News Nasa Finds 7 Rocky planets in 1 star system

[Linguofreak]

Hm, the star is only 2300K. Isn't that too low spectrally to support photosynthesis?

With chlorophyll, probably. That doesn't rule out photosynthesis with a chemical with good absorbtion in the IR.

 

[boogabooga]

With chlorophyll, probably. That doesn't rule out photosynthesis with a chemical with good absorbtion in the IR.

Not the same to a molecule and there are fundamental differences:

IR absorptions: molecular vibrations- bending, wiggling, etc. In addition, there are extra geometrical constraints on the molecule in order to be IR active. The radiation energy is turned into heat (and vice versa).

UV/visible absorption: Electron transitions. Basically, you need this to happen to store light energy chemically.

It's why visible spectroscopy and IR spectroscopy are different disciplines.

Most organic compounds are white because they absorb only in the UV. It already takes a lot of molecular bonding kung fu (conjugation, etc.) to get a low enough electron transition energy for a molecule to absorb visible rather than UV. I find it highly improbable that IR can practically take the place of UV-vis for photosynthesis.

 

[Linguofreak]

I wonder what color could be the hypothetical vegetation. Black?

The color in visible light could be anything: the photosynthesis agent would have to be a chemical that absorbed IR well, but could be completely white in the visible without losing much efficiency (bizarrely, though, green chlorophyll actually reflects the wavelengths that the sun emits most strongly. There is purple chlorophyll, which you'd expect would be more widespread, but, AFAIK, is only used by certain algae).

Speaking of color, artists impressions of red dwarf systems tend to be a fair bit oranger than what the human eye would actually see. TRAPPIST-1 is similar in temperature to the cooler end of the range of incandescent light bulbs, so, like incandescent lighting, it would have an orangey cast if you really thought about it, or took a picture with a camera white balanced for Earth daylight, but would otherwise appear more or less white, as the human eye can adjust its white balance over a very broad range.

---------- Post added at 17:01 ---------- Previous post was at 16:10 ----------

Not the same to a molecule and there are fundamental differences:

IR absorptions: molecular vibrations- bending, wiggling, etc. In addition, there are extra geometrical constraints on the molecule in order to be IR active. The radiation energy is turned into heat (and vice versa).

UV/visible absorption: Electron transitions. Basically, you need this to happen to store light energy chemically.

It's why visible spectroscopy and IR spectroscopy are different disciplines.

Most organic compounds are white because they absorb only in the UV. It already takes a lot of molecular bonding kung fu (conjugation, etc.) to get a low enough electron transition energy for a molecule to absorb visible rather than UV. I find it highly improbable that IR can practically take the place of UV-vis for photosynthesis.

I thought there were at least a few animals with vision in the near-IR? If you have an IR pigment for color vision, shouldn't you be able to use it for photosynthesis as well?

 

[boogabooga]

I thought there were at least a few animals with vision in the near-IR? If you have an IR pigment for color vision, shouldn't you be able to use it for photosynthesis as well?

I'm not an expert, but I think some animals are ultra-sensitive to regular visible light and get "night vision" that way.

Snakes have a sort of IR-vision, but seems to be a heat-sensing membrane and uses a different organ from the eye.

I'll leave these here:
https://en.wikipedia.org/wiki/Night_vision#Biological_night_vision
https://en.wikipedia.org/wiki/Infrared_sensing_in_snakes

 

[Artlav]

There is IR and there is IR, as i had explained many times in several places.
The IR we are talking here is NIR - near infrared, which is just outside our visible spectrum.
Thermal IR is much longer waves, and need completely different things to detect.

NIR, however, is quite accessible by our biology. Even humans can be made to see it with proper diet (you need to replace all vitamin A in your body with another form of it, thus changing the structure of the pigments). Does not work too well in practice, since you lose the ability to see blue as a side effect and the diet is pretty bad, but still.

In some animals it occurs naturally, giving them an ability to either see an extra color, or to see better in low light, along with other things.

But as far as i understand it, that's not helpful for photosynthesis, since it's quite a bit different from just vision.

 

[Linguofreak]

I'm not an expert, but I think some animals are ultra-sensitive to regular visible light and get "night vision" that way.

Snakes have a sort of IR-vision, but seems to be a heat-sensing membrane and uses a different organ from the eye.

I'll leave these here:
https://en.wikipedia.org/wiki/Night_vision#Biological_night_vision
https://en.wikipedia.org/wiki/Infrared_sensing_in_snakes

I wasn't talking about snakes, whose pit organs are geared toward thermal IR (such as emitted by objects in the ~300K range), I was talking about near IR, which is characteristic of temperatures in the low thousands of Kelvin.

 

[jedidia]

In some animals it occurs naturally, giving them an ability to either see an extra color,

Am I the only one who just thought "woah, octarine!" :lol:

 

[Linguofreak]

But as far as i understand it, that's not helpful for photosynthesis, since it's quite a bit different from just vision.

I thought I had heard of bacteria that used rhodopsin (the pigment in rod cells) for photosynthesis, and it turns out I was half right: There are rhodopsin phototrophs (ie, organisms that get energy from light), but not rhodopsin photosynthesizers (organisms that use light to create oxygen and sugar from CO2 and water).

Looking a bit further into it, there actually are bacteriochlorophylls that have sensitivity in the near IR. Once again, the organisms involved are phototrophs only, but it does establish that a living organism can at least get energy from near IR. But I'd think if you have a way to get energy from a given wavelength, it shouldn't be too much of a leap to full photosynthesis.

See:

https://en.wikipedia.org/wiki/Bacteriochlorophyll
https://en.wikipedia.org/wiki/Rhodopsin

 

[Keatah]

I wonder what space travel is like for the people that live there? Going from one planet to the next is gotta be pretty easy. And what about telescopes? Their telescopes should be able to see the other worlds easily in detail. And perhaps they (at first) communicated between planets with powerful search-lights.

 

[Andy44]

I wonder what space travel is like for the people that live there? Going from one planet to the next is gotta be pretty easy. And what about telescopes? Their telescopes should be able to see the other worlds easily in detail. And perhaps they (at first) communicated between planets with powerful search-lights.

The Saturn system with its many moons is a popular choice for sci fi settings and starry-eyed futurists, and this star system reminds me of it.

 

[Linguofreak]

I wonder what space travel is like for the people that live there? Going from one planet to the next is gotta be pretty easy.

Unfortunately, it's getting off your own planet that's the hard part. You have to put on ~8km/s of delta V at over one G, which demands quite a bit of performance from your launch vehicle.

 

[Proximus]

I thought I had heard of bacteria that used rhodopsin (the pigment in rod cells) for photosynthesis, and it turns out I was half right: There are rhodopsin phototrophs (ie, organisms that get energy from light), but not rhodopsin photosynthesizers (organisms that use light to create oxygen and sugar from CO2 and water).

Looking a bit further into it, there actually are bacteriochlorophylls that have sensitivity in the near IR. Once again, the organisms involved are phototrophs only, but it does establish that a living organism can at least get energy from near IR. But I'd think if you have a way to get energy from a given wavelength, it shouldn't be too much of a leap to full photosynthesis.

See:

https://en.wikipedia.org/wiki/Bacteriochlorophyll
https://en.wikipedia.org/wiki/Rhodopsin

I'm sure I read that all chlorophyll photosynthesis came from one single mutated organism on earth. The ability to light into energy in such a manner has occurred only once in the history of our planet.

It just makes me wonder what the chances are of such a thing happening in another system? Quite slim I would imagine

 

[Linguofreak]

I'm sure I read that all chlorophyll photosynthesis came from one single mutated organism on earth. The ability to light into energy in such a manner has occurred only once in the history of our planet.

It just makes me wonder what the chances are of such a thing happening in another system? Quite slim I would imagine

Your second sentence does not follow from your first. All we know is that all photosynthesizers today are related. That does not mean there have not been photosynthesizers in the past that are unrelated to any current photosynthesizer, but had no descendants that survived to the modern day.

 

[Ravenous]

I'm sure I read that all chlorophyll photosynthesis came from one single mutated organism on earth. The ability to light into energy in such a manner has occurred only once in the history of our planet.

It just makes me wonder what the chances are of such a thing happening in another system? Quite slim I would imagine

It only has to happen once, as the abundance of green stuff here shows.

Anyway there may have been lots of competing types around in the early years, which were rapidly swamped by the one most successful example.

 

[Proximus]

There are many examples of unrelated organisms evolving in the same manner on this planet.

Chlorophyll organisms are not among them.

As previously stated, the green stuff is all related which suggests to me its a little bit special and not something that would be common on other worlds.

 

[boogabooga]

I thought I had heard of bacteria that used rhodopsin (the pigment in rod cells) for photosynthesis, and it turns out I was half right: There are rhodopsin phototrophs (ie, organisms that get energy from light), but not rhodopsin photosynthesizers (organisms that use light to create oxygen and sugar from CO2 and water).

Looking a bit further into it, there actually are bacteriochlorophylls that have sensitivity in the near IR. Once again, the organisms involved are phototrophs only, but it does establish that a living organism can at least get energy from near IR. But I'd think if you have a way to get energy from a given wavelength, it shouldn't be too much of a leap to full photosynthesis.

See:

https://en.wikipedia.org/wiki/Bacteriochlorophyll
https://en.wikipedia.org/wiki/Rhodopsin

Rhodopsin is a protein, while chlorophyll is just a large molecule. Big difference.

For true photosynthesis, you still need to excite an electron, and that becomes increasingly difficult as the wavelength goes up. Not to say that it can't happen. (And yes, there are still molecular vibrations that occur in the near-IR)

If all that you need is an energy source, then you don't necessarily need EM radiation at all. There are still hydrothermal vents, which increasing look to be a source for early life on earth:
http://www.bbc.com/news/science-environment-39117523

So all you really need is the liquid water part for that. TRAPPIS-1 system may get a bonus there for tidal heating, with all those large planets orbiting close together. The water may also protect organisms from the dangerous red dwarf activities.

My bet is that if there is life in the system, it is hydrothermal.

 

[Unstung]

Probing Seven Worlds with NASA's James Webb Space Telescope

With the discovery of seven earth-sized planets around the TRAPPIST-1 star 40 light years away, astronomers are looking to the upcoming James Webb Space Telescope to help us find out if any of these planets could possibly support life.

“If these planets have atmospheres, the James Webb Space Telescope will be the key to unlocking their secrets,” said Doug Hudgins, Exoplanet Program Scientist at NASA Headquarters in Washington. “In the meantime, NASA’s missions like Spitzer, Hubble, and Kepler are following up on these planets.”

“These are the best Earth-sized planets for the James Webb Space Telescope to characterize, perhaps for its whole lifetime,” said Hannah Wakeford, postdoctoral fellow at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. At Goddard, engineers and scientists are currently testing the Webb telescope which will be able to view these planets in the infrared, beyond the capabilities we currently have. “The Webb telescope will increase the information we have about these planets immensely. With the extended wavelength coverage we will be able to see if their atmospheres have water, methane, carbon monoxide/dioxide and/or oxygen.”

When hunting for a potentially life-supporting planet, you need to know more than just the planet’s size or distance from its star. Detecting the relative proportions of these molecules in a planet’s atmosphere could tell researchers whether a planet could support life.

“For thousands of years, people have wondered, are there other planets like Earth out there? Do any support life?” said Sara Seager, astrophysicst and planetary scientist at MIT. “Now we have a bunch of planets that are accessible for further study to try to start to answer these ancient questions.”

Launching in 2018, one of Webb’s main goals is to use spectroscopy, a method of analyzing light by separating it into distinct wavelengths which allows one to identify its chemical components (by their unique wavelength signatures) to determine the atmospheric components of alien worlds. Webb will especially seek chemical biomarkers, like ozone and methane, that can be created from biological processes. Ozone, which protects us from harmful ultraviolet radiation here on Earth, forms when oxygen produced by photosynthetic organisms (like trees and phytoplankton) synthesizes in light. Because ozone is largely dependent on the existence of organisms to form, Webb will look for it in alien atmospheres as a possible indicator of life. It will also be able to look for methane which will help determine a biological source of the oxygen that leads to ozone accumulation.

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