Hi
I’ve been studying pharmacy/medical sciences for all my adult life when i stumbled upon “a brief history of time” by stephen hawking
Anyway,for a person who hasn’t studied physics much..how does “spacetime” exist? I mean einstein abandoned the idea of absolute time
But what is spacetime? And how does time exist as a physical dimension? I mean it’s just something we measure as it passes
How does all this exist?
In: 3
Spacetime exists as an absolute. Space and time are now known to not be entirely seperable. A thing which approaches the speed of light trades ever greater proporitions of its time component to increase its speed component.
Although objects with mass cannot reach the speed of light, a/an (massless) object at the speed of light does not experience time, just as an object (massive) very close to the speed of light experiences very little time.
This was predicted in theory and has been confirmed experimentally with extreme confidence. Any evidence contrary to this could completely revolutionize our understanding of physics.
I’m somewhat sure that time is not a physical dimension.
We can measure time as it passes. We predicted time would pass differently relating to being in a gravity well (on earth’s surface vs not-so-far away in space) and confirmed that being in a gravity well speeds up time. Clocks on the ISS record being slowed down by 0.007 seconds every six months. The planet curves every path towards it, as the planet has mass. This is different (yet obviously related) to time dilation from velocity. Less related would be length contraction, the measurable change in length of a thing as it approaches the speed of light.
Latest Answers