of the deep layers of live rock and bottom substrate, as organisms begin to utilize either of these they excrete catabolic chemicals, but at the same time oxygen rapidly drops, the only form of oxygen left is sulfate, cellulose, nitate and nitrite in that order. So basically bacteria start producing sulfide, but those bacteria are still not the most efficient, at even lower depths, the anaerobes can afford to produce even more of these catabolic compounds and they recover the material and produce ammonia, phosphorus compounds, these reduced compounds are dangerous also to the system, but as they are exiting the their local system where oxygen is increasing they are rapidly reintegrated into biota and become part of the nutrient procurement process. Thus anaerobes help to keep micronutrients in the photosphere and away from the lithosphere and they do this without overloading the system with nitrogen, in fact if biologically available nitrogen gets to high, there are bacteria that convert it to N2. 

Productivity of systems like the eastern pacific upwelling (ecuador chile) this is actually driven by turnover from the anaerobe/photosynthetic system, with some contribution by upwellings, but we also have to consider that over millions to billions of years that volcanism turnover photosynthetic compunds via upwellings and subduction/volcanism. Any imbalance of phophate and nitrogen can be corrected at the surface by cyanobacterium. 

When we talk about anaerobic living systems that we see on earth is largely driven by photosynthetic inputs, just as anaerobes are a MUST for efficient photosynthesic production, photosynthesic production is a MUST for optimal long term anaerobic activity. The problem for evolution is that we complex sentient things are the result of sustained diversity, such as diversity seen in rainforests and open savannahs. The rate of evolution in the arctic is fast, but diversity is limited by extinction potentials, thus selection drives equilibrium diversity down. Anaerobic life is inadequate to compensate for this, in the equatorial systems things evolve  slowly but can sustain higher levels of diversity providing more raw materials for each subsequent speciation cycle. Over time things like birds, humans evolve. Its is the surface thermodynamic potentials created by light that drive competition and diversity. 

The other gain on anaerobic life is they themselves become food for the system. Being fed upon does not sound advantageous, but burrowing worms have worked out a way to feed on these without suffocating,, they provide ubiquitous bioturbulation that drafts sulfate, nitrate and DOCs into the anaerobic layers and prevent the accumulation of waste (micronutrients). In addition these organisms draft certain essential organic nutrients for animals. As a consequence the surface system composed of multitolerant biota stimulate nutrient turnover, bioturbulation, etc, that is just not possible at level without oxygen.

Light, IOW, the type of hv energy that can bump electrons to that next higher orbital creates a magnitude more energy potential for living systems than black body radiation that degrades inorganic molecules at relatively high temperatures deep in the earth. You can think about it like this, the amount of useable energy available in 1/10th of a millimeter at earths square meter of surface is equivilent to thousands of cubic meters at precisely the right temperature and hydration levels deep in the earth (not too cold or heat chemistry stops, not to hot or DNA melts and pressurized water boils). Light drives expansion of the system upwards and downwards, and deep enough that it becomes an umbilical cord for anaerobes.

If you want to find a planet in our system where anaerobes have done very well, look no further than Earth, but their well living is fractional to other complex life. This is because even though the flow of energy to anaerobic layers is higher than any other planet in our system, herbivores, scavengers and saprophites get the overwhelming share of post photosynthetic chemical energy. This flux is the basis of complex life, anaerobes are part of that flux, and are apart of the living diversity on earth that creates humans.

 

The alternative to phtosynthesis is a lower flux, that is to say lower diversity, and a lower potential for complex life and sentients, and also lower biomass and diversity of anaerobes. There are other sources of flux, radioactivity can also provide ionizing energy, that when captured and placed in cascades can result in hv that can be used by life, the problem is that radioactive isotopes that reach high levels tend to undergo nuetron induced fission instead of simple neutron decay and if the mass is critical the radiation simply reacts, blows, and the isotopes disappear too quickly for life to use. So getting a world with a lot more radioactivity in its crust than earth, but not blow up, is a problem. Second problem for complex life is the random selection effects of radiation, particularly neutron radiation. 

 

[PB666]

https://thespacereporter.com/2016/04/extraterrestrial-life-might-resemble-microbes-found-antarctic-lake/

[Elukka]

You would have visible light available for photosynthesis on a brown dwarf. The larger the dwarf, the more visible spectrum light you'd have to play with, but any dwarf will probably generate some suitable light for photosynthesis. (which is apparently possible in the near infrared too: https://en.wikipedia.org/wiki/Chlorophyll_f)

Edited May 1, 2016 by Elukka

[PB666]

3 hours ago, Elukka said:

You would have visible light available for photosynthesis on a brown dwarf. The larger the dwarf, the more visible spectrum light you'd have to play with, but any dwarf will probably generate some suitable light for photosynthesis. (which is apparently possible in the near infrared too: https://en.wikipedia.org/wiki/Chlorophyll_f)

Only as long as they have lithium to burn, they quickly burn through this and brown down. 

Chlorophylls spectrum tapers down in the orange part of the spectrum, near infrared will not suffice. 

https://en.m.wikipedia.org/wiki/Chlorophyll_a#/media/File%3AChlorophyll_ab_spectra-en.svg

Youll be hard pressed to find something that can feed 

https://en.m.wikipedia.org/wiki/Photosynthesis#/media/File%3AZ-scheme.png

even the second low energy part of the equation requires more hv than a brown dwarf can provide. 

[Spaceception]

Squeals like a little child who got their foot stepped on.

http://www.eso.org/public/news/eso1615/?lang

 

These planets orbit a BROWN DWARF, these are the first potentially habitable worlds that orbit these strange "stars", I really hope JWST looks at this "star".

 

Edited May 2, 2016 by Spaceception

[Scotius]

Less than 48 hour orbital period (year) On the other hand those planets are almost certainly tidally locked, so it doesn't mean much. Still, sky observed from the nigtside must present an interestig view.

[Spaceception]

4 minutes ago, Scotius said:

Less than 48 hour orbital period (year) On the other hand those planets are almost certainly tidally locked, so it doesn't mean much. Still, sky observed from the nigtside must present an interestig view.

Tidally locked planets could have some really interesting life.

[insert_name]

What would we do if we found signs of life?

[A Fuzzy Velociraptor]

15 minutes ago, insert_name said:

What would we do if we found signs of life?

Given my knowledge of Star Trek, either interfere in its development, mate with it, or get into a fight with it, most likely all three.

[HebaruSan]

24 minutes ago, insert_name said:

What would we do if we found signs of life?

At a distance of 40 light years, probably talk about it very excitedly for a while, and maybe revise some models of solar system formation.

(Side note, the article says the inner two are too close to their star to be in the habitable zone, and they're not sure about the outer one.)

[Spaceception]

1 minute ago, HebaruSan said:

At a distance of 40 light years, probably talk about it very excitedly for a while, and maybe revise some models of solar system formation.

(Side note, the article says the inner two are too close to their star to be in the habitable zone, and they're not sure about the outer one.)

The terminator of the planets might be habitable though.

[Spaceception]

Since planet d's orbit is uncertain, it may be on the very outer edge of the habitable zone, but we need more data.

 

[A Fuzzy Velociraptor]

Just now, Spaceception said:

post

What was the program/source for that image?

[PB666]

59 minutes ago, Spaceception said:

Tidally locked planets could have some really interesting life.

The probabilty of three habitable planets around a dim red dwarf is next to zero. See other thread you created for red dwarves, where this thread should have been placed. 

[Spaceception]

3 minutes ago, A Fuzzy Velociraptor said:

What was the program/source for that image?

http://phl.upr.edu/projects/habitable-exoplanets-catalog

2 minutes ago, PB666 said:

The probabilty of three habitable planets around a dim red dwarf is next to zero. See other thread you created for red dwarves, where this thread should have been placed. 

Well, we found it, didn't we? At least 2.

I didn't want it buried under everything else, but I'll ask for a mod to merge them.

Edited May 2, 2016 by Spaceception

[Rakaydos]

A tidaly locked dayside, just outside the nominal habitable zone, could be an intereting place for life if it had sufficent water that terminator glaciers can keep the dayside hydrated.

[PB666]

2 hours ago, Spaceception said:

http://phl.upr.edu/projects/habitable-exoplanets-catalog

Well, we found it, didn't we? At least 2.

 

You found two tidally locked planets that have their Water, CO2, frozen nitrogen all piled up on the dark side, even if you termination glaciers the atmosphere at the termination too low to support life, as for the video and the article its nothing more than prefunding-cycle hype.  The third is a speculative planet. 

The third is actually the most plausible, if it rotates, then it might have deep rock microbes, but no photosynthetic life. 

Before you go about believing this hype, read the Mercury and Moon pages carefully, even Mercury, so close to the sun, can liquify gases on its dark side, but just like all planets so close to the host stars the occasional magnetic storms suffice to blow off its atmosphere. 

[Sorry for the Apple-ization of the text I have tried to correct as many errors as I could]

Quote

I didn't want it buried under everything else, but I'll ask for a mod to merge them.

There is a reason we thread things, for historic searches of the archives have single well tagged threads make searching easier, rather than having to search multiple threads or threads with useless tags. Now if i want to go back and link an old thread i have to search through three threads with overlapping content

Why exactly do you create so many threads anyway?

Edited May 2, 2016 by PB666

[Spaceception]

14 minutes ago, PB666 said:

The third is a speculative planet. 

I'm quite sure we know it exists, we just didn't get enough data to firmly determine its orbital period.

[Elukka]

13 hours ago, PB666 said:

You found two tidally locked planets that have their Water, CO2, frozen nitrogen all piled up on the dark side, even if you termination glaciers the atmosphere at the termination too low to support life, as for the video and the article its nothing more than prefunding-cycle hype.  

I was under the impression that whether volatiles pile up on the dark side or remain thawed depends on your assumptions on atmospheric and other conditions.

Edited May 3, 2016 by Elukka

[Spaceception]

Oooh, this is cool; http://www.trappist.one/

[Mitchz95]

TRAPPIST-1 isn't technically a brown dwarf, is it? Every source I've read describes it as a red dwarf (spectral type M8, according to Wikipedia).

[Spaceception]

2 hours ago, Mitchz95 said:

TRAPPIST-1 isn't technically a brown dwarf, is it? Every source I've read describes it as a red dwarf (spectral type M8, according to Wikipedia).

Yeah, pretty much, but I think it's on the edge of 2 extremes tbh, I don't know if it just has to be a teensy bit bigger to be a star, or a teensy bit smaller to be a brown dwarf.

[insert_name]

Looks like Hubble has ruled out hydrogen/helium atmosphere's on b and c

http://'NASA's Hubble Telescope Makes First Atmospheric Study of Earth-Sized Exoplanets': http://mobile.nasa.gov/press-release/nasa-s-hubble-telescope-makes-first-atmospheric-study-of-earth-sized-exoplanets via #NASA_APP