4 ms·

"Starlink is currently in orbit at 340 miles" Can we please stop using miles etc :( I am tired when people makes mistake like this.

VWWHFSfQ 5y ago
what should they use
- azernik 5y ago
  Kilometers. If they're writing for a US audience and absolutely need miles, put one or the other in parens after the "main" one.
  - krapht 5y ago
    People who get irritated over units of measure are themselves irritating. It is not so hard to round, double it 4 times and then divide by 10.
    - skissane 5y ago
      When US-based companies put things in US measurements and don't provide metric conversions, it makes me (as a non-American) feel like they aren't thinking about their non-US customers. It appears parochial. Miles I can roughly convert in my head, but I have really no idea what a gallon or a fluid ounce is. I remember a pound is a bit under 500 grams but can't remember how many ounces in a pound. Fahrenheit to Celsius, I know there is a 5/9 and a 32 involved, but I don't remember exactly what to do with them. What makes it worse here is that the original measurement was in kilometres – kilometres are the standard unit for measuring orbital altitudes in the space industry, even in the US-based space industry – and someone has gone to the trouble of converting that to miles and then omitting to include the original measurement.
    - lutorm 5y ago
      For practical purposes, I get by 99% of the time with 1 (statute) mile == 1.5km.
      - cryptonector 5y ago
        The conversion factor is very close to the golden number, so if you just remember the Fibonacci sequence up to around 89 you'll be able to do mental conversions easily enough. E.g., what's 65mph in kmh? Well, the nearest Fibonacci number to 65 is 55, so 65 == 55 + 10, and the next Fibonacci number to 55 is 89, so 65mph will be 89kmh + ??, now we turn to 10mph and notice it's 8 + 2, so it's really 13kmh + 3kmh, which brings us to 65mph ~= 89kmh + 13kmh + 3kmh = 105kmh. My calculator says the actual conversion of 65mph to kmh is 104.60736, so... that's really close! This is a very fun little mental exercise to do. Obviously it works in both directions. Let's apply it to 340mi. The bracketing Fb numbers are 233 and 377. 377 - 340 == 33. Next after 377 is 610, so 377mi ~= 610km. Next after 33 is 55, so 340mi = 377mi - 33mi ~= 610km - 55km = 555km. My calculator says it's 547.17696km. Close!!
    - hackeraccount 5y ago
      I agree with that. Also I used to run road races so I know 10K is 6.2 miles - it also helps because I have a feel for just what 10K means if you follow. Also - drive around and you more or less know what 100kph is in a car. But mainly - I understand the point but the reasonable complaining gets mixed up - in a frankly counter-productive way - with political signaling.
ncmncm 5y ago
Yes, the useful unit is light-milliseconds: $ units You have: 340 mi You want: light ms * 1.8251859 / 0.5478894 So, 3.6 ms round-trip. In practice, the route will be slanted, so could just exceed 5 ms. $ sudo apt install units Once the constellation is mature, certain very-high-paying subscribers will get the packets forwarded from one satellite to the next via laser links, across oceans, before being downlinked, and get there a few ms before packets dawdling along on fiber links below 0.7c, to trigger securities trades ahead of the crowd acting on now-ancient information. The time by fiber from Singapore to New York is on the order of 90 ms, where Starlink ought to get them there in well under 70 ms, leaving a good 20 ms to arbitrage. In investment banking, they say "a microsecond is an eon, a millisecond is an eternity". Even just between New York and London, they can gain a few ms headway, enough to dominate. It would not be surprising if the US military, and maybe some others, will have access to satellite-to-satellite routing. (They have their own WGS, "Wideband Global SATCOM", but it is GEO, thus high-latency.) AFAIK, only the polar-orbit nodes have inter-satellite laser links, thus far, so this is a phenomenon of the near future, not the present. Other things to expect in the near future are lofting them with a few TB of storage, to minimize uplink bandwidth by edge-serving Disney and Netflix blockbusters; and multicast downlinks for real-time soccer games and maybe even time-binned shows.
- cryptonector 5y ago
  Why was this downvoted though?
  - ncmncm 5y ago
    This one guy watches and downvotes everything I post, lately.
    - NetOpWibby 5y ago
      And continues to, welp. Someone apparently has time today.
- nonameiguess 5y ago
  Military already has this: https://en.wikipedia.org/wiki/Wideband_Global_SATCOM https://en.wikipedia.org/wiki/Wideband_Global_SATCOM The SpaceX edge here is making this kind of thing cheaper and scalable to the point that a global community of hundreds of millions of users can multiplex signals on it, but for a sufficiently well-funded organization with fewer users, it was already possible.

VWWHFSfQ 5y ago

what should they use

azernik 5y ago
Kilometers. If they're writing for a US audience and absolutely need miles, put one or the other in parens after the "main" one.
- krapht 5y ago
  People who get irritated over units of measure are themselves irritating. It is not so hard to round, double it 4 times and then divide by 10.
  - skissane 5y ago
    When US-based companies put things in US measurements and don't provide metric conversions, it makes me (as a non-American) feel like they aren't thinking about their non-US customers. It appears parochial. Miles I can roughly convert in my head, but I have really no idea what a gallon or a fluid ounce is. I remember a pound is a bit under 500 grams but can't remember how many ounces in a pound. Fahrenheit to Celsius, I know there is a 5/9 and a 32 involved, but I don't remember exactly what to do with them. What makes it worse here is that the original measurement was in kilometres – kilometres are the standard unit for measuring orbital altitudes in the space industry, even in the US-based space industry – and someone has gone to the trouble of converting that to miles and then omitting to include the original measurement.
  - lutorm 5y ago
    For practical purposes, I get by 99% of the time with 1 (statute) mile == 1.5km.
    - cryptonector 5y ago
      The conversion factor is very close to the golden number, so if you just remember the Fibonacci sequence up to around 89 you'll be able to do mental conversions easily enough. E.g., what's 65mph in kmh? Well, the nearest Fibonacci number to 65 is 55, so 65 == 55 + 10, and the next Fibonacci number to 55 is 89, so 65mph will be 89kmh + ??, now we turn to 10mph and notice it's 8 + 2, so it's really 13kmh + 3kmh, which brings us to 65mph ~= 89kmh + 13kmh + 3kmh = 105kmh. My calculator says the actual conversion of 65mph to kmh is 104.60736, so... that's really close! This is a very fun little mental exercise to do. Obviously it works in both directions. Let's apply it to 340mi. The bracketing Fb numbers are 233 and 377. 377 - 340 == 33. Next after 377 is 610, so 377mi ~= 610km. Next after 33 is 55, so 340mi = 377mi - 33mi ~= 610km - 55km = 555km. My calculator says it's 547.17696km. Close!!
  - hackeraccount 5y ago
    I agree with that. Also I used to run road races so I know 10K is 6.2 miles - it also helps because I have a feel for just what 10K means if you follow. Also - drive around and you more or less know what 100kph is in a car. But mainly - I understand the point but the reasonable complaining gets mixed up - in a frankly counter-productive way - with political signaling.

ncmncm 5y ago

Yes, the useful unit is light-milliseconds: $ units You have: 340 mi You want: light ms * 1.8251859 / 0.5478894 So, 3.6 ms round-trip. In practice, the route will be slanted, so could just exceed 5 ms. $ sudo apt install units Once the constellation is mature, certain very-high-paying subscribers will get the packets forwarded from one satellite to the next via laser links, across oceans, before being downlinked, and get there a few ms before packets dawdling along on fiber links below 0.7c, to trigger securities trades ahead of the crowd acting on now-ancient information. The time by fiber from Singapore to New York is on the order of 90 ms, where Starlink ought to get them there in well under 70 ms, leaving a good 20 ms to arbitrage. In investment banking, they say "a microsecond is an eon, a millisecond is an eternity". Even just between New York and London, they can gain a few ms headway, enough to dominate. It would not be surprising if the US military, and maybe some others, will have access to satellite-to-satellite routing. (They have their own WGS, "Wideband Global SATCOM", but it is GEO, thus high-latency.) AFAIK, only the polar-orbit nodes have inter-satellite laser links, thus far, so this is a phenomenon of the near future, not the present. Other things to expect in the near future are lofting them with a few TB of storage, to minimize uplink bandwidth by edge-serving Disney and Netflix blockbusters; and multicast downlinks for real-time soccer games and maybe even time-binned shows.

cryptonector 5y ago
Why was this downvoted though?
- ncmncm 5y ago
  This one guy watches and downvotes everything I post, lately.
  - NetOpWibby 5y ago
    And continues to, welp. Someone apparently has time today.
nonameiguess 5y ago
Military already has this: https://en.wikipedia.org/wiki/Wideband_Global_SATCOM https://en.wikipedia.org/wiki/Wideband_Global_SATCOM The SpaceX edge here is making this kind of thing cheaper and scalable to the point that a global community of hundreds of millions of users can multiplex signals on it, but for a sufficiently well-funded organization with fewer users, it was already possible.