TRAPPIST-1 now has seven planets. (Possible life?)

[RuBisCO]

2 hours ago, Shpaget said:

On a planet where visible light is scarce, organisms may just as well find a way to utilize IR. The process may be significantly different than what we call photosynthesis.

Probably, but the end result of water cracking is going to be necessary for complex life. Other potential eco-chemical cycles such as hydrogen sulfide cracking and oxidation with sulfur would result in much more sluggish organisms as the amount of energy they could extract per mole of sulfur compound would be less than per mol of oxygen, worse many sulfur compounds are not even gaseous, so no land life, and are also very reactive/corrosive like H2SO4. More important a thick oxygen atmosphere with ozone is going to be vital to an ecosystem to survive the occasion solar flares red dwarfs are known to give off. These flares can double the solar output of a red dwarf star for a few days and much of that output would be in UV light. http://astrobiology.com/2017/02/uv-surface-habitability-of-the-trappist-1-system.html

Certainly the biochemistry of utilizing NIR to water cracking would be very different from the plant photosystems life on earth uses. One idea as I stated above is to collect one NIR photon, store it and combine with with a second to get the needed energy. Here is a paper that did it by taking chlorphyll and replacing the manganese light absorbing center with a Yttrium-Ytterbium-Erbium complex that when hit by NIR photons of ~1000 nm can store that energy for many milliseconds (compared to normal chlorophyll which can store that energy for only a few billionths of a second), enough time to catch a second, even third and forth NIR photon and spite out that energy as a much higher energy red, green and even blue photon. Obviously that Ytterbium and Erbium are going to be too rare for life to use, but perhaps life can find another up-converting phosphor. 

Another way would be to capture the NIR energy directly into a chemical compound, for example many primitive algae here on earth use Bacteriorhodopsin which takes light of ~550 nm (green) and uses it to pump a proton, which needs only 35-40 kj/mol (obviously it is not very efficient, hence why more advanced algae and plants dominate the planet) Perhaps another system could evolve that does the same with NIR. So NIR absorbing protons pumps would make a proton gradient, which would store energy in ATP (or equivalent 35-40 kj/mol energy carrier) that energy would then have to be convert into an electron carrier like NADH and finally be used to dump the electron in cracking of water through some kind of biochemical chain. All of that would likely be very inefficient. 

Edited February 25, 2017 by RuBisCO
added link

[ProtoJeb21]

How about a different type of cell? Trappist-1 and similar stars produce most of their light in the infrared spectrum, rather than visible like our Sun. Creatures on the Trappist planets would have to develop ways to absorb that type of light in an efficient manner. Maybe with sodium? That's possibly what makes Tres-2b so dark. Or it could be larger photosynthetic cells to maximize intake of sunlight.

[RuBisCO]

24 minutes ago, ProtoJeb21 said:

How about a different type of cell? Trappist-1 and similar stars produce most of their light in the infrared spectrum, rather than visible like our Sun. Creatures on the Trappist planets would have to develop ways to absorb that type of light in an efficient manner. Maybe with sodium? That's possibly what makes Tres-2b so dark. Or it could be larger photosynthetic cells to maximize intake of sunlight.

Well light catching antenna can be many times smaller than the light wavelength, so the cells don't need to be larger. Rather a whole new kind of biochemistry would be needed for oxygen producing photosynthesis with light >800 nm. I don't know of any sodium based phosphor. It should be noted that there is photosynthesis here on earth that can use NIR light but again it does so by cracking hydrogen sulfide instead of water, these are known as purple sulfur bacteria and they ruled the earth for billions of years before oxygen producing green bacteria came about. The lack of complex life during the purple bacteria eons may be added evidence that sulfur powered life will simply be too sluggish to every become complex. Looking into it though and bacteriochlorophyll b can utilize light as high as 1050 nm. So perhaps the TRAPPIST system would have purple bacteria and nothing complex.

 

[ProtoJeb21]

39 minutes ago, RuBisCO said:

perhaps the TRAPPIST system would have purple bacteria and nothing complex.

That seems likely, given the age of the system at between 500 million to 1 billion years. Also, purple planets are cool.

But I've been thinking about the possibility of some other biology-based chemical reaction to create energy. For Trappist-1d (Thallo), it would probably be chemosynthesis due to the high abundance of metals in the planet. Some creatures could use a slightly different version of photosynthesis. In PS, sunlight breaks apart CO2 and H2O to create ATP with a side chemical of oxygen. This is possible with the rather high light energy of our sun. However, as you said before, plants on the Trappist planets won't get the same amount of sunlight as on Earth. It might be too weak for Terran PS to happen on these worlds. So, to compensate for this, cells would be larger to collect enough photons to break apart these molecules. Or they might use weaker molecules to break for energy so they won't have to be so big.

BTW I'm not the greatest at plant biology, so feel free to correct me.

Edited February 26, 2017 by ProtoJeb21

[RuBisCO]

Just now, ProtoJeb21 said:

That seems likely, given the age of the system at between 500 million to 1 billion years. Also, purple planets are cool.

But I've been thinking about the possibility of some other biology-based chemical reaction to create energy. For Trappist-1d (Thallo), it would probably be chemosynthesis due to the high abundance of metals in the planet. Some creatures could use a slightly different version of photosynthesis. In PS, sunlight breaks apart CO2 and H2O to create ATP with a side chemical of oxygen. This is possible with the rather high light energy of our sun. However, as you said before, plants on the Trappist planets won't get the same amount of sunlight as on Earth. It might be too weak for Terran PS to happen on these worlds. So, to compensate for this, cells would be larger to collect enough photons to break apart these molecules. Or they might use weaker molecules to break for energy so they won't have to be so big.

 

Last I check that was the minimum age of the system, it could be much older. Again it is not the amount of photons that is the problem it is their low quality of energy, again photons of wavelength beyond 830 nm CAN'T crack water. Already Light-harvesting complex in plants do a very good job of capturing light, even under low light conditions. Chlorosome of deep-sea green sulfur bacteria are the biggest photon collecting and shuttling structures in biology and they are only 200 nm big and yet can operate in nearly complete darkness 100 m below the black sea.

If biology can find a way in the TRAPPIST system to take two NIR photons and directly combine their energy to crack water it would not require a very big light antenna to do so considering TRAPPIST NIR flux is so strong. And yes the TRAPPIST system does appear to have a higher metal content then our solar system, which mean that perhaps (but unlikely) life could utilize more rare earth elements. 

[oguz]

I watched one video about Trappist-1 system, the guy said that "if planets don't have any magnetosphere, they possibly lost all the water and atmosphere by now". If that is true, which planet could have bigger iron mass/total mass ratio? I checked universe sandbox 2 and all planets have tiny iron core  

Edited February 26, 2017 by oguz

[UmbralRaptor]

2 hours ago, oguz said:

I watched one video about Trappist-1 system, the guy said that "if planets don't have any magnetosphere, they possibly lost all the water and atmosphere by now". If that is true, which planet could have bigger iron mass/total mass ratio? I checked universe sandbox 2 and all planets have tiny iron core  

1c looks to be the densest, but mind the error bars.

[YNM]

Some more interesting (exciting ? ionizing ? ) things to add (esp. @Shpaget@ProtoJeb21@RuBisCO) :

This is the absorption spectrum of water (copy source, with explanation, mind the logarithmic representation used) :

And this is the spectrum of a M8 dwarf star (taken from this paper, yes not TRAPPIST-1 but is from the same data source (2MASS)) :

I don't think IR/NIR would be a reliable source of photon underwater... If anything, even on Earth's ocean floor I don't think they have done that (absorb IR/NIR) from the Sun. It must come from something else (heat of the water itself, for example - hydrothermal vents should be a likelier place than any random ocean floor.)

Edited February 26, 2017 by YNM
leaned

[RuBisCO]

YNM,

I agree totally. Between 800-1200 nm water has an average absorption coefficient of 0.4 that means the first 10 cm of water absorbs 98% of this light, and every 10 cm low is another ~1/100 reduction!

None the less Purple Sulfur Bacteria managed for billions of years taking in light between 800-1050 nm, they simply swim up to the top centimeters of water. 

[YNM]

9 minutes ago, RuBisCO said:

None the less Purple Sulfur Bacteria managed for billions of years taking in light between 800-1050 nm, they simply swim up to the top centimeters of water. 

So in the "old days" sulphur was an easier compound to access ? Basic logic (of stellar nucleosynthesis) would say that sulphur is only half as abundant as oxygen. Though it is noted that volcanic activity means more sulphur.

I don't really say that life in the broadest sense is impossible on these objects - I just say that it's tough time for them to flourish and develop to something SETI would detect.

Edited February 26, 2017 by YNM

[RuBisCO]

45 minutes ago, YNM said:

So in the "old days" sulphur was an easier compound to access ? Basic logic (of stellar nucleosynthesis) would say that sulphur is only half as abundant as oxygen. Though it is noted that volcanic activity means more sulphur.

I don't really say that life in the broadest sense is impossible on these objects - I just say that it's tough time for them to flourish and develop to something SETI would detect.

No, sulfur is energetically easier to use then oxygen at the sacrifice that it is rarer, is a solid that can't support complex life, etc. Yes if we have not heard signals from the system probably no sentient life or even animals life, although SETI only looks at a narrow radio band range and only for high power signals. 

[Spaceception]

Only about a week before we get new data on the system, fingers crossed for moar planets and atmospheric detection's for most of them  

[RuBisCO]

1 hour ago, Spaceception said:

Only about a week before we get new data on the system, fingers crossed for moar planets and atmospheric detection's for most of them  

Sweet!, who going to announce in a week?

[Spaceception]

1 hour ago, RuBisCO said:

Sweet!, who going to announce in a week?

The Kepler telescope will finish its (I believe) 80-day observation, which means it'll be abe to nail down planet h's orbit and mass, and possibly find even more planets (All the planets orbit within 20 days, there has to be at least a couple more), the HST will also hopefully be finished, and we should have atm signatures from the system.

[ProtoJeb21]

1 hour ago, Spaceception said:

The Kepler telescope will finish its (I believe) 80-day observation, which means it'll be abe to nail down planet h's orbit and mass, and possibly find even more planets (All the planets orbit within 20 days, there has to be at least a couple more), the HST will also hopefully be finished, and we should have atm signatures from the system.

Yeeeaaaaaah!! I was hoping Kepler would eventually look at the system, but it looks like my wish came true early. However, I can't go through a whole week of school before new data. The hype will kill me.

Something that I (finally) noticed were the huge mass error bars of Theros, Auxo, Thallo, Eiar, and Carphos. That means they can be any mass in that range, right? I did some math and the answer is NO, NO, and more NO. The densities for the planets with the upper mass limits are impossibly high for objects of such radius. Expect for Theros (whose real mass could be closer to the upper limit), the densities are between 8 and 10 g/cm^3. The lower limits are even worse, implying at densities between 2 and 0.4 g/cm^3. That is impossible for Earth-sized planets around a star more metal rich than our Sun. For every planet except Theros, the predicted mass is likely the real mass. Theros could be more massive than 0.86 Earth masses.

[Spaceception]

6 minutes ago, ProtoJeb21 said:

Yeeeaaaaaah!! I was hoping Kepler would eventually look at the system, but it looks like my wish came true early. However, I can't go through a whole week of school before new data. The hype will kill me.

 

Yep, the studies will be done on March 5th I believe, and it'll be made public either, on that day, or on March 7th.

Found it!

 

[RuBisCO]

Not a Kerbals as I though

So I calculated the orbital velocity of each of the TRAPIST planets, subtracted the difference and assume 75% of that to guess at how much delta-v would be needed to go from low orbit of one world up to a transfer orbit to the next world.

	Venus	Earth	Mars	Tb	Tc	Td	Te	Tf	Tg	Th
r (m)	1.08E+11	1.50E+11	2.28E+11	1.66E+09	2.28E+09	3.14E+09	4.19E+09	5.54E+09	6.73E+09	9.40E+09
v (m/s)	35017	29781	24127	79964	68231	58141	50332	43772	39714	33604
v diff.		5236	655		11733	10090	7809	6560	4058	6110
est. dv needed		3927	4241		8800	7567	5857	4920	3043	4583

So for a civilization on say Te to go to Td would take ~6 km/s of delta-v, from Te to Tf would take ~5 km/s, from Tf to Tg would be ~3 km/s, etc. For comparison from Earth to Mars is typically 4.2 km/s. So it is going to take equal or greater amounts of rocket fuel to hop planets here, even though travel times will be a few days rather than many months. With such short orbital periods gravity assists would make huge amounts of sense as when hoping two or more planets up or down.   

 

Edited February 26, 2017 by RuBisCO

[Spaceception]

12 minutes ago, RuBisCO said:

Not a Kerbals as I though

So I calculated the orbital velocity of each of the TRAPIST planets, subtracted the difference and assume 75% of that to guess at how much delta-v would be needed to go from low orbit of one world up to a transfer orbit to the next world.

	Venus	Earth	Mars	Tb	Tc	Td	Te	Tf	Tg	Th
r (m)	1.08E+11	1.50E+11	2.28E+11	1.66E+09	2.28E+09	3.14E+09	4.19E+09	5.54E+09	6.73E+09	9.40E+09
v (m/s)	35017	29781	24127	79964	68231	58141	50332	43772	39714	33604
v diff.		5236	655		11733	10090	7809	6560	4058	6110
est. dv needed		3927	4241		8800	7567	5857	4920	3043	4583

So for a civilization on say Te to go to Td would take ~6 km/s of delta-v, from Te to Tf would take ~5 km/s, from Tf to Tg would be ~3 km/s, etc. For comparison from Earth to Mars is typically 4.2 km/s. So it is going to take equal or greater amounts of rocket fuel to hop planets here, even though travel times will be a few days rather than many months. With such short orbital periods gravity assists would make huge amounts of sense as when hoping two or more planets up or down.   

 

 

 

 

In our solar system, a grand tour takes years and years, in that system, it'd only take a few weeks, maybe a few months, I wonder how they would view space travel, and if they would observe it as easy, can you imagine an alien public that expects interstellar travel to only take a few years with normal rockets? And then their shock that it would take decades at a minimum with extremely advanced rockets?

 

Thinking about that, what are the nearest stars to TRAPPIST-1? Maybe someone could check in Space Engine, I dunno.

Edited February 26, 2017 by Spaceception

[ProtoJeb21]

9 minutes ago, Spaceception said:

Thinking about that, what are the nearest stars to TRAPPIST-1? Maybe someone could check in Space Engine, I dunno.

Here are the nearest real stars within 15 light years of Trappist-1:

WISEPC 23402-07450 (6.19 ly)

HIP 112774 (7.04 ly)

2MASS 22244-01585 (7.60 ly)

HIP 116317 (8.84 ly)

WISEA 23540+02401 (11.03 ly)

Iota Piscium (11.37 ly)

WISEPC 22262+04400 (11.64 ly)

HIP 111313 (11.99 ly)

HIP 108782 (12.42 ly)

ULAS 23212+13545 (13.15 ly)

2MASS 00242-01582 (13.30 ly)

HIP 114233 (13.34 ly)

Gliese 849 (13.66 ly)

2MASSI 23565-15531 (14.63 ly)

[Spaceception]

3 minutes ago, ProtoJeb21 said:

Here are the nearest real stars within 15 light years of Trappist-1:

Iota Piscium (11.37 ly)

 

That must be a pretty bright star in the sky.

[ProtoJeb21]

2 minutes ago, Spaceception said:

That must be a pretty bright star in the sky.

Actually not really. Iota Piscium is over 11 light years from the system and is about 3.6 times more luminous than our Sun. However, Sirius is about 8.6 light years away from our system with over 24 solar luminosities. So the Trappistians won't have such a good sky as ours, especially since almost every other nearby star I mentioned is either a red dwarf or a brown dwarf. Only one is an orange dwarf.

[RuBisCO]

13 minutes ago, Spaceception said:

That must be a pretty bright star in the sky.

Stars... OH DAM STARS! Inhabitants on these worlds might not even know of stars! Their worlds are tidal-locked so they have no day or night (they probably don't sleep either!), only unless they travel to the dark side of their world would they see stars. Atmospherics scattering of light on their day side would cover up any star even a bright one like Iota Piscium. The other planets being definite worlds in their sky would likely give the inhabitants an edge over us that their world is one of several, but the discovery that their sun is only one of trillions upon trillions would come later then it did for us in their civilization's development. 

Edited February 26, 2017 by RuBisCO

[Spaceception]

10 minutes ago, RuBisCO said:

Stars... OH DAM STARS! Inhabitants on these worlds might not even know of stars! Their worlds are tidal-locked so they have no day or night (they probably don't sleep either!), only unless they travel to the dark side of their world would they see stars. Atmospherics scattering of light on their day side would cover up any star even a bright one like Iota Piscium. The other planets being definite worlds in their sky would likely give the inhabitants an edge over us that their world is one of several, but the discovery that their sun is only one of trillions upon trillions would come later then it did for us in their civilization's development. 

 

If they evolved on the terminator, they could see really bright stars. And we already know the planets could rotate, but are there any Earth examples of animals that don't sleep? Or any close to it?

[RuBisCO]

25 minutes ago, Spaceception said:

If they evolved on the terminator, they could see really bright stars. And we already know the planets could rotate, but are there any Earth examples of animals that don't sleep? Or any close to it?

Well their planets rotate, just as the same speed as they go around the sun, hence tidal-locked. If they live near the terminator, depends on a whole lot of unknowns unknowns, how well their atmosphere moves heat, what is the tectonic activity? how much surface water do they have? If their world has up-welled continents and volcanic islands on near side and subduction on the far side then our kerbals might come about near the center of the near side assuming they have a super-rotor atmosphere and not a turbulent-convecting atmosphere that would put a perpetual hurricane at the center of the near side. Worlds like Tb and Tc are likely venus like hells, Td perhaps habitable along the terminator if its atmosphere is think enough and it retained enough water, Te more so towards the center, Tf and Tg would need thick high green-house gas atmospheres to prevent all their water from freezing up on the far side leaving the near side and even terminator a desert.   

As for earth examples of animals that sleep: google, but alas no life on earth evolves in a world with perpetual day light.

Edited February 26, 2017 by RuBisCO

[ProtoJeb21]

1 hour ago, Spaceception said:

If they evolved on the terminator, they could see really bright stars. And we already know the planets could rotate, but are there any Earth examples of animals that don't sleep? Or any close to it?

I don't think ALL life will evolve on the terminator. Depending on the planet's equilibrium temperature, all of the front side will be the right temperature for life with a circulating planetary wind system that would distribute the heat around the planet. Look at this model for Proxima Centauri b made by the ESO:

https://upload.wikimedia.org/wikipedia/commons/transcoded/a/a4/Numerical_simulation_of_possible_surface_temperatures_on_Proxima_b_(synchronous_rotation).ogv/Numerical_simulation_of_possible_surface_temperatures_on_Proxima_b_(synchronous_rotation).ogv.480p.webm

The front side has a nice warm temperature of 30-35 Celsius, or around 80-90 Fahrenheit. That's similar to summertime temperatures in our northern hemisphere. This model was made with Proimxa b having an atmosphere Earth-like in pressure and density, and possibly in CO2 quantities. Keep in mind that Proxima b's equilibrium temperature is 234*K, higher than those of Trappist-1f (Irene) and Trappist-1g (Carphos). Trappist-1e (Eiar) does have an Earth-like ET of 251.3*K, so some of the front side would be up to 100-110 Fahrenheit. Basically, a pretty big sauna. The rest of the sun-lit side would range from 90*F at the high to -20*F at the low. Keep in mind that these are just estimates.

So what about good ol' 0.9 ESI Thallo?

Yeah...the front side is going to be a bit too toasty for water. But fear not, because that could make the back side more prime for life. Warmer air will be circulated back there and possibly cause some ares to rise above the temperature to melt water. I would say that for Thallo, the first half of the front side is a no-go zone, unless you're a hardy organism that can access possible pockets of underground water.