If you mean gravitation, no one has any idea - from the dullest of the dull to the most credentialed and accomplished physicist.
Gravity (a scientific law, millennia old), on the other hand - is another matter entirely.
Why do things fall?
Because they weigh more than the media they displace. Weight is an intrinsic and inexorable property of matter, and not imbued by magical "fields" of perpetually (3+ centuries now) mysterious and completely imaginary (at best) composition and mechanism.
why do other planets have more or less gravity than earth
Do they? Or do you just believe that they do because someone told you that was a fact? Because you saw someone playing an astronaut hit a golf ball on the tv?
In my view, and that of our ancestors, the planets we see in the heavens are nothing like the earth we stand on. They are wandering stars; luminaries. They are above us, not below. They are not giant rocks or balls of gas. Admittedly, i know how insane that sounds to most.
or does weight magically change depending on where the weight exists in space ?
No, weight remains more or less constant. Effective weight (what we commonly/colloquially refer to as weight : i.e. measured on a scale) varies with many factors - most notably buoyancy - but its intrinsic/actual weight generally does not. Although a battleship floats on water or a dirigible measures 0 when placed on a scale, that does not make their actual weight any less phenomenal or different than the materials they are built/composed of.
Huh? All the planets are shaped like discs. It's the earth which isn't a planet [wandering star].
What shape the earth is has no relevance to the shape of the things in the sky which are obviously not the earth.
And if they are, are they all facing us?
It sure appears as though they are.
The only object I can think of that looks like a circle when viewed from different angles is something shaped like a ball.
It depends on your vantage point and the relative distances involved. For instance, a concave shape can be perceived as a convex one depending on your vantage. In the case of very distant objects, as the lights in the sky are assumed to be; if the amount of distance we travel to change our vantage point is small in comparison to our initial distance to the object - then the visual deformation (making a circle seem like an oval, for instance) would be expected to be very small as well. For instance, during the course of the day, the sun changes distance from us as it rises and sets - yet it does not appear to us to be getting smaller or bigger as it does so. Of course it does get smaller and larger as the distance to us changes - but because the change in distance (or vantage) is so small compared to the distance of the object - we can't perceive this size change.
When you drop an object and it goes down, what is causing it to go down?
Its weight. Weight is an intrinsic and inexorable property of all matter. It "goes down" aka falls, because you lift it, because the matter you place it on cannot support its weight, and because the object weighs more than the media it displaces.
Objects of different weight fall at the same speed in a vacuum. Why?
They don't really, but the difference in speed is very small. Effectively so small that we teach this "rule of thumb" as "practically" correct.
The speed and acceleration profile of something falling is most influenced by the media through which it is falling and the buoyancy of the object. A balloon does not fall like a brick for this reason. When you remove as much of the air as you can and make a partial vacuum (full vacuum is not attainable) the brick and the balloon fall more similarly because the media you removed was most responsible for the differences in the way they fell.
If you could remove all the matter and achieve a perfect vacuum, then we would expect things to fall at the same rate. The why is the same as before, when the air was present - because the weight of the object is greater than the weight of the media they displace (which in the case of the perfect vacuum would literally be nothing/0)
The fact that things fall at the same rate, and instantaneously upon dropping them, is a bigger problem for the concept of gravitation than you likely realize. How would these imagined "fields" know to apply different amounts of force to overcome differing inertias and to accelerate equivalently? How could they do so instantaneously at infinite distance (or even a finite distance, for that matter)? It is much more natural, intuitive, realistic, and sound from the perspective of physics to recognize that the objects fall because they have nothing holding them up, and are heavier than the media they displace - rather than requiring magical and unequivocally unempirical fields that must violate multiple laws of physics in order to do what we observe.
If you mean gravitation, no one has any idea - from the dullest of the dull to the most credentialed and accomplished physicist.
Gravity (a scientific law, millennia old), on the other hand - is another matter entirely.
Because they weigh more than the media they displace. Weight is an intrinsic and inexorable property of matter, and not imbued by magical "fields" of perpetually (3+ centuries now) mysterious and completely imaginary (at best) composition and mechanism.
Do they? Or do you just believe that they do because someone told you that was a fact? Because you saw someone playing an astronaut hit a golf ball on the tv?
In my view, and that of our ancestors, the planets we see in the heavens are nothing like the earth we stand on. They are wandering stars; luminaries. They are above us, not below. They are not giant rocks or balls of gas. Admittedly, i know how insane that sounds to most.
No, weight remains more or less constant. Effective weight (what we commonly/colloquially refer to as weight : i.e. measured on a scale) varies with many factors - most notably buoyancy - but its intrinsic/actual weight generally does not. Although a battleship floats on water or a dirigible measures 0 when placed on a scale, that does not make their actual weight any less phenomenal or different than the materials they are built/composed of.
Huh? All the planets are shaped like discs. It's the earth which isn't a planet [wandering star].
What shape the earth is has no relevance to the shape of the things in the sky which are obviously not the earth.
It sure appears as though they are.
It depends on your vantage point and the relative distances involved. For instance, a concave shape can be perceived as a convex one depending on your vantage. In the case of very distant objects, as the lights in the sky are assumed to be; if the amount of distance we travel to change our vantage point is small in comparison to our initial distance to the object - then the visual deformation (making a circle seem like an oval, for instance) would be expected to be very small as well. For instance, during the course of the day, the sun changes distance from us as it rises and sets - yet it does not appear to us to be getting smaller or bigger as it does so. Of course it does get smaller and larger as the distance to us changes - but because the change in distance (or vantage) is so small compared to the distance of the object - we can't perceive this size change.
Its weight. Weight is an intrinsic and inexorable property of all matter. It "goes down" aka falls, because you lift it, because the matter you place it on cannot support its weight, and because the object weighs more than the media it displaces.
They don't really, but the difference in speed is very small. Effectively so small that we teach this "rule of thumb" as "practically" correct.
The speed and acceleration profile of something falling is most influenced by the media through which it is falling and the buoyancy of the object. A balloon does not fall like a brick for this reason. When you remove as much of the air as you can and make a partial vacuum (full vacuum is not attainable) the brick and the balloon fall more similarly because the media you removed was most responsible for the differences in the way they fell.
If you could remove all the matter and achieve a perfect vacuum, then we would expect things to fall at the same rate. The why is the same as before, when the air was present - because the weight of the object is greater than the weight of the media they displace (which in the case of the perfect vacuum would literally be nothing/0)
The fact that things fall at the same rate, and instantaneously upon dropping them, is a bigger problem for the concept of gravitation than you likely realize. How would these imagined "fields" know to apply different amounts of force to overcome differing inertias and to accelerate equivalently? How could they do so instantaneously at infinite distance (or even a finite distance, for that matter)? It is much more natural, intuitive, realistic, and sound from the perspective of physics to recognize that the objects fall because they have nothing holding them up, and are heavier than the media they displace - rather than requiring magical and unequivocally unempirical fields that must violate multiple laws of physics in order to do what we observe.