How many galaxies actually exist in the Universe

Galaxies come in different shapes and sizes. For example, we live in a barred spiral galaxy called the Milky Way, which is considered a large object among its kind.

It takes a particle of light, that is, a photon, 100 thousand years to fly from one end of our galaxy to the other. That is, the approximate diameter of the Milky Way is 100 thousand light years, given that photons travel at the speed of light (300,000 km/s).

But our galaxy is one of a huge number of galaxies in the Universe. So how many are there really?

Astronomers can only see a small part of the Universe

It may be, at first glance, easy to answer the question about the number of galaxies in the Universe, but this is far from true. Firstly, astronomers, even with the most powerful telescopes, can see only a small part of the Universe, that is, this is a local area of ​​​​the vast cosmos or the observable Universe.

Astrophysicist Kai Neuske from the European Space Agency explains that the observable Universe is considered to be that part of space from which the light has managed to reach telescopes.

Although the universe has been around for 13.8 billion years according to current estimates, it is larger than 13.8 billion light years in any direction from us.

The fact is that the Universe is constantly expanding, and at the early stage of its existence, when space was smaller, light received significant acceleration. Therefore, the current size of the visible Universe is approximately 46 billion light years in all directions from us.

According to Pamela Gay of the Planetary Science Institute in Arizona, USA, astronomers can only see about 3% of the total size of the Universe.

“We see at most 3% of the universe,” Pamela Gay told Live Science.

Another problem arises when estimating the total number of galaxies. There are so many galaxies that scientists can estimate their number only based on what can be seen in the local Universe.

Gay explains that astronomers look at a small area of ​​space, count the number of galaxies in it, and then multiply it by the size of visible space.

On the other hand, the existence of different masses and sizes of galaxies adds complexity to the calculations. Some are 10 times larger than the Milky Way, and some are 10 times smaller. Therefore, astronomers determined the minimum mass of the galaxy in order to make more or less correct calculations.

How many galaxies are there in the visible Universe?

Based on this, an average of 1 to 2 trillion galaxies have existed in the visible Universe throughout its history. It is believed that there were more galaxies in the early Universe, so average estimates are given.

But these results were obtained based on data from the Webb Space Telescope, which is located relatively close to Earth. This means that some of the light that the telescope received came from sources other than galaxies.

As shown by data from NASA’s New Horizons spacecraft, which is now the most distant probe in the solar system and is not strongly influenced by extraneous light, estimates of the number of galaxies differ.

These data allowed astronomers to find out that there are from 100 to 200 billion galaxies in the visible Universe. But scientists still leave the number of galaxies in the range from 100 billion to 2 trillion, because it is not yet possible to make more accurate calculations.

How many galaxies are there in the entire Universe?

According to Gay, if we see 3% of the universe, then we can multiply the presented range of galaxy numbers by the rest of the universe to get the total number of galaxies in space.

But astronomers do not know the true size of the Universe, and therefore any estimates will be very rough.

On the other hand, if the Universe is infinite, then there is an infinite number of galaxies in it, scientists say.