Comment on Do straight lines and flat planes exist in nature?
Blue_Morpho@lemmy.world 9 months agoLight is going straight from it’s point of view . It is following the shortest path between two points. The transform from different reference frames is why we see it as curved.
But if that’s your definition, then there are no straight lines in mathematics either because you could transform the straight line from one system into a curved line in another system.
gedaliyah@lemmy.world 9 months ago
Yes, nature is not objective - it is relative. Mathematics is a discipline that is based around an *objective *framework. Lines and planes are mathematical constructs. Mathematics gives us an objective framework that can be used to model a natural world, but they are just models.
Some things are “line-like” or “plane-like,” in that modeling them as lines or planes is helpful to describe them. You can measure a distance “as the bird flies” because birds fly in lines compared to how humans travel along roads and paths. You can describe a dense, heavy, falling object as traveling in a straight line, because air resistance may be negligible over short distances.
A model is only useful insofar as it accurately represents reality. Lines and planes are mathematical constructs, and they may be incorporated into models that describe real things. “A beam of light crossing a room travels in a straight line” is probably a useful construct because the effects of gravity and refraction of the air are probably negligible for nearly all purposes. “The surface of a pond is a plane” is probably an acceptable model for a cartographer, since the height of ripples and the curvature of the earth are negligible at that scale.
The initial question was not “Do straight lines and flat planes model anything in nature,” but whether they exist in nature. They do not. They only exist in mathematics.
Blue_Morpho@lemmy.world 9 months ago
The curved light path is because a mathematical transform is done between two different frames of reference.
It’s no different than taking a mathematically straight line and performing a transform function to map it to a curved coordinate system. Because you allow transformation functions, there would also be no straight lines in math.
bitwaba@lemmy.world 9 months ago
Light travels along geodesics that curve because spacetime itself is curved. Geodesics are curves that minimize distance between two points in a curved space. They are considered straight lines in a curved space, but it’s right there in the definition. Geodesics are curves. Our reality is a curved space, therefore straight lines in our curved space are curves. They are not straight.
Our reality is not matiematically flat. It is matiematically curved.
Blue_Morpho@lemmy.world 9 months ago
From the point of view of light, it is traveling in a straight line. It does not observe the curve therefore spacetime isn’t curved to it. There is no preferred reference frame.
It is the same with special relativity. If a particle is moving at near light speed, you observe it as heavier. But from the particle’s point of view it is you who are moving and you are heavier.
Curved spacetime is a mathematical transformation to reconcile the different reference frames in the same way time dilation is a transform between reference frames.
There is no absolute frame of reference.