You might have wondered why, in my post number 100 on page 5 of this thread
https://www.trekbbs.com/threads/man-trap-versus-turnabout-intruder.309135/page-5
I wrote:
What is the size of planet M-113?
The planet Earth is famous for being a planet which is habitable for humans, with an atmosphere which humans can breath. Planet Earth has a mean radius of 6,371.0 kilometers or 3,958.8 miles, and a surface area of 510,065,623 square kilometers or 196,927,438 square miles.
In
Habitable Planets for Man, 1964, Stephen H. Dole estimated the required properties for a planet to be habitable for humans.
https://www.rand.org/content/dam/rand/pubs/commercial_books/2007/RAND_CB179-1.pdf
He decided that a surface gravity of 1.5
g, 1.5 times as strong as Earth's surface gravity, would be the maximum that humans would tolerate.
His calculatins indicated that an Earthlike planet with a surface gravity of 1.5
g would havean escape veloocity of 15.3 kilometers per second and 2.35 times the mass of Earth, and aradius of 1.25 Earth radius. Thus it would have a radius of 7,963.75 kilometers or 4,948.5 miles, and an area of about 796,975,737 squae kilometers, or 307,720,914 square miles.
It is possible that planet M-113 is smaller than the largest possible planet habitable for humans. It might be the size of Earth, which has a mean radius of 6,371.0 kilomters or 3,958.8 miles, and a surface area of 510,065,623 square kilometers or 196,927,438 square miles.
Planet M-113 might be much smaller than Earth, maybe as small as the smallest planet that could possbilbly be habitable for humans.
Dole decided that the smallest planet which could form and retain a breathable atmsophere would have a mass 0.4 of the mass of Earth, a surface gravity of 0.68
g, and a radius 0.78 times the radius of Earth. That wuld be a radius of 4,969.38 kilometers or 3087.864 miles, and thus a surface area of 310,323,225 square kilometers or 111,819,138 square miles.
But Dole selected a mass of 0.40 earth mass rather arbitarily. He used 2 different methods to estimate or calculate the minimum mass of a planet which could form a breathable atmosphere, ad got2 differnt results 0.25 mass Earth and 0.57 mass Earth, and selected 0.40 mass Earth as an approximation.
So some people might imagine that the smallest planet which could retain a breathable atmosphere for about 100,000,000 years might possibly also be able to form such an atmosphere in the first place, despite Dole's doubt that it could.
That would be a radius of 4,013.73 kilometers or 2,494.044 miles, and thus a surface area of 202,444,589 square kilometers or 78,166,035 square miles.
This questina sks about hepossibility of a habitable world having a radius only 0.58 that of the Earth.
https://astronomy.stackexchange.com...-be-smaller-than-0-58-earth-radii/41599#41599
And it was decided that it was possible for a planet with a radius of 0.58 the Earth's radius to have sufficient escape velocity to retain a breathable atmsophere if it was made of unusally dense maaterials.
That would be a radius of 3,695.18 kilometers or 2,296.104 miles, and thus a surface area of 171,585,688 square kilometers or 66,251,081.8 square miles.
That answer also considered a hypothetical planet made of the very, ver rare element, Osmium, with a thin surface layer of other materials. If such aplanet had the miniumamount of mass for ahabitable world (though not necessarily for a worl dhabitable for humans) it could have a radius as small as 0.29 that of Earth..
That would be a radius of 1,847.59 kilometers or 1,148.052 miles, and thus a surface area of 42,896,422.1 square kilometers or 16,562,770.5 square miles.
I note that in "That Which Survives" the Kalandan planet has a breathable atmopshere. It is also very unusual.
KIRK: A ghost planet?
SPOCK: I suggest no supernatural explanation, Captain. I merely point out that the facts do not fit any known categories of planets.
KIRK: Let's take the facts one by one. That should explain something.
SPOCK: Undoubtedly. The age of this planet would seem to be only a few thousand years. It would be impossible for vegetation to evolve in so short a period.
KIRK: Its size is approximately that of Earth's moon.
SPOCK: But its mass and atmosphere are similar to Earth.
KIRK: That would be difficult to explain.
SPOCK: It would be impossible, Captain. An atmosphere could not evolve in so short a period of time.
KIRK: And yet it has.
SPOCK: Evidently. But the inconsistencies are so compounded as to present a seemingly impossible phenomenon.
So the planet is approximately the size of Earth's Moon.
The Moon has a radius of 0.2727 of Earth's radius;1.737.4 kilometers or 1,079.6 miles, and thus a surface area of 37,932,328.1 square kilometers or14,645,601.6 square miles.
And Krk and Spock agree that a planet with the size of the Moon and a mass and atmosphere similar to Earth would be impossible. Planet M-113 has been known for years or decades, and it has an atmosphere similar to Earth's, so therefore planet M-113 can not have the diameter of the Moon with the mass of the Earth.
Thus it seems extremely probable that Planet M-1333 has a larger radius than the Moon, though possibly a radius of 1,847.59 kilometers or 1,148.052 miles if it is made almost entirely of osmium, the densest known element.
Planet M-113 would have a surface area of 42,896,422.1 square kilometers or 16,562,770.5 square miles.if it was made of the extremely rare elment osmium.
If it was made out of a very exceptionally dense mixture of the elements that a planet which formed naturally could be made of, planet M-113 could have a surface area as small as 171,585,688 square kilometers or 66,251,081.8 square miles.
With such a vast surface area, and apparently only two perment human residents during the last few years, how could any person, human or native, know that there was one and only one surviving M-113 native?