Station - Simulation of space-time geometry

Science trails have existed at Príncipe island since 2013. Every year, teachers and students from the Secondary School in Santo António create new experiences. This was one of them!

Try it… Place the ball of greater mass in the center of the lycra fabric

What happens to the lycra?

Why is this?

The Theory of General Relativity describes the gravitational field of a body through deformations of space-time, in 4 dimensions.

Thus, space-time, in the absence of gravitational forces, can be compared to a piece of lycra stretched horizontally. In the presence of a body, for example a star, space-time “sinks” just like what happens when you place a heavy ball on the lycra. Thus, the way in which one body moves around another is not due to a force of attraction, but to the curvature of space-time itself.

Also try… throw the other ball, in a straight line, to the lycra so as not to hit the ball in the center.

Did the trajectory of the ball with the lowest mass remain in a straight line or did it follow the curvature caused by the first?

Space-time geometry simulation experiment.

Did you know?

Light rays from stars behave as if they have weight and suffer deflection as they pass near a large gravitational mass, like the Sun. When they graze the surface of the Sun, the value of this deflection is 1.75 arcseconds (1 arcsecond corresponds to 1 part of a degree divided into 3600 parts).

As we have just seen, the movement of the second, less massive ball follows the curvature caused by the larger ball.

Now it’s your turn… throw several marbles at the same time and observe their trajectories.