What is mass

Coincidence happens everyday and most of the time it's just an accident but sometimes it's sign of something deeper going on in the world so it's a bit unsettling that there's a huge councidence lurking at the heart of one of the most fundamental concepts we know you may know mass is the thing that causes gravity the more mass of an object the stronger gravitational field it creates but mass is also key to understanding how things move at all it's what gives something inertia these are two completely different ways to look at mass but in experiments they always seem to give the same number the things is we don't know why it would be really weired if these two unrelated concepts just happen to always agree so may be they're not's so unrelated that's what einstein thought to come up with the thoery of gernal relativity he said that inertia is real but gravity is an illusion so the two types of mass are really just the same fundamental thing this work of gravity is no longer a force but rather just what happens when something moves through warped space and time so say you're in a spaceship approaching a massive planet you may fell like you're accelerating but according to einstein you're actually moving normally it's just that the space you're passing through gets more and more compacted thr closer you get the planet so your slupcover greater distances in the same amount of time as far as thoeries go gernal relativity is hard to beat it's been confirmed by tons of experiments but then again so is quantum mechanics and when you get down to the level of individual particle these two theories don't agree that means we may need to bring back the idea that gravity is an actual force and just like electricforce is determined by positive (+)or negative(-) electric charges this new view of gravity would need a gravitational charge in otherword mass so we're kind of back us interia and another gives us gravity and they still just happen to always be the same number now we might be able to sort this out by finding an experiment where gravity and interia don't agree that would mean the coincidence was just an accident that explain why these two masses always have to be the same either way if we want to truly understand and why the universe works the way it does this cosmic coincidence has to