[jojo]

The experimental principle is based on a sphere, which is different from a plane。
1：Assuming that the earth is round, we select the latitude and longitude of the equator on the globe. According to this mark, we go to the corresponding place to put down the eye-catching sign, and then use the drone to observe. If the sign is a straight line, it means the earth is round, otherwise it is flat.
2:We all know about the Japanese nuclear radiation leak。
We can take advantage of these trajectories of nuclear radiation. If the earth is round, these nuclear radiation trajectories will continue to circulate and the concentration will continue to increase. If the nuclear radiation trajectories continue to spread to the outside and the concentration weakens, it means that the radiation flows to the outside, and the earth has boundaries!

[Tumeni]

we select the latitude and longitude of the equator on the globe. According to this mark, we go to the corresponding place to put down the eye-catching sign, and then use the drone to observe. If the sign is a straight line, it means the earth is round, otherwise it is flat.

The equator of the Earth, or any sphere, is not defined by a combination of latitude and longitude. It is a longitudinal line which does not deviate in latitude.

It is not a "mark"

You may want to rethink.

[Srilikhith Sajja]

I agree with jojo

[Tumeni]

I agree with jojo

Great. Can you explain further?

[BillO]

2:We all know about the Japanese nuclear radiation leak。
We can take advantage of these trajectories of nuclear radiation. If the earth is round, these nuclear radiation trajectories will continue to circulate and the concentration will continue to increase.

Can you explain this?  Normal rules for turbulence/wind/moving atmosphere/mixing/settling would suggest that the concentration of radioactive particles would decrease regardless whether the earth was flat or a globe.

[jojo]

2:We all know about the Japanese nuclear radiation leak。
We can take advantage of these trajectories of nuclear radiation. If the earth is round, these nuclear radiation trajectories will continue to circulate and the concentration will continue to increase.

Can you explain this?  Normal rules for turbulence/wind/moving atmosphere/mixing/settling would suggest that the concentration of radioactive particles would decrease regardless whether the earth was flat or a globe.

The earth is likely to be an island, and the nuclear radiation at the boundary of the earth will be scattered around the earth along with ocean currents

[buoyantOne]

If the nuclear radiation trajectories continue to spread to the outside and the concentration weakens, it means that the radiation flows to the outside, and the earth has boundaries!

If the earth had boundaries caging in the oceans and seas, the radiation would build up at the boundaries.  The boundaries should have a buildup of radiation outlining their presences.  Well, also trash and pollution would be built up at the boundaries.