According to the first pages of *Action Comics #1*, Clark Kent's "physical structure was millions of years more advanced" than the ordinary human's. His strength was explained right away as being analogous to that of an ant's, which "can support weight hundred of times its own." His strength was, therefore, explained to be more a part of his "advanced" genetics rather than being tied to the physical demands of living on Krypton, which his species would have adapted to even when they were in their primitive stages. The current theory behind his strength is that it is, in part, the result of Krypton's gravity. There is still something to be said for his genetic structure being more advanced than ours. The very first panel of *Action Comics #1* says that Krypton died of old age. It is now universally accepted into the Superman mythology that Krypton had an old, red sun. Life in Krypton probably started out with a yellow sun like our own but eventually had to become more "advanced" after millions of years in order to survive under the sun's gradually less life-giving rays. With weaker sunshine, plants would not be able to photosynthesize as well. The ecosystem in general would have less nutrients. According to *Superman: The Movie*, Earth people "are primitives thousands of years behind [Kryptonians]." Thousands, not millions. Therefore, we can assume that Kryptonians did not begin to evolve technologically until several thousand years ago. Let's assume that they were technologically equivalent to us ten thousand years ago, wen we were still writing *The Epic of Gilgamesh*. This would make sense, as it would be difficult to create any advanced structure that could endure Krypton's gravity. They would need to invent materials as endurable as themselves, so technological advancement for them would probably need to first happen in one giant leap in order to overcome the challenges inherent in raising a society on Krypton. It is reasonable to assume that they had invented electricity and other technologies long, *long* ago, but they probably hit a technological plateau as they would have likely been unable to raise buildings and other large constructs, due to the gravity of their planet. Ergo, Kryptonians might have had Earth-level technologies for thousands of years but had almost nothing, as it would have been almost impossible for them to have an industrial revolution.

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This is a size comparison between Krypton and its sun, Rao, taken from *Smallville*. It is very similar to the size comparison in *Superman: The Movie*, and in fact directly homages the Christopher Reeve legacy. In the film, the sun is closer to the viewer and the planet is behind the sun. Therefore, this is not a trick of the camera where the planet looks bigger due to optic illusions. It really is quite big compared to its red giant sun. The size of a red-giant varies, but let's assume that Krypton was once much like our own sun. In approximately 12 billion years, our sun will have a maximum radius of 1.2 astronomical units, or a diameter of 2.4 astronomical units. This is is considerably more than "millions of years advanced" of our timeline, however. Let's assume that Krypton isn't *that* old. Besides, in the first comic it states that Krypton died because of the *planet*'s old age, not the sun's. Besides, the size comparison between Krypton and Rao is considerably less contrasting than the size comparison between the sun's present and future self in this Wikipedia image. If Rao was 1.2 AU in radius, then Krypton by comparison would have to be larger than our current sun, both in radius and certainly more in mass. In that hypothecal scenario, the planet would be the center of the solar system and the sun would have revolved around Krypton, which isn't a bad idea for science fiction, but it doesn't seem to be in keeping with how Krypton has been depicted. Therefore, we will assume that Rao is a red star, but not necessarily a gas giant. For the sake of these calculations, Krypton will have a radius estimated to be equivalent with either Jupiter's or one lunar unit. Jupiter's radius is 43,441 miles. One lunar unit (the distance between Earth's center of mass and the moon's center of mass) is 238,900 miles. First, however, let's calculate the gravitational pull of Earth, which pulls with a force of 1 Newton per kilogram of mass at its surface. The radius of Earth is 3,959 miles at the equator. The volume of Earth is therefore approximately 260,000,000,000 (260 billion) cubic miles. The mass of the earth is approximately 5.972x10^{24} kilograms. The average density of the Earth, therefore, is 22,970,000,000,000 kilograms per cubic mile (yes, I'm mixing metric units with English units, which would be a no-no in a formal paper, but practically speaking it won't make any difference in the end conclusions given here). Therefore, let us assume that Krypton's average density is equal to Earth's. In reality, it would probably be even denser on average, due to intense amounts of pressure creating a larger solid core, but I do not have the math to calculate the internal makeup of Krypton anyway, and there's no guarantee that it has the same metals in its mantle as Earth does. If Krypton was the size of Jupiter, it would have a volume of 343,390,000,000,000 cubic miles and a mass of 7.887x10^{27} kilograms. That's over a thousand times that of Earth's mass, but the distance from the surface to the center of mass is greater. Therefore, the gravity should be less than Earth's. Thus, we look again at the radius, 43,441 miles. For the sake of the ensuing calculations, this will have to be converted into metric, so it's 69,911,513 meters. To double-check our work here, the mass of Earth is 5.97x10^{24} kilograms. The mass of Jupiter is 1.90x10^{27} kilograms. Earth's density is 4.15 times that of Jupiter's. If Jupiter had Earth's density, it would be approximately 7.885x10^{27} kilograms. This alternative way of calculating the mass of Krypton renders a result almost exactly the same as the previous calculation. If a mass of 1 kilogram is on Krypton's surface, 69,911,513 meters away from the core, and Krypton's total mass is 7.887x10^{27} kilograms, then we have enough information to "plug and chug" the data into the formula given in Newton's Law of Gravity: GM_{1}M_{2}

^{____________}

R^{2}

G is the gravitational constant

G = 6.67x10

^{-11} m

^{3}kg

^{-1}s

^{-2} M

_{1} = 1.000 kg

M

_{2} = 7.887x10

^{27} kg

R = 69,911,513 m

Therefore:

(6.67x10^{-11} m^{3}kg^{-1}s^{-2})(1.000 kg)(7.887x10^{27} kg)

^{_____________________________________________________________________________}

(69911513 m)^{2}

First, let's cancel out the units. (kg^{-1})(kg)(kg) becomes kg. The top has m^{3} while the bottom has m^{2}, which cancel out to become just m. The rest is easily solved with a calculator, and the end result becomes 1.08x10^{2} kg m s^{-2}

A kilogram-meter per square second is the definition of a newton. Therefore, the gravitational pull of Krypton, if it was equivalent in average density to Earth and in radius to Jupiter, would be 108 G. This is truly monumental. To put this into perspective, some humans can survive up to 9 g continually if they are in special suits that force blood to the brain, and if they strain their muscles. These, however, are trained fighter pilots. The typical person can survive up to 5 g before passing out. Meanwhile, the rapid negative acceleration of a racecar crash is about 100 g and lasts only for a moment. People do not always survive these. However, let's think like Siegel and Sushter, who needed to compare Superman to existing specimens of life already found in nature. According to them, he was comparable to an and, which could lift *hundreds* of times its own weight, not a mere one hundred and eight times its own weight. This is somewhat of an overstatement on the creators' part, since an ant can really only sustain up to fifty times its weight, but this is where they estimated Superman's natural strength to be nevertheless. There are other remarkable examples in nature of living organisms enduring extreme conditions. For example, bacteria has been cultivated in an ultracentrifuge subjecting them to *over 400,000 g*, and they not only survived, *but thrived* (source). What if not only single-celled organisms, but larger members of the animal kingdom could endure similar extremes? Clearly, we're limiting Kryptonian life by assuming that its natural habitat exhibits only 108 G. Therefore, let us not assume a conservative estimate of Krypton's size as being equivalent to Jupiter's but instead place its radius as equivalent at that of one lunar distance. Pulling from earlier data, this is approximately 238,900 miles (or 384,472,282 meters). The volume of such a planet would be 57,113,000,000,000,000 (approximately 57 quadrillion) cubic miles. This is about 219,750 times Earth's volume, so assuming equivalent density, its mass would also be 219,750 times that of Earth's, or 1.312x10^{30} kg. It should be noted that this is only about two thirds the mass of our sun. Let us revisit the formula for gravity to find the amount of pull on a one-kilogram object on Krypton's surface, assuming these variables: G = 6.67x10

^{-11} m

^{3}kg

^{-1}s

^{-2} M

_{1} = 1.000 kg

M

_{2} = 1.312x10

^{30} kg

R = 384,472,282 m

(6.67x10^{-11} m^{3}kg^{-1}s^{-2})(1.000 kg)(1.312x10^{30} kg)

^{_____________________________________________________________________________}

(384472282 m)^{2}

5.93x10^{2} kg m s^{-2}

593 Newtons

Ergo, the gravitational pull would be 593 G on Krypton should it be the size of the moon's orbit around the Earth. While hardly over 400,000 g, it's closer to what Siegel and Sushter imagined when they said that Superman's natural strength was comparable to the ant that could lift hundreds of times its own weight. This is indeed several hundred times Earth's gravity, close to six hundred times our everyday experience. There is little to compare 593 g to. It is far more than a car crash. If a person was subject to 593 g for even a thousandth of a second, he would surely die. The highest recorded g-force ever survived was 214 g. This 2.77 times that. Before we move on to some of the further implications of the gravity, it would be useful to create an expanded formula to make any further computations easier, if one wants to find the gravitational pull of Krypton at any given radius, assuming average density consistent with Earth's. M

_{2} = (5.97x10^24 kg){[(4/3)R

π]/[(4/3)(6378100 m)

π]}

(6.67x10^{-11} m^{3}kg^{-1}s^{-2})(1.00 kg)(5.97x10^24 kg){[(4/3)R^{3}π]/[(4/3)(6378100 m)^{3}π]}

^{________________________________________________________________________________________________________________________________}

R^{2}

or

R(1.53 kg s^{-2})

^{______________________}

10^{6}

There we go. Every variable is taken care of for us except for R. Therefore, if we wish to quickly calculate the gravity of a terrestrial planet of density equivalent to Earth at any given radius (measured in meters), simply place the radius into this equation. Likewise, if we wanted to learn the inverse and know what the radius of such a planet would be given a specific gravitational pull, the formula can simply be rearranged. Radius would be equal to: 10^{6}G

^{_______________________________}

(1.53^{ }kg s^{-2})

Returning to the bacteria experiment mentioned earlier, how large of a planet would they have to be on in order to experience similar forces? Plug and chug: G = 400,000, therefore R = 261,437,908,496 m, which is about 40,990 times as wide as Earth. Converting this into miles, the radius is approximately 152,000,000 miles, the circumference is approximately 325,000,000 miles, and the surface area is approximately 332,000,000,000,000,000 (332 quadrillion) square miles. That would be one big planet. Since it's difficult to determine *exactly* what Krypton's radius or gravitational pull is, however, we will settle for the assumption that its the size of a lunar orbit and has a gravitational pull of 593 G. This could also be expressed as there being an acceleration of downward movement of 5,800 meters per square second, but this might not be entirely accurate, since wind resistance could mess with that figure. With a gravitational pull as heavy as that, Krypton must have dense atmosphere consisting mostly of hydrogen. It would be very difficult to breath in. Perhaps the Kryptonians are forced to be able to break the triple bonds of N_{2} in order to breathe (we humans only break up double O_{2} bonds). In any case, their environment is harsh for more than just the gravity alone. Not only is the atmosphere hardly breathable, but it should provide plenty of resistance to movement. Imagine being at the bottom of a very deep swimming pool trying to do aerobic exercises. At the same time, it would not make the body feel any lighter or buoyant. There would be less atmosphere, of course, if the planet was closer to the sun, in which case the solar winds would blow most of it away. In the case of it being further away from the sun, the atmosphere would be so strong that it would prevent most of the sun's rays from getting to the surface. It would be very much like living at the bottom of the ocean. How does an ecosystem thrive under these conditions? An organism must adapt to be able to function off of the least nutrients possible. Kryptonians would have also needed spectacular sight in order to see in the thick atmosphere, which would have been like an impenetrable fog to them. Perhaps, when these acute senses are enhanced, they could lead to x-ray or cut-away vision. Furthermore, it must have taken ages before Krypton could develop technology that could generate over 5,800 m/s^{2} thrust necessary in order to escape Krypton's gravity, or accelerate an object so that it reached the planet's escape velocity, which can be calculated this way: (2gr)^{1/2}

Which is

[2(5800 m/s^{2})(384472282 m)]^{1/2}

or

2,111,842 m/s

2,112 km/s

4,724,000 mi/hr

0.007c

It is entirely possible that Krypton's first space mission utilized a method similar to the one used in *Superman Returns*, in which a rocket shuttle was lifted high into the atmosphere using a plane. Krypton's dense atmosphere would have made this fairly feasible. Over the course of time, however, the most likely means of propulsion into space was anti-gravity rockets, which slip by the problem altogether. It's possible that this technology would have been easier for Kryptonians to develop, since Lex Luthor theorized that Superman's flight came from a Kryptonian biological development that allowed them to manipulate the gravity waves around them to make life on Krypton more durable (Superman could develop this into total defiance of gravity due to his enhanced health under Earth's sun). Given that it might have been part of their natural ability in the first place, such technology would be easier to study in nature. After Krypton became industrialized, its conditions may or may not have changed over a long period of time. In order to industrialize, they needed a major technological breakthrough in order to create structures that could endure Krypton's gravity. In order to do this, they needed to create a new substance. This would be the crystal seen in *Superman: The Movie* and *Smallville*. What we know is that this crystal can seemingly produce matter out of nowhere. We also know that it covers almost all of Krypton. It would be reasonable to assume that it also grew *into* Krypton and infested the mantle until it worked all the way down to the core. If the planet was converted into this crystal, which was strong enough to form large free-standing (sometimes diagonal!) structures under 593 G, then its density might have changed, and therefore so would its gravitational pull. The density of Earth is 5.52 times that of water. The density of a (pure) diamond is 3.52 times that of water. Therefore, the Earth's average density is 1.568 times as dense as a pure diamond, or a pure diamond is only 63.77% as dense as the Earth. If Krypton was as dense as a diamond, it will have lost mass. If we were to assign an arbitrary density to these crystals, however, and give them a density equivalent to steel, for the namesake of Krypton's last son, which has a density of up to 8.05 times that of water. If that was the case, Krypton would have grown to be 145.8% its original mass. Since any technology sufficiently advanced is indistinguishable from magic, we will not ask where that matter came or went from (though I'm assuming it's the Phantom Zone). The interesting part in all this is that this crystalization might have been what destroyed Krypton in the first place. By "dying of old age," the original authors implied that it was a natural death. Since then, of course, we have come to accept that Krypton has died of unnatural, man-made reasons that were long in the making. It is more like the mistakes of Kryptonian society reached an old age where they finally came to fruition. Therefore, after ages of making its way down to the Kryptonian planet core, the crystals probably changed under intense pressure. Under these pressures, it is my theory that Kryptonite formed and created an unstable planet core, primed for destruction. My theory for thy the destruction happened in one fast instant instead of gradually was because of the Phantom Zone, which may or may not have used technology closely related to the technology that allowed the crystals to develop. By opening the Phantom Zone, it is possible that Jor-El or the counsel (probably the counsel, using the technology against Jor-El's wishes), causes a rift in space-time that affected the crystals on their planet and made them become hyper-active on an atomic level, which expotentially sped up the process in which Kryptonite formed and even caused it to stat acting on its instability. It is difficult to say how Kryptonite destroyed the planet. From a human standpoint, Kryptonite is a seemingly innocent substance. Yet, it reacts destructively with other Kryptonian materials and has an askew relationship with the very laws of physics that, according to *Smallville*, allows people who come in contact with it to develop abilities that defy said laws. Therefore, my theory concludes that Kryptonite affected space-time until either one of two things happened. Either it created a black hole, sucking the planet in, or it reversed the law of gravity, causing the planet to explode, as is traditionally depicted. Or it somehow managed to do both, thereby sucking the rest of the planet in while creating an alternative plane of existence where gravity pulled the Kryptonite outward. 24601