Observing a planetoid orbiting fra from the sun astronomers notice that the object slows down in its orbit in a way they did it expectt. Which is a reasonable conclusion
One reasonable conclusion is that there is an external force acting upon the planetoid, causing it to slow down in its orbit. This force could be gravitational, meaning there is another massive object nearby exerting a gravitational pull on the planetoid. Alternatively, it could be due to some kind of atmospheric drag or other frictional force. Further investigation and analysis would be needed to determine the exact cause of the unexpected slowing.
