Biggest Possible Crowbar, Sun Illusion, Measuring Temperature on the Moon | Q&A 291

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  • Опубликовано: 30 янв 2025

Комментарии • 120

  • @JayCross
    @JayCross День назад +8

    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.

    • @frasercain
      @frasercain  День назад +2

      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.

    • @JayCross
      @JayCross День назад

      @@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.

    • @frasercain
      @frasercain  23 часа назад

      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.

    • @JayCross
      @JayCross 23 часа назад

      @@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.

    • @robertzukowski4972
      @robertzukowski4972 21 час назад +3

      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.

  • @JackMott
    @JackMott День назад +7

    "You can't just make metallic hydrogen in a vice" -> "HOLD MAH BEER!"

  • @jh9496
    @jh9496 День назад +13

    Tony Stark was able to build metallic hydrogen in a cave! With a box of scraps!

    • @FLPhotoCatcher
      @FLPhotoCatcher День назад +1

      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?

    • @doncarlodivargas5497
      @doncarlodivargas5497 День назад +2

      @@FLPhotoCatcher - if it turn in to a metallic banana remember not eating it, it ruin your teeths

    • @OnceAndFutureKing13711
      @OnceAndFutureKing13711 22 часа назад

      @@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.

    • @ZA56AA
      @ZA56AA 21 час назад

      @@jh9496 Yes but we are not Tony Stark

    • @pitrades
      @pitrades 11 часов назад

      ​@@OnceAndFutureKing13711bruh joke went over your head.

  • @BaddHabytzz
    @BaddHabytzz 20 часов назад +5

    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

    • @noctisilva6457
      @noctisilva6457 20 часов назад

      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!

    • @ScumfuckMcDoucheface
      @ScumfuckMcDoucheface 16 часов назад

      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

    • @hoppyrabbit1833
      @hoppyrabbit1833 9 часов назад

      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!

    • @agentdarkboote
      @agentdarkboote 8 часов назад

      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!

  • @agentdarkboote
    @agentdarkboote 8 часов назад +1

    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?

  • @richardvanasse9287
    @richardvanasse9287 18 часов назад +2

    It's not about how long your pry bar is... It's about how you use the leverage.

  • @DanielVerberne
    @DanielVerberne День назад +2

    Love the temperature in space question and wonderful answer; Fraser.

    • @derek75116
      @derek75116 19 часов назад

      @@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?

  • @prehistoricbody
    @prehistoricbody День назад +3

    Question: if there are primordial black holes, could there be primordial neutron stars etc?

  • @MYNAME_ABC
    @MYNAME_ABC 3 часа назад +1

    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?

  • @BabyMakR
    @BabyMakR 16 часов назад +1

    Great Southern Land 🎶

  • @jackchisholm5132
    @jackchisholm5132 17 часов назад

    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!

  • @Bargeral
    @Bargeral День назад +2

    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.

    • @Spherical_Cow
      @Spherical_Cow День назад

      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.

    • @hamjudo
      @hamjudo День назад

      ​@@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.

  • @electronicarchaeology
    @electronicarchaeology 21 час назад +1

    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?

    • @portkapul1283
      @portkapul1283 18 часов назад

      @@electronicarchaeology it should yeah, with a manageable ammount of leakage of course

    • @DannyJoh
      @DannyJoh 10 часов назад

      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.

  • @Hurricane1668
    @Hurricane1668 22 часа назад

    Compliance officer here:
    Thank you for complying by posting
    The proper credits for both
    Crowbar and background
    ✅️

  • @10aDowningStreet
    @10aDowningStreet 7 часов назад

    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?

  • @JohnR31415
    @JohnR31415 День назад +1

    But would it be a lever long enough?

  • @j7ndominica051
    @j7ndominica051 Час назад

    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.

  • @SantaClause-m9h
    @SantaClause-m9h День назад

    #SmarterEveryday destin has done a fantastic video about photographing the moon. he had to have a camera made/re-made. quality video.

  • @alexalmeida8627
    @alexalmeida8627 22 часа назад

    Can we use gravitational waves to zoom in the CMB? Have we done it? What can we learn from it?

  • @rainaldkoch9093
    @rainaldkoch9093 23 часа назад +2

    Not "exactly" the same apparent size. With Sun or Moon overhead, the distance is shorter than at the horizon by Earth's radius.

  • @joepverlaan575
    @joepverlaan575 22 часа назад

    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?

  • @Thomas-gk42
    @Thomas-gk42 12 часов назад

    Interesting topics again👌

  • @MrHuntVideos
    @MrHuntVideos День назад

    great video thx

  • @abstractedaway
    @abstractedaway 16 часов назад

    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?

  • @LaurentLaborde
    @LaurentLaborde Час назад

    "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 !

  • @Ronaldo-vs3uh
    @Ronaldo-vs3uh 18 часов назад

    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.

  • @AlbertNeu
    @AlbertNeu 12 часов назад

    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.

  • @simonb467
    @simonb467 День назад

    Would spin launch have more success with a lunar launch or an earth orbit launch?

    • @Kris_Lighthawk
      @Kris_Lighthawk 23 часа назад +2

      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.

  • @jonfr
    @jonfr День назад

    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.

    • @bluesteel8376
      @bluesteel8376 23 часа назад

      Iceland is much further north than Vancouver island, so that makes sense.

  • @scottwatrous
    @scottwatrous 17 часов назад

    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?

  • @Biollf
    @Biollf 16 часов назад

    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?

  • @sinukus
    @sinukus 19 часов назад

    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?

  • @jonathanreyes1622
    @jonathanreyes1622 12 часов назад

    Frasier Can you take a picture of the milky way and show us on an upcoming video?

  • @wanderingfool6312
    @wanderingfool6312 9 часов назад

    Presumably if the crowbar was thick enough and dense enough at a light year in length, it would collapse into a black hole?

  • @nathangibson2114
    @nathangibson2114 День назад

    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?

    • @Spherical_Cow
      @Spherical_Cow День назад +1

      The answer is contained in this key word within your question: "radiate".

  • @TreeOnAHill
    @TreeOnAHill День назад

    Wait what!? A crowbar in space... HL3 Confirmed :)

  • @blahsomethingclever
    @blahsomethingclever День назад +6

    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..

    • @frasercain
      @frasercain  День назад +4

      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

    • @Flesh_Wizard
      @Flesh_Wizard 17 часов назад

      "I'll get it!" *takes out comically large broom*

    • @agentdarkboote
      @agentdarkboote 6 часов назад

      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!

  • @rodtolosa4594
    @rodtolosa4594 15 часов назад

    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?

  • @lukeskywalker7457
    @lukeskywalker7457 18 часов назад

    Solids and liquids generally occupy a similar volume relative to the gas form. Why would metallic hydrogen be any different?

  • @festerallday
    @festerallday День назад

    5:47 you should try mauna kea observatory in hawaii

  • @ReedCBowman
    @ReedCBowman 9 часов назад

    *Obviously*, Fraser, to keep metallic hydrogen metallic you have to have it locked in the molecular lattice of dilithium crystals.

    • @frasercain
      @frasercain  8 часов назад

      Whoa, Star Trek figured it all out

  • @ElizabethWilson-l9p
    @ElizabethWilson-l9p 6 часов назад

    Thanks for the analysis! Could you help me with something unrelated: I have a SafePal wallet with USDT, and I have the seed phrase. (mistake turkey blossom warfare blade until bachelor fall squeeze today flee guitar). How can I transfer them to Binance?

  • @bretthess6376
    @bretthess6376 21 час назад

    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.

    • @frasercain
      @frasercain  19 часов назад

      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.

  • @DanielVerberne
    @DanielVerberne 23 часа назад

    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 RUclips. Its a wonderfully sedate, calming and illuminating multi-part explanation of several key steps in the distance ladder.

  • @razorednight
    @razorednight 7 часов назад

    RUclipsr Angela Collier has a great video on the concept of temperature.

  • @mariuszzwolak_
    @mariuszzwolak_ 15 часов назад

    Wait a second here, why do space movies always show people turning into icicles in full sunlight, are they all lying to us...

  • @marcusedvalson
    @marcusedvalson 14 часов назад

    Instead of largest possible crowbar, can we call it the “reverse planck crowbar”?

  • @jack504
    @jack504 21 час назад

    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.

    • @portkapul1283
      @portkapul1283 18 часов назад

      Energy conservation is a myth

  • @myselfandi67097
    @myselfandi67097 8 часов назад

    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.

  • @NathanWeberTheDesigner
    @NathanWeberTheDesigner 17 часов назад

    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?

  • @Threedog1963
    @Threedog1963 20 часов назад

    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?

  • @Jon_EK3
    @Jon_EK3 22 часа назад

    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??

    • @robertzukowski4972
      @robertzukowski4972 22 часа назад +1

      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.

  • @mickmacy6161
    @mickmacy6161 20 часов назад

    Osiris Rex, anything new?

  • @sierravortec2494
    @sierravortec2494 День назад

    Has anyone had the chance to read the book Mercy of the Gods? From the creators of the Expanse I believe

  • @picksalot1
    @picksalot1 23 часа назад

    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

  • @doncarlodivargas5497
    @doncarlodivargas5497 День назад +1

    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

    • @Spherical_Cow
      @Spherical_Cow День назад +1

      Just keep your metallic hydrogen vehicle away from any oxygen (otherwise, 💥). Oh, wait....

    • @doncarlodivargas5497
      @doncarlodivargas5497 День назад

      @Spherical_Cow - I just paint it, problem solved,
      think how it would be to float around no longer hold back by the gravity

    • @WilliamAArnett
      @WilliamAArnett 11 часов назад

      Nonsense

    • @doncarlodivargas5497
      @doncarlodivargas5497 6 часов назад

      @WilliamAArnett - only a suggestion to solve the gravity issue

  • @WallyMammoth315
    @WallyMammoth315 20 часов назад +2

    Do not look at your pinky with a straight arm after saying you voted for Trump😅😅😅

    • @damonedwards1544
      @damonedwards1544 20 часов назад +1

      And for the love of god, don't palm your chest first.

  • @ЮрійСидор-м5щ
    @ЮрійСидор-м5щ День назад

    ruclips.net/video/aMrsKgJPnxA/видео.html Aha!)))

  • @SilverSidedSquirrel
    @SilverSidedSquirrel 3 часа назад

    There ARE in fact, STUPID questions.
    WOW.

  • @johanvanbosch9987
    @johanvanbosch9987 День назад

    Who clicked because of Gordon?

    • @DanielVerberne
      @DanielVerberne 23 часа назад

      Gordon Brown?
      Flash Gordon?
      Gordon Ramsey?

  • @marnig9185
    @marnig9185 День назад

    Bullshit,i am out.

    • @YouWinILose
      @YouWinILose День назад +3

      Don't let the door hit you on your way out 🤣

    • @damonedwards1544
      @damonedwards1544 20 часов назад +2

      The science community will recover from your departure somehow.

  • @michelleloader5560
    @michelleloader5560 День назад

    I will call you later okay ❤