The political blog DailyKos has a weekly science section written by a man known only as DarkSyde (though leads to his identity aren’t all that difficult to turn up). This week’s post is interesting: he put up a very pretty illustration by artist Karen Wehrstein of what the sky might look like from Gliese 581c, the planet recently discovered that is slightly larger and more massive than the Earth.
To my delight, he makes it clear this is pure speculation based on the little we know about the planet, but there is enough in the image to spark the imagination (I’ll note that he and I corresponded a few times over what should be in the picture). Red dwarfs are notoriously active stars, with magnetic fields that drive flaring activity on the surface and corresponding starspots. However, they are not flattened– that’s an atmospheric effect, just like how the Sun and Moon look flattened when on the Earth’s horizon.
Adding that was my idea. 
At the distance of the planet from its star, the red dwarf would be bigger in apparent size than the Sun is in our skies, and the total brightness would be higher. However, the surface brightness would be lower — the amount of light you see from the star per square degree. Hanging low on the horizon, with the Moon Illusion in full force, the star would look positively enormous, glowering, and surface features would be easier to spot. It would be very dramatic, and incredibly beautiful.
Ms. Wehrstein has some more artwork of the night side as well, speculating on how things might look there too. Some folks might protest this sort of thing; letting our imagination run ahead of our science. In fact, I support this. As long as people understand it is speculation and not necessarily reality, this lets us visualize these alien vistas and maybe spur us on to think more about what circumstances really are like in such places. Who knows who will be inspired by such artwork, then go on and study the real thing?
April 28th, 2007 at 9:45 am
You may want to add to the description the assumption that the planet may be tidally locked, and so day and night are solely a function of location.
So tha ancients on this planet, as they saw the fireball stationary on the horizon, would try to go after it, and the fireball would retaliate by rising up in anger and getting hotter
April 28th, 2007 at 10:00 am
Meh, you’ve seen one actual, bona-fide Earthlike planet around a red dwarf, you’ve seen them all.
NB:
April 28th, 2007 at 10:11 am
Phil, Thanks so much for the expert advice on the knowns regarding Gliese 581 and the feedback through multiple iterations of the artwork! And yes, the Moon Illusion Effect — as well as a few other things Phil didn’t mention — were his ideas.
April 28th, 2007 at 10:27 am
Don’t you mean “spur them on”? If it spurned me, I’d surely not want to study it as much.
April 28th, 2007 at 10:31 am
Who would have a problem with “letting our imagination run ahead of our science” a little bit? Who isn’t speculating on what it’s like on Gliese 581c?
It’s imagination after all that, as you put it, spurs (”spurns” means to reject something disdainfully) thinking about science, and will lead ultimately to new breakthroughs and discoveries. But even if it has no scientific results, imagining is one of the noblest pleasures and prerogatives of the human species, especially if it results in such beautiful works of art as this one.
April 28th, 2007 at 11:17 am
But I don’t understand: where are the chihuahua-sized heavily-muscled aliens who intercepted our earliest radio signals and whose invasion fleet is currently en route to Earth? We’ll be so screwed once they arrive and begin jumping on our heads! Let’s just hope their muscle-cognates begin to atrophy in our weaker gravity, freeing us from inevitable enslavement and extermination!
I’m already hearing some grumblings from laymen to the effect of “Earth-like? How can you call it Earth-like if it’s got twice our gravity? We’d be crushed if we went there!” (Leading in some cases to the conclusion “So, clearly, God designed Earth specifically for us!” I’ve said it before and I’ll say it again: Aaaaaargh.
April 28th, 2007 at 1:16 pm
On that planet i would weigh what amounts to 160 kg on earth. It’s not THAT much, but it’ll sure as hell be a tough job to climb up a mountain to have a look at that beautiful view.
Worth it? Hell yeah.
– End of speculation.
April 28th, 2007 at 1:45 pm
Ah, nuts. I know the difference between “spur” and “spurn”, but my fingers don’t when I type. I fixed it.
April 28th, 2007 at 7:34 pm
Sounds like a novel by Frank Herber(Dosadi), heavily muscled humans from a high G world. Such speculation was once regarded as purely SciFi, since the only high-G worlds we knew of were all gas giants with H2 and Methane atmospheres. Nice to see emperical evidence catching up with “speculative fiction”,,,
Really cool art work!
GAry 7
April 28th, 2007 at 9:58 pm
I’ve always wondered what the sky must look like from a planet in the Magellenic Clouds with our enormous galaxy dominating the sky.
April 29th, 2007 at 3:40 am
[...] De Amerikaanse Karen Wehrstein heeft de ontdekking van de aardachtige planeet Gliese 581c aangegrepen om een artistieke impressie te maken van een zonsondergang aldaar. Nou ja, meer de ondergang van rode dwerg Gliese 581 natuurlijk. Ze had het verhaal over de ontdekking van Gliese 581c gelezen op de blog van Daily Kos en met die informatie heeft ze een heel mooie en misschien ook wel realistische impressie gemaakt. Zo zien we bijvoorbeeld grote ‘zonnevlekken’ op de ster, veroorzaakt door grote magnetische activiteit, hetgeen kenmerkend is voor rode dwergsterren. Omdat Gliese 581c veel dichterbij z’n centrale ster staat (11 miljoen km afstand) ziet die er aan de hemel groter uit. Z’n lichtkracht daarentegen is weer minder dan die van de Zon. De sterrewind van Gliese 581 veroorzaakt aurora in de atmosfeer van Gliese 581c. In het (wellicht aanwezige) water drijft een soort van ijsberg, afkomstig van de koudere schaduwkant van de planeet. Hier slaat de fantasie van mevrouw Wehrstein wellicht ietwat op hol. Maar ach, er is altijd zoiets als artistieke vrijheid, dus daar maakt ze graag gebruik van. En wat geeft het. Ze heeft op haar site trouwens ook een kunstwerkje van die bevroren achterzijde van Gliese 581c staan. Twee eigenlijk, want ze heeft van die achterzijde ook een versie gemaakt met een dansend schaatspaar erop. Nou, toen had ze volgens mij echt een paar borrels te veel op. Bron: Bad Astronomy Blog. [...]
April 29th, 2007 at 7:09 am
Thankyou BA & DarkSyde.
Superluminous. (ie. beyond just brilliant’.)
Beautiful.
Very Well – & quickly – done!
April 29th, 2007 at 7:45 am
Now I look more closely there seems to be a little bit of a resemblence to a reddened moon in that there star … Starspots like Sinus Irridium anyone?!
More thanks to Karen Wehrstein – the actual artist – who I wasremiss not tonote first in theabove post. Try the link from here (or via that DailyKos site) which has a couple of extra visualisations of the Dark Side of Gliese 581-”Sea” – these are well worth checking out too.
April 29th, 2007 at 9:34 am
I grew up fascinated with the illustrations of planetary systems by Chesley Bonestell. (’Conquest of Space’ Willie ley and Chesley Bonestell)
That sort of art always inspires. Karen’s picture is enchanting.
April 29th, 2007 at 10:15 am
A co-worker, with whom I share space stuff often, told me about a photograph he’d seen of an exrta solar planet and its star. I had to tactfully suggest, because he’s sort of my boss, that it was not likely this was an actual photo. My point is not that my boss is an idiot, but that there are folks who really will see this and not realize it’s conjecture. We BA devotees have to talk it up. Bore our friends with science trivia. Dominate dinner parties with long explanations of how the universe works. I explained to my friend how the distance from us, the distance between the star and its planet, and the two’s comparitive brightness would prevent us from taking the picture he saw. He learned something, and maybe he’ll explain the same thing to someone else. Maybe he’ll start reading Bad Astronomy and become an obnoxious geek like the rest of us (just kidding, there).
The only way to get more people to understand reality is to explain it to them. Somebody’s gotta do it. It should be all of us.
April 29th, 2007 at 4:12 pm
Space Cadet, send your sort-of boss to this page: http://www.badastronomy.com/bablog/2005/04/29/first-exoplanet-imaged/
April 29th, 2007 at 4:42 pm
I tried several times to pass this most interesting report on to some of the folks I work with and unfortunately, the most dramatic response I got was a smile accompanied by a shrug. The ironic thing about this is that I work in the aerospace industry. You would think that with all the techno-geeks that occupy positions in that arena, there would be more interest. I wonder what is wrong with people these days. Are they so wrapped up in the minor details of their own lives that they are incapable of seeing a bigger picture? I don’t know, but I have to say I was really disappointed.
April 29th, 2007 at 6:21 pm
There is a series of SF short stories based on a world a bit like this one. The book is “Medea: Harlan’s World”. The world is a moon tidally locked to a super-jovian, which orbits a red dwarf. The red dwarf is an active star, and Larry Niven’s story “Flare Time” uses a flare on the red dwarf as a main plot point.
April 29th, 2007 at 6:42 pm
If anyone is curious about the night sky as seen from the Gliese 581 system, I have a celestia picture of Orion and Taurus here:
http://lablemminglounge.blogspot.com/2007/04/possible-terrestrial-planet-around.html
As you can see, Orion looks mostly the same, as the main starts are hundreds of light years away. However, the nearby stars of Procyron, Sirius, and alpha Centauri are all in the field of view. Procyron is part of Orion’s bow, and Sirius and Alpha Centauri are just below Taurus. Sol is also visible- can you find it?
April 29th, 2007 at 10:02 pm
First let me say this is an awesome image and the fact they consulted with Phil the bad astronomer is fantastic, it is unfortunate more artists don’t!
I wonder if the planet is really tidally locked, it was believed Mercury was tidally locked and almost all the moons in the solar system are but Mercury ended up being a rotator, so maybe this world will as well. Either way it would be an interesting vista. Maybe the poles would be the sweet spot on the planet. (I imagine a sci-fi story about the ‘darkies’ on the dark hemisphere with their melon shaped heads for echo location waging a war against the ‘lighties’ for dominance.)
April 30th, 2007 at 5:44 am
“Hanging low on the horizon, with the Moon Illusion in full force…surface features would be easier to spot.”
Honest question: if the increased size is entirely a perceptual illusion, *would* the surface features be easier to spot?
April 30th, 2007 at 12:04 pm
Transits of the inner Neptune-mass planet Gliese 581 b across the star would be pretty impressive too, since the planets probably come very close together.
However, from what the numbers come out as when you work out the solar constant at Gliese 581 c, it looks like this planet is hotter than Venus. I suspect the solid surface of the planet may well be a layer of high pressure ice beneath a deep atmosphere, the lower part of which may well be supercritical… light from the star would not penetrate down to the crushing depths.
The regions of the planet which experience habitable temperatures are high in the atmosphere – maybe an ecology of balloon organisms like Carl Sagan envisaged for Jupiter could exist there. If, like on Venus, the atmosphere superrotates, such organisms would be carried around the planet in a matter of days.
Meanwhile, on the outer planet, the local equivalent of climate change activists point to Gliese 581 c as an example of what happens when global warming gets out of hand…
April 30th, 2007 at 3:11 pm
Love this one!
You are my favorite astronomer ever.
May 2nd, 2007 at 5:12 am
Hey, this one’s the APOD for today! Very nice.
May 6th, 2007 at 8:27 pm
Andy :
Sounds like areasonable model youve come up & not going toargue tehe numbers – my maths ability is,alas, lamentable.
But doesn’t it all depend on the atmospheric composition? Water and CO-2 are both good greenhouse gases but what if the planets atmosphere is helium-lithium or methane / nitroen or suchlike exotic mix? Clouds can both reflect and absorb, cool and heat – we find Pluto’s atmosphere makes it colder and Venus’es (& Earth’s) much hotter than it otherwise would be.
Plus do we really know what the basic nature of the planet is whether its a rocky super-Earth, outsized old SF idea of Planetary Ocean Venus (eg. as imagined in Isaac Asimov’s Lucky Starr &the Oceans of Venus’) or some sort of warmed -up pygnmy exoNeptune.
Where exactly is the line between gas / ice Giants like Neptune and Super_Earths -is it 5-Earth masses -or 7? Or ten? Or three? (After all Neptune & Ouranos are 17 & 14 Earth masses respectively & Earth, our system’s largest rocky world 1 by definition – that’s a big gap in-between …)
Is this world a waterworld or a rockball? Can we actually find out somehow if it transits -or doesn’t? Another site linked to on the original “Huge News -Gliese 581c found” thread here “Okri /Systematic” notes that a lot depends on where the planet formed – if it migrated inwards it may be more a micro-Neptune; if it formed in situ where it is then it may more likely be a huge globe of rock with perhaps limited water.
Not having any 5-earth mass range planets in our solar system makes it very hard to tell what their really like – theoretical models are fascinating, their all well & good but I think it may be a case of admitting we really need more data …
May 8th, 2007 at 1:48 pm
C may be too hot for earthlings, but i think if there’s indigenous water-based life, it won’t be discouraged by 160 degrees Fahrenheit.
on the other hand, D looks pretty good for an “ammonia world”:
http://graywyvern.livejournal.com/tag/gliese+581+c
m.
September 18th, 2009 at 3:14 pm
> 18. Erik Says: April 29th, 2007 at 6:21 pm … “Medea: Harlan’s World”. The world is a moon tidally locked to a super-jovian, which orbits a red dwarf. The red dwarf is an active star, and Larry Niven’s story “Flare Time” uses a flare on the red dwarf as a main plot point.
…. in fact, minor correction, the superjovian Argo orbits the binary Castor C, a pair of white stars that flare. There’s no red dwarf in Medea, and Argo doesn’t flare.