Mysteries of the Universe

The universe we live in is a fascinating and mysterious place, still filled with countless unanswered questions. Although humanity has been studying it for centuries and has achieved significant milestones, we continually encounter phenomena that defy the laws of physics, leaving us without explanations.

The sheer size and complexity of the universe are both unimaginable and incomprehensible.

Billions of galaxies stretch across the infinite expanse of space, each containing billions of stars and planets, including our home, Earth.

Deep in the cosmos, far beyond the safe boundaries of our galaxy, the Milky Way, lies a monstrous entity that slowly and inexorably draws us toward it. The only force capable of exerting influence over such immense distances and cosmic timescales is gravity. Whatever it may be, it is colossal and relentless. Known as the Great Attractor, this enigmatic phenomenon is a supercluster within intergalactic space. This cluster is formed by a loose grouping of galaxies, with their relative velocities defining its structure.

Superclusters are the largest known structures in the universe, formed by groups of galaxies. One of these includes Earth, along with the Solar System it resides in, the Milky Way Galaxy that contains it, and the local galaxy group to which the Milky Way belongs. Although not dense enough to be gravitationally bound, it should theoretically disperse with the expansion of the universe. Instead, a gravitational focal point holds it together. However, there’s a truly massive problem. Our galaxy is filled with gas, stars, and dust, all of which block light from distant parts of the universe. Whatever the Great Attractor may be, it lies in the direction of the Centaurus constellation, but we cannot observe it properly because it is obscured by our own Milky Way.

Physicists believe that a surprising portion—27%—of the known universe's matter and energy content consists of so-called dark matter. Dark matter is a type of substance that cannot be directly observed with astronomical instruments because it neither emits nor absorbs any electromagnetic radiation.

The presence of dark matter can only be inferred from its gravitational effects on visible matter and background radiation. Observable matter makes up just 5% of the universe's total mass, while dark matter accounts for 27%, and dark energy comprises 68%. Some astronomers argue that dark matter does not exist and that the phenomena attributed to it can instead be explained by the differing behavior of gravity over vast distances.

Another piece of evidence for dark matter is that when light from distant galaxies passes through regions filled with dark matter, it bends. The gravitational effects of dark matter are most easily observed in the outer regions of galaxies, where stars move at speeds that can only be explained if there is more matter present than what is actually visible.

The observable universe encompasses all the space we can observe and measure based on the light that reaches us. We estimate the age of our universe to be approximately 14 billion years. However, light from regions farther away has simply not had enough time to reach us, making those areas unobservable to us. The issue here is not a technical limitation—it is not that we lack the advanced tools to see farther. The limitation arises from the speed of light; it’s similar to being unable to read a letter that has not yet been delivered.

Moreover, the universe itself is expanding faster than the speed of light, which means that the boundary is moving farther and farther away from us.

So, if a foreign civilization were to send signals toward us from the edge of the universe, they would never reach us, even if they traveled toward us for an infinite amount of time.