Chuck GPT 3.0: Gravity, rocket Propulsion, space Tethers, and more!

Does sound travel faster in space? Is the multiverse theory true? Can gravity escape a black hole? In our latest episode of our popular “Chuck GPT” series, Dr. Charles Liu and co-host Allen Liu welcome our Social Media/Patreon Community Director Stacey Severn to answer fan questions collected from Patreon patrons, students, Facebook and UA-cam.
As always, though, we start off with the day’s joyfully cool cosmic thing: the recently released Euclid space telescope image of galactic cluster Abell 2390, which is about 2.7 billion light years away from Earth, in which more than 50,000 galaxies are visible. You’ll also hear about the Coma Cluster, the Virgo Cluster, the closest galactic cluster to us, and the planned Nancy Grace Roman Space Telescope.
Our first fan question comes from Emil R. on Patreon: “I wonder what would happen, if you tied one end of a really, really long rope to the International Space Station and have the other end hang down all the way down in the Earth's atmosphere. Would the current speed of the ISS circling the globe counteract the fact that the rope is in the atmosphere and experiencing drag? Would people on airplanes be able to see a rope swing by? Would the end of the rope on the ISS be stretched out or loose, and would it drag the ISS down in its orbit?”
Allen, who loves this question, addresses orbital velocity, drag, momentum, conservation of energy, space tethers, sky hooks, space elevators, and the ISS. Chuck talks about having seen the Tethered Satellite System trailing behind the Space Shuttle through the telescope he was using for his doctoral dissertation in the 1990s!
Our first student question comes from Michael L.: “Is the multiverse theory true?” Chuck’s answer involves eternal inflation, bubble universes, quantum mechanics, many worlds, and, somehow, Schrödinger’s cat.
From Facebook, Steven B. asks: “We all know that warp drive is still science fiction. But what is developing with other kinds of propulsion? Have we reached the limit of chemical propellants? What is happening with ion drives and nuclear systems?” Allen reviews the state of the art, including Ad Astra’s VASIMIR engine, which we covered in our 2-part episode Star Trucking with Franklin Chang-Diaz and Miranda Chang.
Our next student question is from Roberto J.: “How was gravity created?” Chuck says that while we just don’t know for certain, gravity may have come into existence during the “Plank time” at the very start of our universe before cosmic inflation began.
UA-camr @UnexpectedBooks asks, “How can gravity be “transmitted” via gravitons? It seems that a black hole would have no mass, because gravitons, like everything else, couldn’t escape it.” Chuck explains that even though definitely black holes have mass, if gravitons exist, they must be able to leave the event horizon, and Allen points out that gravitational waves do just that.
Our last student question is from Omar: “Does sound travel faster in space?” Chuck describes how sound waves travel, and why there’s enough particulate matter in space to still allow it, possibly even faster than here on Earth.
We end on a Patreon question from Eric S.: “The Heisenberg uncertainty principle is a casualty of the particular mathematics we have used to explore the quantum world. If we were to adjust those mathematics to a less consistent but more complete axiomatic viewpoint, could it be possible to 'see deeper'?” Chuck and Allen’s answer involves high-order math, the Heisenberg uncertainty principle, string theory and quantum mechanics.
We hope you enjoy this episode of The LIUniverse, and, if you do, please support us on Patreon at / theliuniverse .
Credits for Images This Episode:
- Euclid telescope image of Abell 2390 - ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi, ESA license
- Virgo Cluster of Galaxies - Chris Mihos (Case Western Reserve University)/ESO, CC BY 4.0
- Coma Cluster of Galaxies - Nielander, Public Domain
- Hubble telescope image of Abell 2390 - NASA, ESA, & Johan Richard (Caltech, USA), Public Domain
- Roman Space Telescope under construction - NASA/Chris Gunn, Public Domain
- Space Elevator Artist’s concept - Andrei Sokolov
- The ISS in orbit - NASA, Public Domain
- The Tethered Satellite System - Space Shuttle - NASA, Public Domain (Image: commons.wikime...)
- Many-worlds depiction of Schrödinger’s cat - Christian Schirm, Public Domain
- NEXIS Ion thruster - Jet Propulsion Laboratory, Public Domain
- Design of NASA & DARPA’s DRACO nuclear rocket - DARPA, Public Domain
- History of the universe diagram - NASA/WMAP Science Team, Public Domain
- Artist’s animation of gravitational waves - LIGO/T. Pyle, free to use
- Fourier transform of a signal - Wawo1102, Public Domain
- Waveform of same signal - Made with Desmos, Attribution
- Wavelet (Gabor) transform of same signal - Wawo1102, Public Domain

[@theFoodieCyclist]

Love the show!

[@aclearlight]

Lovely stepwise intro to the galaxy clusters, thank you! And I love the vibe of your show.

[@stonerainproductions]

Chuck and Allen! I was excited to see this new episode! Thank you for the terrific content!

[@dtmoore500]

You’re awesome

[@CharlesSagan1]

My theory Is that Gravity Is born of the Solid State.
When subatomic matter overheats and switches Atomic electromagnetic spin around the nucleus ⚛️, such internal subatomic spin must now reconfigure itself into a polarised solid, with no more spin, instead a North and South Pole with a nuclear energy Plasma core.
Gravitational Force Is basically the baby of the Electromagnetic Force and the S&W Nuclear Forces.
Quantum Gravity being too weak to add mass, cannot overcome the stable Subatomic Spin. But once overheated into solid Mass, Gravity begins to have more Power, enough to gather more mass, that cannot be combated by the rigid polar regions and a nuclear core, as opposed to the Proton Electron Neutron spin around a Nuclei remaining stable, and too strong for quantum gravity to interfere.
The State of Matter change causing a readjusted Electromagnetic and Nuclear process likely enhances Gravity. Which Is possibly why they’re still considered stronger Fundamental Forces even in the Astronomical.
Congratulations, it’s a beautiful baby Gravity. Have you chosen of a name yet?

[@CaymenCider]

Dr. Liu you are awesome in every way. I love it when you get philosophical

[@Darker_Void_Scientist]

Liu, I've gone beyond. Have you ever wondered how a direction stores and passes on positional values or data from other directions? Say that you have a forward ticking direction from 1 tick to 10 ticks. It has no other directional storage, so anything else is null or non-existent. If you introduce an upward direction, you'll only be able to use upward values for upward direction. So, how does forward know where to meet upward on a graph? Unless there is something else connecting them ,or there is a general direction that stores any directional value, because I can't say that this forward at 9 has an upward value of 3. Forward is only one dimensional and never has an upwardness ever. What do you think? You can tell Neil that I asked if he knows anything about it.

[@Darker_Void_Scientist]

Even if I rotate the forward directional vector super fast to mimic a two dimensional circle, it won't be able to move upward.

[@TheLIUniverse]

Hey, Allen here! This is a super fun mathematics question that gets into the realm of linear algebra and topology. Usually when you have a system with two variables there's one obvious way to describe the system, but there are other valid descriptions as well.
If I have 9 apples and 4 oranges and I wanted to describe that with a pair of numbers, I would usually say (9,4). I could instead, however, say I have 13 total fruits and 5 more apples than oranges and describe that as (13,5). As long as I know the math to convert from one system to the other, I can use either just fine.
The math of linear algebra says that changing your reference frame for your position in space, like for example by rotating, moving to a new location, or changing what speed you're going, is just changing which numbers you're using to describe the same underlying system. So if you rotate yourself so "up" and "forward" change for you, your new up and new forward are just different combinations of your old up and your old forward.
Isaac Newton figured out that what makes space so special is that there's no one "up" and "forward" (or left and right) that's more special than the rest, but that any perspective where you aren't accelerating is equally valid. Physicists say this as that there's no "preferred reference frame". Albert Einstein realized this more generally applies to the combination of space and time (spacetime), but you have to treat time as in some sense the negative of the three directions of space.
It's pretty cool that by thinking about these questions we can get to the same problems that made Newton and Einstein's careers. What makes them so important to science is that they figured out the math and the experiments to back it all up and confirm their ideas.

[@Darker_Void_Scientist]

@@TheLIUniverse I appreciate your reply Allen, but I'll have to respectfully disagree with some notions and agree with some. Fruits, and equivalence of rotation to acceleration with shifting positions, I agree.Yet, I don't know if it is accurate to assume there is a more general direction because we still haven't answered how a forward one dimensional vector reacts to an independent upward one. Isaac Newton's notion of non-acceleration frame, negatives..., I do not agree while residing in a rotating galaxy. Both Einstein's and Newton's notion that there is no significant preferred directional vector over another... I'm in total disagreement, Allen Liu... respectfully. Later on, I'll clarify myself to LiUniverse with real and thought experiments that even you can do anywhere at anytime.

[@TheLIUniverse]

Totally ok to have respectful disagreement - that's how we build knowledge as a planet. I will add that the rotation of the galaxy does matter but it's a very slow effect since it takes millions of years to spin once. Even detecting the rotation of the Earth on the scale of a few feet or meters is doable but hard - you can watch Veritasium and Smarter Every Day's video on how they found the Coriolis effect in a kiddie pool to get a sense of just how hard. So standing on Earth is very close to being a non-accelerating frame, even if it's not quite there. --Allen
(Also P.S., would you want us to talk about your question in a future episode?)

[@Darker_Void_Scientist]

@@TheLIUniverse Sure, you can use it. It's okay to realize going from 0.00000001nm, 0.000000012nm, then 0.00000002nm is still acceleration. It's not a matter of scale in size, but the progress and tracking of moving from one location to another. Acceleration is acceleration. Isaac Newton's integrals should be ignored then if that's the case.