The Skybox in Combat Evolved Makes NO SENSE

[00:00:01]Halo is a game about a big hula hoop in space.

[00:00:03]>> [music] >> A few videos on the science of Halo have focused on the ring itself, but in this video I want to talk about everything around the ring.

[00:00:11]Installation 04 has been orbiting around this gas giant for 100,000 years.

[00:00:16]In that time, any life on the ring >> [music] >> could look up at this alien sky and experience day and night in different ways than we do on Earth.

[00:00:25]In this video, I'll answer questions about how the day and night cycle works, how large the orbits are, and whether the creators of the game know what a Lagrange point is.

[00:00:37]The original Halo Combat Evolved strategy guide and some now deleted Waypoint articles tell us a bit about the solar system that the game takes place in.

[00:00:44]The events of Combat Evolved and some of Halo 2 take place around this planet in a system called the Soell system.

[00:00:51]It's named that because the star at the center is called Soell.

[00:00:55]There are nine planets and one asteroid belt.

[00:00:57]We're going to focus on the seventh planet from Soell, Threshold. Threshold is the biggest planet in the Soell system. It has 12 moons, but we only ever see one of them in game.

[00:01:08]This could be that the other moons are smaller, further away, or they're just on the other side of the planet.

[00:01:14]The one moon we can see is called Basis.

[00:01:18]We only ever see one side of Basis, so there's a good chance that it's meant to be tidally locked to Threshold.

[00:01:23]This would mean that the same side of Basis faces Threshold, just like the moon does to Earth. Or it could be like a Mercury situation where it's kind of tidally locked, but still spins a little.

[00:01:33]Given how close we'll find that Basis is to Threshold, it would make sense for it to be tidally locked.

[00:01:39]Well, things aren't going to make sense, [music] but you'll see later.

[00:01:52]Before that, we should probably get to the point of the whole series, Halo.

[00:01:56]Installation 04, otherwise known as Alpha Halo, stays at Lagrange point one between Threshold and Basis. A Lagrange point is basically just a place where the gravitational force of two orbiting objects and the orbital momentum cancel out in a way that traps a less massive object, like a Halo ring.

[00:02:13]Lagrange point one, or L1, is probably the easiest to understand because it's right in the middle of the two big objects.

[00:02:20]As you can see in game, the ring is always in between Threshold and Basis.

[00:02:24]The ring also has a 24° axial tilt from Threshold's orbital plane.

[00:02:29]Due to this, any given point on the surface of the ring will get sunlight half of the time that it's on the bright side of Threshold, and it will get no sunlight when it's on the dark side, because, you know, there's a planet in the way.

[00:02:43]This creates a weird day-night cycle where it's dark 3/4 of the time and there's no sunset or sunrise, similar to a planet.

[00:02:50]Now that we know what we're told about the solar system in Combat Evolved, let's compare to what we actually see in game.

[00:03:03]Halo has two types of night. I'm going to call them ring night and Threshold eclipse night.

[00:03:09]I'm going to call ring night whenever you're standing on the floor of the ring and the floor of the ring is blocking light coming from the star Sol A.

[00:03:20]And then Threshold eclipse night is when the ring is eclipsed by Threshold.

[00:03:25]Make sense?

[00:03:29]On the bridge of the Pillar of Autumn, we see the ring spinning about once per hour. It looks slow, but that would actually feel pretty fast if you were standing on it.

[00:03:37]We don't actually see the skybox move around in real time like that until Halo Infinite.

[00:03:43]If it did, then locations on the ring would experience day for about 30 minutes and then night for another 30 minutes.

[00:03:50]You'd probably want the ring to rotate slower in to avoid the weird jolts of the circadian rhythm.

[00:03:56]Rotating slower would make it so that the artificial gravity experienced would be less, but they have weird magic sci-fi gravity from the Forerunners.

[00:04:03]They don't really need to spin to make gravity.

[00:04:08]I spent a lot of time looking at the skyboxes on each mission, and I've come up with the following timeline for the orbit of Basis, and by extension, Halo.

[00:04:15]If I'm right, then it should take around 76 hours, which is a little over 3 days for Basis to get most of the way from one side of Threshold to the other.

[00:04:24]Based on this, it should take about a week to make one full rotation.

[00:04:29]The closest real-world example is Jupiter's moon Ganymede, which also takes about 7 days to make an orbit.

[00:04:35]Of course, Ganymede orbits a million kilometers away from Jupiter, which is way farther than Basis appears to be from Threshold. And that implies that Threshold would need to have a crazy low density.

[00:04:45]But, that's a discussion for later.

[00:04:47]This orbit is using information that we get from the original game and from the book.

[00:04:52]If we include Anniversary graphics, then we have one small problem. We can see Basis up in the skybox of the mission two Betrayals.

[00:04:59]The problem is, for Basis to be lit up at this point, it would need to be past Threshold, which speeds up our orbit.

[00:05:06]And for that to be the case, Halo would end up taking place [music] in between Soell and Threshold. And that's clearly not what we see in game.

[00:05:16]For that reason, I'm just going to ignore [music] this detail. Basis should be in the shadow of Threshold at this point.

[00:05:22]Now, speaking of eclipses, those should be happening pretty often, but not quite as often as the strategy guide makes it seem.

[00:05:29]From my measurements of the orbits, the ring should only be behind Threshold about 21% of the time, which is less than half what it says in the strategy guide.

[00:05:39]Basis would be in the shadow of Threshold less than 10% [music] of the orbit.

[00:05:43]And for about 11% of the orbit, Basis should be lit up while the ring is still in the dark.

[00:05:49]Depending on how well aligned Basis's orbit is with the orbit of Threshold around So Well, there should also be some time per day where Basis eclipses So Well.

[00:05:59]However, as we'll find, it wouldn't be a total eclipse because So Well is actually larger in the skybox than Basis.

[00:06:06]Which is weird, but we'll get to that.

[00:06:08]But before that, I want to talk about this half of the orbit that we don't see [music] in game.

[00:06:13]During this part of the orbit, each part of the ring is supposed to receive light half of the time and darkness the other half.

[00:06:20]There's just one giant problem.

[00:06:23]You're not going to have a dark night with a giant planet-sized mirror shining down on you.

[00:06:29]For reference, Earth receives anywhere from 10,000 lux to 100,000 lux in brightness from the sun during a sunny day.

[00:06:36]A full moon will give you at most a third of a lux reflected down to the Earth.

[00:06:41]That makes sense as the moon only covers half a degree of angle in the sky and only reflects 7% of the light back into space.

[00:06:48]If you were on the moon, Earth would make things even brighter. It's 3 and 1/2 times wider and reflects about a third of light it receives, making it 43 times brighter. Now, compare that to Threshold, which takes [music] up almost the entire sky. It's also a gas giant and gas giants tend to reflect anywhere from a quarter to half of the light they receive.

[00:07:08]That would mean that on this side of Threshold, you're not getting a night.

[00:07:11]At most, it's going to be as dark as an overcast day.

[00:07:20]As the thumbnail of this video might suggest, this is where things get even more out of hand.

[00:07:25]Because Bungie was not trying to make a game that strictly obeys real-world physics.

[00:07:29]They were trying to make a cool space game where you shoot aliens and don't afraid of anything.

[00:07:33]A good way to make a cool-looking space [music] setting is to just make everything in the sky really big.

[00:07:38]But how big is everything and why do their apparent size in the skybox cause problems?

[00:07:44]Well, there are two things that we need to find out how far away the objects in the skybox are. The angle that an object blocks in our point of view and the diameter of the object.

[00:07:53]Fortunately, we can get decently accurate measurements for the field of view on PC. [music] And we got the sizes of Threshold and Basis from old Waypoint articles that got deleted years ago.

[00:08:02]As you can see, the apparent sizes of both objects appear to change throughout the campaign.

[00:08:07]You could try chalking this up to an elliptical orbit, taking Basis further and closer to the planet, which would lead to objects appearing to grow and shrink at the same time. But, in reality, it would be far less extreme than we see in game.

[00:08:19]My guess is Bungie wasn't making the skyboxes to stand up to this kind of scrutiny.

[00:08:24]Well, this average Threshold to cover 75° of the field of view and Basis averaging at 1/10 of that at 7.5°.

[00:08:31]That gives us their apparent sizes, but we also want their absolute sizes.

[00:08:36]Threshold is 214,604 km in diameter and Basis is 23,848 km in diameter.

[00:08:45]With those measurements, you'd only be about 174,755 km from Threshold's center and 67,000 km from the planet's surface. Halo would also be 181,143 km from Basis's center or about 169,000 km away from its surface.

[00:09:05]That would leave us with the distance of only 225,000 km from Threshold's surface to Basis's surface.

[00:09:12]Or 356,000 km from center to center.

[00:09:16]Here's what that looks like next to some real-life planet moon systems in our solar system.

[00:09:22]With that distance in mind and an orbital period of a week, that gives us a massive Threshold that's lighter than any gas giant in our solar system, despite it being larger than Jupiter.

[00:09:36]Now, it does make sense for a planet to be less dense than any gas giants in our solar system if it was in a star's habitable zone. Gas giants that get closer to a star are often called hot Jupiters, and they're less dense than our gas giant because heat from the star causes the gas of the planet to have more energy, meaning that the gas can expand a bit further.

[00:09:56]Still, the least dense exoplanet we know is only 22 times less dense than a Jupiter, not 95 times less dense.

[00:10:03]So, that's still pretty ridiculous.

[00:10:06]But, don't worry because the densities in the system are only going to get worse.

[00:10:11]First, I want to address the elephant in the solar system.

[00:10:14]We don't know much about the star Sol, other than that it's somewhat close to Reach, which itself is only 10 light-years away from Earth.

[00:10:21]In game, this star takes up an astounding 8.4 degrees of field of view.

[00:10:28]To put that into perspective, the Sun and Moon each take up half a degree in our field of view from Earth's surface.

[00:10:34]If the Sun were 17 times closer, there wouldn't be any life on Earth.

[00:10:39]There's not even anything in our solar system to compare to. That would be five times closer to the Sun than Mercury at its closest. Now, we don't know what type of star Sol is, so we could say that it's a cooler star.

[00:10:51]Except, cooler stars are cooler because they're smaller and have less mass. So, we'll need to get even closer to the star to make that work.

[00:11:00]Let's just be generous and plug in the smallest star that could maybe sort of have a habitable zone if we squint at it.

[00:11:07]Astronomers have a system from O-type stars to M-type stars, where O-type stars are the biggest and bluest, and M-type stars are the smallest and reddest.

[00:11:16]M9V stars are the smallest type of red dwarf star, which are themselves the smallest type of main sequence star.

[00:11:23]They're made up of only 8% of the mass of the Sun, having 10% of the radius of the Sun, and burning about 40% of the temperature of the Sun on its surface.

[00:11:32]For a star like this to take up 8.4° of your vision, you would need to be only 962,000 km from the star.

[00:11:40]At that distance, even a puny red dwarf would shine five times brighter than the sun does here on Earth's surface.

[00:11:47]Now, there is another way to make this work.

[00:11:51]What if instead of going as small as we could, we exited the main sequence and went with a bigger star?

[00:11:57]When main sequence stars run out of hydrogen, they start fusing helium, and they puff up to red super giants. Maybe if we plug in the biggest red super giant possible, then it would Oh, no, that doesn't work either.

[00:12:11]Even if you could get a red super giant big enough for this to work, it would not have the lifespan for a halo ring to be around it for 100,000 years.

[00:12:18]The bigger star is, the shorter its lifespan.

[00:12:21]Keep in mind, real-world red super giants only last around half a million to a million years, and we need a much bigger star than anything found in reality for this to work.

[00:12:31]If any type of star is taking up 8° of your field of view, then it's safe to say that you're cooked. And I'd like to point out, however close Threshold is to the sun, there are somehow six planets and an asteroid belt that are somehow closer. Now, we could just say that the star looks bigger because it's refracted by our visor or something. In that case, there is a way for us to get a more reasonable estimate for the type of star Threshold is.

[00:12:53]In the book Halo: The Flood, Guilty Spark states that he's been in charge of Installation 04 for 101,217 locally years.

[00:13:02]In one of the terminals of the anniversary edition of the game, we see Guilty Spark beyond a monitor in September of 97,447 BCE, or just barely 99,999 Earth years before the events of Combat Evolved.

[00:13:17]This would make one Threshold year equivalent to 98.8% of an Earth year. To be in a habitable zone with an orbit that similar to our Earth, Threshold would need to be very similar to the sun. The sun is a yellow G-type star. Those range from 80% to 104% of the sun's mass.

[00:13:35]There's a relationship between a star's mass, radius, and temperature. And there's also a relationship between how massive a star is, how long it takes a planet to orbit around it, and how far away it orbits from the star.

[00:13:46]Going through the numbers with an orbit time just under 360 days, most upper K-type stars would leave Halo too far away to have liquid water.

[00:13:55]And an upper G-type star would boil all the water away.

[00:13:59]Even a star 5% more massive than the sun would be too hot.

[00:14:03]So, Swael can only be a G2V-type star at the heaviest and a K1V star at the lightest.

[00:14:09]Now, as I said, the Swael system is supposed to be pretty close to Reach, which is only 10 light-years away from Earth. So, in theory, you could go through the list of closest stars to Earth and come up with a list of possible candidates for where Commonwealth could actually take place.

[00:14:22]But, that seems tedious even for me, so I'm just going to leave that for you for homework.

[00:14:27]And now for the part where this actually gets broken.

[00:14:35]Have you heard of Lagrange points? You should. I mentioned them at the start of the video.

[00:14:39]A Lagrange point is basically just a place where the gravitational force of two orbiting objects and the orbital momentum cancel out in a way that traps a less massive object, like a Halo ring.

[00:14:50]So, at Lagrange point one, Halo should be at a balance point between Threshold and Basis. There's just one problem with that.

[00:14:57]We already found Halo is closer to the center of Threshold than the center of Basis.

[00:15:01]That means that not only does Threshold have a crazy low density, Basis is actually more massive than the planet it's supposed to be orbiting around.

[00:15:10]Here's the equation for Lagrange point one if you want to try and figure it out, but long story short, Basis should be about five times as massive as Threshold. If Threshold is as dense as Jupiter, then Basis will be denser than basically any solid matter in the universe, unless you count white dwarfs or neutron stars as a solid.

[00:15:27]Even if we have threshold the density of the least dense exoplanet we've ever found, that would still be at least as dense as the core of the sun.

[00:15:35]>> The explosion will generate a temperature of almost 100 million degrees.

[00:15:39]>> [music] >> Don't be here when it blows.

[00:15:45]>> So, to wrap up everything, the orbit around Threshold in the skybox is inconsistent at best. Basis is orbiting so close to Threshold that it implies that the planet is less dense than any planet we found in the universe. Except actually, Threshold should be orbiting Basis, since Basis appears to be five times more massive than Threshold based on the placement of the Lagrange point.

[00:16:03]Also, Threshold makes you gay or something.

[00:16:05]Yeah, that's for the video on the remake.