Anybody ever heard of this? But this is not true.

According to precise new measurements of dark energy, scientists believe that our entire universe is totally flat. The Universe is incredibly vast and expanding continuously. In a flat universe, two photons that start moving parallel to each other will never meet. After so long, these questions seem to be answered. The shape of the universe depends on its density.
The Universe is flat.

In a universe that is closed, they will eventually cross paths.

It also turns out that the more we gaze into space in the hope of learning more, the less we really know.

Since the geometry of this universe comes from a flat piece of paper, all the geometric facts we’re used to are the same as usual, at least on a small scale: Angles in a triangle sum to 180 degrees, and so on. It turns out that the Universe is flat. Scientists have long argued that how the Universe looks like, what shape it has. Flat Universe Society.

When astronomers and physicists say that the Universe is flat, they do not mean that the Universe is flat like a leaf. It said in a German video that they calculated the angles of cosmic background radiation in triangles or something and it turned out to be 180°, I'm a noob and English isn't my first language but I thought it was kinda interesting. Imagine you’re a two-dimensional creature whose universe is a flat torus. The universe seems to be flat? The question of whether the universe is spatially flat or round is one of the most contested questions in physics, right up there with whether the cosmos are “open” or “closed”.Eerily, some cosmologists say if recent measurements confirm that the universe is both flat AND “closed,” this would raise the prospect of physical reality wrapping around itself in an infinite loop. Many scientists believe that the Universe is flat. If the density is more than the critical density, the universe is closed and curves like a sphere; if less, it will curve like a saddle. In Euclidean astronomy, the world is a convenient comparative model of the surrounding space. We are talking about the property of three-dimensional flatness – Euclidean geometry in three dimensions.