I told you exactly what the gif is,
It's a sphere scaled to the size of the earth.
The camera originates at the top center on the surface of the sphere, and then ascends at a 90 degree angle until the horizon is no longer visible.
But you're more concerned with where the gif came from.
How bout this,
- go in a 3D program, create a sphere.
- Scale it to the size of the supposed globe earth (24,901 miles = 131,477,280 feet).
- Add a camera and set it at the top of the sphere.
- Animate the camera so that is ascends along the Y axis until the sphere is no longer visible.
- Render it.
- Convert it to a gif.
- Upload the results and show me what you got.