Lots of people these days actually think that the Earth is flat. There's an entire society, The Flat Earth Society (https://www.tfes.org), that is trying to spread this lie as much as they can. Even influential people, such as Shaquille O-neal, are spreading this belief. As a physicist, the existence of this spreading rumor actually hurts me. I hope you fellow members of the Steemit community are smart enough to know the Earth actually isn't flat, but if you're not convinced, check out this experiment I did.
From the Flat Earth Society's website, I went through all of their reasoning on why they think the Earth is flat. They seemed to have an excuse to explain almost everything: photos being altered, space travel being a conspiracy, etc. These can all be found at https://wiki.tfes.org/Frequently_Asked_Questions. While it is difficult to disprove a lot of these beliefs with scientific experiments (because they won't even believe in photos of the Earth being round), I thought of the easiest and most convincing flaw to scientifically disprove: their belief on gravity.
To put simply, they don't believe gravity exists at all. They state, "the earth isn't pulled into a sphere because the force known as gravity doesn't exist or at least exists in a greatly diminished form than is commonly taught. The earth is constantly accelerating up at a rate of 32 feet per second squared (or 9.8 meters per second squared). This constant acceleration causes what you think of as gravity. Imagine sitting in a car that never stops speeding up. You will be forever pushed into your seat. The earth works much the same way. It is constantly accelerating upwards being pushed by a universal accelerator (UA) known as dark energy or aetheric wind."
So I decided to prove that gravity does in fact exist. With their logic, gravity will only have a downward effect on objects towards the Earth. However, any objects in the universe have a force of gravitational attraction between them. We only usually experience gravity pulling things down towards Earth because it is the most significant force of gravity by far while standing on the surface of our planet. This experiment, however, showed that two masses have a force of attraction between them which caused them to move towards each other.
The Setup
Two balls each with a mass m are connected by a rod with length 2l. Two more balls, each with mass M are placed, one on one side of each of the smaller balls, a distances H from their natural equilibrium position. The balls with mass m are attracted to the larger balls with mass M, and the rod moves some angle theta. This is illustrated below. It is crucial to note that the rod had almost no forces of friction acting on it.
The movement of the rod was measured by attaching a small mirror to the center of the rod. A laser was pointed at this mirror from across the room, and its reflection was captured by a photodiode which recorded the movement of the laser. Every few hours, the large masses were moved to the opposite sides of the balls so they can reach a new (opposite) equilibrium point. This was repeated ten times.
Results
In order to prove gravity does exist, I simply needed to show that the rod actually rotated (which it did). Every time the large masses were moved to the opposite sides, the rod rotated accordingly. The figure below (axises not labeled , sorry), shows the movement of the rod over time. The x-axis is time, and the y-axis is the angle (arbitrary units on figure) theta. You see oscillations because as the rod moves past the equilibrium point, it has a certain amount of momentum to make it go past its equilibrium point, but it eventually reaches an equilibrium.
With some further analysis of the results, a gravitation constant, G, was calculated to be 6.85 x 10^-11 NM2/Kg2. This is extremely close to the accepted value for this constant of 6.67 x 10^-11 NM2/Kg2. So yea, gravity is real.
Conclusion
Sorry Flat Earth believers, these masses were attracted to each other by something. Can you explain what their force of attraction was if it wasn't gravity? I would love to hear what you can come up with for this one!
Neil Degrassi Tyson is right on this one. Check out this video of him if you want a good laugh.
I hope this rumor that the Earth being flat ends soon. We have worked so hard to get to the technological advances we have today. Believing things like this is just making us take steps backwards. I hope, as a Steemit community, we can agree that the Earth is not flat!
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