It is odd that you highlight the Bedford Level Experiment, rather than other methods that have been used for thousands of years. The new experiment has the advantage that it can be performed by a single person in a single afternoon. It has the disadvantage that it shows that the Earth is flat.
Eratosthenes measured the north-south curvature of the Earth by making observations separated by hundreds of miles. It could be applied east-west with good clocks, or, as you suggest, with the simultaneity of telephones. Since I’d have to travel hundreds of miles anyway to reach the straight canal in Bedford, it has little advantage over Eratosthenes’s method. I suppose you could make a similar observation by climbing a mast on a ship the right distance from shore, but the ocean waves add noise not present on the canal. It does have the advantage of requiring less geometry. Since the Bedford experiment used 1⁄100 the distance, it required 100x the accuracy of angular measurement. This is easy to overlook, since the measurement is not phrased that way, but I think this is why it encounters new sources of error.
Older experiments are generally easier. While everything is easier to measure today, the main advance is in measuring time.
Bedford Level Experiment [...] has the disadvantage that it shows that the Earth is flat.
I love this. As it happens, I live quite near Bedford and am terribly tempted to actually try it one day. (Edit Looking closer, turns out the Bedford Level is in Norfolk, not Bedfordshire, so a little less nearby than I thought.)
There are loads of fun ways of verifying that the Earth isn’t flat. Some of these were easily available to the ancients—e.g. the shape of the shadow of the Earth on the Moon during a lunar eclipse (it’s always a curve). Others are easier now than they used to be—e.g. the variations in the constellations you can see as you travel north-south (it’s much easier to travel far enough to see this than it used to be).
Some, however, simply weren’t available.
My favourite explanation for how we know for sure the Earth is round is that we’ve been up in to space and looked. You can even verify this yourself with a GoPro and a high-altitude balloon, which many hobbyists have done.
It is odd that you highlight the Bedford Level Experiment, rather than other methods that have been used for thousands of years. The new experiment has the advantage that it can be performed by a single person in a single afternoon. It has the disadvantage that it shows that the Earth is flat.
Eratosthenes measured the north-south curvature of the Earth by making observations separated by hundreds of miles. It could be applied east-west with good clocks, or, as you suggest, with the simultaneity of telephones. Since I’d have to travel hundreds of miles anyway to reach the straight canal in Bedford, it has little advantage over Eratosthenes’s method. I suppose you could make a similar observation by climbing a mast on a ship the right distance from shore, but the ocean waves add noise not present on the canal. It does have the advantage of requiring less geometry. Since the Bedford experiment used 1⁄100 the distance, it required 100x the accuracy of angular measurement. This is easy to overlook, since the measurement is not phrased that way, but I think this is why it encounters new sources of error.
Older experiments are generally easier. While everything is easier to measure today, the main advance is in measuring time.
I love this. As it happens, I live quite near Bedford and am terribly tempted to actually try it one day. (Edit Looking closer, turns out the Bedford Level is in Norfolk, not Bedfordshire, so a little less nearby than I thought.)
There are loads of fun ways of verifying that the Earth isn’t flat. Some of these were easily available to the ancients—e.g. the shape of the shadow of the Earth on the Moon during a lunar eclipse (it’s always a curve). Others are easier now than they used to be—e.g. the variations in the constellations you can see as you travel north-south (it’s much easier to travel far enough to see this than it used to be).
Some, however, simply weren’t available.
My favourite explanation for how we know for sure the Earth is round is that we’ve been up in to space and looked. You can even verify this yourself with a GoPro and a high-altitude balloon, which many hobbyists have done.