TIL about Kirkwood gaps. I knew about Jupiter leading to Hilda and Trojan groupings, but my understanding of the main belt was more in line with a representation like this one from Wikipedia[1]. However, this imaging shows a clear gap and a quick search led me to learn about Kirkwood gaps. Is there a specific reason why the gap is more evident in this imaging rather than the above one from Wikipedia?
You should not be able to see the Kirkwood gaps if the simulation is accurate; the Wikipedia image is more realistic.
The "gap" only applies to the semi-major axis (which is proportional to the 3/2th power of the period); since most asteroids are somewhat eccentric (and since semi-major axis is relative to the center but orbits are based on a focus, which "moves" rapidly as the circle deforms) there are always asteroids crossing the "gap" between perihelion (far short of the semi-minor axis, even) and aphelion (far beyond the semi-major axis).
I'm too lazy to do the math, but based on planets with similar eccentricity, most asteroids are between 10% and 25% farther at aphelion than at perihelion (or, often between 0.25AU and 0.75AU farther), which easily crosses any single gap, and almost always multiple gaps.
I suspect the gap is at least 50% rendering artifact, but all 1.4M asteroids are plotted as (small) fraction of its orbital ellipse, so the density distribution is reflective of the real data (more specifically, orbit types)
If I understand both the code and o11c's comment correctly, it sounds like the difference is less rendering artifact rather than what is being rendered. This code is rendering the asteroids based off their semi-major axis, but Wikipedia appears to be rendering their actual positions at a specific moment in time with the asteroids all at various points in their eccentric orbit.
Care to expand on that? Wikipedia image has the Greeks ahead of Jupiter and the Trojans behind Jupiter. Doesn't that clearly show it is an image of a moment in time? And the only attributes of an asteroid this code[1] seems to use are the eccentricity, semi-major axis, and perihelion. Although I'm no expert in either Python or astrophysics so I may be missing something.
The code draws full orbit ellipse if selected to do so, but the original picture was rendered using a different mode, where just a small slice of the orbit arc is rendered, pretty much showing an instantaneous position of asteroid.
Now, I am pretty sure actual positions are not correct relative to each other (it is the same position on ellipse arc, should be actual position of the asteroid) but MPC file doesn't provide this information - you need ephemeris from here:
https://www.minorplanetcenter.net/iau/MPEph/MPEph.html
After all, it is mostly a data visualization demo (although I tried to be precise with scale too)
>Now, I am pretty sure actual positions are not correct relative to each other (it is the same position on ellipse arc
That sounds to me just like a rephrasing of what I originally said. The locations in the Wikipedia image are correct relative to each other (because it is representing a moment in time) while the locations from the code are not correct relative to each other and are instead "the same position on ellipse arc" (although maybe I was wrong with my assumption that the "same position" was at the semi-major axis).
Lol, I thought our confusion was over astrophysics and not English. The gaps are a real physical phenomenon that may or may not be visible depending on rendering decisions. I wouldn't consider them a "rendering artifact" as I take that to imply the artifact was artificially created by the rendering. Either way, thanks for answering my questions!
> A Kirkwood gap is a gap or dip in the distribution of the semi-major axes (or equivalently of the orbital periods) of the orbits of main-belt asteroids. They correspond to the locations of orbital resonances with Jupiter.
(Similarly, shouldn't it be possible to infer photon phase without causing wave state collapse?)
I have recently managed to open source some of our tools which we use on the NEO Surveyor mission to simulate all of the asteroids. However my code lacks any real sort of visualizations:
Is the lack of asteroids between the Earth and Sun an artifact of our methods of detection? I'd imagine looking outward where light is shining on a surface would be easier to detect stuff than looking inward towards the sun at such a close distance.
Not entirely, but in part! You can see the effect in this animation of asteroid discoveries over time, where the discoveries are concentrated in bursts facing directly away from Earth, or directly parallel to its orbit.
No, they're much further apart than that. Consider that the total number of asteroids is only 7 digits (i.e. not even ten million) and they are spread out across the asteroid belt that is larger than Earth's orbit.
Is there any good way to plot multiple asteroids while maintaining their relative size ie. handling scaling correctly?
The problem with plotting asteroids is that the "pixel" representing an asteroid is a hugely larger chunk of space relative to the actual size of the asteroid itself.
This gives a false feel of density that the asteroid belts simply don't have.
> Is there any good way to plot multiple asteroids while maintaining their relative size ie. handling scaling correctly?
Sure thing! Just look up the sky. They are all there :) Perfectly to scale even!
Or if you want it scaled down look at an empty sheet of paper. That is a true representation of how many asteroids you would see if we would scale the solar system down to fit the paper.
In fact I just calculated and the sun itself would be about 0.06mm in diameter if you want to scale down the solar system such that the orbit of Neptune fits on a standard A4 paper. So by all means an empty sheet of paper sounds like a correct visual aid to illustrate the solar system in its entirety, not just the asteroids.
The problem with ploting the actual size of asteroids (and planets too for the most part) is that you'd just end up with a black screen even with subpixel rendering.
Indeed, even the largest is literally an invisible dot on an invisible dot — a while back I was playing around and made a video of the actual scale of various megastructures with Earth and the sun for scale, starting with a Halo ring next to Earth, zooming out until it was a dot revealed it was in the middle of a Banks Orbital, zooming out further until that was nearly invisible revealed it was next to a Niven Ringworld, and the zoom continued until you could see the sun.
Ceres is the biggest asteroid, is less than 1/10th the diameter of Earth, and orbits the sun between 2.55 and 2.98 times Earth's orbit.
TIL about Kirkwood gaps. I knew about Jupiter leading to Hilda and Trojan groupings, but my understanding of the main belt was more in line with a representation like this one from Wikipedia[1]. However, this imaging shows a clear gap and a quick search led me to learn about Kirkwood gaps. Is there a specific reason why the gap is more evident in this imaging rather than the above one from Wikipedia?
[1] - https://en.wikipedia.org/wiki/File:InnerSolarSystem-en.png
[2] - https://en.wikipedia.org/wiki/Kirkwood_gap
You should not be able to see the Kirkwood gaps if the simulation is accurate; the Wikipedia image is more realistic.
The "gap" only applies to the semi-major axis (which is proportional to the 3/2th power of the period); since most asteroids are somewhat eccentric (and since semi-major axis is relative to the center but orbits are based on a focus, which "moves" rapidly as the circle deforms) there are always asteroids crossing the "gap" between perihelion (far short of the semi-minor axis, even) and aphelion (far beyond the semi-major axis).
I'm too lazy to do the math, but based on planets with similar eccentricity, most asteroids are between 10% and 25% farther at aphelion than at perihelion (or, often between 0.25AU and 0.75AU farther), which easily crosses any single gap, and almost always multiple gaps.
See the images at https://en.wikipedia.org/wiki/Orbital_eccentricity for informative images of ellipses.
I suspect the gap is at least 50% rendering artifact, but all 1.4M asteroids are plotted as (small) fraction of its orbital ellipse, so the density distribution is reflective of the real data (more specifically, orbit types)
If I understand both the code and o11c's comment correctly, it sounds like the difference is less rendering artifact rather than what is being rendered. This code is rendering the asteroids based off their semi-major axis, but Wikipedia appears to be rendering their actual positions at a specific moment in time with the asteroids all at various points in their eccentric orbit.
I am pretty sure it is the opposite :)
Care to expand on that? Wikipedia image has the Greeks ahead of Jupiter and the Trojans behind Jupiter. Doesn't that clearly show it is an image of a moment in time? And the only attributes of an asteroid this code[1] seems to use are the eccentricity, semi-major axis, and perihelion. Although I'm no expert in either Python or astrophysics so I may be missing something.
[1] - https://github.com/DarkStar1982/Orbidium/blob/536afc2e12e9a2...
The code draws full orbit ellipse if selected to do so, but the original picture was rendered using a different mode, where just a small slice of the orbit arc is rendered, pretty much showing an instantaneous position of asteroid.
Now, I am pretty sure actual positions are not correct relative to each other (it is the same position on ellipse arc, should be actual position of the asteroid) but MPC file doesn't provide this information - you need ephemeris from here: https://www.minorplanetcenter.net/iau/MPEph/MPEph.html
After all, it is mostly a data visualization demo (although I tried to be precise with scale too)
>Now, I am pretty sure actual positions are not correct relative to each other (it is the same position on ellipse arc
That sounds to me just like a rephrasing of what I originally said. The locations in the Wikipedia image are correct relative to each other (because it is representing a moment in time) while the locations from the code are not correct relative to each other and are instead "the same position on ellipse arc" (although maybe I was wrong with my assumption that the "same position" was at the semi-major axis).
Yeah, I changed the orbit position to randomly sampling orbit locations and asteroid belt gaps are definitely rendering artifacts.
Lol, I thought our confusion was over astrophysics and not English. The gaps are a real physical phenomenon that may or may not be visible depending on rendering decisions. I wouldn't consider them a "rendering artifact" as I take that to imply the artifact was artificially created by the rendering. Either way, thanks for answering my questions!
TIL about Kirkwood gaps too: https://en.wikipedia.org/wiki/Kirkwood_gap :
> A Kirkwood gap is a gap or dip in the distribution of the semi-major axes (or equivalently of the orbital periods) of the orbits of main-belt asteroids. They correspond to the locations of orbital resonances with Jupiter.
(Similarly, shouldn't it be possible to infer photon phase without causing wave state collapse?)
/? Jupiter’s effect on Earth’s climate https://www.google.com/search?q=Jupiter%E2%80%99s+effect+on+...
I have recently managed to open source some of our tools which we use on the NEO Surveyor mission to simulate all of the asteroids. However my code lacks any real sort of visualizations:
https://github.com/Caltech-IPAC/kete
(note that installation is about 100mb, as it carries a large data file containing high accuracy positions of the planets for +- 100 years)
Is the lack of asteroids between the Earth and Sun an artifact of our methods of detection? I'd imagine looking outward where light is shining on a surface would be easier to detect stuff than looking inward towards the sun at such a close distance.
Not entirely, but in part! You can see the effect in this animation of asteroid discoveries over time, where the discoveries are concentrated in bursts facing directly away from Earth, or directly parallel to its orbit.
https://www.youtube.com/watch?app=desktop&v=BKKg4lZ_o-Y
That's very interesting. Thanks for posting that.
Wow, what happened around 1999?
There are not that many, less than a 100 with apoapsis inside of the Earth orbit.
Rendering can be adjusted for better visibility, but 4 inner planets swept the interior volume pretty thoroughly during earlier times of Solar System.
Demo written by the team from Exodus Orbitals.
We have a few more cool projects in the pipeline - sign up to learn about them here
https://exodusorbitals.us4.list-manage.com/subscribe?u=959a0...
older video but doesn't require downloading and compiling https://www.youtube.com/watch?v=vfvo-Ujb_qk Also if you are worried, here is a good video talking about it https://www.youtube.com/shorts/gBzDC6yMw9Y?feature=share
This is rendering survey data? We don't really have literally every asteroid cataloged do we?
What is mean distance between asteroids? Would it be possible to send probe randomly and have it photography new asteroid very closely every day?
No, they're much further apart than that. Consider that the total number of asteroids is only 7 digits (i.e. not even ten million) and they are spread out across the asteroid belt that is larger than Earth's orbit.
* That we know of.
Is there any good way to plot multiple asteroids while maintaining their relative size ie. handling scaling correctly?
The problem with plotting asteroids is that the "pixel" representing an asteroid is a hugely larger chunk of space relative to the actual size of the asteroid itself.
This gives a false feel of density that the asteroid belts simply don't have.
> Is there any good way to plot multiple asteroids while maintaining their relative size ie. handling scaling correctly?
Sure thing! Just look up the sky. They are all there :) Perfectly to scale even!
Or if you want it scaled down look at an empty sheet of paper. That is a true representation of how many asteroids you would see if we would scale the solar system down to fit the paper.
In fact I just calculated and the sun itself would be about 0.06mm in diameter if you want to scale down the solar system such that the orbit of Neptune fits on a standard A4 paper. So by all means an empty sheet of paper sounds like a correct visual aid to illustrate the solar system in its entirety, not just the asteroids.
Couple ideas to help with that,
1. Use heatmap i.e. total mass of asteroids at each pixel
2. Use log scale
The problem with ploting the actual size of asteroids (and planets too for the most part) is that you'd just end up with a black screen even with subpixel rendering.
Indeed, even the largest is literally an invisible dot on an invisible dot — a while back I was playing around and made a video of the actual scale of various megastructures with Earth and the sun for scale, starting with a Halo ring next to Earth, zooming out until it was a dot revealed it was in the middle of a Banks Orbital, zooming out further until that was nearly invisible revealed it was next to a Niven Ringworld, and the zoom continued until you could see the sun.
Ceres is the biggest asteroid, is less than 1/10th the diameter of Earth, and orbits the sun between 2.55 and 2.98 times Earth's orbit.
https://m.youtube.com/watch?v=JvKSRKT0nzM
First step to mining a NEO is knowing where they are.
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