4 ms·

Mapping the Solar System

81 points by betolink 5y ago

ncmncm 5y ago
I like to see a stat: orbital velocity at minimum altitude. Uranus and Neptune have similar surface (OK, cloud-top) gravity to Earth's, but ~2x delta-V to orbit. And Saturn, but 3x. We will need some sort of skyhook apparatus to get back out of the atmosphere, if we visit. Besides fission or fusion power, because dark.
- KineticLensman 5y ago
  And escape velocity. I believe I'm right in saying that we don't have any proven technology that could leave Jupiter after having 'landed'.
  - ClumsyPilot 5y ago
    There are fozens of moons avaliable for gravity assists and refuels, those are definitely reachable and leave-able, although i dont have a totally clear image of where they are in the gravity well
    - KineticLensman 5y ago
      Gravity assists primarily work when you are inbound at speed to the body you'll slingshot around, not struggling to reach it's altitude from beneath (i.e. you are lower in Jupiter's gravity well than the moon, because you are launching into space from a stationary start).
  - ncmncm 5y ago
    Escape velocity can be achieved after refueling from a depot in low orbit, if you can get there. That's just operations, not fundamental physics. I wonder why people talking about skyhooks never talk about ring-shaped ones. It seems like the timing demands on users would be radically looser. I think the structural stress problems would be a lot easier, too, maybe enough to make up for the 22/7 size ratio.
once_inc 5y ago
for those interested: there's a larger resolution picture on her blog.
- pmontra 5y ago
  And a lot more, wonderful site https://eleanorlutz.com/ https://eleanorlutz.com/
  - JKCalhoun 5y ago
    I got lost going down the rabbit-hole that is her GitHub. Some amazing and creative illustrations. Art + Engineering is my fave. Wow, her blog. I hope she's making money selling the posters. I want several of them — worry that the quality from RedBubble will be crap. Maybe I'll pull the trigger and pick up one and see how it looks. She seriously ought to partner with a company that could do her art justice. I picked up a poster Map of the Moon recently (an updated version of the National Geographic classic from 50 years ago) and it was very nicely printed, laminated....
dotancohen 5y ago
There seems to be a huge difference in the quantity of asteroids below 1 AU, and those above. Almost as if something changes at exactly 1 AU. Even though Earth is special for harbouring life, is the location of Earth really that significant from the perspective of how many objects could have smaller orbits? The "goldilocks zone" shouldn't determine the density of objects in any particular orbit. Or is the issue that it is easier to detect asteroids further away than it is to detect asteroids closer to the sun?
- jcims 5y ago
  Note the scale, it appears to be logarithmic, so the effect is a bit exaggerated. The band of asteroids between Mars and Jupiter probably would have coalesced into a planet but Jupiter kept perturbing their orbits enough to prevent that from happening. Great image!
- tomr_stargazer 5y ago
  There are a few observational biases at play here: * objects closer to the Sun are intrinsically brighter (as they are simply reflecting sunlight; their intrinsic brightness follows an inverse-square law[0]) * objects closer to the Earth are easier to see (for a similar reason: the amount of light that reaches us depends on those objects' distance from our telescopes; the combined effects of the above two points means that the observed brightness of asteroids approximately follows an inverse-fourth-power law far from the Earth) * objects interior to the Earth's orbit are hard to see because the Sun is in the way (it's usually daytime when these objects are "up"). So, even if there was a uniform distribution of asteroids as a function of orbital separation from the Sun, an observed overdensity of objects should be apparent just outside the Earth's orbit. [0] https://en.wikipedia.org/wiki/Inverse-square_law https://en.wikipedia.org/wiki/Inverse-square_law See also sibling comment from jcims noting the logarithmic scaling, which would compress large separations and expand small separations.
  - Symmetry 5y ago
    Those biases exist but don't explain why we see more asteroids between Jupiter and Mars than between Mars and Earth. There really is a much larger concentration of asteroids in the asteroid belt.

81 points by betolink 5y ago

I like to see a stat: orbital velocity at minimum altitude. Uranus and Neptune have similar surface (OK, cloud-top) gravity to Earth's, but ~2x delta-V to orbit. And Saturn, but 3x. We will need some sort of skyhook apparatus to get back out of the atmosphere, if we visit. Besides fission or fusion power, because dark.

KineticLensman 5y ago
And escape velocity. I believe I'm right in saying that we don't have any proven technology that could leave Jupiter after having 'landed'.
- ClumsyPilot 5y ago
  There are fozens of moons avaliable for gravity assists and refuels, those are definitely reachable and leave-able, although i dont have a totally clear image of where they are in the gravity well
  - KineticLensman 5y ago
    Gravity assists primarily work when you are inbound at speed to the body you'll slingshot around, not struggling to reach it's altitude from beneath (i.e. you are lower in Jupiter's gravity well than the moon, because you are launching into space from a stationary start).
- ncmncm 5y ago
  Escape velocity can be achieved after refueling from a depot in low orbit, if you can get there. That's just operations, not fundamental physics. I wonder why people talking about skyhooks never talk about ring-shaped ones. It seems like the timing demands on users would be radically looser. I think the structural stress problems would be a lot easier, too, maybe enough to make up for the 22/7 size ratio.

once_inc 5y ago

for those interested: there's a larger resolution picture on her blog.

pmontra 5y ago
And a lot more, wonderful site https://eleanorlutz.com/ https://eleanorlutz.com/
- JKCalhoun 5y ago
  I got lost going down the rabbit-hole that is her GitHub. Some amazing and creative illustrations. Art + Engineering is my fave. Wow, her blog. I hope she's making money selling the posters. I want several of them — worry that the quality from RedBubble will be crap. Maybe I'll pull the trigger and pick up one and see how it looks. She seriously ought to partner with a company that could do her art justice. I picked up a poster Map of the Moon recently (an updated version of the National Geographic classic from 50 years ago) and it was very nicely printed, laminated....

dotancohen 5y ago

There seems to be a huge difference in the quantity of asteroids below 1 AU, and those above. Almost as if something changes at exactly 1 AU. Even though Earth is special for harbouring life, is the location of Earth really that significant from the perspective of how many objects could have smaller orbits? The "goldilocks zone" shouldn't determine the density of objects in any particular orbit. Or is the issue that it is easier to detect asteroids further away than it is to detect asteroids closer to the sun?

jcims 5y ago
Note the scale, it appears to be logarithmic, so the effect is a bit exaggerated. The band of asteroids between Mars and Jupiter probably would have coalesced into a planet but Jupiter kept perturbing their orbits enough to prevent that from happening. Great image!
tomr_stargazer 5y ago
There are a few observational biases at play here: * objects closer to the Sun are intrinsically brighter (as they are simply reflecting sunlight; their intrinsic brightness follows an inverse-square law[0]) * objects closer to the Earth are easier to see (for a similar reason: the amount of light that reaches us depends on those objects' distance from our telescopes; the combined effects of the above two points means that the observed brightness of asteroids approximately follows an inverse-fourth-power law far from the Earth) * objects interior to the Earth's orbit are hard to see because the Sun is in the way (it's usually daytime when these objects are "up"). So, even if there was a uniform distribution of asteroids as a function of orbital separation from the Sun, an observed overdensity of objects should be apparent just outside the Earth's orbit. [0] https://en.wikipedia.org/wiki/Inverse-square_law https://en.wikipedia.org/wiki/Inverse-square_law See also sibling comment from jcims noting the logarithmic scaling, which would compress large separations and expand small separations.
- Symmetry 5y ago
  Those biases exist but don't explain why we see more asteroids between Jupiter and Mars than between Mars and Earth. There really is a much larger concentration of asteroids in the asteroid belt.