Where is science going?

[thinkandmull]

It makes me dizzy to think that the shortest distance between two points is not a straight line except in pure hypothetical mathematics

 

[GEddie]

Nope, but the divergence is so small (unless you were sending a laser-flash to Mars) that you’d never see it.

ICXC NIKA

 

[Iron_Donkey]

Geocentrists like to quote Einstein as saying that it doesn’t matter whether you say the earth revolves around the sun or vice verse. General relativity makes it relative/irrelevant. According to videos I’ve seen, Einstein believed that when you drop something the earth goes up to the object instead of the object going down, and this based on GR. But if I drop something on one side of the earth and someone drops something on the other side of the earth, which way will the earth go? This is so confusing for me. Is science/physics getting into the realm where lay people can’t even understand it anymore? Take non-Euclidean geometry. Is this saying there is no straight lines on a table? I have never understood why non-Euclidean geometry has been used at all

Regarding the bolded portion: it is very unlikely that Einstein would have “believed” that, in the sense of saying that in some absolute sense the earth is moving and the object is not. More likely, he would have said that one conception is just as valid as the other.

Regarding the two objects dropped scenario specifically, we’re now into semantics. There is no absolute statement on which way or how fast the earth moves, in the same way that there is no absolute, across all possible circumstances, answer to “is Dallas or New York closer?” Which is closer depends on where you are, or in physics terms, on your frame of reference. Likewise, which way the earth is moving depends on what you consider still.

So you can say the earth moves towards the first object (in one frame of reference), the second object (in another), stays still (in a third), or is writing your name in cursive across the sky over and over (though in this case, you’d have to add in a whole bunch of forces somewhat similar to the centrifugal force to account for the fact that we’re not being jerked around every time it crosses a t).

Just like all other relative statements, the statements become absolute when you specify the things that can change. So just like “Dallas is closer than New York [for a person in Texas]” is now absolutely true, “the earth is moving towards the pen I just dropped [in the frame of reference which considers the pen to be stationary]” is also absolutely true, as are the appropriately modified statements for other possible ways of saying the earth is moving.

So - which way the earth is moving (just like how far away Dallas is) has an infinite number of answers, until you specify a frame of reference. Only once you specify that frame of reference does the question “is it moving this way or that way?” really have any value or useful meaning.

Non euclidean geometry is a whole nother beast, the short version being that is useful because the universe might be weird on a large scale.

 

[Iron_Donkey]

Does anyone claim to understand what curved space even means?

Imagine that we were 2d dots living on a piece of paper. Life would be different based on whether that paper was rolled up (just bent up at the edges, rolled into a tube, donut, saddle shape, etc) or not. We can’t imagine rolling 3d space through 4d, but it’s a similar idea.