111–119 of 119 posts
Earlier quoted context omitted.
Low earth orbit satellites orbit about once per 90 minutes, so in 10 minutes they go about 40 degrees across the sky. The comet is not even orbiting the earth, it's essentially fixed in the sky. The earth only rotates about 2.5 degrees in 10 minutes. So the satellites streak is 16 times longer than the comets.
40 degrees around Earth (central angle) but it increases to much more when you are much closer to the arc
Earlier quoted context omitted.
It is obvious that the 9 million current customers are just the beginning of where SpaceX wants to take Starlink access. Easy to imagine Starlink serving 1 billion + customers in the near future.
Its already quite cheap so why are people are not running to Starlink? Probably because a land line has still less latency, doesn't consume that much energy and everyone has either a land line or mobile connection. When Amazon Leo, Eutelsat, Telesat, Chiense and co enter the market, the margin will go down significanlty. The effort for handling the space and crashes etc. will increase. Additional to this, my landline…
To me, this is no different than the adoption of mobile phones: "Cell phone usage will never overtake landlines, we'll never fix the problems of bandwidth and cell phone towers that need to be installed everywhere. Sure there might be a market for a few million in the US but no more than that".
We do not need Starlink! It only provides service to 9 Million! People We are a planet with 8 Billion People. Do i want cheap and reliable internet everywhere and perhaps work remote? Yes. Should someone like Musk destroy our look into space for just me and my use case? No.
Not to play the musk’s advocate, but there is a case to be made that proving internet access in remote places is more valuable than a perfect night sky. If you live in the cities you can barely see the stars anyway, so you’re not missing much. But in an austere environment, connectivity can be the difference between life and death. It also lowers the bar, encouraging more people to visit wild places and make them mor…
And People survived fine without Starlink
Earlier quoted context omitted.
Its already quite cheap so why are people are not running to Starlink? Probably because a land line has still less latency, doesn't consume that much energy and everyone has either a land line or mobile connection. When Amazon Leo, Eutelsat, Telesat, Chiense and co enter the market, the margin will go down significanlty. The effort for handling the space and crashes etc. will increase. Additional to this, my landline…
I've had no issue with starlink when using it at a friend's house, and I would be happy to use it myself if my internet provider decided to charge me more than what Starlink costs. And fiber has its own costs to install and maintain. A lot depends on the economies of scale for both systems, but to think that base station capacity and kessler syndrome fears are insurmountable obstacles is ridiculous. To me, this is no…
https://www.space.com/space-exploration/international-space-...
https://www.chosun.com/english/industry-en/2025/12/11/55MMV2...
And Starlink, Amazon, China, etc. and co want to send up A LOT more.
We do not need Starlink! It only provides service to 9 Million! People We are a planet with 8 Billion People. Do i want cheap and reliable internet everywhere and perhaps work remote? Yes. Should someone like Musk destroy our look into space for just me and my use case? No.
Not to play the musk’s advocate, but there is a case to be made that proving internet access in remote places is more valuable than a perfect night sky. If you live in the cities you can barely see the stars anyway, so you’re not missing much. But in an austere environment, connectivity can be the difference between life and death. It also lowers the bar, encouraging more people to visit wild places and make them mor…
If you're relying on starlink via a smartphone, you're basically unprepared in any case.
Nice to have, better to be better prepared.
Why doesn't the comet "streak" also, given the Earth's rotation? 10 minutes is a long enough window to have an appreciable impact on the comet's image. Or is it the case that the telescope is stabilized to the Earth's rotation?
Low earth orbit satellites orbit about once per 90 minutes, so in 10 minutes they go about 40 degrees across the sky. The comet is not even orbiting the earth, it's essentially fixed in the sky. The earth only rotates about 2.5 degrees in 10 minutes. So the satellites streak is 16 times longer than the comets.
Let's start with "fixed in the sky" and qualify your frame of reference as the field of distant stars, or the celestial sphere. The common coordinate system is right ascension (RA) and declination (dec).
The GP question was about the Earth's rotation, which would be in terms of azimuth and altitude, and that question's been asked and answered. The key terms there: "equatorial mount" and "clock drive".
The comet C/2025 R3 (PanSTARRS) is in fact near its highest velocity (with reference to the Sun especially), being near perihelion while this photograph was taken. The comet is swinging around the Sun, and it was about 0.49 AU from Earth at the time of the photograph.
https://en.wikipedia.org/wiki/C/2025_R3_(PanSTARRS)
I chose an approximate time on April 27: in 10 minutes of wall-clock time, with the J2000 epoch, the comet's apparent motion is from RA 02h 49m 07.1s, dec +06° 02' 56.5" to RA 02h 49m 15.4s, dec +06° 02' 13.3"
That is a distance of 2' 11.13" across the celestial sphere. For reference, Venus is 11.6" wide in the sky as we see it this week.
24 hours later, we find it at RA 3h 08m 44.1s, dec +04° 19' 27.8". Its apparent motion was 5° 10' 46.02", which is approximately the width of your three middle fingers held together, at arm's length.
So, "fixed in the sky" is not a scientifically useful description of astronomical objects: we need to put that in terms of at least one frame of reference, and "apparent motion" which is how an observer perceives it.
https://soho.nascom.nasa.gov/data/LATEST/latest-lascoC3.html (grab this today; scroll between 4/23 and 4/27)
Earlier quoted context omitted.
I've had no issue with starlink when using it at a friend's house, and I would be happy to use it myself if my internet provider decided to charge me more than what Starlink costs. And fiber has its own costs to install and maintain. A lot depends on the economies of scale for both systems, but to think that base station capacity and kessler syndrome fears are insurmountable obstacles is ridiculous. To me, this is no…
For me its a night sky and astrophotography issue. https://www.space.com/space-exploration/international-space-... https://www.chosun.com/english/industry-en/2025/12/11/55MMV2... And Starlink, Amazon, China, etc. and co want to send up A LOT more.
Earlier quoted context omitted.
Our telescopes actually need the (or at least an) atmosphere to function. There are some classes of observatories, which you cannot build in space but which are still affected by satellites to some degree.
> Our telescopes actually need the (or at least an) atmosphere to function. What about Hubble, Chandra, Spitzer, JWST, etc? As of my understanding, the only reason we haven't built radio and and other long-wave telescopes in space is because of their impractical size preventing them from being deployed in orbit. > There are some classes of observatories, which you cannot build in space but which are still affected by…
The particles need the atmosphere to interact, Cherenkov light is only emitted in an optical medium and because it's optical light we measure we are affected by satellites. Not as strongly as optical telescopes though, because the air showers last for only tens of nanoseconds.
Hot take: We're in the first stages of building our own Dyson sphere and therefore comets are only useful in the context of capturing them for that purpose. ;)
The idea of a Dyson sphere is that it's built around a star, in attempting to capture and utilize 100% of its energy output. So a shady shell around the Earth is not "the first stages" of a Dyson sphere, because our energy source is on the other side of the shell, and the orbits are completely different.