<human>: Is there evidence that the earth is round?
<bot>: Yes, there is a lot of evidence that the earth is round. For example, we can see the curvature of the Earth from space with satellites and astronauts have even photographed it from the moon. Additionally, gravity measurements taken by spacecraft show that the force of gravity varies depending on location on the surface of the planet. This suggests that the gravitational pull of the Earth is not uniform across its entire surface. Finally, scientists have used radar to map out the topography of the ocean floor, which has been found to be very similar in shape to the continents. All of this points to the conclusion that the earth is indeed spherical.