Pardon my lack of knowledge about this.
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Satellites are expensive and offer less bandwidth.
If you need a extremely fast connection with nearly perfect reliability, laying cables always will be the best option.
Satellites are great for “send out a signal that every TV dish and every phone GPS can pick up” but the actual bandwidth, the number of bits they can transmit per second, is relatively low. Thus, they aren’t great for sharing two-way communications among millions of pairs of computers.
Fiber optics have fantastic bandwidth. It’s also a lot easier to lay additional cables than to launch additional satellites.
Fiber optics are capable of *far* more bandwidth than even the fastest satellites. Without fiber optics we wouldn’t be able to handle nearly the volume of data that we do. Satellites are also subject to space weather (and occasionally normal weather) disruption, fiber optics are essentially immune except for the occasional backhoe blade.
Nothing travels faster than light*, and that’s what fiber optics rely on for signals. It’s also very hard for weather to get in the way of a fiber optic cable the way it can for satellites.
Speed. The lights blink quicker than the waves pulse. Also there is less of a worry about interference. Lights go anywhere the cables go, but radio waves can be blocked by walls, bad weather and stuff.
Satellites, especially those in a traditional geostationary orbit are actually really far away. So far that the time it takes for a signal to go from the surface, to the satellite and back to the surface would introduce a pretty noticeable lag.
Not to mention the cost of launching and maintaining a satellite.
Satellites are useful in situations where you can’t put in infrastructure, and that is the main business case for Starlink at the moment, but laying cables will be the better option, for the foreseeable future.
So here’s my boxed explanation for bandwidth;
Picture all the information you’re sending and receiving as literal printed out paper, put into manilla envelopes and then stuffed inside bankers boxes.
If you want to send and receive that data, you have to load it into your car and take it somewhere and drop it off/pick it up
The bandwidth (commonly, erroneously referred to as speed) of your plan determines how many boxes fit in your car. If you’ve got a 100 Mbps plan you can fit 10 boxes in the back of your car. If you’re on 1gbps you can fit 100 boxes in the back of a pick up, that kind of thing.
The actual speed (this is what ping measures) of your connection is determined by the medium. Think of that as the speed limit on the road for your car/truck full of boxes.
A higher bandwidth plan isn’t “faster” than a low bandwidth one on the same style of connection because it’s strictly faster, it’s “faster” because it’s more.
If you have a car and a truck on the same road but you have 200 boxes to move the truck will get it done faster, not because the truck itself gets to the pickup/dropoff point faster, but because it gets it all done in 2 trips instead of 20.
So essentially in this example fibre optic has a much better highway and a much better pick up/drop off point. Satellites are very expensive and because they’re broadcasting over the air instead of a nice private cable they have to contend with interference, capacity and so many more issues that people have already covered here.
I used to build products to support satellite communications. A geosynchronous satellite is ~1/8 of a second away at the speed of light. That’s REALLY far away!!!
So if you want to connect to something, your signal first goes to the satellite (.125s), then back down to earth (.250s), then out to the actual internet and back (.325s), then back up to the satellite (.5s) then back to you (.625s).
That’s two thirds of second for each round trip. While the amount of satay that is returned to you might stream quickly after that, these latencies cause huge delays in communications.
For instance, if you want to open pets.com. You will send the request for the address of pets.com, which you’ll get back in, say, .75 seconds. Now you need to connect, that’s a connection request, an acknowledgement from the server, acknowledgement from you, so another .75 seconds. Now you need to request what you want from them, another .75 seconds. Your best case for a page to start loading is .75×3 or just over two seconds.
Now each image you want to load has another 1-2 second delay on top of that. You won’t be happy…
Starlink eliminates this problem by having thousands of low orbit satellites, so the time to reach them is much faster.
Believe it or not, but optic cables are faster basically no matter the distances involved.
Fiber optic cables go a bit slower than satellite (due to all the repeaters and routing involved), but it’s really not *that* big a difference. For the purposes of discussion we can say they both go roughly the speed of light.
The satellites are generally in geostationary orbit, roughly 22,236 miles straight up (though usually not straight up, so the actual distance between you and the satellite is longer). A signal has to go from ground to satellite to ground, so it has to travel ~44,000 miles.
For comparison, the entire circumference of earth is about 24,901 miles. It takes a bit less than twice as long for the data to be sent via satellite than to go the long way around to your neighbors house.
Obviously it’s more complicated than that. There’s the time it takes for routing, the time it takes for repeaters extend the range of the signals, the distance the data has to travel to/from the ground stations, the fact that fiber cables don’t run straight across the planet, you might have to bounce a signal from satellite to satellite to get line of sight, etc, etc, etc.
Lots of factors, but it all ultimately adds up to even if we completely disregard the cost of lofting the hardware into space and the incredible amounts of hardware required to be in space for everyone to use satellite-only, the fastest the data can go is still far slower than any reasonable, or even unreasonable, fiber optic routes.
Going pure satellite when fiber is an option is worse in every possible way. It’s slower, it’s more expensive, it’s dependent on the weather, it requires clear line of sight to the sky. It’s just worse except in very narrow circumstances.
Some elaboration on why fiber has more bandwidth than satellite, and why it’s easier to increase bandwidth with fiber than copper.
Transfer of any data over a channel is bandwidth limited. For a satellite channel (or a broadcast tv or radio channel, or an analog telephone modem) the limit is based on the frequency of the carrier wave. For a simplified example, clap your hands about 1x/second. Consider that as sending a series of “1s” at the rate of 1Hz (one/second). Now skip a clap every once in a while – you’ve now demonstrated the ability to send 0s (no clap) and 1s. Increasing the frequency at which you do this increases the bandwidth. There’s a physical limit to every transmission mechanism for the maximum amount of data that can be encoded in a carrier wave.
For satellite communications the major limitation is that there are a limited number of Ku-band frequencies that are available for use by all commercial satellites – your data has to share bandwidth with everyone else in your region (where the satellite transmitter/receiver is pointing). No matter how fast it is there’s only so much data that can flow through the pipe.
Copper wires are point-to-point, so are less convenient than satellites in some ways, but copper wires are very fast – electrons move at decent fraction of the speed and with shielding to insulate wires from one another they can be bundled together. However shielding is expensive and as bandwidth needs have increased copper became less practical.
Fiber optic cables are also point-to-point. Unintuitively, light transmission through fiber optic cables is actually slower than electricity through copper, the bandwidth on any given strand of fiber is less than that of a copper wire. However because of how light reflects down a relatively straight strand of fiber the light in that strand stays within the strand, so there is zero interference between strands in a fiber optic cable bundle. That means you can get an incredible amount of bandwidth out of the many strands of fiber that make up a cable.
So when you hear people say that fiber has more bandwidth what they’re really saying is that a fiber cable, made up of many data transmission channels (1/strand) has more bandwidth than a less easily multiplexed copper or satellite transmission channel.
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