Rings Around the Earth, Iron Planets, Asteroid Mining Race | Q&A 220
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- Äas pĆidĂĄn 25. 05. 2024
- How big can iron planets get before collapsing into black holes? Why is the Moon floating away from Earth? Will Mars bases have glass domes? How will the asteroid mining race unfold? Will we create rings of satellites around the Earth? All this and more in this week's Q&A!
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00:00 Start
01:00 [Tatooine] How big can rocky planets get?
03:51 [Coruscant] How big can an iron planet get?
08:13 [Hoth] Why is the Moon floating away?
11:43 [Naboo] What happens if you jump in artificial gravity?
14:56 [Kamino] Will glass domes on Mars ever be real?
17:31 [Bespin] Are they still looking for Planet 9?
19:33 [Mustafar] Are there more galaxies than stars?
21:23 [Alderaan] Return to British Columbia?
24:02 [Dagobah] Missions to explore Europa?
25:51 [Yavin] When will we see the next images from Webb?
28:42 [Mandalore] How will the asteroid mining race go?
30:14 [Geonosis] Will Earth have rings?
33:48 [Corellia] How big is the expansion of the Universe?
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You are free to use my work for any purpose you like, just mention me as the source and link back to this video. - VÄda a technologie
Naboo!
Thanks for another fantastic video, Fraser! đ
Stay safe there with your family! đđ
a question for the next Q&A: considering that neutrons are electrically neutral, how can a neutron star have a magnetic field?
7:53 if the sun did that, we'd be ROYALLY SCREWED.
i haven't watched that spacex video either but it sounds like yet another one of elon's flights of fancy.
nice scenery or not, i wouldn't want to live in a place where there is snow for half the year. too cold for me. i'd prefer to go to the mediterranean for the winter and then back to the UK for the summer.
I would guess, because neutrons have a magnetic moment. But I'm not an expert. Just a guess.
Because neutron stars aren't made only from neutrons, and actually neutrons are composed particles made from quarks that have electric charge, it's a entire branch of physics that try to explain what inside those bodies, and the current explanation is nuclear pasta, basically many large atomic nucleus surrounded by a neutron matrix, but are alternate explanation that are assuming that some free quarks flow in the matrix and are the source of magnetic field.
Kamino - I know people talk about lava tubes on Moon and Mars but have we actually found any for certain?
Absolutely. Here are some pictures: www.nasa.gov/feature/goddard/2022/lro-lunar-pits-comfortable/
mars.nasa.gov/resources/26349/hirise-spots-the-mouth-of-a-martian-lava-tube/
@@frasercain Wow thatâs awesome and thanks for the links! The stable-ish temperatures is really interesting! No mention of a mission to check them out though⊠just âone dayâ.
Now Iâm imaging SpaceX astronauts racing through lava tubes in modified cybertrucks đ€Ł
Naboo:
Also, if the artificial gravity generated is low enough and you jump in the opposite direction of the rotation you could jump to precisely the centre of the cylinder. In that case, you would just float there and see the station rotate under your feet. Of course, you could overjump and end up falling head-on on the other side of the station.
youd still be spinning with the floor
@@wodthehunter8145 Not if you cancelled it mid-jump.
However, coming to rest at the middle of the station can't be achieved by merely jumping. In a gravity field (true force) you're constantly accelerating downwards, so your vertical velocity is briefly zero at the apex of your jump. On a rotating spacecraft, however, you're always travelling in a straight line. That line might intersect the axis of rotation but you will always overjump no matter how slow you go.
You'd need to throw a reaction mass or grab something. Rope tied to the ground would work. Having two would suffice for indefinite stability up there.
Naboo I have long thought about what might be possible inside an O'Neill cylinder. While you couldn't jump in the air and float because you retain your momentum from the cylinder rotation, what would happen if you sprinted in the opposite direction of rotation and then jumped? It would, of course, depend on how large the station was and the speed of its spin, but I think some athletes might be able to cancel out enough of their momentum to allow some pretty awesome long jumps. There might be some really awesome athletic events at the 2124 Olympics with Lunar events, space station events, and maybe even Martian events. Unfortunately, I doubt I will live to see it absent some radical life extension tech being developed in the near future.
if the cylinder has an earthlike gravity, and rotates once per day. the radius of it will be about 20km.
so the runners will have to run 50,000 km/h to cancel it out.
don't think they can do that without Redbull.
It's like asking if you could jump up in a falling elevator to avoid hitting the ground. It's only possible if you can jump up the entire height of the building.
â@@frasercain In The Expanse - Book 6: Babylon's Ashes (that part of story was left out from series - because season 6 was shortened), they explore this. On Medina station, some kids figured how speed up in direction opposed to rotation and than jump to float a little bit above "the ground". Mimicked gravity there is about 1/3 of Earth's gravity.
@@frasercain After the elevator crashed, I could jump up the entire height of the building with my new bionic legs. Speaking of bionic legs, in the novelizations of The Six Million Dollar Man, Steve Austin was famous for being the last man to walk on the Moon. I don't recall if that fact was in the original Martin Caidin novel Cyborg or if it was one of his sequels. You might know better than I do since you are a space journalist, but I am reasonably sure that Gene Cernan never became a cyborg, before or after, being the last man to walk on the Moon. I suppose that depends on the definition of cyborg though. Does a stent or pacemaker make you a cyborg? What about a denture? But he couldn't run 60 mph. I am reasonably certain about that.
I have a theory... an idea really- lol, that if a star's core of iron collapses inward before the outer layers begin to fall inward, (it compression limit for a neutron star is reached from within) then the star winks out of existence because the black hole absorbs everything before the collapse can rebound off anything- as the iron is now gone, and the ripple of gravity spaghettifies any infalling matter. If the star begins it's collapse before the core implodes, then there is a iron ball to explode off of once the infalling matter reaches the core, and you have a nova. I believe there have been two such cases where the star didn't explode, it just vanished altogether...
The issue is that the upper layers are also repelled by the heat of the _surrounding_ plasma, so it might be a delicate balancing act to keep any rebound from that from overpowering any "undermining" effects like spaghettification. Figuring out how things work in such cases could tell us very interesting things about the inner workings of stars.
There definitely are core collapses where the whole Star can disappear. I just read about a potential example on Universe Today actually.
Well for a star to just dissapear into a black hole i think its called nutrinos so they arent produced in enough numbers so the rest of the star doesnt bounce off the core
The explosion isn't "bouncing off the core." There are spherical shells of lighter elements. Initially, it is just hydrogen fusing in the core. The pressure isn't high enough once you get it off the core.
Once the hydrogen is nearing being used up in the core, the rate of fusion decreases and the core temperature cools down some. Then the balancing act between gravity pulling in and hot plasma pressure pushing it changes and gravity wins for a while.
As the pressure is increasing (highest in the core, but throughout), either the hydrogen in the next shell will increase its rate of fusion or the helium in the core will increase its fusion enough to raise the temperature-related pressure sufficiently to match the attractive force of gravity.
This proceeds in steps through the elements up to iron. I think each new element takes less time to fuse enough for the rate to slow down and have gravity winning for a while because less and less energy is liberated by fusing higher-atomic-weight elements.
The point is that there is still a lot of hydrogen in the outer layer (and of helium in the next outer, etc.) and as the star collapses, the increasing density and temperature (albeit from lower values than at the core) will allow fusion to start happening at that distance from the core.
Keep doing what you like to produce! I enjoy both the informative videos and the videos dunking on that site.
CoruscantâŠ.. this was such a fascinating concept!
Alderaan... I've recently moved to the PNW (near Oak Harbor, WA). It is great to learn about some of the "local" places, as well as the more "remote" ones!
Hoth! Its crazy how far away the moon is from Earth, yet its still categorised as a satellite because of its orbit. Great question!
Best part of my week!!
Wow, I hope you enjoy this one.
Transparent aluminum (Aluminium oxynitride) with coatings would be strong enough and could block UV. This could work for Mars dome material.
Stopping UV is easy compared to cosmic rays. Only protons will stop them. You need a meter of water or rock (or metal) to really be safe.
I cherish the decision to make the question boxes larger†Thank you!
Hah, no problem. đ
That was Anton's idea and design! I'm happy it's well-received.
Speaking of Vancouver and Vancouver Island, the move from MontrĂ©al to Vancouver was to have been a short stay, e.g., a year or two, yet eleven years (9yrs in Vancouver and 2yrs in Victoria) went by in a blink of an eye. But, the cost of living in BC far exceeded my income as a gig worker and I was torn. So, back to MontrĂ©al it was for me. It is often that I think of the nature, bodies of water, and mountains of BC and there is this sadness that emerges for how much I miss those elements. đș
The solution for me was to move to a small town. My costs dropped dramatically moving to Courtenay from Vancouver.
@@frasercain So true. Even the move from Vancouver to Victoria was a huge change in our rental/living costs and groceries. I could imagine moving further away from a main city would be a greater change. Fraser, forgive me for sharing this, my love and I went on a cycling camping trip to Tofino. We saw our first sea lions in the wild there. They were what would wake us up in the early mornings with their grunting sounds. You live on an island full of wonders.
Naboo. If you run opposite the spin at the rate of spin you would seem to float "up" from the surface as it continued to spin underneath you. If you jumped with enough horizontal component to counteract the rotation speed and opposite from the spin you would become "weightless" as the station floor seems to spin out from under you. You would then float there "in space" with the floor continuing to move away. Eventually the resistance caused by the drag of the air that has spun up to the same speed as the surface due to the interference drag of the surface interacting with turbulent air would accelerate you and then inertia would make you drop to the floor. That is, unless you jumped with the exact opposite vector so you'd float up to the center. When the station was first spun up with air inside there would have been a temporary wind as the air slowly acquired the spin as surface drag accelerated it to the same speed.
Even if it's not practical for a green house, *reflected* light in Space/Mars would be safe. Mirrors would not reflect protons, so habitats could benefit from mirrors and conduits that collect light from the surface and bring it below the surface or to places with just roofs.
Yeah, domes are out but side windows are okay with mirrors reflecting the light in.
Thanks for displaying the questions in big letters :) This is helpful! Nice improvement.
Thanks, I'll let the team know you like that better.
Thanks! That was Anton's idea an design. I'm glad you like it. I'm guessing it makes it waaaay easier to read along on phones.
Thanks for these news đ
hi Fraser, can I ask a question? what if they send probe or something in orbit "above/below" the sun to find the unknown planet ? can this be done, and how much energy will it need to get there?
To grow a plant you need not only light but also Heat. Light will provide for photosynthesis but at least somebody of water is needed to turn the shorter wave sunlight radiation into longer wave heat radiation and this heat would need to be captured and maintained within the environment that the plant is to grow in.
Re: Martian Greenhouses. One possible solution I heard about involved inflatable units with regolith thrown on top, but with filtered light being reflected in from the sides via mirrors.
Yeah, I like the idea of having reflected sunlight through mirrors. that would do the trick.
Naboo - Needs to be about 200 meters in diameter as I recall.
Yeah, something like that.
Thank you for your show đđ
Thanks for watching!
Naboo - I'm still waiting for that O'Neil cylinder that Werner Von Braun promised in one of his astronomy books when I was in elementary school!
You will wait forever
Did he promise you personally? If you've got that in writing we could take it to the courts. đ
To build a reen house on mars you can use windows for light, you just need to use mirrors to bounce the light that are transparent at the more dangerous wavelengths.
Thank You for giving such great and easy to understand answers to so many questions. Since you are located in Vancouver Island perhaps you are familiar with Salt Spring Island, BC, Canada? My wife's late brother lived there and designed and helped build a theater /opera house there.
Bespin. Exciting news.
AWESOME!!!
such great questions. domes on Mars would be made of diamond coated ultra-polarized lead crystal. SPF 150 million.
I love 'The Island,' and can't get enough of it. Will definitely retire over there once I'm done in Vancouver. Maybe on the western side though... More feesh.
The West Coast is pretty amazing, but it's so wet. The rain there is unbelievable.
@@frasercain Oh yeah. Been camping when that kind of rain hit. It's like tropical rain, without the tropical heat.
I think âplanet 9â is I small black hole outside the solar system. How or why itâs there I donât know. But it would explain why we canât see it.
Kamino. Presumably the "glass" wouldn't be glass. My dad works with "bullet proof glass" which is transparent but strong (and heavy) as heck. Never thought about the radiation aspect though. Probably some materials scientist out there is doing that right now.
There is radiation shielding glass made with lead particles specifically made for nuclear plants so maybe it can be viable for space.
Bespin.
Could the perturbations described in the 'Planet 9' hypothesis be caused by the phases/distributions of matter in the kuiper/asteroid belts, or some other similar undetected matter belt?
Naboo... practical large inspace construction
Hoth. I never thought it through to realize that dragging the tidal bulge around the planet faster than it is rotating will speed up the planets rotation.
Yeah, it works both ways.
Do you think the concept suggested by Quantum Entanglement of two particles "entangled" by a great distance, doing exactly the same thing, from a great distance at the same time, would be the basis of what is called in Star Trek, "sub-space communication?" I have always wondered how Star Trek came up with that concept of almost immediate communication from light years away.
No, unfortunately quantum entanglement can't be used for FTL communication. Although the two particles are entangled, you still need to communicate at light speed to discuss the results. If you have a particle in a box, you don't know when my particle has been observed.
Hoth
Hi Fraser, love your show.
Q: If the space around Earth becomes too crowded to further proper exploit it could the use of synchronised layers of nuclear detonations be used in order to deorbit the increasing high orbit debris? The first layer of nukes is the most desired outer one and the next ones are closer and closer to Earth. We are also putting aside the global issue of the generated EMPs.
Thanks!
Excellent video Can I ask a question?
If, for arguments sake, there is a tunnel from the north to the south pole. If I then jumped down the tunnel would I slowly decelerate as I approach the centre of the Earth - i.e. assuming as I fall the mass around me would decrease ? And once at the centre would I just float there?
32:11 Regarding the risk that rockets will be brought down by orbiting space debris, "you'll probably never get to this point where space is impassable...you may lose spacecraft from time to time..." I suspect (don't know) the risk may be even lower than that of jetliners being down by birds being sucked into the engines. It does happen and some planes have been brought down by birds; the risk is there, but apparently not enough to ground fleets despite there being a lot more birds near all the airports on earth than space debris circling it. Note that birds aren't "inventoried" so to speak, whereas I think (total guessing) we know a lot about what/where the space debris is located.
Of course all it may take is one small high speed weather satellite bringing a spacecraft down and all space travel will be shut down for a year; but for the near future I suspect birds to jets are more risky that space-junk to spacecraft, and even that risk is relatively low.
God, I love Vancouver Island. I got to go back to Canada and Vancouver in 2015 and even played Victoria and Nanaimo when we were on the west coast. It was late April/early May and so, so nice. I lived in New Westminster and Surrey (in the suburbs of Vancouver) for a while as a kid, then we moved back to the antipodes. But going out to Vancouver Island is one of the things I remember from all that time ago. Can't recommend it enough!
May is absolutely perfect. Everything is lush and green, before the fires start.
@@frasercain We had some unbelievable weather at that time of year too - about 20ÂșC and clear blue skies (which is pretty rare for Vancouver, I'm told). Would love to spend a heap of time exploring that Pacific Coast of Canada (and the whole thing, really). I'm a tragic train nerd, so if it can be done by rail, it WILL be done by rail. The 2015 trip saw me insist that a band and (quite a modest amount of) gear travel by train for NYC (Penn) to Toronto on the "Maple Leaf", and Edmonton to Vancouver over the Rockies via Jasper. Even about to board at Penn Station the others were still groaning. Took about five kilometres following the banks of the Hudson for them to shut up; it was magical ... but YEG to Vancouver over the Rockies by train was totally mind-blowing and became _the_ highlight for everyone. Not so much groaning about my insistence on trains after that. I mean, as if you'd fly over scenery like that. Granted, from the air is also pretty special in many instances, and the only way when it comes to Antarctica, for example. Not too keen on going overland down there. Haha.
But one day, I'd love to spend a couple of weeks on Vancouver Island alone. Probably not in August-September, because we get coverage in Australia of the "wildfires" from the whole American west coast, and it looks so intense. Fire is no stranger down here, and bushfires can get pretty nuts, but the different geography and flora makes American fires look so different, and way more frightening. Courtenay must be a pretty small town surrounded by dense, virgin forest, so have you ever had a fire threaten the town while you've lived there; or anywhere on/around the island, for that matter?
Kamino Transmitting light through 1 meter of glass is trivial as it's already transmitted many kilometers through glass fiber optics. You could grow plants underground, but only just underground with leaded glass skylights a meter thick. Old crt tv's are made with this tech, it's easy. There are no technological barriers to making glass that thick or simply layering thinner glass.
Long form podcast of the year recommendation: you and Arv Ash..
Weird pouring up a drink in a rotating space station. You need to purposefully pour "wrong" so that you hit right đ€
Mandalore. As an important reality check for all of us.
Hey Fraser⊠like the mesosphere or ionosphere, should wee call the growing layer of orbital debris the Shrapnelsphere? What about the Junkopause? Maybe the Great Atmospheric Garbage Patch? What should er name these orbital debris belts?
I like space garbage patch.
Oh boy when we get the mining corps we may get unreal tournament :p
It's counter intuitive for a fast moving moon to move towards a planet when you think that the faster you launch from a planet the farther you can break away from it.
For the Solar Einstein Ring Telescope could there be a closer useful ring in a longer or shorter wavelength of light?
LED lights are great for growing plants, cost effective too
Naboo.
As for the person in the middle of a rotating station coming down fast or slow, I assume that his downfall will start slowly but then accelerate the further down he goes. By the time he approaches the surface, he will hit hard if the rotation is 1G. Maybe not as hard as he would if he sprung from the same altitude as Earth, but hard nonetheless.
There is also a limit to how fast a person can fall due to wind resistance though I don't know if this will make a difference.
As far as living on Mars is concerned (Kamino), there is a problem that wasn't mentioned is the low gravity and the impact it will have on children growing up. Their muscle mass and bone density will be low, and they might grow up to be freakishly tall. Even if they could adapt themselves to Mars, they probably won't be able to return to Earth's gravity after a generation of having been raised on Mars.
Worthy of note is the fact that astronauts living on the ISS have to do two hours' worth of exercise on a treadmill in order to return to Earth after months in space.
Question: Could accreating giant black holes distributed very evenly outside our observable universe be the reason the universe is pulled apart? (dark energy)
23:47 LOL I wouldn't be TOO quick to compare anywhere in Canada to Florida. It's a pretty scary place rn lol.
The rest of Canada might argue that the analogy holds
@@frasercain đđđ fair
Geonosis
Follow up: if we enter a Kessler syndrome, how potentially effective would it be to put magnets into orbIt to cause debris to collect more densely in some areas (also they could actively deorbit themselves)?
Not sure about the interaction between these magnets and earth's flux lines, but Kessler seems more threatening than you implied, as each launch that gets shredded by debris further increases the amount of debris
Geonisis
Mandalor is interesting too
Geonosis. A question I had, JUICE just launched and will take about a decade to be operational with all the gravity assists it needs. If all goes well with Starship over the next few years, is it possible for someone to build a comparable spacecraft with a direct trajectory to Jupiter that gets there before JUICE?
That's a FANTASTIC question, I'd love to get an answer on that. And to be fair, I think the Space Launch System would be an option to consider here too theoretically, it's just that they aren't planning to use entire SLS rockets right now to launch these flagship interplanetary missions anymore.
Europa Clipper *used to be* planned for a launch on the ol' Space Launch System, but at some point the government decided to hand it to a SpaceX Falcon Heavy. So yeah, I'd love to hear some numbers on this!
@Zachary Fluke yeah that's fair. I was thinking more from a cost perspective where if you could suddenly launch an interplanetary mission for the launch cost of a Falcon 9(optimistic)...that might add some urgency to an agency's design and planning process.
Absolutely, a fully refueled Starship could make the flight dramatically faster. Those gravitational slingshots are necessary to get a heavy spacecraft launched with a rocket that's too small. :-) If you're patient, you can use a smaller rocket.
Great information Fraser. đđđđđ
Well if there is life on that massive planet "Tatoonie" they would be 1 inch tall and 10 feet wide. đ
Or living in oceans. That would be fine.
@@frasercain You sure? Heavy water is pretty dramatic. Could a being even respire either on a planet's surface or in the water? Seems like the cell membranes would also need to be so strong...
â@@chrisgriffith1573 hydrostatic equilibrium (equal pressure on both sides) will avoid most problems. On the other hand any internal air spaces will be a big problem under water. The absolute pressure is not the real problem. It is the rapid change when moving vertically in the water.
coruscant for the singular win
If we had a neutron star and added one teaspoon of mass at a time, would there be a point where adding one more teaspoon turns it into a black hole? In which case if it went under no change from the slight addition of that mass do we know what is inside this black hole? Ie just the same thing as before
Hoth!
Question: Why do astronauts tend to use the term on orbit rather than in orbit?
Starship is the first launch system that could reasonably build a rotating space station. Hopefully once Starship is stable and tossing 150t into orbit with a two week turn around, people will quickly realise this potential and we will finally get to see one!
Naboo - thereâs a great Babylon 5 episode that shows this.
Would love to see a space station that has multiple rotating rings that simulate different gravity one for Mars and one for the moon and another one that is variable to determine whatâs the lowest gravity that humans can cope
Such a great show, we recently re-watched it and it totally holds up.
@@user-zo2pc5lu5q I know, I would love to see something like that. Even if it was only a smallish temporary test platform in its own orbit, just to confirm the theories. One full G is a non-starter but even a small fraction of Earth could be vital for long term missions.
Kamino , what if a Mars greenhouse had water sandwiched between the layers of glass or whatever ? water storage and radiation shielding just like a long range vessel.. but how thick would it have to be?
Question for next week in case I miss the live stream:
How many seconds after the Big Bang did the density of Universe crossed beyond Event Horizon ?
Other words, for how long was the universe expanding before it became less dense than the density required to create Black Hole event horizon? What about Neutron Star?
I understand there was a time of inflation and whole space time was expanding together, but just wondering if I took a chunk of universe at few seconds after BB how would it compare to a neutron star or BH material
Since ion drives move a payload using atomically light exhaust that can operate continuously for days/years,
Doesn't that same type of force (from a shower of light particles imparting momentum) mean that neutrinos should move black holes over long stretches of time?
Neutrinos comprise about half of the energy budget of ordinary matter (2% vs 4%), and flow throughout space.
Neutrinos have non-zero mass, thus momentum.
They travel at very close to c (speed of light in a vacuum), and c^2 can compensate for the miniscule mass of each individual neutrino.
They can't pass through an event horizon, so they deposit their mass/energy and momentum in the black hole.
Unless the frame-dragging mixes the vectors?
If not, I think this might be happening but I can't find any papers on it. Thoughts?
Kamino: Mars dome: multi-layer clear polyethylene with water between the layers. I need to read "A city on Mars" by the Weinersmiths. Maybe they talk about it.
The question is just how much water you can put in between you and space and still have sunlight get through.
re - Naboo quandary
If the station has a radius of 25 meters and is spinning at a leisurely 4 RPM, if you come from zero relative velocity and make contact with the spinning outer wall (the rim), the linear velocity would make that an impact of 40 km/ hour or 25 miles per hour. That's gonna be a BAD day for anyone. To avoid killing every visitor to the station, you could either stop-start the rotation every time someone gets on board, or you could impart a gradually increasing magnitude of rotational velocity to them. If you had a ladder running from the centre (hub) to the rim, the linear-velocity-equivalent at the hub is going to be negligible. The ladder is also rotating at 4 RPM, so as soon as you climb on the ladder, you'll start experiencing gravity. The farther you go from the centre, out towards the rim, the more gravity you'll experience.
By the time you reach the rim, thanks to the ladder, you will also have a rotational velocity of 4 RPM, so upon contacting the outer wall, your impact speed drops to 0 instead of 40km/ hour.
If your station is spinning fast enough to generate 1g at the edge, you are going to hit that edge moving very quickly, relative to its motion. If the rotating air has accelerated you up to close to the rotation speed, it will be like falling at close to terminal velocity. If there is no air you will drift slowly towards a surface that is moving sideways at high speed. If that surface is really smooth it might be survivable, but any bumps will make for a very bad day.
Yeah, I wasn't sure how to approach the question, but that makes sense. You'll get up to terminal velocity.
These are my thoughts on this as well. Also, the Coriolis effect might make for some interesting wind currents in the cylinder. That would certainly complicate things.
I havenât been around the world but I know few countries already and I could say that glaciers are the must mesmerizing place on earth , follow by Victoria island. I enviĂ© you
Since dark energy doesn't seem to internally affect our local group of galaxies... If we can say that the same for other local groups of galaxies, and we also assume that each local group has never interacted with any other local group, then wouldn't that imply that the big bang was not a single location event and instead was a bunch of simultaneous smaller big bangs each resulting in their own local groups of galaxies?
Coruscant, clearly!
Thanks!
Naboo
The gravity effect is the centripetal acceleration = v^2/r.
Drifting "down" from the center one needs to gain sufficient tangential velocity in order to closely match that velocity to get a safe touchdown. Radial velocity also needs to be minimized.
This is a non-trivial exercise to model, even before considering how the wind will be distributed in a circular frame of reference.
This may keep me up nights; good problem posed.
Hah, let me know what you discover. I sensed that it was going to be more complicated than I could answer quickly in the video.
Tatooine: TOI-849 b is 3.4 times larger than Earth. Makes it 39 times the volume of Earth. So just a tiny bit denser. Precision is key here, because if it had only been 3.0 times larger, then its density would have been greater than iron.
You can have a greater density than iron when you've got gravity pulling the planet in on itself. Superdense iron?
@@frasercain I wonder how compressed iron can be before becoming degenerate matter, when the electron pressure is at the limit of giving up.
Is there some material that can be added to the water to make it more radiation-proof for the windows?
Hi Fraser
Have you asked Chat GPT some of these kinds of questions? It's AMAZING what it can do, it really is!!! On a whim, I asked it:
*"Could astronauts on the surface of Mars be protected from radiation by some kind of mobile magnetic field generator?"* THIS was the response:
_It is currently unclear if a mobile magnetic field generator could provide sufficient protection for astronauts on the surface of Mars from radiation. While magnetic fields can help deflect charged particles from the sun, such as solar flares, they may not be effective against the more energetic cosmic rays that are a constant background radiation source in space._
_Additionally, a mobile magnetic field generator would need to be quite powerful to create a protective bubble around astronauts and any equipment they use. Such a device would likely be large, heavy, and consume a lot of power, which would be difficult to sustain on a long-duration Mars mission._
_Other potential solutions for protecting astronauts from radiation on Mars include designing habitats with thicker walls or radiation-absorbing materials, locating habitats in naturally shielded areas, or developing new drugs or medical treatments to mitigate the effects of radiation exposure._
_Ultimately, more research is needed to determine the feasibility and effectiveness of a mobile magnetic field generator for radiation protection on Mars._
How awesome is that?
Yup, that's a pretty great answer. I've been using ChatGPT like crazy, but I don't think it's ready to take the wheel yet
I always wondered if maybe the mirror array on the moon could be sinking in the regulus a cm every year, but idk about the Martian moon đ
I don't know if I'm doing this right but I have a question.
I notice that dark energy is this nebulous thing that we don't know what it's made of, we can't DIRECTLY measure it or interact with it and all we really know is that it or something like it exists because it interacts with space-time in a measurable way. All these statements also hold true for Black holes.
And so my question is, are there any other commonalities between dark energy and black holes that you can think of? If yes, what would be the implication of these commonalities beyond simple coincidence?
Is the barycenter of two equal mass objects/a binary, also a lagrange point? With perfectly circular orbits and equal masses, could you situate yourself exactly at the center and stay there?
It's not a Lagrange point, but it's theoretically a point of balance. Of course, in practice there's no place that would be perfect, so it would be unstable, but you could use propellent to remain in that balance point.
Weird Question. Could light from normal matter travel on different curved fields than dark matter?.
Maybe we need to get deep into space way beyond our galaxy, to see light from a dark matter curve field?
[Kamino] If the glass dome has a layer pf protection like the window of a microwave oven, would that offer the kind of protection that Martian greenhouses would need without having the glass, be as you said a meter in thickness to compensate for the radiation? I have also heard that some window films have ultraviolent light filters which could also give some protection from the sunlight and its radiation. [Kamino]
You need protons. It's not about ultraviolet radiation, that's easy to protect against. It's about cosmic rays, which are extremely dangerous. They're only blocked by stuff. A meter of water or rock does the trick.
Maybe could grow underground with fiber optic lights
@@frasercain Cosmic Rays! I know about those and completely forgot about them. If I were to make a guess you probably even mentioned them in the video, and I just missed it. You, see? This is why I could never be a scientist or an astronaut. I guess there is a reason my friends call me Scott forgot. đThank you for the kind answer and the great videos!
Scott Manley have a video about Russian experiment with people spending weeks in rotating structure to simulate cetrifugal "gravity"
Yeah, we showed off some clips of NASA's tests too. There have been some ground-based experiments done, but nothing in space.
I reckon would be more like two layers of glass and 2m of water between on mars
great video I have a question, would mars be a great place for old people due to the low gravity?
It's an interesting idea, a sci-fi retirement community. Lower gravity would definitely help, but everything else would be harder: cardiovascular damage, eyesight problems, cancer caused by radiation.
Finally got here early
You did it!. First!
How about leaded glass? Corning makes some glass that has a considerable amount of lead and barium, intended for x-ray shielding in medical settings, that still lets through most visible light, and I'm sure there are other companies that make similar products. Wouldn't this allow the use of natural sunlight in a Mars greenhouse? Or, if it took out some needed frequency, minimize the amount of artificial light enrichment needed. Granted, this stuff is heavy, and would add a lot to the load of stuff taken up, but it might be makable on Mars, using Martian ores.
Sure, more protons are always good. The question is just how much visible light can get through to balance the radiation protection. I'm sure someone will work out the best material at some point.
Corella gets my vote. Both for the question and answer.
Thanks!
We know the universe is expanding. Does it do anything else? Like does it spin?
It doesn't spin, but it's hard to define what spinning would even mean if the Universe was infinite.
Re Coruscant:
Playing devil's advocate.... Maybe the un-novas are completed Dyson spheres
Yikes. To go from a bright star to nothing in 6 months. They work quickly.
Question - Iâve heard that the LIRPA 1 satellite recently detected lightning on the moon. Is it the same as lightning here on Earth?
Tatooing - Could it be that our own systems planet Jupiter has a rocky core like this ?
Jupiter's core is probably about 23 times more massive than the Earth.
I vote for Naboo!!!
It's VERY easy for people to get these kinds of answers wrong, thanks to Hollywood nonsense.
Fraser answered it absolutely correctly and he did it in an easy-to-understand way, while explaining the salient details very well.
Hells, this is "Answer Of The Year" material!!!
Ps: The crap on movies and TV shows is based on a LOT of mistaken assumptions and as a result, a LOT of people have a mistaken notion of how rotationally simulated gravity works. They either misunderstand or fail to understand the application of forces involved. When science-communicators spread that same misinformation, it becomes VERY hard to repair that kind of damage. Thankfully Fraser is better than that.
Naboo: if the space station is small, than it will have to spin very fast to reach earth like gravity.
which mean, your radial speed (falling outwards) will be slow, but the ground will be moving sideways (spinning) very fast.
so you will die as a skid mark on the ground. as if you were shot out of a cannon parallel to the ground on earth.
if the spaceship is big enough so that the rotational speed won't kill you, you will drift down so slowly, you will die of old age before you get there.
Hmm, interesting. I've been thinking that terminal velocity plays some kind of role. You'll be hit by wind until you reach the maximum speed.
Additional question for Glass Domes on Mars: would something like this wok: a dual layer glass dome with water in between (simulating a meter or so thick glass)?
Bespin
Sure, but the water will make it pretty hard for sunlight to get through. And Mars gets 1/4th the sunlight of Earth.
I know that solar power is too weak for outer solar system missions. But, could we have mega missions to Mercury because of all the sunlight available? Like, using super heavy duty equipment that wouldnât make sense anywhere else in the solar system?
My suggestion for artificial gravity in a space-station is based on a HVAC system that suck air from small holes in the "floor" which will make people "clinging" to that "floor", by placing the air exhaust in the middle of the space-station the "gravity" will be enhanced by the air direction
That might help keep your feet on the ground, but it wouldn't solve the other problems like eyesight and fluids pooling in the head.
â@@frasercain - the eyesight will be solved by a mirror arrangement mounted in spectacles we can wear, and the pooling in our head we fix by a valve mounted just beside the chip from Elon Musk, also placed directly in the brain
About mining, the people who made buck where those who sold shovels and buckets. The same thing will hold in space!
The artificial "gravity" in rotating space stations... is making my head spin: You talked about how the differential of the force between your head and your feed could make you feel sick. But isn't there also a problem with the liquids in your ear which let you experience movement in space? I imagine the liquids spinning with the rotating station but if you turn your head the liquids would keep spinning in that direction while the "head around the liquid" changes it's position (including the fine hairs that pick up the liquids motion). Wouldn't that instantly lead to you stumbling and falling? I also can't imagine that you can get used to that effect.
Nobody has ever done and experiment long enough to find out, but people do become accustomed to motion sickness over time.
You are right, people get accustomed to motion sickness, but what we call motion sickness on earth is usually caused by a completely different mechanism: It is rather a difference between what our eyes vs. to what our sense of balance perceive. I find that topic really fascinating. Thanks and please keep up the good work! đ„°
Hoth! Im also wondering, what exactly will happen to Mars the day its moon crashes into it?
It'll be an enormous impact, like a 10 km asteroid striking the surface.
@@frasercain that would be an amazing view!
So many planet size queens. Itâs not the size of the planet itâs the tidal motion of the ocean.
That's meta.
Hoth. As the Moon floats away, is it's orbit getting more eccentric or more circular?
Neither.
I have some astronomical complaints with that ringed planet emoji. But maybe the version I'm seeing on Chrome/MacOS are different from what you see.