Were there conditions created on earth to see how space would be like? What was the theory based on if an experiment was conducted? Or what’s it literally just – let’s just send it up and see what happens to it?
In: Physics
Gravity is very much present in space. Our first observations of gravity as a universal force (as opposed to just “object go down durr”) involved looking at the motion of planets. Johannes Kepler observed the elliptical motion of celestial bodies, and came up with a few basic mathematical rules to describe them. These are kepler’s laws, and you can look them up if you’re curious.
Decades later, Isaac Newton realized that an inverse square law force could cause the motion that Kepler had observed. This lead him to develop an equation for gravity, based on the inverse square of distance; F=k/r^2 – this is to say that the force between two objects decreases with the square of the distance between those objects. He also noted that this force scales with the mass of each object; this is fairly easy to prove. An object with double the mass experiences twice the force. Since all forces experience and equal and opposite reaction, this force must apply similarly to both objects, allowing us to come up with a more sophisticated equation. We replace “k”, the unknown number in our earlier equation, with M1 x M2 x some new unknown number, known as G. Thus, F=M1 x M2 x G / r^2
This gives us the modern equation for gravity, which predicts its exact force at any location in the universe based upon what is nearby.
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