Next stop: Timeshares on Uranus


All right, all you far-out space nuts: Here's a visual and riddle. I got these images from the indispensable Ernest Hancock. I have no idea where he got them:

Now riddle me this: Is the sun really this small? I'm surprised that you can see Earth, let alone fleet Mercury, in the sun-scale picture. Shouldn't there be a legend in the corner that says something in the neighborhood of, Sun is shown at 1/500th scale?

Because if this really is the correct proportion, I say we could build a Dyson Sphere, or at least a complete Ringworld, in no time flat.

Update: Jeff P outgrooves these pictures by hipping us to the The Maine Solar System Model, built by the People of Aroostook County, Maine. Grok relative scale and distance while enjoying beautiful Pine Tree State views as you drive 40 miles on Highway 1 from Presque Isle to Houlton.


NEXT: Attn, DC Reasonoids: See the Silent Sea Hawk, July 12

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  1. A Dyson sphere? We can’t even finish the big dig in Boston!

  2. Yes, it really is that size, relative to the planets. I remember learning long ago in some Astronomy book (yes, I’m an astronomy nerd) that the Sun was about 11 times the diameter of Jupiter, if I’m not mistaken.

  3. That proportion seems about right. The Earth is 7909 miles in diameter. The Sun is 861,800 miles in diameter. Therefore, around 109 Earths can be strung horizontally across the middle of the Sun.

    I feel like Cliff Claven now.

  4. As a supplementary remark, it’s not the relative size so much as the vast distances seperating the objects in our solar system that is the primary issue.

  5. The Sun is about 835,000 miles in diameter and Earth is about 8,000 miles in diameter, so the pictures seem to be correct.

  6. Put your money on Matrioshka Brains.

  7. A million Earths could fit inside the Sun.

  8. What happened to the future where we were supposed to be living in sunny, efficient villas on some groovy off-world colony? I want that future instead of the one we got, and I’m ready to play hardball to get it. I see a massive false-advertising class action suit on the horizon. Doesn’t Arthur C. Clarke owe everybody for the lousy year the actual 2001 turned out to be? And the authors of You Will Go To the Moon-they made that promise to me!

  9. The future ain’t what it used to be.

  10. To put the effort needed for a Type II Dyson culture in perspective, drive the 40 mile scale model of the solar system in Maine:

  11. A million Earths could fit inside the Sun.

    The sun is far away…

    About 93,000,000 miles away
    And that’s why it looks so small

    Jennifer, is that a Rhythm Corps reference?

  12. Jupiter is a failed star, essentially what happens when you don’t have enough mass to sustain fusion. So the proportion of it to the Sun is about what you’d expect.

    Next time you’re in DC, go in front of the Air and Space museum on the mall for their scale model. And be prepared to do some walking.

    Actually, the biggest problem with a Ringworld or Dyson Sphere is, where the hell do you get that much material? If one whole Earth takes 1/117th of the diameter of the Sun, how are you going to get a ring of that stuff at a suitable distance not to be fried?

  13. They have a scale solar system model at Arecibo as well. Sol is about the size of a basketball and Pluto is a few miles off in the surrounding mountains.

  14. Could be, M; I’m not familiar with Rhythm Corps. I just figured it was a natural response to Tim’s comment.

  15. it’s They Might Be Giants

  16. And I still don’t have a flying car.

  17. My reference was of course TMBG (what else). There’s a TMBG reference for many, many occasions since they have hundred’s of songs.

    Rhythm Corps – The Future’s Not What It Used to Be
    ?1991 Sony Music Entertainment Inc.

  18. er…”hundreds”, not “hundred’s”. I can’t believe that’s rubbed off on me. Embarrassing.

  19. It’s not the size that matters, it’s the motion of the ocean.

    Incidentally I was at the beach last weekend and our oceans are rockin’. The sun couldn’t hold a, err, candle to that…!

  20. Haven’t the terrorists had flying carpet technology for centuries? What oil company conspiracy prevents us from reaping the benefits of magic flight and propulsion?

  21. Here are two comparisons of our sun with bigger stars.

  22. The reason you can’t build a ringworld is that the tension would exceed the nuclear strong force if you built it 2 AU in diameter, and spun it fast enough to give you 1G of acceleration. Larry Niven avoided this problem by inventing a substance called “scrith”, which uses magical alien technology to provide that kind of tensile strength.


  23. The sun is a mass of incandescent gas
    A gigantic nuclear furnace.

    The proportions are right. Tim’s confusion likely stems from two things.

    First is that he’s probably only looking at one dimension. He sees the sun is only about one hundred times wider than the earth, and therefore thinks it’s only one hundred times as big. But in three dimensions the sun is 100^3 or 1,000,000 times as big.

    Second, these pictures show the sun and planets grouped together. The solar system is really really spread out. Note that in Aroostook County’s model, a 5.5″ diameter earth is a full mile from the sun.

    Now, bonus question. If the sun really is a mass of incandescent gas, why does it have a discernable edge? Shouldn’t it just get dimmer as it gets thinner and thinner out into space?

  24. Actually I’ve heard it may have a solid surface underneath its thin atmosphere. Why would there be sunquakes in a mass of incandescent gas? Helioseismologists wouldn’t have any work.

  25. Warren,
    After starring straight into a ligh blub for 15 mins this is as good as I can come up with…
    What we see is the light emitted from the nuclear reactions taking place on or near the Sun’s surface. Thus, the volume of the Sun has little to no effect on how we perceive it, since the reaction is taking place near the surface. Somewhat different explanation: we’re not looking through a cloud of gas to some light source, we’re look at the light source

  26. Heh heh ….. heh heh…..he said “uranus” …heh heh…..

  27. Gas density should be related linearly to depth though I fear that may oversiplify things. A finite amount of mass aggregated into a sphere should have a rather well-defined edge. The density is not asymptotic so a finite amount of matter cannot fill space to ever greater distances.

    I am doing my best to describe what I see in my mind but I don’t know I’m making any sense.


    The fusion is theorized to occur in the core where temperature and density are high enough to squeeze the various (mostly hydrogen) nuclei close enough together to fuse.

  28. Why is Pluto shown? It hasnt even been determined to be a planet.

    The IAU plans to publish an official definition of “planet” in early September 2006, ruling on whether to call Pluto a planet or a Kuiper Belt Object (KBO).

  29. What happened to the future where we were supposed to be living in sunny, efficient villas on some groovy off-world colony?

    First of all, we found out how much space travel, even within our own solar system, really costs.

    Secondly, Relativity and that whole “speed of light” thing is a bitch.

    Yeah, I know. It sucks. When I was a kid I was hoping for Lunar vacation packages by 2001 too.

  30. OK, what if we settle for a Dyson Swarm, and we leave the gas giants outside? Does it get more feasible then?

  31. Tim,
    Not very much, no. I mean not if you want to put up enough to be noticeable.

    Try to grasp the size here. That dot at the end of the red arrow (the one labeled Earth) that represents The Whole Goddamned World! Everywhere you’ve ever been, and will ever be, and everywhere everyone you have ever met has ever been, wouldn’t cover half that dot. If you’ve ever flown from NY to LA and looked out the window the whole way, you didn’t see as much as the period at the end of this sentence.

  32. I like how neatly earth fits into jupiters big storm….and that it is older then jesus

  33. Doesn’t Arthur C. Clarke owe everybody for the lousy year the actual 2001 turned out to be?

    dude in Clarkes 2001 we were still in a cold war and by 2010 come close to nuclear anihalation…i like our 2001 where only New York is slated to being nuked.

  34. The future ain’t what it used to be. – Yogi Berra

    Usually, when someone says something clever, a great philosopher got there first.

    I know that Terra has a 25k mile circumference, `cause it was a Flash “fact”.


  35. The sun is exactly wider than the Moon by the same factor as it is further away, so that’s why in a total solar eclipse the Moon’s disk exactly fits over the Sun.

    Also, if the Earth was reduced to the size of a billiard ball, it would be smoother than a billiard ball!

  36. talking about ringworlds i think you should look at Iain m banks orbitals in his culture books or if you like video games then try Halo…smaller and if you want day/night cyles far easier then ringworlds big black rectangles in the sky.

  37. Hit&Run deserves yet another award. It should be recognized as having the best science topics in a non-science specific blog. Kudos to Tim and the rest. This place is just f***ing stellar. Ok I’m staring to get a little vaklempt. Talk amongst yourselves…

  38. This place is just f***ing stellar.

    Pun not intended.

  39. A Dyson sphere? We can’t even finish the big dig in Boston!

    Cuz the government is doing the big dig.

  40. Do nerds turn into libertarians, or does libertarianism turn people into nerds?


  41. Definitely the first, if either.

  42. It depends on which you read first: The Moon Is A Harsh Mistress or Atlas Shrugged.


  43. I’m currently reading Accelerando by Charles Stross, which tackles what steps would be need to prepare or change an economy in order to “take it with us” as become a Type II culture.

  44. [Insert “Size Matters” Joke Here]

  45. So here’s the plan. In the same speech where Bush eliminates gasoline, he can expand our vision by scrapping the Mars mission and a international cooperative to build a Dyson Sphere!

  46. It depends on which you read first…

    Or whether you listened to Rush as a youngster. Way back in ’76, they talked about the Solar Federation on an album with a dedication to Ayn Rand, and as late as ’02 you have an ode to an astronomical event:


    On certain nights
    When the angles are right
    And the moon is a slender crescent

    It’s circle shows
    In a ghostly glow
    Of earthly luminescence

  47. Just to start the data collection ball rolling, I was a nerd first (and still am) and then found libertarianism.

    Maybe that’s why there are so few libertarian women!

  48. Just to start the data collection ball rolling, I was a nerd first (and still am) and then found libertarianism. Maybe that’s why there are so few libertarian women!

    I’ll have you know that I was a little fact-spouting astronomy geek before I could even pronounce libertarianism.

  49. In order to have enough material to build a Dyson sphere, I’m pretty sure we’d need to have practical transmutation, in order to work with the gas giants.

    Sure hope we come up with that hyperdrive instead. Much less work. . .if it’s possible, that is.

  50. Just to clarify a few things about the Sun:

    There isn’t a sharp boundary at the Sun’s surface — the density falls off exponentially, but we see a fairly well-defined layer called the photosphere, not because the Sun stops there, but because that’s how far down into the Sun it’s possible to see. (Or rather, that’s the depth from which visible photons start having a real chance of escaping without recapture.) The Sun’s outer atmosphere, or corona, extends well beyond the earth — essentially, we live inside the Sun’s atmosphere. But because the density fall-off is so fast, the photosphere is a relatively thin layer, and we see the Sun as having a “surface”, when in fact the major change at that point is in transparency.

    As MarkV pointed out, the light we see from the Sun is most definitely NOT generated at the surface, where the temperature is ~6000K, totally inadequate for fusion. The surface of the Sun glows merely because it is hot — the energy to KEEP it hot is generated in the core, the central 10% or so of the Sun where temperatures exceed 10,000,000K and the pressure is sufficient to sustain hydrogen fusion. And those poor photons can take tens of thousands of years to get to the surface through all that material!

    And the Sun most definitely doesn’t have a solid surface. Helioseismologists will tell you that the Sun only supports the waves you would expect from a gas (plasma, really). It can be compressed and rarefied, it vibrates up and down in response to gravity and pressure, but there’s no indication that any of it behaves as a solid. It’s simply too hot for that, given the materials it’s made of. But helioseismology gives us a way to measure the density and structure of the inside of the Sun (at least until we get the hang of neutrino astronomy!)

  51. joshua corning & Jeff P,

    Iain M. Banks’ notes on The Culture:

    Gives a bit more detail on Orbitals and his take on what it takes to become a spacefaring species.

  52. Oh, and to Russ R,

    I was definitely a nerd first. I read The Moon is a Harsh Mistress first, but the ideas didn’t click until I read Ain’t Nobody’s Business If You Do! by Peter McWilliams.

  53. AstoPaul wins the prize.
    That was great, much better than I’d have done.

  54. In other words, if you want to be the first man to land on the sun, definitely do it at night.

  55. Astro Paul said: Just to clarify a few things about the Sun…

    You read my mind. That’s what I meant to say! 😉

  56. Why does the sun have a (relatively) sharply defined surface? I am gonna hazard a guess here– to a first approximation, it’s because the visible part of the spectrum is so narrow. The photons that come out of the core of the sun collide inelastically (the visible photon you see started out as some highe energy gamma ray). They lose a little energy each collision. and eventually get down to visible light energies and then we see them. Photons that make more collisions after they leave the photosphere are predominantly IR (or less).

    Although some visible photons may originate from below the photosphere and some from above it, the majority originate from within it since, and the photosphere is so thin because, as noted above, the range of wavelengths that are visible is tiny in comparison to the breadth of wavelengths possible from the sun.

    This is all a guess in the sense that I didn’t have time to go look it up, but I like it. It sounds like it would be nice if it were true. It would also make sense that wherever the photon energies were such that they were mostly grouped in the visible, there also would the temperature of any gas in equilibrium with them be one characterized by a temperature of a visibly glowing object.

    The flaw in this idea is that it does not by itself explain why different stars have different brightness temperatures. Perhaps how rapidly the gas density changes near a star’s “surface” dictates how deeply into the photosphere we can see. In any case, I advance this idea only as a sort of zeroth order approximation. Does this make sense?

  57. I received the email with the sun and planets. It also had some Giant Stars to compare to the Sun. They made the Sun look very small in comparison.

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