Yes, they did otherwise. How would they have made the first model of solar system it was wrong because gravity wasn't factored into it when the second model came out it traced orbits based on the concept of gravity, well the calculations were not hundred percent it still was close enough when you applied it in small numbers to find location of said item. Considering there limited tech and understanding it's amazing how well they did.

Second Ancient thinkers, from Aristotle in the West to Brahmagupta in the East, had theorised that objects were attracted to each other. Which is partially right as Newton would add direction(towards the centre) and give it mathemical representation/ gravitational force direction which change how the angle of force. Even though they math was off, they still had gravational force as a force of attraction espressesed as the orbital pathes of planets. The method was not perfect as it only counted gravational force, but that still put into their measurements and comparison.

Yes, they did when a commit is tracked for say a long time and their machine. https://en.m.wikipedia.org/wiki/Antikythera_Mechanism

Was off on predicting a comets path, which means they knew some new or force was being but on it. Considering greeks and Roman's had many scientist back then tracking things with similar results they estimate more planets or forces out there affecting a comets path, especially since the mass moved in the sky as disruptions were tracked as planets moved in their orbit.

This theory was still theory, but they knew more forces were out there. Because well not perfect as ours they had working orbit and trackable system. They were able to track and predict comets' paths with it when something moved a commit and no planet was around to have force on is how they realized other wandering masses must be out there. They knew there had to be other things affecting that they could observe things like this. So the theories were write just not provable. At there level of ablities.

Like I said, they couldn't prove they were but estimated planets of other data. they had tools that would help them find objects such as Mars or a comet around Mars, etc. When in certain areas, there tools would be slightly off due to gravitational fields of large masses out beyond visible range. Well, the math was basic it proved there was what essentially was discovered. I'm not saying they had the tech or power that was used to conferm them like others later, only that in certain areas, masses existed and likely to be planets.

They used math well not as good as what we had. There are many asteroids that went of course due to what we now call Neptune and Pluto as the gravity it caused movements inconsistent with its path. Since they corectly guessed objects had no mass and traveled straight short of external forces such as gravity or transition of energy such as object acting to them selfs. This led to them thinking there were more plants based on this but could prove more than a gravitional force more likely planet based on planet behaviors they could observe. Like I said they knew about it but could say 100 what it was.

Sorry, I think it was Greeks they did math and found grational forces outside of expectations, according to their limited data. They knew something else orbited out there just obviously couldn't prove it with telescopes. Which was the transfered to Pluto in Roman mythologies. If greeks/Roman's named planets how was Pluto named after this object?

You do know Roman's actually figured out Pluto before 1930. Just was observable till 1930

Hey hey hey, I put the die in diabeties, or close enough lol

Fat Albert haunting your bathroom. Lmao