It's actually really simple: (1) space is a 3D grid which determines what volume the universe can physically occupy; (2) when you add time, that gives you spacetime which is the 4D fabric of reality; (3) all matter has mass and density values which give rise to gravity; (4) gravity warps the grid lines of spacetime, therefore bending reality and causing the effect of gravitational lensing.
This happens due to the fact that light now has to follow a "curved" path to get from point A to B, just like you would have to curve your pencil to follow the lines of a warped square grid in your notebook (but in 3 dimensions). Note that both space and time are affected by gravity, which displays a fundamental property of general relativity - the fact that distance, motion, and time are all relative to the reference frame of the observer.
Incredible to see a picture like this! I just wish I was smart enough to comprehend the explanation given to the phenomenon.
Still don't get it sorry
I found this image absolutely fascinating. If you look carefully, you can literally see a 3D "sphere" of space, as if the coordinate grid of reality has been warped by matter. Might be the best one I've ever seen to visualise the fabric of spacetime in relation to mass & gravity.
For those who may not be familiar with relativistic physics, this phenomenon is referred to as gravitational lensing. It's particularly visible around high-density objects like black holes, galaxy clusters, etc. and is actually one of the main techniques we use to detect dark matter, as well as exoplanets in distant solar systems.
NASA's Hubble Space Telescope peered into the distant universe and revealed a galaxy cluster so colossal it warped the very space & time of its environment, causing light to travel along distorted paths through space.
Galaxy clusters such as this one contain thousands of galaxies of all ages, shapes and sizes, together totaling a mass thousands of times greater than that of the Milky Way. These groupings of galaxies are colossal — they are the largest structures in the Universe to be held together by their own gravity.
Clusters are useful in probing mysterious cosmic phenomena like dark energy and dark matter, which can contort space itself. There is so much matter stuffed into a cluster like Abell 2537 that its gravity has visible effects on its surroundings. Abell 2537’s gravity warps the very structure of its environment (spacetime), causing light to travel along distorted paths through space. This phenomenon can produce a magnifying effect, allowing us to see faint objects that lie far behind the cluster and are thus otherwise unobservable from Earth. Abell 2537 is a particularly efficient lens, as demonstrated by the stretched stripes and streaking arcs visible in the frame. These smeared shapes are in fact galaxies, their light heavily distorted by the gravitational field of Abell 2537.
This spectacular scene was captured by Hubble’s Advanced Camera for Surveys and Wide-Field Camera 3 as part of an observing program called RELICS
We're talking about relativity here, so do NOT feel bad that it's confusing. This image just shows that there is so much mass in the cluster that the gravitational fields are literally warping space-time. So, it's gonna look funny.
Curved space is absolutely proven to exist and has been since the early 20th century!
I understand orbit to be a combination of gravity producing an attractive force
This is where your understanding is conceptually inaccurate - it's a very common simplification so it's to be expected. We refer to gravity as a force to make things easier, but it's not actually the same kind of phenomenon as other forces. The most accurate definition of gravity we have is that it represents the distortion of spacetime caused by mass density. So curved space isn't just "another way" of looking at things, it's the most fundamental description of what is going on.
The reason we refer to gravity as a force is because our understanding of it started off with classical mechanics based on Newton's laws of gravity. However, with Einstein's revolutionary theories on special relativity in 1905 and then general relativity in 1915, we came to understand that gravity doesn't just cause "attraction" between bodies, it bends the very fabric of space and time.
I'd like to know if Earth orbiting the Sun is the result of gravity being an attractive force between the objects and gravity is the reason why objects move, or the result of gravity being a warping force on space, and space is the reason why objects move. Do you know?
To answer your question, definitely the latter!
You're a doctor. I trust you.
Basically, if a gravitational field is strong enough, it bends light around it in the same way that a normal lens might. This gif does a decent job of showing it.