Statites & Quasites

[Music] until two days ago that sound had never been heard on this earth suddenly it has become as much a part of 20th century life as the whirr of your vacuum cleaner in 1957 the Soviet Union launched Sputnik 1 into orbit of the earth humanity's first artificial satellite Sputnik jump-started the space race and since then over 8,000 satellites have been put into space of which nearly 5,000 are in orbit right now every single one of these follows a trajectory dictated by Kepler's laws of planetary motion which limits the types of operations which they're capable of but there might be a way to construct a spacecraft which can cheat Kepler's laws today we're going to be talking about an emerging technology which can literally defy gravity called status and quasi welcome to another episode cool welders I'm Professor kipping and today we're going to be talking about a new type of satellite technology which we might see in the foreseeable future at the most basic level as satellite is simply a body which orbits a more massive one so perhaps the most familiar example is the moon which is a natural satellite of the earth but in addition to the moon we've launched another 8,000 artificial satellites into space for purposes such as geo-positioning communications surveillance and science now an orbit is one of those deceptively simple concepts that is often misunderstood for example even NASA often referred to a tional it's in orbit of the earth as being in zero gravity but that's rather misleading as Earth's gravitational pull is only 12 percent weaker at the altitude of the International Space Station than it is here on the surface in fact the real reason why astronauts experienced this sense of weightlessness in orbit is not because gravity has been shut off or somehow diminished rather it is because they are in a state of continuous freefall towards the ground the classic pedagogical example is Newton's cannonball where a cannonball is shot off a mountaintop and follows a curved path towards the earth increase the power and the ball will of course go further around the earth and fire it even harder and the ball will never even touch the ground it's always falling but never actually getting any closer to the surface and that's an orbit now orbits only really work many miles of the Earth's surface where the air pressure is so thin that it doesn't stop the object's motion too quickly but even the International Space Station feels a tiny amount of air resistance and consequently loses about two and a half kilometers in altitude every month thereby requiring regular thruster Corrections aside from the small effect of air resistance and some other even smaller effects such as tides and general relativity satellites follow elliptical paths around the earth dictated by Johannes Kepler's laws of planetary motion now Kepler's third law is particularly important it states that the time that it takes for a satellites are complete an orbit it's orbital period is proportional to the square root of its orbital distance cubed now because humans have understood Kepler's third law since the 17th century then we are able to exploit it to our own benefit so for example a geosynchronous satellite is one where the orbital distance of the satellite is chosen specifically so that its orbital period equals the rotation period of the earth 24 hours as a result these satellites hang about in roughly the same part of the sky tracing out a figure 8 shape known as an analemma geostationary orbits are special cases of geosynchronous orbits where the orbital plane lies along the equator shrinking the analemma down to a point a satellite which appears to be suspended in the same position all the time now there are many advantages to being in a geostationary orbit but it's also kind of a victim of its own success I mean this is a fairly narrow ring around the earth where you have to place a satellite and it's becoming an increasingly popular and crowded place to put a satellite it's a little bit like how Facebook used to be this cool trendy thing many years ago and when everybody gets onboard with it including your parents and grandparents it might not be so appealing to want to be there anymore there are now 400 geostationary satellites but there's probably only space for 1800 before things start getting messy just ask Sandra public about that so how do we solve this well this is where science fiction writer and physicist Robert forward comes in forward suggested that a geostationary orbit could be achieved out of the equatorial plane by applying just a little bit of lifting force specifically he suggested using sunlight bouncing off a mirror to apply the necessary radiation pressure to counterbalance gravity as depicted here forward even suggested that it might be possible to twist these orbits all the way over so they actually end up being in a geostationary orbit over the pole of the earth what we might call a pole sitter now a pole sitter is kind of pushing things a little bit there was a recent paper by Baig and the kins that looks at the physics of this situation they find that at best you could probably twist these satellites by about 10 to 20 kilometers above the equatorial plane these would be strange orbits they kind of follow the cylindrical orbits around the earth now forward thinks that this shouldn't really be called satellites any longer because they don't really follow Kepler's laws anymore instead he dubs them statics he even patented the idea inspired by the fact that fellow sci-fi writer arthur c clarke devised the geostationary concept but failed to ever cash in on it without Payton protection what Ford was waiting for his patent to be published the Stata idea was independently discovered by physicist Coulomb Atkins and John Simmons their work not only discusses the idea of using solar radiation pressure to hack geocentric orbits but they also explore the possibility of hacking heliocentric orbits as in things which orbit around the Sun rather than the earth when we orbit the Sun things are somewhat simpler because the force lines are aligned we have an inward pull due to the Sun's gravity and an outward push from radiation pressure now usually gravity completely dominates but make your object very thin and reflective and you can actually balance on a beam of Sun this should not be surprising because solar radiation pressure forms the basis of solar cell technology something experimentally verified with the Japanese Space Agency's Icarus prototype okay so let's work through what it would take to engineer a spacecraft that could balance on a Sun beam like this okay so I'm gonna go through a little bit of math if you don't like math whatever reason then you can just skip ahead to here and get past that but I encourage you to stick with this you'll hopefully learn something the force of gravity is given by Isaac Newton's famous equation that's G multiplied by M Sun multiplied by M divided by d squared we're here G is the gravitational constant M Sun is the sun's mass M is the spacecraft's mass and D is the distance between the two objects now the outward force which remember is coming from radiation pressure is actually really simple it's just the power received by the static divided by the speed of light in fact for a highly reflective object we get another factor of two here that's because the light is both received given one push and then emitted back in the opposite direction giving another the power received from the Sun equals the spacecraft's area multiplied by the stellar flux which will be the star's luminosity divided by the surface area of a sphere with a radius D ik weighting these two forces simplifying a little bit and then rearranging things around we can solve for the required mass per unit area of our state so plugging in all the numbers and working it through it turns out that a heliocentric state ID would have to have a mass per unit area of 1.5 grams per meter cubed that's a ridiculously thin sail it's about seven times thinner than the Icarus prototype it's not actually unreasonable that we might be able to build such a sail this would be a very strange object though as everything else orbits around the Sun this thing just sits there like some kind of weird alien artifact in fact if other civilizations ever built these they would be extremely difficult to detect since they don't actually move meaning that we can never see them transit in front of their star now one interesting side note here is that because the luminosity of a star is proportional to its mass ^ for at least four dwarf stars like the Sun then it turns out that heliocentric statites would be eight times easier to build around stars which are two times heavier than the Sun okay so to recap we have these geocentric statics which seem to hang in the same point in the sky all the time and we have these heliocentric statics which seemed to hang physically in the same point in the solar system all the time now as a final twist I want to introduce you to the idea of what I'm gonna call a quasi and I'm not gonna lie I literally made that name up for the purposes of this video all right so let's take that heliocentric static case again and I'm gonna modify it I'm just gonna make it maybe a little bit less shiny or a little bit heavier so that now the outward force of radiation pressure is slightly less than the inward force of gravity so this thing will fall towards the Sun or remember that's what everything in orbit of the Sun is doing they're all falling towards the Sun so all we need to do is give it a small amount of sideways momentum and this thing would maintain an orbit but it would be a very weird orbit from the spacecraft's perspective the Sun's gravity is not as strong as it should be because we've canceled out a large fraction of it using radiation pressure so yes it falls towards the Sun but much slower than it would naturally and that means that we only need a relatively small amount of sideways motion to keep it at the same orbital distance now this isn't really a stat site anymore because it's not static it's in motion and hence my nickname quasi now other objects which are the same orbit or distance as this quasi would have to move much faster in order to maintain the same orbital distance so they would be whizzing by overtaking our quasi and a quasi it would just seem to be bizarrely and slowly cruising around the solar system at its own gradual pace I guess it's kind of like your granddad driving down the freeway now an alien civilization which would see this thing transit in front of the Sun say they would immediately notice that this thing was artificial it should not exist it's literally a gravity defying feat if we can build a static then it would actually be even easier to build one of these quasi since it's just a heavier or less shiny version and in fact we could engineer it to move at any pace that we desire anywhere from being completely stationary like a static to moving it the regular full pace of a capillary an object we've hacked Kepler's laws of motion and this would have some interesting benefits here's one possibility we could place a quasi at the orbital distance of say mercury a planet at 40 percent the Earth's orbital radius and orbits once every 88 days thanks to its closer proximity now quasi could be engineered so that it orbits not once every 88 days but rather once every 365 days the same as that of the earth despite the fact it's much closer to the Sun than we are we were there for half a geo synchronized quasi co-orbiting with the earth ensuring a constant and open line of communication this would be fantastic for space weather monitoring purposes the quasi could detect then warn us about giant coronal mass ejections coming off the Sun things like the Carrington event in 1859 that was an event that was so powerful that if it happened again today it would lead to widespread blackouts here on the earth now because radio waves travel much faster than coronal mass ejections they travel at the speed of light then this quasi system it's warning would be able to outpace the coronal mass ejection and at least give us a few hours warning before we get stroke now it's worth pointing out here that other civilizations might realize the physics behind quasi --ts and construct their own space where the monitoring system and if they did they would surely put them close to the star where there's a decent chance that we could see these quasi transit in front blocking out starlight so this would be what we would call a techno signature and the duration of this transiting quasi event would be so anonymously long because it's moving so slowly that we will be able to tell it was likely artificial just from the shape of the light curve we see so I had this idea whilst making this video and I got so excited about it that I decided I should write it up into a short research paper which I've now put together and there's a link down below so that you can check that out isn't that a great example of how do outreach videos like this can be of manifest benefit to science there's some other possible uses of this technology too one can even imagine using lasers on the earth or some of the world to support non Keplerian orbiting spacecraft that could be particularly useful for asteroid mining operations where the lower gravity of those objects means that you'd only be looking about a kilowatt of laser power to support each kilogram of mass that you hold in an artificial orbit you know the more I think about space travel and technologies the more I appreciate just how powerful and amazing light really is whether it be for trying to fly to alpha centauri with a breakthrough starshot project or we're trying to use it to create the halo drive system that we've talked about in a previous video or like we've talked about today for generating these artificial orbits engineers of the future may very well think about light has been a key instrument in their engineering toolkit so thank you so much for watching this video I hope you enjoyed it and if you did then make sure you do all of those youtubey things to let the algorithm know that you liked this video if you are new to the channel then be sure to subscribe so you can become part of our space crew and see all of the future videos from this channel and if you have any questions or ideas that have been generated by watching this video then please do put them down below in the comments and I'll do my best to get back to you all so until the next video stay thoughtful and stay curious [Music]

Channel: Cool Worlds

Views: 54,360

Rating: 4.9671302 out of 5

Keywords: quasite, statite, satellites, space technology, orbital physics, orbital motion, kepler's laws, hacking physics, hacking kepler's laws, hacking orbital physics, cool worlds lab, cool worlds, astronomy, astrophysics, stationery satellites, geostationery satellites, emerging technology, novel technology, advanced civilizations, technosignatures, artificial orbits

Id: jxN--4BKH7g

Length: 17min 22sec (1042 seconds)

Published: Thu Jun 27 2019