Crowbar question: A crowbar can be arbitrarily long depending on how much Iron you can get ahold of ... but if the cross section of the crowbar is too thick, the crowbar will collapse into a black hole. That cross section is surprisingly small, but I haven't calculated it recently, IIRC it's less than a meter diameter.
I calculated a light-year long crowbar with a radius of 2 cm. It only made a sphere of iron about 20 km across, so it wouldn't even have hydrostatic equilibrium. It would be like a mini-Psyche.
@@frasercain I'm seeing that it would take a cross-section of 1000 km to get to that result. In my college-years calculation I must have taken a cube root when a square root was called for.
I just used Wolfram Alpha. I asked it to calculate a cylinder 1 light-year long with a radius of 2 cm. Then I took that volume and asked it to calculate a sphere.
@@frasercain I recall that my calculation was for a near infinitely long square-cross-section piece of steel, and the question was at what cross-section was it so massive that the one-over-x gravity of the structure made it not strong enough to prevent the crushing. This is initially much smaller than one light-year long cylinder collapsing to a black hole.
Another crowbar question: if you had a several-megaparsec-long crowbar (2cm diameter) in space, assuming no objects were near enough to distort it via their gravitational attraction, would that crowbar be pulled apart by the expansion of space?
The most counter-intuitive thing is when they take an area of a very spread out gas and say it has an extreme temperature. So it is almost empty then and could not heat up another thing to this temperature. I thought you would say that the enormous G-man's crowbar would collapse into a planet or a black hole.
@@DanielVerberne hey? He didn’t really answer the question. People do commonly state with the average temperature of space is and a figure is given therefore , Is the answer that’s given the -average- of all the material and non-material in a given volume?
Having spent a lot of time on boats, I have seen many beautiful moon "rises and sets". With only the water on the horizon, the size is the same as when it is high in the sky. Yet filtered through many times the atmosphere on the horizon, the colors can be spectacular as with the sun.
I thought the moon illusion was some sort of atmospheric lensing trickery, I'd never thought of testing it. Going to have to keep the kids up late this weekend lol
My science teacher once told me to look at the moon while bent over, through your legs. That way your brain can't use reference objects any longer and the moon will be a lot smaller all of a sudden. Fun with the kids!
right? I was/am thinking the same...? i could swear ive heard it explained by the greater depth of atmosphere magnifying the mooon/sun. This is rather irksome. haha
The only thing you will notice which I don't think Fraser mentioned is that when either disk is right at the horizon, atmospheric distortions get quite noticeable!
@hoppyrabbit1833 why do you need school to tell you something doesn't get bigger at the horizon? Somethings should just be known without hanging to spoonfeed people.
Serious question: If a banana was lowered into Jupiter, but was insulated from the heat, would you have a metallic banana? Or a super dense fruit smoothie?
@@FLPhotoCatcher Wind speed is too strong... it would be ripped into tiny fibers and scattered around. Let's say that didn't happen, the atmosphere is too dense which would cause the banana to be too buoyant to be lowered down into it. The banana would need to be pushed into the atmosphere which would then result in the same ripping. The only way to do it, put it in a pressure chamber at room pressure then increase pressure over time. Long answer for pointless question.
I was in Algonquin Park, which is in northern Ontario, with my girlfriend in the early 90's when, while star gazing, she saw the milky way for the first time and said "what is that!?!" I lmfao & told her it was our galactic home, but in her defense I have never seen such a perfectly clear sky as it was that night, because we could actually see the galactic arms in 3 dimensions like an I-max movie, it was unbelievable how amazing it looked...so I keep looking up, clear skys to all!
"I'm not a scientist, just a journalist reporting on the scientific concesus". We want to know about the scientific concesus on the length of the crowbar !
Regarding the size of the sun at the horizon. The question also touched on brightness and warmth, and those do change at the horizon. Because of the amount of atmosphere the light has to pass through at dawn and dusk is much greater than at high noon. So there is a difference there that is not just an illusion.
No, this only affects the color (e.g. the Sun or the Moon appearing redder when near the horizon, thanks to light-scattering particles in the air preferentially scattering and blocking blue light while letting longer-wavelength red light through.) But the primary reason the Sun is "colder" when near the horizon and "hot" when in zenith, is the angle at which its light is striking the ground. When shining from above, the light is at its maximum intensity; when shining from a low angle, the same light is smeared across a much larger surface area on the ground - so that there is less light (or energy, or heat) per unit area.
@@Spherical_CowYou can compensate for the changing angle by holding the back of your hand perpendicular to the sunlight. Close your eyes, so the color won't matter. You will indeed discover that the back of your hand warms up much more quickly on a clear day when the sun is high in the sky than when it is near the horizon.
I would guess the a primordial neutron star would have different attributes such as mass and size that would be easier to look for than primordial black holes. Love to hear more of a discussion about what such stars would be like and whether there has been any attempt to find such things.
I think in order to have a neutron star, you would need to have a lot of neutrons and they were not made in the big bang. The only atoms made in the big bang was hydrogen (zero neutrons) and a little bit of helium (2 neutrons).
@@MrT------5743exactly, there are no primordial neutrons and hence no primordial neutron stars. To the OP: you're thinking of a specific mechanism of forming black holes, that of collapsing stars. But this mechanism doesn't apply in the case of primordial black holes. Think of kugelblitz black holes that are formed by putting enough photons in a small enough space at the same time. If you use a bit fewer photons than is required to form a black hole, you don't get a neutron star, you get a bright flash.
If you pushed one end of the 1 light-year-long pole, the other end wouldn’t move for about 3 million years (depending on the metal). The delay happens because forces propagate through materials at the speed of sound within them-not instantly.
Personal question: Say you are given the chance to design a space mission but the only rule is that it is limited to the solar system (not just planets...literally anywhere, even sedna). Where would you go? Why would you go there? What kind of mission would it be? I feel like any space nerd has a place they really want to see get more love. For me it would be triton. So many unknowns and its just something about it that has captured my attention over anything else.
Question: In the case of a massive, rapidly spinning neutron star, how does the frame-dragging effect contribute to the dynamic stability of the star? Given that the outer parts are affected by time dilation more than the core, how can the neutron star remain a cohesive object despite the differences in time experienced by its various parts?
How strange...I haven't thought about crowbars in a while but I had to find one when I raised the flag yesterday...it wasn't this size but worked as needed.
QUESTION. STAR FORMATION AND SIZE. My understanding is that gas / matter coalesces until it reaches a particular size/density whereby nuclear fusion starts. The star essentially ignites. At that point it pushes away the remaining gas and fine dust out of the solar system via solar winds. The exact mass for solar ignition is known and understood. So why aren't all stars the same size.
Like the great red spot? It's a storm of gas. Gas and/or hydrogen is a real substance. Jupiter doesnt have a solid surface, but a surface none the less.
@MYNAME_ABC because the gas isn't transparent. Ever see a cloud of water vapor? It isn't transparent either. You know there is this new invention called 'the internet'. You can look up and get answers rather than rely on some random in TH-cam comments section. 🤣
Question: about panspermia from Mars to Earth, what are the factors that would make that more easy or hard for Martian life? For instance, what is the shortest amount of time an object that got ejected from Mars would have to travel between planets?
I would assume for a 1ly crowbar, the mechanical forces holding the crowbar together are negligible. Basically, it will act like you put a row of disconnected pebbles stretching the whole distance.
If metallic hydrogen did require pressure to be maintained to keep in its state, how would it compare to the energy density of anti-matter's needs for containment?
Question for the next question show: Why don’t we hear about the experiments being done on the ISS ? They’ve been doing 1000s(?) of experiments for decades now. What progress has been made? What discoveries have been made?
I do hear about the occasional experiment done on the ISS from popsci sources. But of course in general only an absolute miniscule percentage of the science done world-wide ever gets picked up by any journalists. For the vast majority, you'll have to use primary sources, i.e. read the papers. That'll be the same for the ISS.
Launching from the moon is moon easier no matter the launch type. This is becouse of the much lower gravity, and becouse you have no atmosphere getting in the way. The lack of an atmosphere is especially good for spin launching, so that method could work very well on the moon.
Is neutronium stable? If two neutron stars crash against each other and they break up, would the pieces remain as pure neutrons or would they immediately decay into protons?
Underdtanding that the word "temperature" translates to english as "vibration", there must be at least an atom to vibrate, measuring a billion atoms vibrating is easier than measuring sparse atoms in intersolar or intergalactic space but there is space that measures "absolute zero" aka no vibration
You are actually further from the moon when it is on the horizon vs. striaght up. So, if anything, it would appear to be smaller on the horizon than straight up. It's not measurably different because the distance doesn't change that much.
I think the important consideration would be to keep some semblance of proportion to the crowbar, so, let's take the example in the picture provided, if we keep those physical proportions and the same material, and lets put it in the middle of some huge void space, and just start scaling it up rapidly but not instantly: how far can it be scaled until its own gravity starts to significantly alter its ability to retain the shape of a crowbar? Like stay at least 95% the original shape? I also wonder if, lets say this scaling happens instantly, how big the crowbar has to be scaled before it would form at least 1 black hole from its mass once released? I mean, due to the shape being very long and thin you'd have to get the typical cross section beyond the Schwarzschild Diameter of steel. So at that point would we have different parts of that freed crowbar collapse independently into some sort of resonance cascade?
Should we really be looking to make alloys or compounds like Moonium, or Marsium, that really augment the in SITU opportunities? Shoveling regolith, and or re-creating traditional earth base building materials likely shouldn’t apply?
Question: Is it possible, would it be beneficial to spin up the moon? e.g. Spin the moon clockwise with 1 Rotation/month to have a permanent night- and day-side.
It already spins one rotation per month. This is why one side faces earth always. You would have slow it's rotation to have zero rotation from the sun's perspective. This permanent day/night side would still have the exact same phases as seen from earth, but we would see all sides of the moon over the course of each month. It wouldn't benefit or help us at all.
I was watching Elysium the other day, and it got me thinking, if there were an extremely large rotating space station or habitat like the one in the film Elysium, with the top side of the ring exposed to space, would the atmosphere remain inside due to its rotation, or is that purely fictional?
Well, the atmosphere should get pushed out. So you get a denser atmosphere further out and very little air in the middle right? Unless you have enough gravity in the middle.
Here's a question. Why don't we have a pair of satellites at the eath sun L4 and L5? I think they could off amazing benefits such as: Provide constant communication between earth and mars, act as interferimetors, make a solar system equivalent to GPS, etc...
I assumed a long crowbar with a normal crowbar cross section. BUT, if the crow bar is in proportion: 10^16 crowbar length => (10^16)^3 crowbar mass. ie 10^48 kg ie 10^48 / (2*10^30) => 5*10^18 solar masses. THIS WOULD MAKE THE BIGGEST EVER SUPER MASSIVE BLACK HOLE. (I want one)
A crowbar that is proportional in design to the one you showed would be limited by it's cross section, and by how many thousands of years you would be willing to wait while it cooled off from being cast. I doubt the main body could be more than 500 miles in diameter, as internal pressure would cause it to never cool to a solid. I have an antique crowbar 60 inches long and one inch through the body. Therefore at 60 to 1 your mega-bar would be 30,000 miles long. It might not be possible to cast a piece so large that would not crack during cooling, And at 1/10 degree per year cooling rate it would take about 25,000 years to cool. Another consideration is how much iron, carbon, and alloy metals you can access. You would need about 15 million cubic miles of materials for the project. That would require the iron core of at least one super-Terrestrial planet. So you have to have the tech to travel FTL and disassemble and transport planetary masses. That kind of stuff. Just a thought.
I'm imagining it just appears. I calculated that a crowbar one light-year long would melt down to a sphere of metal about 20 km across, which isn't that big.
Regarding measuring distances across the cosmos, I recommend folks check out the "How Far Away Is It" video playlist on the channel of David Butler here on TH-cam. Its a wonderfully sedate, calming and illuminating multi-part explanation of several key steps in the distance ladder.
The universe is expanding in all directions, therefore all the light emmitted is being redshifted. What is happening with energy conservation? Redshifted light has energy.
Question: They always explain how it's possible that ice persists on a hot planet like mercury by explaining how cold the permanently shadowed regions of craters are. But they never explain how that ice got there to begin with. For sure when the crater was created by an impact event there was no ice there to begin with. So why after a crater is created on mercury does ice somehow manage to migrate to and accumulate in those crater shadows? Nobody ever explains that. Where is that water coming from? They act like the whole mystery is solved just by saying shadows are cold.
Why did NASA use gold for the golden records to make them last longer? Isn't gold used on earth because it's nonreactive to other elements? There's not much to react to in space, so wouldn't it make more sense to use a very hard material instead?
Here's one for you... Read an article that The American Astronomical Society, among others are calling for a ban on space advertising. I'm all for a ban on that nonsense, but do you think it would pose a real threat? I can't imagine any company advertising something in space to a civilization that rarely looks up. Would CocaCola really spend millions of dollars to advertise something that 99% of people wouldn't even see?
Crowbar = Supermassive Black Hole The Average crowbar is 48" long and 1.5" thick. 1 lightyear = 9.46 Trillion km. Our solar system, to the edge of the Oort cloud is only 10 Billion km. One lightyear is equal to 946 solar systems laying side by side. Length - That means the Crowbar would be as long as 946 Solar Systems laying in a row. Every inch of a 48" Crowbar is roughly equal to 19.7 Solar Systems long. Thickness - So, a crowbar 1 lightyear long, would be as thick as 29.5 Solar Systems laying side by side. (Since the average crowbar is 1.5" thick.) 946 Solar Systems long. 29.5 Solar Systems thick. Now, fill those dimensions with iron. I think the Crowbar collapses into a Supermassive Black Hole. Unless I'm wrong.
@ The relative difference is 1/60 for the Moon, easily measurable. It is 43 ppm for the Sun. Whether that is measurable.depends on the sharpness of the Suns's surface. Because of the immense gravity, the pressure scale height is only 100 km, which is 143 ppm of the solar radius. So the effect is 30 % of the scale height.
@rainaldkoch9093 none of that matters for apparent size difference from when the moon is at the horizon vs overhead. Also, can't you tag the person you are talking to? 🤣
Actually the light started traveling over 15 billion years before humanity. But it’s fifteen billion light years distant from us, so it is just now getting to our eyeballs. When you look out at that distance, you are looking back in time. Those objects no longer exist, for the most part.
To the person asking the crowbar question: Fraser really misunderstood your question, his intuition isn't that good. But I'm on your wavelength. Here's the correct and INTERESTING answer: For the maximum physically allowed size pretty bar, let's assume 100 percent solid maximum hardness steel at room temperature just appearing. No worries about compression heating etc. It will reach Max size at the point at which it will deform from gravity getting enough force to squish the steel. The limits for rocks in space bodies before they become rounded is a few hundreds of kilometers. Steel is both softer than most rocks and denser. So let's assume 500km for the diameter of the rod max. The pry bar could be roughly as long as Earth's diameter before it collapses! Much longer if it's hollow. A Galaxy spanning pry bar would instantly rip itself into billions of implosions! My intuition says that these implosion will lead to the efficient creation of black holes, especially as iron is so atomically stable and produces no heat from fusion to keep matter apart. Your prybar would start exploding within a few seconds and release more energy than any other cosmic boom ever by a factor of billions. The milky way is utterly blown away, as it weighs only a tiny fraction of the pry bar. What's left would be an enormous, expanding and pleasantly glowing cloud of heavy element dust, surrounded by an expanding sphere of trillions of black holes of many sizes. I'd definitely put sunglasses on, and even then don't look at that Galaxy sized pry bar too long. The gravity waves might make you nauseous, take some Dramamine beforehand. So just take a glance, enjoy the show, then walk away and let someone else clean up the mess..
I calculated after that a crowbar 1 light year long would only make a sphere a few dozen km across. Not big enough for hydrostatic equilibrium, but it all depends on the specifics of the scenario
One thing though, there is no reason for anywhere in the middle of the crowbar to collapse, as it's feeling approximately the same gravitational force from both sides. This only breaks down at the end of the crowbar, and even then the gravitational force is almost negligible. For a linear density of 30g/cm of length, considering the force on the final centimeter of crowbar exerted by the entire galaxy wide length, I get a force in the nano-newton range. The total mass of the crowbar may be quite high but it's also ridiculously spread out and 1/r^2 diminishes very rapidly!
Per Perplexity AI, "While empty space isn't "hot" or "cold" in a classical sense, its entropy can be associated with a temperature via quantum and thermodynamic principles. The relationship between entropy (S) and temperature (T) in thermodynamics can be expressed as: Delta S = Q / T" Cosmic Microwave Background (CMB) temperature is ~2.7 K
@wanderingfool6312 not scaled up, just lengthened to 1 light year. It wouldn't be a crowbar anymore if it was the big around. Probably wouldn't even be classified as a bar any longer either.
Crowbar question: A crowbar can be arbitrarily long depending on how much Iron you can get ahold of ... but if the cross section of the crowbar is too thick, the crowbar will collapse into a black hole. That cross section is surprisingly small, but I haven't calculated it recently, IIRC it's less than a meter diameter.
I calculated a light-year long crowbar with a radius of 2 cm. It only made a sphere of iron about 20 km across, so it wouldn't even have hydrostatic equilibrium. It would be like a mini-Psyche.
@@frasercain I'm seeing that it would take a cross-section of 1000 km to get to that result. In my college-years calculation I must have taken a cube root when a square root was called for.
I just used Wolfram Alpha. I asked it to calculate a cylinder 1 light-year long with a radius of 2 cm. Then I took that volume and asked it to calculate a sphere.
@@frasercain I recall that my calculation was for a near infinitely long square-cross-section piece of steel, and the question was at what cross-section was it so massive that the one-over-x gravity of the structure made it not strong enough to prevent the crushing. This is initially much smaller than one light-year long cylinder collapsing to a black hole.
But it would cease to be a crowbar after only a few hundred meters as it would bend like wet noodle. Crowbars gotta be rigid.
Another crowbar question: if you had a several-megaparsec-long crowbar (2cm diameter) in space, assuming no objects were near enough to distort it via their gravitational attraction, would that crowbar be pulled apart by the expansion of space?
The most counter-intuitive thing is when they take an area of a very spread out gas and say it has an extreme temperature. So it is almost empty then and could not heat up another thing to this temperature.
I thought you would say that the enormous G-man's crowbar would collapse into a planet or a black hole.
TH-camr Angela Collier has a great video on the concept of temperature.
"You can't just make metallic hydrogen in a vice" -> "HOLD MAH BEER!"
It's not about how long your pry bar is... It's about how you use the leverage.
Love the temperature in space question and wonderful answer; Fraser.
@@DanielVerberne hey? He didn’t really answer the question. People do commonly state with the average temperature of space is and a figure is given therefore ,
Is the answer that’s given the -average- of all the material and non-material in a given volume?
Having spent a lot of time on boats, I have seen many beautiful moon "rises and sets". With only the water on the horizon, the size is the same as when it is high in the sky. Yet filtered through many times the atmosphere on the horizon, the colors can be spectacular as with the sun.
I thought the moon illusion was some sort of atmospheric lensing trickery, I'd never thought of testing it. Going to have to keep the kids up late this weekend lol
My science teacher once told me to look at the moon while bent over, through your legs. That way your brain can't use reference objects any longer and the moon will be a lot smaller all of a sudden. Fun with the kids!
right? I was/am thinking the same...? i could swear ive heard it explained by the greater depth of atmosphere magnifying the mooon/sun. This is rather irksome. haha
So did I. How did we not learn the real answer in school? Fraser is such a great teacher, and I'm always learning new things!
The only thing you will notice which I don't think Fraser mentioned is that when either disk is right at the horizon, atmospheric distortions get quite noticeable!
@hoppyrabbit1833 why do you need school to tell you something doesn't get bigger at the horizon? Somethings should just be known without hanging to spoonfeed people.
Tony Stark was able to build metallic hydrogen in a cave! With a box of scraps!
Serious question: If a banana was lowered into Jupiter, but was insulated from the heat, would you have a metallic banana?
Or a super dense fruit smoothie?
@@FLPhotoCatcher - if it turn in to a metallic banana remember not eating it, it ruin your teeths
@@FLPhotoCatcher Wind speed is too strong... it would be ripped into tiny fibers and scattered around.
Let's say that didn't happen, the atmosphere is too dense which would cause the banana to be too buoyant to be lowered down into it. The banana would need to be pushed into the atmosphere which would then result in the same ripping.
The only way to do it, put it in a pressure chamber at room pressure then increase pressure over time.
Long answer for pointless question.
@@jh9496 Yes but we are not Tony Stark
@@OnceAndFutureKing13711bruh joke went over your head.
I was in Algonquin Park, which is in northern Ontario, with my girlfriend in the early 90's when, while star gazing, she saw the milky way for the first time and said "what is that!?!" I lmfao & told her it was our galactic home, but in her defense I have never seen such a perfectly clear sky as it was that night, because we could actually see the galactic arms in 3 dimensions like an I-max movie, it was unbelievable how amazing it looked...so I keep looking up, clear skys to all!
Compliance officer here:
Thank you for complying by posting
The proper credits for both
Crowbar and background
✅️
"I'm not a scientist, just a journalist reporting on the scientific concesus". We want to know about the scientific concesus on the length of the crowbar !
Great Southern Land 🎶
Under the milky way tonight... 🎶
Regarding the size of the sun at the horizon. The question also touched on brightness and warmth, and those do change at the horizon. Because of the amount of atmosphere the light has to pass through at dawn and dusk is much greater than at high noon. So there is a difference there that is not just an illusion.
No, this only affects the color (e.g. the Sun or the Moon appearing redder when near the horizon, thanks to light-scattering particles in the air preferentially scattering and blocking blue light while letting longer-wavelength red light through.)
But the primary reason the Sun is "colder" when near the horizon and "hot" when in zenith, is the angle at which its light is striking the ground. When shining from above, the light is at its maximum intensity; when shining from a low angle, the same light is smeared across a much larger surface area on the ground - so that there is less light (or energy, or heat) per unit area.
@@Spherical_CowYou can compensate for the changing angle by holding the back of your hand perpendicular to the sunlight. Close your eyes, so the color won't matter.
You will indeed discover that the back of your hand warms up much more quickly on a clear day when the sun is high in the sky than when it is near the horizon.
Wait a second here, why do space movies always show people turning into icicles in full sunlight, are they all lying to us...
Interesting topics again👌
Question: if there are primordial black holes, could there be primordial neutron stars etc?
Sure, why not.
I would guess the a primordial neutron star would have different attributes such as mass and size that would be easier to look for than primordial black holes. Love to hear more of a discussion about what such stars would be like and whether there has been any attempt to find such things.
I think in order to have a neutron star, you would need to have a lot of neutrons and they were not made in the big bang.
The only atoms made in the big bang was hydrogen (zero neutrons) and a little bit of helium (2 neutrons).
@@MrT------5743exactly, there are no primordial neutrons and hence no primordial neutron stars.
To the OP: you're thinking of a specific mechanism of forming black holes, that of collapsing stars. But this mechanism doesn't apply in the case of primordial black holes. Think of kugelblitz black holes that are formed by putting enough photons in a small enough space at the same time. If you use a bit fewer photons than is required to form a black hole, you don't get a neutron star, you get a bright flash.
If you pushed one end of the 1 light-year-long pole, the other end wouldn’t move for about 3 million years (depending on the metal). The delay happens because forces propagate through materials at the speed of sound within them-not instantly.
Personal question: Say you are given the chance to design a space mission but the only rule is that it is limited to the solar system (not just planets...literally anywhere, even sedna). Where would you go? Why would you go there? What kind of mission would it be?
I feel like any space nerd has a place they really want to see get more love. For me it would be triton. So many unknowns and its just something about it that has captured my attention over anything else.
Question: In the case of a massive, rapidly spinning neutron star, how does the frame-dragging effect contribute to the dynamic stability of the star? Given that the outer parts are affected by time dilation more than the core, how can the neutron star remain a cohesive object despite the differences in time experienced by its various parts?
How strange...I haven't thought about crowbars in a while but I had to find one when I raised the flag yesterday...it wasn't this size but worked as needed.
QUESTION. STAR FORMATION AND SIZE.
My understanding is that gas / matter coalesces until it reaches a particular size/density whereby nuclear fusion starts. The star essentially ignites. At that point it pushes away the remaining gas and fine dust out of the solar system via solar winds. The exact mass for solar ignition is known and understood. So why aren't all stars the same size.
If the jupiter is hydrogen and helium, then how the gas at the surface can build structures? There should be no real surface at all, right?
Like the great red spot? It's a storm of gas. Gas and/or hydrogen is a real substance. Jupiter doesnt have a solid surface, but a surface none the less.
OK, a storm of gas. But why does it have colour contrast? Why is the great spot visible at all?
@MYNAME_ABC because the gas isn't transparent. Ever see a cloud of water vapor? It isn't transparent either.
You know there is this new invention called 'the internet'. You can look up and get answers rather than rely on some random in TH-cam comments section. 🤣
Can we use gravitational waves to zoom in the CMB? Have we done it? What can we learn from it?
Question: about panspermia from Mars to Earth, what are the factors that would make that more easy or hard for Martian life? For instance, what is the shortest amount of time an object that got ejected from Mars would have to travel between planets?
I would assume for a 1ly crowbar, the mechanical forces holding the crowbar together are negligible.
Basically, it will act like you put a row of disconnected pebbles stretching the whole distance.
But would it be a lever long enough?
If metallic hydrogen did require pressure to be maintained to keep in its state, how would it compare to the energy density of anti-matter's needs for containment?
Question for the next question show: Why don’t we hear about the experiments being done on the ISS ? They’ve been doing 1000s(?) of experiments for decades now. What progress has been made? What discoveries have been made?
I do hear about the occasional experiment done on the ISS from popsci sources. But of course in general only an absolute miniscule percentage of the science done world-wide ever gets picked up by any journalists. For the vast majority, you'll have to use primary sources, i.e. read the papers. That'll be the same for the ISS.
Metallic hydrogen is the real world analogue of Nibbler’s “fuel” on Futurama.
#SmarterEveryday destin has done a fantastic video about photographing the moon. he had to have a camera made/re-made. quality video.
Frasier Can you take a picture of the milky way and show us on an upcoming video?
Would spin launch have more success with a lunar launch or an earth orbit launch?
Launching from the moon is moon easier no matter the launch type. This is becouse of the much lower gravity, and becouse you have no atmosphere getting in the way. The lack
of an atmosphere is especially good for spin launching, so that method could work very well on the moon.
Is neutronium stable? If two neutron stars crash against each other and they break up, would the pieces remain as pure neutrons or would they immediately decay into protons?
Underdtanding that the word "temperature" translates to english as "vibration", there must be at least an atom to vibrate, measuring a billion atoms vibrating is easier than measuring sparse atoms in intersolar or intergalactic space but there is space that measures "absolute zero" aka no vibration
You are actually further from the moon when it is on the horizon vs. striaght up. So, if anything, it would appear to be smaller on the horizon than straight up. It's not measurably different because the distance doesn't change that much.
Solids and liquids generally occupy a similar volume relative to the gas form. Why would metallic hydrogen be any different?
I think the important consideration would be to keep some semblance of proportion to the crowbar, so, let's take the example in the picture provided, if we keep those physical proportions and the same material, and lets put it in the middle of some huge void space, and just start scaling it up rapidly but not instantly: how far can it be scaled until its own gravity starts to significantly alter its ability to retain the shape of a crowbar? Like stay at least 95% the original shape?
I also wonder if, lets say this scaling happens instantly, how big the crowbar has to be scaled before it would form at least 1 black hole from its mass once released? I mean, due to the shape being very long and thin you'd have to get the typical cross section beyond the Schwarzschild Diameter of steel. So at that point would we have different parts of that freed crowbar collapse independently into some sort of resonance cascade?
Should we really be looking to make alloys or compounds like Moonium, or Marsium, that really augment the in SITU opportunities?
Shoveling regolith, and or re-creating traditional earth base building materials likely shouldn’t apply?
Question: Is it possible, would it be beneficial to spin up the moon? e.g. Spin the moon clockwise with 1 Rotation/month to have a permanent night- and day-side.
It already spins one rotation per month. This is why one side faces earth always.
You would have slow it's rotation to have zero rotation from the sun's perspective. This permanent day/night side would still have the exact same phases as seen from earth, but we would see all sides of the moon over the course of each month. It wouldn't benefit or help us at all.
I was watching Elysium the other day, and it got me thinking, if there were an extremely large rotating space station or habitat like the one in the film Elysium, with the top side of the ring exposed to space, would the atmosphere remain inside due to its rotation, or is that purely fictional?
@@electronicarchaeology it should yeah, with a manageable ammount of leakage of course
Well, the atmosphere should get pushed out. So you get a denser atmosphere further out and very little air in the middle right? Unless you have enough gravity in the middle.
Here's a question. Why don't we have a pair of satellites at the eath sun L4 and L5?
I think they could off amazing benefits such as: Provide constant communication between earth and mars, act as interferimetors, make a solar system equivalent to GPS, etc...
great video thx
Length 10^16 meters. Mass about 10^16 kg ie 5 x 10^-15 solar masses. Crow bar would collapse into a sphere.
I assumed a long crowbar with a normal crowbar cross section. BUT, if the crow bar is in proportion:
10^16 crowbar length => (10^16)^3 crowbar mass. ie 10^48 kg ie 10^48 / (2*10^30) => 5*10^18 solar masses. THIS WOULD MAKE THE BIGGEST EVER SUPER MASSIVE BLACK HOLE. (I want one)
According to my discarded junk mail, a crowbar 1 light year long with a 1 inch hexagonal cross section would have a billionth the mass of Earth.
*Obviously*, Fraser, to keep metallic hydrogen metallic you have to have it locked in the molecular lattice of dilithium crystals.
Whoa, Star Trek figured it all out
5:47 you should try mauna kea observatory in hawaii
A crowbar that is proportional in design to the one you showed would be limited by it's cross section, and by how many thousands of years you would be willing to wait while it cooled off from being cast.
I doubt the main body could be more than 500 miles in diameter, as internal pressure would cause it to never cool to a solid. I have an antique crowbar 60 inches long and one inch through the body.
Therefore at 60 to 1 your mega-bar would be 30,000 miles long.
It might not be possible to cast a piece so large that would not crack during cooling, And at 1/10 degree per year cooling rate it would take about 25,000 years to cool.
Another consideration is how much iron, carbon, and alloy metals you can access.
You would need about 15 million cubic miles of materials for the project.
That would require the iron core of at least one super-Terrestrial planet.
So you have to have the tech to travel FTL and disassemble and transport planetary masses.
That kind of stuff. Just a thought.
I'm imagining it just appears. I calculated that a crowbar one light-year long would melt down to a sphere of metal about 20 km across, which isn't that big.
Regarding measuring distances across the cosmos, I recommend folks check out the "How Far Away Is It" video playlist on the channel of David Butler here on TH-cam. Its a wonderfully sedate, calming and illuminating multi-part explanation of several key steps in the distance ladder.
Since the moon lacks an atmosphere, how does the heat radiate away on the dark side to go from the extreme highs to the extreme lows?
The answer is contained in this key word within your question: "radiate".
The universe is expanding in all directions, therefore all the light emmitted is being redshifted. What is happening with energy conservation? Redshifted light has energy.
Energy conservation is a myth
Question: They always explain how it's possible that ice persists on a hot planet like mercury by explaining how cold the permanently shadowed regions of craters are. But they never explain how that ice got there to begin with. For sure when the crater was created by an impact event there was no ice there to begin with. So why after a crater is created on mercury does ice somehow manage to migrate to and accumulate in those crater shadows? Nobody ever explains that. Where is that water coming from? They act like the whole mystery is solved just by saying shadows are cold.
I am from Iceland and I do not remember seeing the center or the milky way bands from Iceland. I might be not remembering this correctly.
Iceland is much further north than Vancouver island, so that makes sense.
You still should be able to see parts of the Milky Way. Just not the center Sagittarius A*.
Why did NASA use gold for the golden records to make them last longer? Isn't gold used on earth because it's nonreactive to other elements? There's not much to react to in space, so wouldn't it make more sense to use a very hard material instead?
Here's one for you... Read an article that The American Astronomical Society, among others are calling for a ban on space advertising. I'm all for a ban on that nonsense, but do you think it would pose a real threat? I can't imagine any company advertising something in space to a civilization that rarely looks up. Would CocaCola really spend millions of dollars to advertise something that 99% of people wouldn't even see?
Crowbar = Supermassive Black Hole
The Average crowbar is 48" long and 1.5" thick.
1 lightyear = 9.46 Trillion km.
Our solar system, to the edge of the Oort cloud is only 10 Billion km.
One lightyear is equal to 946 solar systems laying side by side.
Length - That means the Crowbar would be as long as 946 Solar Systems laying in a row.
Every inch of a 48" Crowbar is roughly equal to 19.7 Solar Systems long.
Thickness - So, a crowbar 1 lightyear long, would be as thick as 29.5 Solar Systems laying side by side. (Since the average crowbar is 1.5" thick.)
946 Solar Systems long.
29.5 Solar Systems thick.
Now, fill those dimensions with iron.
I think the Crowbar collapses into a Supermassive Black Hole.
Unless I'm wrong.
Not "exactly" the same apparent size. With Sun or Moon overhead, the distance is shorter than at the horizon by Earth's radius.
Ah, yes nice clarification.
So close, we can't measure the difference though.
@ The relative difference is 1/60 for the Moon, easily measurable. It is 43 ppm for the Sun. Whether that is measurable.depends on the sharpness of the Suns's surface. Because of the immense gravity, the pressure scale height is only 100 km, which is 143 ppm of the solar radius. So the effect is 30 % of the scale height.
@rainaldkoch9093 none of that matters for apparent size difference from when the moon is at the horizon vs overhead.
Also, can't you tag the person you are talking to? 🤣
Instead of largest possible crowbar, can we call it the “reverse planck crowbar”?
How are we able to see the beginning of the universe if the light started traveling millions of years before humanity was ably to look at the stars??
Actually the light started traveling over 15 billion years before humanity. But it’s fifteen billion light years distant from us, so it is just now getting to our eyeballs. When you look out at that distance, you are looking back in time. Those objects no longer exist, for the most part.
To the person asking the crowbar question: Fraser really misunderstood your question, his intuition isn't that good. But I'm on your wavelength.
Here's the correct and INTERESTING answer:
For the maximum physically allowed size pretty bar, let's assume 100 percent solid maximum hardness steel at room temperature just appearing. No worries about compression heating etc. It will reach Max size at the point at which it will deform from gravity getting enough force to squish the steel. The limits for rocks in space bodies before they become rounded is a few hundreds of kilometers. Steel is both softer than most rocks and denser. So let's assume 500km for the diameter of the rod max. The pry bar could be roughly as long as Earth's diameter before it collapses! Much longer if it's hollow.
A Galaxy spanning pry bar would instantly rip itself into billions of implosions! My intuition says that these implosion will lead to the efficient creation of black holes, especially as iron is so atomically stable and produces no heat from fusion to keep matter apart.
Your prybar would start exploding within a few seconds and release more energy than any other cosmic boom ever by a factor of billions. The milky way is utterly blown away, as it weighs only a tiny fraction of the pry bar.
What's left would be an enormous, expanding and pleasantly glowing cloud of heavy element dust, surrounded by an expanding sphere of trillions of black holes of many sizes.
I'd definitely put sunglasses on, and even then don't look at that Galaxy sized pry bar too long. The gravity waves might make you nauseous, take some Dramamine beforehand. So just take a glance, enjoy the show, then walk away and let someone else clean up the mess..
I calculated after that a crowbar 1 light year long would only make a sphere a few dozen km across. Not big enough for hydrostatic equilibrium, but it all depends on the specifics of the scenario
"I'll get it!" *takes out comically large broom*
One thing though, there is no reason for anywhere in the middle of the crowbar to collapse, as it's feeling approximately the same gravitational force from both sides. This only breaks down at the end of the crowbar, and even then the gravitational force is almost negligible. For a linear density of 30g/cm of length, considering the force on the final centimeter of crowbar exerted by the entire galaxy wide length, I get a force in the nano-newton range. The total mass of the crowbar may be quite high but it's also ridiculously spread out and 1/r^2 diminishes very rapidly!
Osiris Rex, anything new?
Has anyone had the chance to read the book Mercy of the Gods? From the creators of the Expanse I believe
Per Perplexity AI, "While empty space isn't "hot" or "cold" in a classical sense, its entropy can be associated with a temperature via quantum and thermodynamic principles. The relationship between entropy (S) and temperature (T) in thermodynamics can be expressed as: Delta S = Q / T"
Cosmic Microwave Background (CMB) temperature is ~2.7 K
6:58 with metallic hydrogen we could build antigravity vehicles, floating away lighter than air, it would be genious, like a balloon, just more rigid
Just keep your metallic hydrogen vehicle away from any oxygen (otherwise, 💥). Oh, wait....
@Spherical_Cow - I just paint it, problem solved,
think how it would be to float around no longer hold back by the gravity
Nonsense
@WilliamAArnett - only a suggestion to solve the gravity issue
Presumably if the crowbar was thick enough and dense enough at a light year in length, it would collapse into a black hole?
A 2 cm diameter crowbar 1 light year long, is not enough mass to make a blackhole.
@ Ok but why 2cm?
@@wanderingfool6312 that is approximately the diameter of a crowbar.
@ Not if it is scaled up to 1 lyr in length, I thought that’s what the idea was?
@wanderingfool6312 not scaled up, just lengthened to 1 light year. It wouldn't be a crowbar anymore if it was the big around. Probably wouldn't even be classified as a bar any longer either.
The hemisphere of lesser interest...
There ARE in fact, STUPID questions.
WOW.
Do not look at your pinky with a straight arm after saying you voted for Trump😅😅😅
And for the love of god, don't palm your chest first.
th-cam.com/video/aMrsKgJPnxA/w-d-xo.html Aha!)))
Who clicked because of Gordon?
Gordon Brown?
Flash Gordon?
Gordon Ramsey?
Bullshit,i am out.
Don't let the door hit you on your way out 🤣
The science community will recover from your departure somehow.
I will call you later okay ❤