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Living in a city, I didn't understand how big a deal this was until I got a view of the clear night sky in a less populated area recently. The satellites are al

by svara 6y ago

Living in a city, I didn't understand how big a deal this was until I got a view of the clear night sky in a less populated area recently. The satellites are already visible by eye everywhere, and there are only 655 Starlink satellites. There's approval for 12000, and SpaceX is seeking approval for 30000! If they're all going to be this reflective, satellites will be the main thing we see in the night sky a few years from now. Forget about astronomy; 10 years from now you'd be telling your kids "when I was your age we used to be able to see constellations of stars in the sky". By eye, only about ~5000 stars are visible in the night sky.

modeless 6y ago
It's not as big a deal as you think. The satellites are only visible to the naked eye for a few weeks after launch as they travel to their final orbits; after that they are too dim to see. The sky will not appear different than it does now to the naked eye; you will never see thousands of satellites. Most of the bright satellites you see now have been there for many years already; Starlink will not be visible like those.
- Thlom 6y ago
  Maybe, but with tens of thousands of satellites, each with a life expectancy of about 3-5 years then Space X will have to re-fill the constellation constantly.
  - modeless 6y ago
    Sure, you'll be able to see the most recent launch, just as you can now. But you won't see 30,000 in the sky, which is what everyone assumes. Also note that you can't see them at all in the middle of the night; only for an hour or so around sunset and sunrise.
    - totetsu 6y ago
      Isn't sunrise and sunset the prime time for people looking at the sky for aesthetic reasons?
      - valuearb 6y ago
        People yes, who will enjoy seeing satellites. Prime astronomy hours are when Starlink is in the earths shadow.
- svara 6y ago
  How do you know what the final orbits are? Why would they not be visible on the final orbits? Sure, only a fraction of the satellites will be above you and illuminated by the sun, but at 30000 that's still bound to be a huge number. See for example this guy who tried to model this for the lower number of 12000: https://twitter.com/Alex_Parker/status/1132335640605945856 https://twitter.com/Alex_Parker/status/1132335640605945856
  - modeless 6y ago
    The final orbits are approved in advance by the government; there's no mystery. They are not visible to the naked eye in their final orbits because they are farther away and they maintain an orientation that allows their sunshade to reflect sunlight away from Earth instead of toward it.
    - svara 6y ago
      There's actually a good primary source for this cited in the article [0], stating: "However, at low elevations near twilight at intermediate latitudes (45°–55°, e.g., much of Europe) hundreds of satellites may be visible at once to naked-eye observers at dark sites." This is referring to Starlink's 12000 satellite constellation, so thousands absolutely is the order of magnitude we're talking about when (if) they go to the planned 30000 and when other companies do the same. [0] https://iopscience.iop.org/article/10.3847/2041-8213/ab8016 https://iopscience.iop.org/article/10.3847/2041-8213/ab8016
      - modeless 6y ago
        That was before SpaceX added sunshades to Starlink, which reduces their brightness in their final orbits to below the threshold for naked eye visibility. https://www.spacex.com/updates/starlink-update-04-28-2020/ https://www.spacex.com/updates/starlink-update-04-28-2020/
      - valuearb 6y ago
        Only at dusk and dawn, and not when they have visors.
valuearb 6y ago
Starlink is only ever visible at dusk or dawn. It’s orbits are so low they are in the earths shadow for the rest of the night. And new Starlink have visits limiting their reflectivity even during dusk and dawn.
- svara 6y ago
  > And new Starlink have visits limiting their reflectivity even during dusk and dawn. I hope this really does work; as far as I could tell no such satellite has yet reached its final orbit. It boggles the mind that this seems to be an afterthought to something this potentially consequential.
jniedrauer 6y ago
I recently went for a run around Mt Saint Helens, which I started before sunrise. It's a very desolate area, with limited light pollution. I suddenly noticed dozens of satellites flying overhead and was startled by how vivid they were. First time I've ever seen them. My response was to become a little bit choked up. I haven't felt pride in humanity like that for a while. As we become a space faring civilization, the night sky will be influenced by us more and more. It's not worth holding progress back for the sake of a nice view.

by svara 6y ago

modeless 6y ago

It's not as big a deal as you think. The satellites are only visible to the naked eye for a few weeks after launch as they travel to their final orbits; after that they are too dim to see. The sky will not appear different than it does now to the naked eye; you will never see thousands of satellites. Most of the bright satellites you see now have been there for many years already; Starlink will not be visible like those.

Thlom 6y ago
Maybe, but with tens of thousands of satellites, each with a life expectancy of about 3-5 years then Space X will have to re-fill the constellation constantly.
- modeless 6y ago
  Sure, you'll be able to see the most recent launch, just as you can now. But you won't see 30,000 in the sky, which is what everyone assumes. Also note that you can't see them at all in the middle of the night; only for an hour or so around sunset and sunrise.
  - totetsu 6y ago
    Isn't sunrise and sunset the prime time for people looking at the sky for aesthetic reasons?
    - valuearb 6y ago
      People yes, who will enjoy seeing satellites. Prime astronomy hours are when Starlink is in the earths shadow.
svara 6y ago
How do you know what the final orbits are? Why would they not be visible on the final orbits? Sure, only a fraction of the satellites will be above you and illuminated by the sun, but at 30000 that's still bound to be a huge number. See for example this guy who tried to model this for the lower number of 12000: https://twitter.com/Alex_Parker/status/1132335640605945856 https://twitter.com/Alex_Parker/status/1132335640605945856
- modeless 6y ago
  The final orbits are approved in advance by the government; there's no mystery. They are not visible to the naked eye in their final orbits because they are farther away and they maintain an orientation that allows their sunshade to reflect sunlight away from Earth instead of toward it.
  - svara 6y ago
    There's actually a good primary source for this cited in the article [0], stating: "However, at low elevations near twilight at intermediate latitudes (45°–55°, e.g., much of Europe) hundreds of satellites may be visible at once to naked-eye observers at dark sites." This is referring to Starlink's 12000 satellite constellation, so thousands absolutely is the order of magnitude we're talking about when (if) they go to the planned 30000 and when other companies do the same. [0] https://iopscience.iop.org/article/10.3847/2041-8213/ab8016 https://iopscience.iop.org/article/10.3847/2041-8213/ab8016
    - modeless 6y ago
      That was before SpaceX added sunshades to Starlink, which reduces their brightness in their final orbits to below the threshold for naked eye visibility. https://www.spacex.com/updates/starlink-update-04-28-2020/ https://www.spacex.com/updates/starlink-update-04-28-2020/
    - valuearb 6y ago
      Only at dusk and dawn, and not when they have visors.

valuearb 6y ago

Starlink is only ever visible at dusk or dawn. It’s orbits are so low they are in the earths shadow for the rest of the night. And new Starlink have visits limiting their reflectivity even during dusk and dawn.

svara 6y ago
> And new Starlink have visits limiting their reflectivity even during dusk and dawn. I hope this really does work; as far as I could tell no such satellite has yet reached its final orbit. It boggles the mind that this seems to be an afterthought to something this potentially consequential.

jniedrauer 6y ago

I recently went for a run around Mt Saint Helens, which I started before sunrise. It's a very desolate area, with limited light pollution. I suddenly noticed dozens of satellites flying overhead and was startled by how vivid they were. First time I've ever seen them. My response was to become a little bit choked up. I haven't felt pride in humanity like that for a while. As we become a space faring civilization, the night sky will be influenced by us more and more. It's not worth holding progress back for the sake of a nice view.