There is no center of the cosmos, according to all present observations. In order for a center point to exist, it must be unique in relation to the rest of the universe. Since we now know that there are other galaxies outside of ours, this means that our galaxy cannot be at the center of everything.
Our galaxy is a huge mass of stars and interstellar gas that lies within a giant elliptical galaxy. The galactic nucleus is where all the stars are packed together into a small area with nothing around them. This is why astronomers call it a black hole: it has a large mass but no size. The only way to escape its grip would be if you could travel faster than light, which is impossible.
Our galaxy is one of many such galaxies in the Universe. It's very big, almost 100 thousand light-years across, and contains about 200 billion stars. But unlike our galaxy, others have centers of gravity where the matter is clustered together in great numbers.
In fact, scientists think that most galaxies were formed when their cores collapsed due to high rates of star formation within them. Only those cores that survived this "galactic nuclear explosion" remain today as mature galaxies with central black holes. The rest were destroyed by the energy released during this process.
There is no such thing as a center of the universe! According to mainstream cosmological theories, the universe began with a "Big Bang" roughly 14 billion years ago and has been expanding ever since. The growth, however, has no center; it is the same everywhere. The stars in the sky are not closer to us on the Earth's surface than any other stars, but because the earth travels around the sun every year, the stars that rise over one side of the earth are seen by people on the opposite side as having moved away from them.
In reality, there is no such thing as a single point in space. Space itself is filled with energy, or matter, which is what we experience as gravity. This energy creates a gravitational force that draws objects together, even if they are far apart. So even though there is no single point in space, there is still a strong attraction between all objects.
Our galaxy alone contains hundreds of billions of stars, so you might think that there would be at least one star in the galaxy that is close to the earth. But this isn't true because the earth travels through space at more than 300,000 miles per hour, so any star that was close enough for us to reach with an interstellar spacecraft would have gone by long before humans evolved.
Even though there is no single point in space, there are still areas of space where things are clustered.
As far as we know, the cosmos lacks a center of mass because it lacks a center. One of the fundamental assumptions we make when defining the universe is that it is, on average, the same everywhere. This is referred to as the cosmological principle. It implies that there is no single point in space from which all other points can be seen. Instead, the universe appears to be uniform on large scales.
The cosmological principle allows us to calculate the average density of the universe by assuming that it may be divided into regions of equal size but different composition. The weight of the universe is therefore said to be zero relative to any one place but non-zero overall. The critical density required for its existence is so close to what we observe that this means that about 85% of the energy in the universe is in the form of dark energy and 15% is in matter. If the energy were distributed evenly between matter and radiation, then at the time of decoupling after the Big Bang, each particle species would have been in thermal equilibrium with the others. But since that's not the case, we must conclude that before that time, something forced all the particles of matter out of equilibrium with each other. That "something" could be a field such as gravity or the vacuum itself, which exhibits an anti-gravitational force over large distances.