[schiffern]

>Obviously, to size would be less scary.

I was expecting this, since it's probably the most common criticism of this type of visualization.

Problem is, that analysis only looks at half the dataviz fidelity coin. It recognizes the (unavoidable) loss of fidelity in size, but it ignores the (also unavoidable) loss of fidelity in time.

In the real world these objects do not remain orbiting Earth for a few minutes (ie the interval you're likely to look at this visualization). Instead, objects above ~800 km remain in Earth orbit for hundreds to thousands of years.[1]

Mathematically this second inaccuracy tends to cancel out the first inaccuracy, therefore (presumably) making this "a lot more scary/impressive."

Strangely I always see the criticism about size, but I never see the countervailing criticism about time. I suppose it's just like you said: the size factor is "obvious", but the time factor much less so.

Eta: For some great visualizations of the space debris problem, I can heartily recommend this (slightly older) ESA video.[2] It's basically a full-length documentary crammed into 15 minutes.

[1] https://commons.wikimedia.org/wiki/File:Orbital_Debris_Lifet...

[2] https://www.youtube.com/watch?t=13s&v=9cd0-4qOvb0

[WastingMyTime89]

> I was expecting this, since it's probably the most common criticism of this type of visualization. Problem is, that analysis only looks at half the dataviz fidelity coin. It recognizes the (unavoidable) loss of fidelity in size, but it ignores the (also unavoidable) loss of fidelity in time.

It’s a real time visualisation. There is no loss of fidelity in time.

Noticing the important distortion in size is legitimate. It’s not really a criticism by the way. It’s simply that the impression of fullness inherent to this visualisation is misleading. Space is obviously mostly empty.

> Instead, objects above ~800 km remain in Earth orbit for hundreds to thousands of years.[1]

And satellites bellow 600km are only there for a couple of years and those bellow 500km a year top. Let’s not forget that area scales with the square of radius.

> Mathematically this second inaccuracy tends to cancel out the first inaccuracy, therefore (presumably) making this "a lot more scary/impressive."

I’m guessing you mean we have to take into account the fact these objects orbit a long time when considering collisions but that’s a separate issue entirely. The two don’t cancel out at all mathematically in any meaningful way.

Don’t get me wrong, I’m not saying debris are not an issue. The new deorbiting rules are definitely a good thing.

[schiffern]

>It’s a real time visualisation. There is no loss of fidelity in time.

Unless you're going to spend multiple lifetimes watching it in "real time," there is unavoidable loss of fidelity here.

I don't mean fidelity in rate-of-time, but in duration-of-time. The total time available limits the duration fidelity, just as our eyeballs and screens limit the size fidelity.

Again it's less obvious (hence this confusion), but it's no less unavoidable.

>Noticing the important distortion in size is legitimate. It’s not really a criticism by the way. It’s simply... misleading.

Extrapolating real-time events into long stretches of time is also demonstrably misleading to humans. See: the history of scientific discoveries in geology.

Your point about "legitimacy" is right on. In data visualization the goal is finding the most useful (least misleading) transform of the data, not raw fidelity.

It's just that, for the purposes of lifetime collision probability estimation, rate-of-time fidelity is more misleading than duration-of-time fidelity (since you can't have both!).

>the fact these objects orbit a long time when considering collisions

Bingo. The "scariness" comes from (where else?) the collision probability, and our estimate thereof.

>The two don’t cancel out at all mathematically in any meaningful way.

I don't claim perfect cancellation with nothing left, just that it "tends" to cancel out (ie it pushes in the opposite direction), and that this factor was being ignored.

[WastingMyTime89]

> Your point about "legitimacy" is right on. In data visualization the goal is finding the most useful (least misleading) transform of the data, not raw fidelity.

I made no point about legitimacy. The fact remains. It is a real time visualisation. It’s interesting to consider what’s currently flying above. It’s not a collision estimation tool.

> Bingo. The "scariness" comes from (where else?) the collision probability, and our estimate thereof.

There is nothing scary about the probability of collision however. Even when you take the very large safety margin the monitoring organisations like to take probability is very low.

[schiffern]

>It’s not a collision estimation tool.

Agreed, but then why did you say it gets less "scary" when you realize the size is exaggerated here?

What else could you be scared of, if you're not (implicitly) using the visualization to estimate collision probability?

Some sort of thalassephobia for giant space objects, perhaps?

>probability is very low

Now keep rolling those dice every day for hundreds or thousands of years. Thousands of dice, for thousands of objects.

People are historically bad at imagining that (just like we're bad at large distances), which is why compressing the duration is misleading.

Risk = probability * cost. The cost of collisions (both the immediate cost and the long-term cost from additional debris generation) is very high.

>There is nothing scary about the probability of collision

If you watch the video I linked earlier, it explains how we're already past the "tipping point." Even if all launches cease (spoiler: they won't), the debris problem would continue to get worse.

Maybe that isn't a scary situation to you, but it is to me.

[WastingMyTime89]

> It’s not a collision estimation tool.

It’s a comment about how full it is, not about how likely things are to collide and a reply to a previous comment.

> Now keep rolling those dice every day for hundreds of years. Thousands of dice, for thousands of objects.

Still low.

Orbits between 700km and 800km are mostly lost after the past two decade antisatellites tests. Lower orbits clean fast especially the ones used by the recent large satellites fleet and space above 800km is mostly empty apart from the band with large USSR boosters which is easy to avoid.

Risk is not very high. It is managed adequately and the legislation is properly anticipating current developments.

It’s important to remember that space is extremely large and we are talking about thousands of things. Having too much debris clustered in a small range of altitude makes it not economically viable to operate there but it doesn’t prevent us from going through at all.

[schiffern]

>It’s a comment about how full it is

Why is that "scary," though?

It's not like "running out of room" is a plausible risk. Kessler Syndrome limits you long before that.

>Risk is not very high. It is managed adequately and the legislation is properly anticipating current developments

See my edit to parent, and watch the video (especially the future simulations). The situation is far from "managed adequately" IMO.

This has been fun, and I sense we're starting to go in circles (no pun intended). My upvotes, for being such a good sport. Cheers!

[tshaddox]

> Unless you're going to spend multiple lifetimes watching it in "real time," there is unavoidable loss of fidelity here.

I don’t understand this argument at all. As stated previously, it’s a real time visualization, thus there is trivially no loss of fidelity in time. To claim that is like claiming that a live web cam of a city street has a loss in fidelity because it doesn’t show what the street will look like in 100 years.

[schiffern]

Not fidelity in rate of time. Fidelity in total duration of time.

Just like humans have trouble imagining/seeing large spans of space (hence the necessity of size enlargement), humans also have trouble extrapolating to long spans of time (hence the necessity of using actual collisional evolution simulations, not "guesstimating" based on pictures or animations).

The size enlargement effect makes the "guesstimate" tend to overestimate, and the time duration compression effect makes it tend to underestimate. From the start the whole thing is fundamentally a bad method of "guesstimation," but for some reason people tend to quickly raise the former issue and completely overlook the latter.

[rlt]

Maybe I’m optimistic, but I believe within a decade full and rapid reusability of launch vehicles, i.e. Starship (if successful), will radically change what is economical in space, to the point of collecting/deorbiting space debris.