Honestly I hope someone figures out how to shoot these down. I feel like the planet isn't getting a say. In fact only a few people are getting a say that this network should even exist. Astronomy is dead. A dark sky with just stars, yeah dead.
Because you're thinking of "space" as just boring orbital stuff. Astronomers think of our solar system, deep space, distant stars... a bunch of gadgets blocking the view of that is a legitimate concern.
It's not like the constellation move in unpredictable manner. The orbits are known, the movements are predictable, surely with some processing it shouldn't affect astronomy too much? If astronomers can overcome random atmospheric dispersion, surely they can elimitate starlink from post-processed images too?
I agree with the sentiment of the parent comment. Not because I have a huge passion for astronomy, but because I think we're prioritizing things in a wrong way.
We're prioritizing yet another billionare's networking business over the capacity to study our night's sky. Much like other types of pollution, this is something that could stick around for hundreds of years, even after all its utility is gone.
Cell towers, like most structures, can be brought down, repurposed, updated and altered. We can't do nothing about satellites, and don't know how to clean space pollution.
Firstly, the satellites fall out of orbit automatically within 5 years even if they break because they're in LEO. Secondly, again because they're in LEO they are invisible for most of the night while they are in Earth's shadow, not affecting stargazing or astronomy in the slightest during that time. It's only an hour or so near dawn and dusk where the satellites are visible.
Trying to match up that claim with the claim of https://james.darpinian.com/satellites/?special=starlink that satellites should be visible at 12:10am this Saturday over Boston. 12:10am is nowhere close to dusk in Boston this time of year.
12:10 AM Saturday in your device's time zone. 6:10 PM Friday in Boston's time zone. It's on my to-do list to change the displayed time zone when you select a faraway location instead of your current location, but just figuring out which time zone a given location is in is a non-trivial problem. Time zones are kind of bonkers, as I'm sure you're aware.
I just pushed a fix for timezones. It should convert to the local timezone if you choose a faraway location, and show the correct timezone abbreviation.
I feel that's a super limited point of view of the whole affair.
Starlink is here not because it makes a networking business (although it doesn't hurt).
Starlink is here because on Mars you need reliable communication and positioning over the planet, and you can only do that efficiently with satellites, and Starlink is destined for Mars, not Earth. What we have here is just the testing grounds for the technology.
Personally I'm stoked about pushing 1200 sattelites in orbit to Mars - highly automated, and it would make the current 2 orbiters by NASA as peanuts.
This is such an overly dramatic way of looking at it. Even at its most extreme Starlink will not really hurt our capacity to study our night's sky.
We are talking about a extremely tiny part of the sky that will only be visible very infrequently and the position is known at all times.
This does not impact most of astronomy at all.
Cleaning up space is not a technically impossible problem. It just has not yet been done because nobody had a need for it.
The waste majority of these satellites would fall back to earth, they can not stay 100s of years even in the worst case. Those few that do actually break and are to high up to wait out, can be collected once we have the scale of launch and service infrastructure. Until that point they would be on known location and SpaceX could make sure they don't hit anything.
It seems utterly absurd to me to ignore a massive technological leap for humanity because a tiny part of it hurts research (or is assumed to possible hurt research) and the idea that there is not enough space in orbit and that is not convincing at all.
tl;dr: starlink and its competitors pose serious Earth-based observation problems across the spectrum (§§4.1-4.2) especially for faint variable objects which require long exposures and for which any missed pixels matter.
The missed-pixels problems run around the clock, not just when the sattelites are visibly flaring, as do non-visible-spectrum noise problems.
From a first-principles perspective, it's baffling to me why this would ever be a serious problem. We know the ephemerides of all objects in Earth orbit, and they are traveling at a fast enough angular speed to not linger in an observational spot. We're not working with long-exposure film here - we can manipulate pixels over time. On a technical level it should be trivial to mask out the pixels where satellites are located at each moment. I think 1% is far too high a guesstimate, but say that artificial satellites end up covering 1% of the full night sky (for context the moon takes up under 0.001% of the sky's area). That still leaves you with 99% observability - hardly an effect on the amount of data you can bring in, especially compared to such problems as clouds.
And more complex ones for professional astronomers should still be super simple to implement compared to many of the algorithms astronomers have to wrangle with.
We don't want to manipulate pixels; the goal is not to produce pretty pictures of known things. The goal is to collect as much data as possible about things which are not well understood (because, in part, of a lack of data), especially those that are time-varying on short human timescales.
The objects in question are often extremely faint, and even if one knows a lot of the details of periodic noise, removing the noise does not recover the faint signal.
> baffling
Stand by, there will be lot of professional science communication on this topic in due course.
> moon, 1%, ...
Suppose right now at the very limb of the sun we detect an extremely interesting light curve that is clearly not extragalactic yet still atypical of supernovae, but know that it is in the process of moving directly behind the sun (from our perspective). How do you propose to remove the sun from the image of the suspected supernova?
Here's a list of solar-system objects that moved directly behind the sun in 2019: https://sungrazer.nrl.navy.mil/index.php?p=transits/transits... This Christmas would have been an interesting time for 2010: The Year We Make Contact's great black spot of Jupiter to appear.
The moon also occults Jupiter fairly regularly. If Jupiter was doing something strange behind the moon, think of the loss for all the Earth-based observatories. Or would it be trivial for them to faithfully reconstruct the unusual behaviour of Jupiter?
Yes, the sun and moon are slow-moving, bright, and high-solid-angle obstructions compared to any spacecraft. However, so is Jupiter and a galactic supernova, and neither of them are usually interestingly variable on the scale of a glitching millisecond pulsar (for example) or the electromagnetic counterparts to a gravitational wave detection.
In short
> algorithms to erase satellite trails
are doing cosmetics, not astronomical or astrophysical research.
And if cosmetically you erase the wrong pixel, you miss out lots of observation time of events like https://en.wikipedia.org/wiki/ASASSN-15lh#Discovery and end up regretting missing early data (as in e.g. SN 1997D).
A recent tweet is interesting: 'This is, by the way, a discovery made in "astronomical twilight" - one way Itagaki and other amateur astronomers can discovered such events before professional astronomers is by observing fields (galaxies) quite close to the Sun.' (although that's in large part because bigger observatories deliberately aim away from the sun, because it's very noisy and its luminosity may damage sensitive detectors).
I understand the goal is not pretty pictures. But you're not using a hammer to remove random white noise from all your observations, you're using a scalpel to mask out completely predictable errors for very short periods of time. My amateur astronomer link was not meant as a scientific how-to, but as an illustration that even simple hammer-y methods work to mask out satellite trails.
There are very few non-periodic events in the universe that happen over the fraction-of-a-second timescale for which a satellite occludes an area of the sky, the linking of EM to gravitational wave events being perhaps the only notable exception. Meteor impacts on planets happen over the course of seconds. Supernovae occur over the timeframe of hours. Glitches in millisecond pulsars (the millisecond name notwithstanding) occur over the timescale of days.
This is also the issue with using occlusion by the sun and moon as analogy - their occlusions do operate on the timescale of interesting astronomical events. If the moon whipped around the Earth at the same rate as LEO satellites it might occlude Jupiter, but you would have plenty of vision between the shutters to reconstruct events on the timescales we are interested in. I'll also note that the analogy breaks down with the focus on objects in the solar system since they all roughly lie on the ecliptic - you've reduced the occlusions over a 2D sky to occlusions between objects that live on a 1D slice of it. The Sun and Moon both take up 0.3% of the angular diameter of the sky, but only 0.001% the angular area.
Are you losing real data with a sky full of 10's of thousands of LEO satellites? Yes. Is it a significant amount? Not by any reasonable metric. Is it over a significant timescale? No.
An analogy: If you have some video footage and for whatever reason have a punchhole in the corner of every 100th frame, that by no means precludes you from doing analysis on the video. I'd expect the video conservationists to be up in arms about any blemishes on their original film, but I'd argue that that is the position from aesthetics. To answer questions such as "how many times does the ball in this video bounce" or "how does the lighting in this video change over time" or "how does that person's hair react to the wind visible in the video" the hole is insignificant to obtaining the answer, even if the area of interest is directly covered every 100th frame.
I'll close with the acknowledgement that radio interference is a legitimate concern here. But satellites are hardly the only emitters which are increasing in number at an increasing rate, and that commons will be polluted whether we launch them or not.
Even if astronomy isn't affected. Can you imagine a grid/net of fast moving satellites, 80,000 satellites covering the entire globe that are visible for 2 to 3 hours every night. This is the thing that creates global suicides. Mark those words. It will happen.
Sorry this is worth more commenting - I am just imagining this network above us. Every centimeter to an inch "visually" a grid pattern crossing over us for a period of 2 hours a night.
No, a website that tells you when it's coming, ooooh... No this is every single night, and morning, a grid from HELL.
I'm a fairly regular poster, a software engineer, decently intelligent guy - and this future absolutely disgusts me. I hope things change and it ends up not happening. I would rather telephone pole the world.
Not really true:
"For his analysis, he factored in the first leg of SpaceX’s Starlink constellation — about 1,600 satellites — as there are better details about the orbits they’re going to. Based on just that initial batch, he estimated that at a latitude of 52 degrees north (about where London is located), there will be 84 Starlink satellites above the horizon at all times. And for many hours around dusk, dawn, and in the nighttime during summer, 15 of those satellites would be visible in the sky at all times, about 30 degrees above the horizon."
From here: https://www.theverge.com/2019/5/29/18642577/spacex-starlink-...
Maybe the historical form of amateur astronomy with a telescope in the garden might die out (others have made some reasonable counter-arguments). But maybe instead, space based astronomy will become cheaper and more accessible due to the drop in launch costs? My understanding is that a lot of astronomy research (as distinct from amateur stargazing) is limited by atmospheric concerns, so maybe that would be an improvement.
