The Jovoscope

space is vast so vast that even a tiny local pocket called the solar system has a size which defies ordinary understanding if the earth were shrunk down to the size of a pea then Pluto which would now be the size of a flea would lie at a colossal seven kilometers away over the last few decades humans have constructed a handful of small machines that we've flung out into the dark to explore a cosmic backyard sensory extensions designed to give us our first glimpses of what lies beyond our cosmic shoreline faced with these interplanetary distances which are meager by the universe's standards but epic by our own trying to communicate with these probes is like trying to hear a distant whisper on the wind as if the universe were not hostile enough to us already its immense scale means that even simple communication is a major challenge presently our most distant orbiter probe is the Juno spacecraft which was designed to study Jupiter our closest giant planet it's a mission which has returned unprecedented insights into how Jupiter's atmosphere is structured and behaves as well as many spectacular images that have captivated the public junot sends this data back to us using his high gain antenna which at 2.5 meters across is literally as big as they could physically make it yet still able to fit inside the rocket fuselage with jupiter being over five times further away from the Sun than the earth 'as juno solar cells trickle in 27 times less flux making power the precious commodity and so when Juno fires up his high gain antenna and tries to send data back to earth a distance of 500 billion miles it does so with just 27 watts of power that's less than an incandescent light bulb as this radio signal travels across the ocean of space the wave spreads out just like how waves spread out in water this spreading out known as diffraction causes the energy of the wave to diffuse over an ever larger region and so by the time it reaches the earth it's barely detectable to give us the best chance possible of detecting Juno's whispers across the dark we use giant 70-meter receivers known as the deep space network DSN to give you a sense of how difficult this is when DSN listens to juno its colossal 70 meter receiving dish is only able to soak up 200 Atta watts of power from juno that's point zero zero zero zero zero zero zero zero zero zero zero zero zero zero zero [Music] oooh watts of power it is completely ridiculous that we are able to detect that let alone use it for useful communication data transmission rates are limited by the bandwidth and signal-to-noise of your receiver so the more power you receive the higher the signal-to-noise the power is so small here that this is a major limiting factor and thus Juno is only able to transmit data back at about 200 kilobits per second that's about the same as dial-up modems meaning that each three color 1600 P image takes about a minute to download from Juno for context that's about 500 times slower than the average american's internet connection those of you old enough to remember know that dial-up modem speeds are painful to work with there is simply a huge amount of data that we cannot download off the spacecraft it means things like live streaming or delayed telepresence high resolution video are simply out of reach and so is this the best we can do are we forever limited to grainy images downloading at pedestrian speeds how could that be another way [Music] in my last video I talked about a special project for me something that I've been thinking about the 13 years now the Terra scope I'm gonna direct you to the video for the Detailers but the basic idea is that the Earth's atmosphere refracts ends light and thus can serve as a lens and therefore we can turn the Earth's atmosphere into a giant telescope this idea was inspired by the earlier proposal by von Ashley man of using the Sun as a gravitational lens the main advantage over that idea is that the terror escapes focus point is about the same as the Earth Moon orbit whereas the Sun's gravitational focus is outside of the solar system altogether now what has this got to do with Juno when data transmission rates you are probably rightly asking yourself at this point in the video well it has long been recognized that this solar gravitational lens could not only be used as a telescope but it could also be used as an antenna instead of placing a detector at the solar focus one could put a transmitter emissions from the transmitter spread out as a wave just like before but now when they reach the Sun gravitational lensing amplifies the light bringing it back into a sharp beam now as others have noted this would be a fantastic system for interstellar communication potentially linking distant stars together but it's not going to work within the solar system for interplanetary communication and that's because this focus point at 550 au is simply far too distant so this is where the Terra scope comes in because the Terra scope has a focus point which is much closer to home and this could potentially serve as a solution just like the solar lens we can reverse the direction of light in the antenna to turn our telescope into an antenna an antenna of planetary proportions let's now return to Juno orbiting Jupiter Jupiter is a gas giant and so certainly has an atmosphere comprising of largely hydrogen and helium that atmosphere will refract electromagnetic radiation just like the earth does and so in principle we could conceive of a Java scope the same idea just using Jupiter instead of the earth now one might naively think that Jupiter's far greater size will lead to a far greater amplification using this effect but that intuition is actually wrong as I showed in my paper the amplification is directly proportional to the scale height of the atmosphere not actually the size of the planet itself for Jupiter its scale height is only about three times greater than that of the earth most largely because of Jupiter's strong gravity pinning the atmosphere down but nevertheless a factor of three increases something I would happily take okay so let's now use Jupiter's atmosphere as an antenna with Juno's transmitter of diameter 2.5 meters and Jupiter's more extended scale height I estimate that Jupiter could amplify Juno signals by approximately 70,000 now I must caution that this number assumes that Jupiter's upper atmosphere is not opaque to the eight point four gigahertz radio frequency used by Juno another concern one might have is whether Jupiter's focus point is even accessible to Juno maybe Juno's too close a precise calculation of the Java scope in a focus point would require some detailed atmospheric modeling and that would be a big project something I have not yet done but we can crudely estimate from simple geometry that the focus point as compared to the earth should move out by about the ratio of rady between those two planets so for the earth the focus is about 300,000 kilometers and thus I would estimate that the gyroscope focus line begins at about 3 million kilometers in truth we actually need to double that distance now to account for the fact that Jupiter's hydrogen-rich atmosphere bends light by only about half as much as telluric air giving us a final distance of something like 6 million kilometers now if you were any closer to Jupiter than this distance it would not be possible to exploit this atmospheric lensing effect of the Joba scope and so that raises the obvious question is Juno far enough away from Jupiter to be able to do this in short yes Juno resides in a wide elliptical orbit with its farthest separation known as a purge OV being 8.1 million kilometers away from Jupiter comfortably beyond the inner focus it's kind of interesting to note that Juno is actually supposed to conduct what's called a period reduction maneuver in 2017 and come in much closer to Jupiter far closer than the jovis cope focus had it had done so then a JavaScript would not be possible now in the end the team decided not to do this because the problem is onboard with Juno with the helium valves which are very important during the main engine burns so it seems as though these helium valves somehow conspired to give us a chance of maybe one day testing out this Joep idea paetynn protects fools little children and ships named enterprise [Music] so it seems as though juno really could utilize this lensing effect to test out the tera scope idea more broadly but what would this test actually look like well in order for us to use Jupiter as an antenna and send a signal back to earth then we require alignment between these three points so we would actually need that aperture point to line up with Jupiter and the earth in order for sphere to detect the signal back on earth assuming it's possible to inert Juno's orbit into the correct position Juno would then fire up its transmitter and DSN should be able to detect the transmission amplified by a factor about seventy thousand if we see that then we have our validation now I know many of you are probably wondering is this just all talk or is there a chance that Juno might actually do this test for real well all I can really say is that I have contacted and reached out to the Juno team and asked about the possibility and I've not heard back but honestly I really can't blame Juno for not wanting to do this I mean this is certainly not part of their mission objectives and it may represent just too much risk for them to modify the orbit to do this test and after all let's face it the terrorist group idea is very new I mean I really can't blame anyone for being skeptical about its claims however maybe there is just a slim chance that this idea might work well if it's right what would that mean on July 30th 2021 less than two years away from now Juneau will crash into Jupiter after being issued one last command what if in between now and then the JavaScript idea is tested and works with an amplification of 70,000 the signal-to-noise received by DSN would be enhanced by 265 times increasing the data transmission rate by approximately the same amount so we'd go from 200 kilobits per second download speeds 253 megabits per second download speeds that's about the same as your 4G LTE connection speed on your cell phone enough to comfortably live stream 4k video from Jupiter it's also worth highlighting that in many ways using atmospheric lensing to create a giant antenna is easier than using it as a telescope that's because when we use it as a telescope the planets own light has to be removed using a large shade to block out all of that nuisance signal but when we use it as an antenna there is no need for this shade because planets in general do not produce much emission at these very specific communication frequencies that we typically use now the further from Earth we go there greater the drop-off in data rates but there's enough bandwidth to play with here that we could even go to Alpha Centauri and use the EXO planetary atmospheres to reach about a kilobit per second enough to download a high-res photo every few hours one could even imagine going further and using not only at this distant planet as a giant antenna but when that signal comes back to the earth we can use the earth as the original Terra scope concept again and use it as a giant receiving dish creating a kind of atmospheric bridge between these two distant worlds and that would allow us to get amplification effect two times over and so perhaps the terror scope concept could find its best use not as a telescope but as an antenna a high-speed Internet across the solar system each planet linked to the other arm in half using worlds as our antenna and modems maybe you tuned in to a live stream from Saturn - an hour light travel time or explore Venus with a telepresence Android or perhaps watch a grainy video broadcast from another star system or together I believe that when we dream big we can accomplish wonders we can either accept the world the way it is or we could try to use our time to make it better let's try to make sure that we leave a brighter future for those that follow after us and so until the next video stay thoughtful and stay curious [Applause] [Music]

Channel: Cool Worlds

Views: 101,115

Keywords: Jovoscope, Terrascope, Atmospheric Lensing, Interplanetary Internet, Interstellar Internet, Gravitational lensing, Solar lens, FOCAL, Juno Mission, Juno, NASA Juno, High Speed Internet, 4G in space, refraction, astrophysics, astronomy, planetary science, Solar System, Cool Worlds

Id: F9S21HqfNR0

Length: 16min 46sec (1006 seconds)

Published: Thu Aug 29 2019

Reddit Comments

[u/tigersharkwushen_]

I tried, but I can't do it. It's a 16 minute video and I am at the 5 minute mark and it hasn't began to explain how this internet is suppose to work. I can't make myself sit through the rest of the video waiting for the explanation.