*I'm reposting this (again) here, since we explorers finally have the perfect forum for it! The (sorta) original thread is here, in case you'd like to join into the lively discussion we were having there: https://forums.frontier.co.uk/showthread.php?t=106966
FYI, I'm taking this post of mine from another thread (taken from a reply to a post in ANOTHER thread) and reposting it with a catchier title, lol
I have a feeling many other people have been wondering about how 'Earth-like' their favorite Earth-like planets are. So here is, in effect, a (somewhat) complete guide to everything you can find out from the System Map info pane description, and how it relates to how 'Earth-like' (i.e. - suitable and comfortable for humans) a planet is, at least as far as I can figure Enjoy!
I think the point is to calculate it yourself But... it would be nice if FD helped folks figure out HOW to calculate these things by making the information more conspicuous, maybe in a sticky on the boards or something.
FYI, these are my go-to sources for figuring out what all those numbers in the info bar truly mean, at least as things relate to how 'Earth-like' these planets really are, as I've definitely seen some pretty un-Earth-like "Earth-like" worlds out there:
http://en.wikipedia.org/wiki/Surface_gravity#Mass.2C_radius_and_surface_gravity - For figuring out surface gravity. You can just read the fourth paragraph, and the accompanying equation, to figure things out. No need to read the first three paragraphs in that section, if you don't want to. And for an article on why the more Earth-like a planet's gravity is, the healthier it likely is for us humans, see this article: http://www.wired.com/2014/02/happens-body-mars/
http://www.metric-conversions.org/temperature/kelvin-conversion.htm - For figuring out how temperatures in Kelvin relate to the more common Fahrenheit and Celsius scales, among other temperature-measuring systems.
http://www.climate-zone.com/climate/united-states/new-york/new-york-central-park/ - To figure out how a planet's average annual surface temperature (which is what I believe "surface temp", as it is called in the info pane, refers to) relates to known average annual surface temperatures in various places in the United States. Sorry to those in the UK, Europe and other environs - I haven't really looked very hard for a site that shows temperatures outside the US.
Day length is important, obviously. I've heard humans can adapt pretty well, particularly to longer day lengths. From various things I've heard, I tend to draw the line at 1.3 Earth days, but 1.6 isn't too bad, in my opinion. Another note - Keep in mind what tidal locking is, and what it would mean for weather and such on an Earth-like world. Here are a few good links to help understand tidal locking, and how it relates to habitability -
http://en.wikipedia.org/wiki/Tidal_locking
http://en.wikipedia.org/wiki/Habitability_of_red_dwarf_systems#Tidal_effects
http://www.astrobio.net/news-exclusive/tidal-locking-could-render-habitable-planets-inhospitable/
Pressure is trickier to understand than the rest of this stuff, in my opinion - I have a number of sites I've found to try to understand that side of things. I can post them if people want, but this site is arguably the most important, at least for humans: http://en.wikipedia.org/wiki/Breathing_gas#Partial_pressure_of_oxygen
It's a bit technical, but as I said, pressure is tricky, at least for this layman! A good rule of thumb, though, for understanding particularly lower-than-Earth-sea-level atmospheric pressure, is to keep in mind that a commercial airliner's cabin is only pressurized to around 0.75 atmospheres when at cruising altitude. Some big cities at higher altitudes on Earth have even lower atmospheric pressures than that.
Soooo... the planet in question:
Based purely on the info pane stats (in other words, not taking into account it's unusual location in our galaxy) I've determined the following:
- Gravity is indeed 78% of Earth's, 0.7840554986810649 to be exact. Sounds pretty nice so far As per the mentioned site, I got to this number by taking the radius of the planet (4,679km) and dividing it by Earth's radius (6,371km). This will result in 0.7344215978653273. Now, square it, which means multiply that number by itself (you ARE using a calculator for this, right?). Now, divide the Earth Masses (0.4229) by the number you just got. That will result in 0.7840554986810649. Remember, the number 1 represents standard Earth gravity (One g), so being as how this number is roughly 78% of 1, the planet has roughly 78% of Earth's gravity. Simple, once you've done it a few times Well, kind of, lol
- Surface temperature is about 65.9 degrees Fahrenheit, which is just a smidgen cooler than the average annual temperature of Savannah, Georgia here in the States. Having spent a considerable amount of time in the South, southeast Georgia in particular, this planet is sounding pretty nice so far!
- Now, the partial pressure of oxygen. This is where things get a little more unpleasant, at least for us 'lowlanders' - Take 0.174 (oxygen percentage) x 0.92 (atmosphere)... There's only 16.008% oxygen in the air to breath, effectively. Oxygen-wise, that's about what it's like in Mexico City (minus the smog, hopefully!) For info on what that means, see this helpfully-specific link: http://www.mexperience.com/blog/?p=35
Oh yeah, almost forgot about axial tilt! Silly me This planet has markedly less axial tilt than Earth's, at 7.61 degrees to our 23.4 degrees, which hopefully is enough axial tilt not to cause too many problems. See these two links for more:
http://en.wikipedia.org/wiki/Axial_tilt#Obliquity_of_the_ecliptic_.28Earth.27s_axial_tilt.29
http://simple.wikipedia.org/wiki/Axial_tilt
http://www.space.com/14295-alien-life-exoplanets-tilt-red-dwarf-stars.html
http://www.astrobio.net/news-exclusive/high-planetary-tilt-lowers-odds-for-life/
Anyways, removed from it's foreboding location at the center of the Milky Way, this seems like quite a nice place, at least by human standards The oxygen partial pressure is somewhat low, and the low axial tilt worries me, but aside from that... yeah, I like it
...Oh, and I just checked the Orbital Eccentricity (forgot about that, too, apparently). It's close to Earth's, which I can only assume is a good thing in these circumstances Earth's orbital eccentricity has apparently varied quite a bit in even the relatively recent past, so a higher orbital eccentricity is not necessarily a game changer, depending on severity, of course.
Those look like they may be cooler M-class suns, so that planet's sky might actually not be blue. If you're thinking that's an obvious statement, you might be surprised how common blue skies on habitable worlds might be Here's the article I consulted: http://epod.usra.edu/blog/2009/02/sky-colors-for-exoearths.html
Oh, one last thing: If any of you have any questions, please feel free to PM me, or I can even help via voice in-game, if you see me (my game name is the same as my forum name). I realize I didn't explain things as well as I could have in some respects. This is in large part due to the sheer complexity of some of these subjects - I'm still constantly figuring and re-figuring things out even now! Also, a lot of this stuff is still highly theoretical, so oftentimes there's not much hard information to work from in the first place. I often have to take things on a case-by-case basis, and return to the literature to try to suss out the most plausible answer I can manage from scarce source material.
Anyways, thanks for reading my spiel - Hope I helped!
UPDATE, 9/1/2017 - I just wanted to add a short addendum to this post, as it's been quite a while since I updated it. Basically, I just wanted to point out that it's important to browse the ENTIRE thread, not just this post, if you want to try to evaluate your ELW in full. I know, it's a pain in the you-know-what, but there are numerous conversations sprinkled throughout the thread that help shed light on even more complex variables, such as a planet's age, and how they effect a given planet's possible 'Earthiness'.
I briefly considered trying to condense all of that information into the already-insanely-long and complex post above, but that would truly be a mind-numbingly long and arduous process to even BEGIN to undertake, so in the interests of preserving my precious sanity, time, and bodily fluids... Yeah, I'll pass, lol
However, I am absolutely still available for 'individual consultation', as I stated before, so please feel free to contact me with any questions or requests for analyses! This has honestly proven to be the easiest way to handle things anyways, so why mess with a good thing, right?
Anyways, yet again, I hope I've helped some folks with my crazy spiel - Take care, everyone, and thanks for lookin'
FYI, I'm taking this post of mine from another thread (taken from a reply to a post in ANOTHER thread) and reposting it with a catchier title, lol
I have a feeling many other people have been wondering about how 'Earth-like' their favorite Earth-like planets are. So here is, in effect, a (somewhat) complete guide to everything you can find out from the System Map info pane description, and how it relates to how 'Earth-like' (i.e. - suitable and comfortable for humans) a planet is, at least as far as I can figure Enjoy!Found one, w00t! 3.66 LY from Sag-A*! Around a binary!
Any astrophysicists or xenobiologists in the house care to comment if this is even possible?
EDIT: If my calculations are correct, surface gravity is 0.78g. Can we have this in the info panel as well, please?
I think the point is to calculate it yourself
But... it would be nice if FD helped folks figure out HOW to calculate these things by making the information more conspicuous, maybe in a sticky on the boards or something.FYI, these are my go-to sources for figuring out what all those numbers in the info bar truly mean, at least as things relate to how 'Earth-like' these planets really are, as I've definitely seen some pretty un-Earth-like "Earth-like" worlds out there:
http://en.wikipedia.org/wiki/Surface_gravity#Mass.2C_radius_and_surface_gravity - For figuring out surface gravity. You can just read the fourth paragraph, and the accompanying equation, to figure things out. No need to read the first three paragraphs in that section, if you don't want to. And for an article on why the more Earth-like a planet's gravity is, the healthier it likely is for us humans, see this article: http://www.wired.com/2014/02/happens-body-mars/
http://www.metric-conversions.org/temperature/kelvin-conversion.htm - For figuring out how temperatures in Kelvin relate to the more common Fahrenheit and Celsius scales, among other temperature-measuring systems.
http://www.climate-zone.com/climate/united-states/new-york/new-york-central-park/ - To figure out how a planet's average annual surface temperature (which is what I believe "surface temp", as it is called in the info pane, refers to) relates to known average annual surface temperatures in various places in the United States. Sorry to those in the UK, Europe and other environs - I haven't really looked very hard for a site that shows temperatures outside the US.
Day length is important, obviously. I've heard humans can adapt pretty well, particularly to longer day lengths. From various things I've heard, I tend to draw the line at 1.3 Earth days, but 1.6 isn't too bad, in my opinion. Another note - Keep in mind what tidal locking is, and what it would mean for weather and such on an Earth-like world. Here are a few good links to help understand tidal locking, and how it relates to habitability -
http://en.wikipedia.org/wiki/Tidal_locking
http://en.wikipedia.org/wiki/Habitability_of_red_dwarf_systems#Tidal_effects
http://www.astrobio.net/news-exclusive/tidal-locking-could-render-habitable-planets-inhospitable/
Pressure is trickier to understand than the rest of this stuff, in my opinion - I have a number of sites I've found to try to understand that side of things. I can post them if people want, but this site is arguably the most important, at least for humans: http://en.wikipedia.org/wiki/Breathing_gas#Partial_pressure_of_oxygen
It's a bit technical, but as I said, pressure is tricky, at least for this layman! A good rule of thumb, though, for understanding particularly lower-than-Earth-sea-level atmospheric pressure, is to keep in mind that a commercial airliner's cabin is only pressurized to around 0.75 atmospheres when at cruising altitude. Some big cities at higher altitudes on Earth have even lower atmospheric pressures than that.
Soooo... the planet in question:
Based purely on the info pane stats (in other words, not taking into account it's unusual location in our galaxy) I've determined the following:
- Gravity is indeed 78% of Earth's, 0.7840554986810649 to be exact. Sounds pretty nice so far
As per the mentioned site, I got to this number by taking the radius of the planet (4,679km) and dividing it by Earth's radius (6,371km). This will result in 0.7344215978653273. Now, square it, which means multiply that number by itself (you ARE using a calculator for this, right?). Now, divide the Earth Masses (0.4229) by the number you just got. That will result in 0.7840554986810649. Remember, the number 1 represents standard Earth gravity (One g), so being as how this number is roughly 78% of 1, the planet has roughly 78% of Earth's gravity. Simple, once you've done it a few times Well, kind of, lol - Surface temperature is about 65.9 degrees Fahrenheit, which is just a smidgen cooler than the average annual temperature of Savannah, Georgia here in the States. Having spent a considerable amount of time in the South, southeast Georgia in particular, this planet is sounding pretty nice so far!
- Now, the partial pressure of oxygen. This is where things get a little more unpleasant, at least for us 'lowlanders' - Take 0.174 (oxygen percentage) x 0.92 (atmosphere)... There's only 16.008% oxygen in the air to breath, effectively. Oxygen-wise, that's about what it's like in Mexico City (minus the smog, hopefully!) For info on what that means, see this helpfully-specific link: http://www.mexperience.com/blog/?p=35
Oh yeah, almost forgot about axial tilt! Silly me
This planet has markedly less axial tilt than Earth's, at 7.61 degrees to our 23.4 degrees, which hopefully is enough axial tilt not to cause too many problems. See these two links for more:http://en.wikipedia.org/wiki/Axial_tilt#Obliquity_of_the_ecliptic_.28Earth.27s_axial_tilt.29
http://simple.wikipedia.org/wiki/Axial_tilt
http://www.space.com/14295-alien-life-exoplanets-tilt-red-dwarf-stars.html
http://www.astrobio.net/news-exclusive/high-planetary-tilt-lowers-odds-for-life/
Anyways, removed from it's foreboding location at the center of the Milky Way, this seems like quite a nice place, at least by human standards
The oxygen partial pressure is somewhat low, and the low axial tilt worries me, but aside from that... yeah, I like it ...Oh, and I just checked the Orbital Eccentricity (forgot about that, too, apparently). It's close to Earth's, which I can only assume is a good thing in these circumstances
Earth's orbital eccentricity has apparently varied quite a bit in even the relatively recent past, so a higher orbital eccentricity is not necessarily a game changer, depending on severity, of course.Those look like they may be cooler M-class suns, so that planet's sky might actually not be blue. If you're thinking that's an obvious statement, you might be surprised how common blue skies on habitable worlds might be
Here's the article I consulted: http://epod.usra.edu/blog/2009/02/sky-colors-for-exoearths.htmlOh, one last thing: If any of you have any questions, please feel free to PM me, or I can even help via voice in-game, if you see me (my game name is the same as my forum name). I realize I didn't explain things as well as I could have in some respects. This is in large part due to the sheer complexity of some of these subjects - I'm still constantly figuring and re-figuring things out even now! Also, a lot of this stuff is still highly theoretical, so oftentimes there's not much hard information to work from in the first place. I often have to take things on a case-by-case basis, and return to the literature to try to suss out the most plausible answer I can manage from scarce source material.
Anyways, thanks for reading my spiel - Hope I helped!
UPDATE, 9/1/2017 - I just wanted to add a short addendum to this post, as it's been quite a while since I updated it. Basically, I just wanted to point out that it's important to browse the ENTIRE thread, not just this post, if you want to try to evaluate your ELW in full. I know, it's a pain in the you-know-what, but there are numerous conversations sprinkled throughout the thread that help shed light on even more complex variables, such as a planet's age, and how they effect a given planet's possible 'Earthiness'.
I briefly considered trying to condense all of that information into the already-insanely-long and complex post above, but that would truly be a mind-numbingly long and arduous process to even BEGIN to undertake, so in the interests of preserving my precious sanity, time, and bodily fluids... Yeah, I'll pass, lol
However, I am absolutely still available for 'individual consultation', as I stated before, so please feel free to contact me with any questions or requests for analyses! This has honestly proven to be the easiest way to handle things anyways, so why mess with a good thing, right?
Anyways, yet again, I hope I've helped some folks with my crazy spiel - Take care, everyone, and thanks for lookin'
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