Red dwarves everywhere.

[Captain Jonah]

http://www.telegraph.co.uk/science/spac ... y-Way.html

Interesting about the number of earth types planets around. 80% of all stars are red dwarfs, 40% of them may have earth type worlds, thats 51 Billion systems with rocky worlds around the habitable zones.

Also less than 12% of the red dwarves have gas giants, refueling on those planets within the liquid water zone then. Pirates, aliens, strange life forms, common solar flares. Ah the life of a space going Traveller

Still if they have been studying 102 worlds withon 30 LYs that makes us a fairly crowded area. Lots of short hops for those stutterwarp drive.

[Rusty_Unycorn]

Huh. You know, that reminds me... We need tables for rolling up stellar classes for systems...
On a tangent, my first thought on seeing the thread title was "Oh no, it's just like Rimmerworld..."

[BP]

Smegg'in daft man!

[crossmlk]

Captain,
Excuse me if this is a dumb question but here it is. Do we have any idea what light levels would be like on a world within a Red Dwarf's habitable zone?

Would they be the same as on earth? I'm thinking of it for purposes of how you describe the place to players.

[Captain Jonah]

Much the same as for yellow stars. The habitable zone inner edge would be high intensity, akin to the equator here so very intense bright sun, the outer edge could be twilight and barely above freezing.

Red dwarfs have a habitable zone that is both smaller and much closer than those of larger suns such as ours.

One of the problems is radiation from the sun, being much closer worlds with weaker magnetic fields would have higher radiation levels. A 0.5 G world at the very inner edge could have no ice anywhere, standing water only at the poles, salt flats round the equators, enough radiation to kill you if you step outside of a shelter without a hostile environment suit and the highest order of life could be giant semi intelligent cockroaches

One a world close to a red dwarf the northern lights would be a sign to run for those bunkers and shielded buildings.

If our sun was a red dwarf and we were still the same distance away we would live on a very dark and cold ball. We would be right at the outer edge of (or outside) the habitable zone. The sun would be a dim red glow above the clouds, there may be no unfrozen water on the surface, water existed as liquid only deep below the ice sheets.

[rust]

I would also think that most planets in the habitable zones of
red dwarfs would be so close to their stars that they would be
tidally locked, which would make them somewhat less habita-
ble.

[Lemnoc]

Do we have any idea what light levels would be like on a world within a Red Dwarf's habitable zone?

I believe I read an article someplace that speculated that on worlds orbiting dim stars with a reduced blue spectrum, photosynthetic plant life would have a black cast. Black jungles, yellow skies.

Lots of info here (EDIT):

http://www3.geosc.psu.edu/~jfk4/Persona ... esInt2.htm

[Captain Jonah]

A tidal locked world, facing is a scorched land of ash and dust, trailing is ice fields and glaciers.

A belt no more than a few hundred miles wide round the world at the solar horizon where heat from facing melts the ice and raises the temperature to liveable and provides standing water.

Almost perpetual rain and storms as the ice is melted by the heat along the border, is caught by the rising warmer air from facing and carried high overheat where it either falls back as rain and snow across the trailing or is spread as clouds high enough over the facing to survive.

Eternal twilight with the sun light being refracted across the horizon, you may never see the sun itself, just the red/orange glow that fills the entire facing horizon.

With a spectrum shift towards red/orange the plants would be much darker to absorb as much as possible, our plants are green to because they reflect the fairly useless green part of the spectrum while using the more useful red and blue parts, remove the blue end and the plants will darken to very deep green, purple and black to absorb as much as possible of the red spectrum without regard to the less important (due to its absence) blue.

Changes in the emission spectrum of the sun can also lead to other problems, higher IR output will lead to sunburn and medical level burns to exposed flesh unless you are careful.

Lower levels of UV may make fungal growths more prevalent. Vast forests of mushrooms, mould mountains, life forms that have evolved to live in this niche area.

Planting terrestrial crops could be a constant battle to deal with moulds and blights that infest the earth plants and the soil. You could sterilise the soil only to have spores cover it again as they drift on the wind.

[crossmlk]

Regarding the vastly increased radiation problem on a Red Dwarf planet, what do you see biological modification being able to do to help humans cope and more importantly to what level?

Niven if I remember correctly in a similar situation (high UV world) had the humans use pharmaceuticals to stimulate their pigmentation levels so they had very black skin as a way to combat the UV.

What ideas can you guys see? Seems to me we'd have to find ways to biologically modify humans living on such a place. Traveller already has anti-radiation pharmaceuticals to make you all better if you are exposed to a high level of radiation. I don't think that would be a viable long term solution (although I guess you might need to take your medicine everyday) for living on such a planet. How would you biologically modify someone to withstand constant exposure to high rad levels?

[rust]

How would you biologically modify someone to withstand constant exposure to high rad levels?

The best way to solve this problem would probably be a modification
of the DNA repair mechanism of the human body, which is rather in-
efficient compared to that of other species. The undisputed master of
fast DNA repair and therefore radiation resistance is "Conan the Bac-
terium", a very simple organism which could perhaps be used as a mo-
del for a genetic modification of other species:

http://en.wikipedia.org/wiki/Deinococcus_radiodurans

[Captain Jonah]

Depends on a lot of factors.

Higher Melanin levels should be easy to modify for though you are also facing a number of related problems such as vitamin deficiency if you end up blocking to much.

DNA modification so the new settlers are born with much higher levels or retro DNA adjustment prior to taking up permanent residence. Though this is an odd one since you would be dealing with a change in the light spectrum so you would need darker skin to deal with higher levels of UV/IR but at the same time you would also need to adjust to the eternal twilight because the direct light of the sun is too dangerous and the colonists leve forever just below the horizon from the Suns glare.

Think of skin a deep purple/black (far deeper than most Africans) but combined with huge pupils and eyes (sort of like the Japanese anime girls)

Medical mites (bio tech/medical nanites) could be used to increase the melanin levels for short periods of time for visitors.

Specific frequency sun block for visitors.

With Twilights overall higher tech and better medical support (the OUT is very primitive in many fields including medical support) short term damage would be easy to deal with. The same sort of anti cancer or radiation treatments in a pot (Fluid mites again) could be very useful in dealing with cell damage caused by over exposure.

In many ways it is going to be an odd situation since half the problems will stem from an environment with much higher levels of sun such as UV/IR levels several times higher than the hottest parts of the Equator but combined with much lower levels of visible light akin to the eternal twilight of the polar nights.

A colonist from such a world would need a lot of medical suppliants off world to avoid vitamin D deficiency since even normal bright sunshine would be far less than he needs but at the same time such a person would be almost blinded by the “Normal light levels”.

[far-trader]

Gen mod etc. are all interesting ideas but the most practical solution is the people live inside. Underground or above. With artificial gravity, lighting, air, etc. and Traveller's radiation screening. Simple if not as interesting as the exotic adaptations.

[crossmlk]

So for purposes of adapting to a high rad environment like we would likely see in a terran planet in a red dwarf's goldilocks zone (you could make a case for Earth normal radiation levels on a super terran sized world with a proportionally larger nickel/iron core thus providing a stronger Van Allen belt). You'd need some sort of hyper skin pigmentation, possibly self adjusting. You'd need far greater DNA repair ability, and in the case of a tidally locked planet you'd need specialized eyes to see in the light terminous zone you'd be forced to inhabit. The tidal locked thing though might be rather rare when you consider that we now know that even Mercury isn't tidal locked with the Sun (it has a 59 day rotation period). Any other genetic modifications that would be necessary or useful?

I don't want this to devolve into a Twilight Sector discussion but from the perspective of the DNA repair gene-mod, it might also translate into an ability for quick healing in general.

A cool idea for a slow rotating planet like Mercury is, where you'd have to stick to the light terminous zone would be rolling habitats. Richard Baker described a very cool one in one of the StarDrive novels. You'd have this huge rolling habitat/city moving through perpetual twilight constantly surrounded by mega-storms. A very cool visual.

Also of note there would have to be a sweet spot in the Red Dwarf's goldilocks zone that would more closely approximate Earth standard. Throw in Super-Terran sized worlds and the possibiltiy of Earth normal planets becomes pretty good as those things go.

[crossmlk]

Gen mod etc. are all interesting ideas but the most practical solution is the people live inside. Underground or above. With artificial gravity, lighting, air, etc. and Traveller's radiation screening. Simple if not as interesting as the exotic adaptations.

True but for long term habitation I don't think anyone would want to live there. I personally couldn't imagine living in a place where you were always inside. Even with cutting edge simulations of wide open spaces and bright sunlight, if you could look outside and see what for the most part looked like an earth normal environment that you couldn't experience because of invisible radiation. I think that would be worse than living in a habitat on a barren moon where it would be easy to reconcile yourself to not being able to go outside.

Many people have claustrophobia (something that a deep space gene-mod would be tasked with removing and would argue for your point. That would seem to be a simpler modification that an extensive radiation modification.) and if you want long term settlement on a large scale you'd look to changing the population to suit the environment, especially if it was relatively easy and reversable or at least could be compensated for if you left that environment.

[Reynard]

Years ago I had an idea to base a Traveller universe on the actual stars centered around Sol. The 2300 Near Star List was a godsend. I planned to use the stars in existance and generate the systems based on the star(s).

First thing I learn is how many flare stars are out there. These pretty much guarantee nothing but the star exists and makes the system a space hazard. Then you see how many dwarf stars there are and realize a lot of systems will have little in the way of hospitable habitation. Throw in a couple A and B stars and the number of 'useful' systems dwindles. Still I generated systems with what was available and mapped the jump distances to connect worlds mostly out to Jump 2. The three dimensional jump map is interesting by itself.

In reality, nearly all worlds should be the same technology level. Many worlds generated normally would never 'realistically' support the hostile conditions compared to the technology, something Mongoose addresses with the Space Opera/Hard Science variant and Environmental Limits. Otherise the number of habital worlds would drop again.

Looking at the overall creation I now studied the interconnections of the worlds. Why in the galaxy would you ever have a colony on THAT world? What makes it worth colonizing? Do the numbers show vital resources that outweight costly hostile conditions or is the world more valuable as a way point to other more resource valuable systems? It really made me think what our reality would be with the advent of Jump Drives. With the information concerning the Sol community since expanded the 1969 data, I wonder how different the landscape will look? For now I think I will redo the star systems using Mongoose's UWP generation including Space Opera/Hard Science variant and Environmental Limits and see how much more empty the neighborhood is.

[far-trader]

Of course in Traveller there is always the old "Grandfather"ed worlds meme. Planets in systems that shouldn't work with obviously enhanced/terraformed work done in the distant past. I mean come on, he and the kids made pocket universes for kicks. How easy would it be for them to rearrange a few orbits, even import a world, plonk it down close to an alien star for warmth then tweak the world so it can provide a habitable surface to establish yet another research (or whatever they were doing) base. If you accept the level of ability and interference The Ancients show then it's not hard to accept just about any randomly rolled up world and star system

[GamingGlen]

I often wonder how many planets are out there that life from Earth could actually live on without modification. I doubt it's more than a few. But the universe may surprise it when we get out there.

All this discussion reminded me of what I've wanted: a set of rules for detailing how hostile or benign a world's environment is. What exactly is the taint in atmospheres 2, 4, 7, and 9? What is an insidious atmosphere? Is there natural life on the planet and how safe is it to interact with (e.g., poisonous, indigestible)?

Would a supplement, say titled "Hostile Environments", be a book worth writing, or be a section in an expanded world generation system supplement? (I miss my World Tamers handbook.. never again will I loan out books as I never got it back from someone who I've rarely seen again and swears he doesn't have it )

Then of couse, how soon would it be out of date as we learn more about the universe? (and can it be any worse than Traveller in general? )

[spirochete]

[Excuse me if this is a dumb question but here it is. Do we have any idea what light levels would be like on a world within a Red Dwarf's habitable zone?

Would they be the same as on earth? I'm thinking of it for purposes of how you describe the place to players.]


For a minimal red dwarf near the tail-end of the main sequence (VB-10), the absolute magnitude is near 17.7, and the illumination level in an earth-equivalent orbit is about 4%. A planet is this orbit will receive the same overall isolation as earth, but only 4% of the illumination.

For a maximal red dwarf near the crossover to spectral class K (Lacaille 8760), the illumination in an earth-equivalent orbit is around 50% - 57%.

[crossmlk]

So to put it succinctly , a planet in the habitable zone around a Red Dwarf is going to range from kind of dim to very dim. Correct?

[spirochete]

[So to put it succinctly , a planet in the habitable zone around a Red Dwarf is going to range from kind of dim to very dim. Correct?]

Not at all.

It will be dimmer than the unfiltered blazing sunlight the Earth and Moon receive, which about 128,000 lux, 2% of that amount is 2,560 lux, which is still considerable. 50% = 64,000 lux. 'Dimmer' in this case is still plenty, since the human eye can operate at very low light levels.

At the Earth-equivalent distance, an atmosphere with the same optical properties as Earth's will attenuate the light of a 'minimal' red dwarf (15 degrees elevation above the horizon) down to about 1,400 lux, comparable to our own sun sitting a disc's width above the horizon. In the temperate regions of the tide-locked planet, the brightness of the star's direct rays will be comparable the first or last minutes of daylight here on Earth (although shining from a higher angle).

A rays of a 'maximal' red dwarf under the same conditions are about 45,000 lux, comparable to the first or last 30 minutes of daylight on Earth.

Either of these lighting scenarios provide plenty of landscape illumination. The light isn't 'red' the way the lay person thinks of 'red', but more like incandescent lighting, or ordinary sunlight under the early morning/late-day conditions I described.