Strange new worlds

[Frelga]

There's light and high beauty up there.

I keep going to Google today any time I have an excuse. I can't get enough of the Moon going all Yay!

[Primula Baggins]

Me, too! It's slowing down my searches that I have to set the doodle off every time.

And yes, it is nice to come in here and talk about something serious and important that is also fun and happy. So far I've come up with several different SFnal explanations for this system, along with cool ways to use them in a story.

But actually, it's even more cool if this is in fact a common thing with M-type (red dwarf) stars—because 85% of the stars in this galaxy are M-type. That's at least 85 billion stars. If planets are common around them, that's a lot of planets. If occurrences of life are proportional to the number of planets, then the more planets, the more chances for life to arise. Which means the more chances that there are, well, other people out there somewhere.

[Primula Baggins]

Here's a virtual reality animation from NASA showing an imagined 360-degree view if you were standing on the surface of Trappist-1d, the middle of the seven worlds. Don't forget to scroll up and look at the sky.

https://www.youtube.com/watch?v=o2MgG6K ... e=youtu.be

[Inanna]

The more I read about this, the more fascinating this becomes.

Regarding possibility of life, didn't a researcher find a few years ago that life can grow even in arsenic?

[yovargas]

Chlorophyll's a unique type of molecule....

One that I doubt any scientists would have been able to conceive of without an example of it to study.

[Primula Baggins]

It doesn't work like that. What it does requires a certain kind of molecular structure--the one it has.

[yovargas]

But would we have known that molecules with that certain structure can do what they do without chlorophyll to study?

[Primula Baggins]

"Whole New Worlds: An Aladdin History of Exoplanets" from A Capella Science.

https://youtu.be/gai8dMA19Sw

Fun. Nice singing. Actual science (and science history). Cool planet images.

[Frelga]

I'm impressed by how well the lyrics scan.

[Primula Baggins]

Geeks write good.

[anthriel]

But would we have known that molecules with that certain structure can do what they do without chlorophyll to study?

Circular thought there, isn't it.

I've often pondered how often our "inventions" are based on structures already in use by nature for time out of mind. The structure of cameras, for example, sure owe a lot to the structure of eyes.

[Primula Baggins]

The arrow on your circle is just going in the wrong direction, yov.

We found the chlorophyll molecule by analyzing photosynthesis—we already knew something existed that converted sunlight into food, because it had been happening in front of our eyes for thousands of years. When we had the tools to discover and understand chlorophyll's structure, we were also able to understand how it worked. Because we understand how it works, we know its limitations—it needs a certain minimum energy of incident photons to function. It's also (after billions of years of natural selection) the simplest molecule that can carry out this function.

We also know what kinds of analogous structures are possible. They have to be made out of carbon—silicon beings are right out; silicon can't make long and complex enough chains for any kind of protein-like or DNA-like structure; and its dioxide form is not a nice, mobile gas, but piles of sand, from which it's energetically extremely hard to re-extract the oxygen atoms. So given that it's got to be carbon, the energy requirements are clear, and there is no molecule that will carry out photosynthesis under a darkroom light. Life instead would have to extract its energy in less direct and efficient ways, which is a handicap. It can exist, but without that key energy source, it won't be complex or versatile.

[axordil]

There's a hypothesis that plant life was once (a looooong time ago) more purple than green, driven by retinal-based photosynthesis. Of course, the sun and atmosphere were also different, so ambient light probably had a different spectrum.