I don't get it, how can something actually that small can reflect so much light? I mean, it's high up in the orbit, and an object at a height of the orbit with a size of billboard should be super small. I know it's reflecting sunlight and in darkness it shines a lot, but still I can't wrap my head around how such a small (relatively, to space) object can create some much reflection.
I know what ISS can do and I regularly observe its passes and how bright it is, but ISS is much, much bigger.
If there's a reflection path from you to the sun hitting the panel, you're looking at a billboard-sized panel that's roughly as bright as the sun. It's far away, yes, but the stuff you're trying to look at is much much farther away, and much much less bright.
Have you ever been in an airplane during a sunny day? You can get blinded by reflections from small objects like windows, or even sparkling from water and the like. And that's sunlight that's gone through the atmosphere and back up for up to 10 kilometers, this one gets hit by direct sunlight.
I'd say that absorbent or light diffusing material should be mandatory, but absorbent material would mean the surface gets really hot.
>absorbent or light diffusing material should be mandatory
Absorbency is bad because it causes overheating and IR astronomy pollution. Diffusion is bad because it reflects light toward Earth.
Specular surfaces (mirrors) can reflect light entirely into space and away from observers on the ground.
This explains why SpaceX created their own radio-transparent, space-rated mirror. They are offering it—at cost—for use by other satellite manufacturers.
The effect of downward-pointing black coatings on LEO satellites is higher spacecraft temperatures, but the cost of those higher temperatures is on spacecraft design/use, not on IR astronomy. Starlink satellites run screamingly hot even without the dark coatings; if they're a problem for IR telescopes, then that should already be a problem. A few extra degrees shouldn't break the budget.
It's like someone using a mirror to reflect the sun at you - it can be quite bright if the angles line up correctly. It's called a satellite flare. Sadly, the best and most easily predictable ones, the Iridium Satellites have all been retired, so you can't easily observe one any more, but if you look on youtube, people have posted observations of them.
Interesting. I found an old page with a photo and a newer one with more recent information. I knew that Iridium as a constellation is still operating, but I wasn't aware that they introduced a different satellite design that mitigates flares. The last Iridium satellite that produced flares was deorbited in 2019. (They folks who made the second page seem disappointed about the end of that era.)
In my experience catching a surprise iridium flare was rarer than catching a non-shower meteor. I think that I had seen maybe less than dozen my whole life of looking up.
There must be some diffusion/refraction from all of the atmospheric particles as well, right? I don't think you'd be able to see it as a bright rectangular object so much as a bright fuzzy blob in the sky.
BlueWalker 3 is already being tracked by some of the night sky tracker websites, maybe get to see it next week here, but so far reported to have a brightness similar to a 1st magnitude star. The same company plans to launch 100 more larger 'BlueBird' satellites (mobile comms?). I had my telescope out a few nights ago and joked about a small child of the near future asking 'What's wrong with that star, it doesn't move...'
500km orbit. It will be in the dark most of the night. They may lose some early evening/morning observation quality but it shouldn't be that bad for the rest of it.
I think you're forgetting that astronomers care about wavelengths of light other than visible light — that is a very, very narrow range of the spectrum of radiation.
In the infrared, for example, every satellite looks like a blazing star. In the radio spectrum, every satellite that transmits signals in this band looks hundreds of thousands of times brighter than a star.
Certainly something should be done to reduce reflectivity, but so many of these pieces about the impact on astronomers are missing the longer view. The sky is going to get more and more crowded as we expand into space, and while terrestrial observatories are amazing, the future of space observation and exploration is, after all, in space.
It's the destiny of the night sky to be filled with our spacecraft. This will surely impact terrestrial astronomy, but a falcon heavy costs $97 million, and would enable detection of threats we'd be otherwise blind to if we stuck to terrestrial observations.
I also feel sad that we have ruined nearly every place on earth and now we must ruin the night sky, one of the last untouched mostly natural places most people can view each day.
Also, what gives the right of peoples in one country to ruin the night sky of others on the other side of the planet.
It's not just about observatories and atronomers that we should consider.
I hope we can solve and compromise and not just push forward without consulting and considering.
And now it will also be ruined if you live in nature. That's an awful attempt at an excuse that doesn't solve anything. We should be fighting to improve this situation, not be complacent and allow it to get worse.
That reminds me of the story of an Old Believer Russian family that moved to Siberia around the 1920s and was only found again by Soviet miners in 1970s. The patriach of the family was not educated, but he and his children managed to infer that the fast moving stars newly risen in the 1950s to be man-made stars (satellites).
Sorry. 1936-1978.
Still
Here you go:
"though he steadfastly refused to believe that man had set foot on the moon, he adapted swiftly to the idea of satellites. The Lykovs had noticed them as early as the 1950s, when “the stars began to go quickly across the sky,” and Karp himself conceived a theory to explain this: “People have thought something up and are sending out fires that are very like stars.”
It’s often claimed how there is no night sky for anyone anywhere near a city these days, so if you prefer to live in one (or believe that is the ultimately sustainable choice to reduce humanity’s environmental footprint) you couldn’t care less about all those satellites flying overhead.
Speaking from experience, that is not true. On a clear moonless night a few months before COVID I saw uncountable stars when I looked up from a rooftop in a moderately busy part of Kowloon of all places. (Sure, I might’ve mistaken a few satellites for celestial bodies, but I made an effort to ignore at least the non-geostationary ones.)
If you cannot see night sky in your city, consider that your AQI may be too high at the moment. (Going up to the roof wouldn’t hurt either.) It doesn’t mean you couldn’t enjoy stars where you live ever again.
Have you ever been to a truly dark sky area though? I used to think I could see a lot of stars and then I went to a truly remote area 100's of miles from a large city and dozens of miles from even small settlements and my mind was blown away by the clarity of the milky way.
I’ve been to pretty wild places with stark skies, though didn’t especially care to observe it at the time to be honest.
Goes without arguing that outside of a city is generally easier to observe night sky because pollution is weaker. However, if the place far from a city has polluted air for whatever reason it’ll still be a problem—and conversely even in a city air and light pollution are not a given, subject to regulations and climate patterns.
I’ve seen our Milky Way, not in HK but in another city (smaller but stronger air pollution). It was very weak (first, air pollution amplifying light pollution; second, it was not too high above the horizon when I was awake), but not seeing it in all of its glory doesn’t mean city dwellers have to concede that they lost the sky completely even now, much less 100 years ago—because they obviously haven’t.
They will continue to whine until all observation is done from outer space.
On the one hand, it's good to have a reminder as it's important that interference with terrestrial astronomy is taken into account when designing new space missions. On the other hand, the degree to which the whining is being amplified by doing it in news articles gives it a bit of "shitting where you sleep" quality - my feeling is they're already quite successfully souring the nascent space industry to the general population, which is extremely counterproductive long-term, especially for people whose fields' existence depends pretty much entirely on goodwill and surplus funding.
In other words: excessive whining about space utilization will not stop launches of telecom satellites and subsequent light and radio pollution, but it may very well make it so no one will have the will and the spare cash to fund the next space-based telescope.
As a sibling comment pointed out, most people impacted by this will be amateur astronomers, and, you know, casual star gazers.
Secondly, this isn't "souring the space industry". LEO satellites mostly serve terrestrial companies and governments, where they're used for military, communication, and, increasingly, other commercial purposes. The complaints aren't about space tourism projects or launching a few space telescopes; they're about launching thousands of satellites, and fueling the commercialization of LEO, where the sky will eventually be littered by these things. We're at the very early stages of this, and individuals are already voicing concerns about it. I hope this "whining" continues, as I sure as hell don't want to also see ads when I look up into the sky.
Except most organizations can barely afford their ground-based observatories as it is, so to think you can chuck enough capacity into orbit to compensate even a fraction of it for anywhere close in budget is wishful thinking.
It will be a nuisance for amateur astronomers too (for astro-photography people anyway), since they are more likely to take wide-angle shots (increasing likelihood of bright transient in shot) and have less technical means to compensate for it.
And they certainly don't have the budget to launch their own satellites..
You already can't see the Milky Way in the way that cave ancestors could see. The future will be advertisements in the sky and brightness 24/7. There will be no "night". But people born in the future will think it's just normal and "cool" or whatever slang they use then. If they want to imagine night they turn on that VR implant in their head to Sim 2022.
> But people born in the future will think it's just normal and nice.
We are ‘people born in the future’ compared to our cave ancestors, and I wager if you asked just about anyone if they thought an unobstructed milky way was ‘nicer’ than the diffuse haze of a city skyline, they’d almost unanimously pick the former.
I think cities are great, but it's nice to leave the city. And with more intelligent lights, we can have lighting when and where we need it. And with lower air pollution, enjoy breathing better and see more stars in the sky.
> Give me a sky full of moving points of light any night.
But at what point does that just become noise? A shooting star is magic. Seeing the ISS float by is a novelty. But a crisscrossing streams of satellites... I'm sure that would get old quick.
And arguably slower. I see a bright star, I look it up, it's so-and-so in the constellation of something-or-other. I see a bright satellite, I look it up, it has a story.
I don't think I made any claim about their actual speed, but I would have thought if they're not geostationary (like the ISS) they are crossing our sky much faster, which is all that matters to this discussion.
> I see a bright satellite, I look it up, it has a story.
It's very subjective I guess, but in stars and nebula I see the history of the universe as a mysterious story in itself. A story that compelled us to explore space in the first place.
I meant it wouldn't become noise any faster than the stars themselves.
Personally, I want us to colonize space more than explore it. I view the stars mostly as, to quote, "enormous heaps of valuable raw materials that had unfortunately caught fire and needed to be scattered and put out", in a Kardashevian, "wake up the universe" sense.
Do you think we’ve been ground down sufficiently by corrupt wholly self interested politicians, so just feel resigned to something like this? When we’ve fucked our biosphere with CO2, a much more dangerous issue we’ve failed to solve?
Collective action can help, but at an industrial scale, a functioning democracy is necessary to mitigate the tragedy of the commons. A functioning democracy requires an empowered and informed voting population. Corruption from industry seeks to minimise both. People need to fight for stronger democratic institutions if they believe the priorities of the majority should come first. And I’m betting the majority want to look up and see real stars
Keep in mind that in this case, even a perfectly functioning democracy may not give you the result you expect: there are many of us here who would vote strongly for continued development of space industry and expansion into the solar system, even if would completely block Earth-based observations, because we believe developing Earth orbit is much more important than astronomy in general, and it also happens to be a necessary stepping stone to enabling affordable space-based observations, so we believe it'll ultimately benefit astronomy mid-to-long term.
> Keep in mind that in this case, even a perfectly functioning democracy may not give you the result you expect
I don't expect to fully know the will of the majority. If the majority think that clearer skies are great, and let's say that took a significant amount of finances to happen (not sure that it would), people might think that lower taxes are even better. Democratic government is just a vehicle for enforcing the interests of the majority, and I present it here as the potential avenue for reducing artificial Night Sky Brightness (in answer to GGP), with the premise that this is actually in the majority interest.
Based on the past, people will just buy these corporations products. Some will post disgruntled messages online. A very small minority will isolate and marginalise themselves by boycotting the products. No-one will care.
There's really not much an individual can do about this. Fighting a powerful corporation is hopeless, and governments won't make them change if it benefits them, and there is no collective push back from citizens.
Besides, this is a global problem, and people from different countries have even less leverage to trigger a change.
Or, they will just book a space trip, to get the slightly more intense experience.
Also there is hopefully a good chance, that since most people have then their advertisement integrated in their VR implant, there is no more need to pollute the skies.
Unless of course we overcome advertisement one bright day.
Till then, I probably make vacation again, or even move to La Palma, a island with lots of telescopes and a ban on all bright lights and advertisements.
You do know how satellite flares work, right? You do know you can only see them when sun reflects off them, therefore they have to be near the horizon or soon after sunset, right? You have seen the ISS streak across the sky at -3 magnitude, correct?
Which ones? Most were developed into farms, cities and industrial zones. All directly responsible for pretty much every thing you're enjoying about your life.
Sure, it would be even better to have both all the forests and plains, and all the food variety, telecommunication, transportation, lifespan and individual freedoms. But it was never a possibility. There was no path from there to here for humanity that didn't mean developing much of the land, cutting down much of the forests and poisoning much of the world - it's because we were (and still are) figuring things out as we went along, acting in an uncoordinated, distributed fashion.
We could eventually restore much of what was; we can see the possibility now, but the path to it starts with developing Earth orbit. The way to get the forests and clear sky back without making life universally worse off leads through weathering the whining of astronomers as infrastructure, industry and habitation is being moved up the gravity well.
(It's either that or making some huge leaps in biotech, but that's pretty much post-singularity regime, in the sense it's too hard - or too scary - to predict how the world would look like after working with DNA becomes as easy as working with code. Expanding to space sounds like a much safer option to pursue first :).)
These satellites aren't affecting anyone except those with access to a radio observatory or a telescope which is probably far less than 1% of the population. It's hard to say this is ruining the night sky. No one can see these satellites with the naked eye. Even if you could, they are neat rather than ruining, unlike light pollution. The ISS looks like a really slow, dim shooting star if you can even spot it, which takes a fair deal of effort and concentration to not lose it.
Launch costs are a fairly small part of most space telescopes. Even for something like Hubble which required multiple incredibly expensive shuttle launches, <10%. Sure, if you treat the telescopes themselves as disposable you can bring R&D costs down a bit.
But imagine how hard it would be to build something like the Square Kilometer Array in space (keep in mind it'll already cost billions to build it on Earth). You'd need hundreds of launches to get each of the 50 ft dishes to space. Not to mention the difficulties of on orbit assembly.
And of course before you do that you have to figure out how to do interferometry in space. AFAIK it's only been done reliably at very long wavelengths, except for a few demonstrators that required non-scalable physical connections. I don't think it'd impossible, but it requires some huge advances in both science and engineering (submillimeter positioning, cryocoolers with orders of magnitude improvement at passing vibe checks, etc)
> a falcon heavy costs $97 million, and would enable detection of threats we'd be otherwise blind to if we stuck to terrestrial observations.
What's the cost of a space-based detection platform compared to a ground based one, and does it impact whether such platforms get built in the future?
Overall I think its the impact on and complete disregard for radio astronomy that gets be about this. I'm sure you're not allowed to do high-decibel audio experiments next to the founder's house, but regulations prohibiting radio emissions affecting particular pockets of land are up for grabs?
FCC regulations on what you can transmit legally (and with appropriate category of license, for things like new FM broadcasters and OTA TV stations) in all the VHF, UHF, S and L bands, and part 101 microwave bands are actually quite stringent.
Not quite. HST was initially supposed to be a 3m telescope, but they had to go down a bit in size for budget reasons. And the reason for going for exactly 2.4m (instead of 2.5m or 2.2m) was that they could save even more money, because the mirror size of the military spy satellites was exactly the same and they could use some of the same manufacturing process.
The rest of the satellite is quite different to a spy satellite however.
It’s just physics. To see further and with higher resolution, you need larger apertures. The Event Horizon Telescope, the one that viewed the supermassive black holes a couple of years ago, is effectively the size of Earth.
Yes. Space manufacturing is the way. Launching everything from down here is madness, constructing telescopes in high lands down here is madness too, those are local minimas. We should be laser 3D printing bunch of self replicating cylinder objects out of Lunar regolith. I don't know why we're not doing it if it weren't for the sole possibility that US Space Force don't have intercept capability for such tubes gone rogue.
SpaceX and trailing competitors are trying to make it cheap enough to get stuff out of the gravity well (including people and our more advanced products) that more permanent installations other places can get started. Elon says Mars a lot, probably because it's popular with the public. It's still expensive to send things up a gravity well, even if it's less expensive. The moon is shallow by comparison, and the asteroid belt far away but barely a dip. It would be safest to send robots first, bootstrap an installation that can manufacture local propulsion of any sort, O2, water, maybe even refine useful building materials, metal, or other resources. Anything so less is sent up.
Hopefully among all those things would also be materials to make large mirrors (optical and other portions of the EM spectrum), in less gravity, where it's cheaper to move them to useful areas of space, or even just truck them to spots around the surface of the moon.
One word: mining. The moon has literal tons of helium-3 that, if brought back to Earth, would tank the market. yes it's a bit capital intensive too get started but the payoff is huge! Just need to borrow the particle physicists' budget for a second.
"Just need to borrow the particle physicist's budget for a second."
I don't think thats enough and I also don't think the market for Helium-3 is that lucrative, since comercial fusion is for some reasons still not in sight.
Apollo took 9 years and about $25 billion to get there, so we can treat that as an upper limit. However, the Capstop cubesat just reached the moon[0] for $30 million[1] so the roughly $5 Billion for the LHC should be enough to get us to the moon these days. And there's plenty of aluminum and titanium to bring back until commercial fusion arrives.
It costs a lot to build them; might as well make it count.
I'm no astro something, but I can imagine it's cheaper to build a large telescope on the ground than it is to build a small telescope in space. I'm sure people have crunched the numbers.
When we got serious about electrification a century ago, we also damaged or destroyed a whole generation of of great observatories with our light pollution. Was that a good trade? The night skies ruined for half the population. Important scientific efforts pushed to more distant and expensive locations. But also, electricity for hundreds of millions of people in the blink of an eye! I think I agree with the early 20th century's prioritization there.
Astronomy is going to lose another generation of observatories and see degraded capabilities in some survivors because, just as it was the right thing to do with electrification, bringing broadband to hundreds of millions of people who live in under-served rural communities delivers more progress to society than the small fraction of time sensitive science that may be lost, interrupted, or delayed as we pivot planning and resources to even more exciting and capable telescopes safe distances (for now) from ever-increasing challenge of local light and radio pollution.
And just as it did a century ago, astronomy is going to move further away from civilization, this time to Earth orbit and the Moon. Today we're capable of putting 5 times the Hubble mass into orbit with a single launch for less than $100 million. Within a decade, that'll likely drop to maybe $10 million to lift something like 10 times Hubble's mass in a single go. We can have large-scale orbital telescopes if we want them. And they can be affordable, well considerably more affordable than was historically possible for orbital observatories. Because launch will be dirt cheap and super-sized, these telescopes won't have to be optimized for size and weight or even long term survivability. Sure, the precision optics aren't getting cheaper quickly, but every other component and set of manufacturing tolerances can be had or done much cheaper. Don't spend 5-10X on that radiation hardened chip. Instead, send up 2 regular priced chips with some extra shielding and software that makes sure they both agree that neither one of them have been hit by a disruptive particle. Aerospace aluminum precision milling and robotic friction stir welding? Screw that, let's stick weld some steel.
Satellites are going to be a significant part of delivering modern broadband to the world's rural populations. LEO Constellations have modest capabilities, limited heavily by the physics of radios. But they can be deployed more swiftly to more people than fiber or cable. In 10 years, we will high speed broadband available for literally all locations on the globe, from at least one but likely several different providers.
Capacity will be the constellation operators' biggest challenge. Governments will increasingly turn to the LEO operators for connecting their hard to reach rural populations, delivering large subsidies and other incentives. The demand will far outstrip what the available spectrum will support. Billions of people will want access to networks that will only be able to support hundreds of millions at best. Whether or not spectrum efficiency will allow satellite constellations to compete in the long run or not, I can't say. But for the next two or three decades for sure they're going to be an increasing presence in the sky. I don't think there's any going back.
So, what about astronomy. Easy, as noted above, we do what we did a century ago and have been doing for ages, we pony up and pay to keep on doing the science, even if it has to be more remote, more expensive, and more difficult. We should commit ourselves, just like we did a century ago, to helping the most affected segments of astronomy move as quickly as possible. We can start by re-designing our in-progress next generation observatories to be either cheap and disposable or permanent and future proof orbital science platforms that we can start launching this decade and the next. And let us also invest in establishing the regular movement of humans to and from the Moon so that we can build scientific outposts and observatories of all kinds, but in particular a few great radio telescopes protected by the Moon itself from Earth's near deafening radio pollution.
This is all within our reach, we have the technology to make it happen and for a modest public and private investment we can do right by the scientific community that brings not only so much understanding, but also such richness and meaning to so many of our lives. All over the world, we must vote in representatives that will support public funding to go hand in hand with charitable and philanthropic spending, and perhaps even inviting commercial investment, to help this noble and enlightening branch of science move forward so that it can continue to help carry our civilization forward.
That is certainly the prevalent narrative and yet we've got roughly 4.5 billion years to solve the sun-eating-the-earth problem. Shitting on our dominant modes of asteroid detection to try to compete for saturated market space (cell service are you fucking kidding me) advances no species preservation goals.
At first glance I thought this was in reference to the Moon.
During last week's lunar eclipse I enjoyed viewing conditions perfect for spotting faint Uranus through my 70 mm refractor. I woke my wife and she and I checked out Jupiter, Saturn, and later on Mars, which she spotted by chance coming up over the horizon. Lunar eclipses are great opportunities for seeing some truly wondrous sights.
I'm pretty sure I saw it in recent days, I went out on my back porch where I saw Jupiter in the sky... and then another Jupiter (same color/apparent magnitude) just coasting away on its satellite track. This thing was bright, I've seen the International Space Station and this was way brighter, and flared a bit when the sunlight caught it right.
How does this compare to eg. starlink? I mean... this is bigger and brighter, but there is one (1) of "this", and that should probably be relatively easy to filter out(?).
Do systems such as stalink with a "bajillion" of small satellites have any effect on (radio)astronomy?
It is sad for backyard astronomers but I am more concerned about these satellites falling onto our heads one day. When a 3rd world country starts sending their satellites with poor development this is going to be unavoidable. Another fear is ahead.
Probably not; if it's a ground-based laser, it would have to get through the atmosphere first which causes a lot of diffusion. Second, it reflects the sunlight, surely it reflects laser light too :p.
That said, I'm pretty confident there's weapons grade lasers in orbit designed to take out or at least disrupt sattelites. They've just not been used yet because that would show their owners' hands.
I don't get it, how can something actually that small can reflect so much light? I mean, it's high up in the orbit, and an object at a height of the orbit with a size of billboard should be super small. I know it's reflecting sunlight and in darkness it shines a lot, but still I can't wrap my head around how such a small (relatively, to space) object can create some much reflection.
I know what ISS can do and I regularly observe its passes and how bright it is, but ISS is much, much bigger.