As an avid lover of conspiracy theories, I recently found myself sucked into the black hole that
is “Flat Earth Theory”. As crazy as it sounds, supporters of this theory claim that the Earth is
a flat disk, that it does NOT rotate nor orbit around the sun, that gravity does not exist and,
obviously, that there are no real proofs that the Earth is round. Just for fun, I have attached
below a picture of their model of the Earth.
But why do the Flat Earthers reject the round model of the Earth? And how do we actually know that
the Earth is round? One of the claims that Flat Earthers utterly reject is that, on the account of Earth’s rotation around its axis, someone on the surface of the Earth is moving at a speed of around 1000 miles per hour!!!
the Earth is round? One of the claims that Flat Earthers utterly reject is that, on the account of Earth’s rotation around its axis, someone on the surface of the Earth is moving at a speed of around 1000 miles per hour!!!
v=w*r=[2*π/(24*3600)]*6.371*1,000,000=463 m/s=1036 mph
Flat Earthers will say that this is outrageous and if the Earth was truly rotating at such speed we
would feel it. But if everything else around you is moving at the same speed, would you notice it?
Think about being on an airplane that is cruising smoothly through the air. As long as there is no
turbulence or abrupt stops, you would not know how fast your moving!
would feel it. But if everything else around you is moving at the same speed, would you notice it?
Think about being on an airplane that is cruising smoothly through the air. As long as there is no
turbulence or abrupt stops, you would not know how fast your moving!
But this in itself neither proves nor disproves that the Earth rotates.
Can we actually measure the Earth’s angular rotation? It turns out that we can!
To do that we will rely on a super cool device called a gyroscope and our concepts of rotational motion.
Can we actually measure the Earth’s angular rotation? It turns out that we can!
To do that we will rely on a super cool device called a gyroscope and our concepts of rotational motion.
A gyroscope is a very simple device that consists of a central rotor and three supporting rings
called gimbals.These gimbals consist of friction-less bearings that isolate the central rotor from
outside torques. In other words, if we rotate the rotor along its spin axis, it will resist torques in other
directions (along other axes of rotation) due to conservation of angular momentum. Thus if we have
a spinning gyroscope on the surface of the Earth for long enough, it will appear as if it’s spin axis is
completing a rotation in 24 hours, but really the axis itself is not moving (since it resists rotation in
other directions), it is us and the Earth that is moving!
called gimbals.These gimbals consist of friction-less bearings that isolate the central rotor from
outside torques. In other words, if we rotate the rotor along its spin axis, it will resist torques in other
directions (along other axes of rotation) due to conservation of angular momentum. Thus if we have
a spinning gyroscope on the surface of the Earth for long enough, it will appear as if it’s spin axis is
completing a rotation in 24 hours, but really the axis itself is not moving (since it resists rotation in
other directions), it is us and the Earth that is moving!
You can see this illustrated and explained in greater detail in this video: https://www.youtube.com/watch?v=XHGKIzCcVa0
Most importantly, however, using high sophisticated gyroscope, people have been able to measure the angle of Earth's rotation and from that, its angular velocity. Thus, we do have proof that the Earth rotates!
Sources:
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.