Combien y a t'il de planètes dans l'univers ?

How many planets are there in the universe?

Astronomy is a fascinating science that allows us to ask essential questions about our place in the universe. One question that often comes up is how many planets there are in the universe. This article will attempt to answer this question by providing clear, easy-to-understand information for astronomy enthusiasts.

The starting point: the planets in our galaxy

Planètes Univers

To estimate the number of planets in the universe, we first need to look at the number of planets in our own galaxy, the Milky Way. With between 100 and 300 billion stars, it is estimated that there are well over 100 billion planets in our galaxy. Since the discovery of the first exoplanet in 1990, thousands more have been identified, and technological advances will probably lead to even more.

Galaxies: billions of worlds to explore

Combien de galaxie dans l'univers

Current estimates suggest that there are more than 2,000 billion galaxies in the universe, each containing billions of stars and potentially even more planets. The diversity and complexity of these galaxies is staggering. Galaxies can be grouped into clusters and super clusters, forming even larger, interconnected structures across the universe.

Astronomers use ground-based and space-based telescopes to study galaxies and their contents. By mapping the distribution of galaxies and studying their composition and evolution, researchers are gaining a better understanding of the formation of stars and planets, as well as the cosmic processes at work in the universe.

An incalculable number of planets

Nombre de planètes dans l'univers

Taking into account the estimated number of stars in the universe (1,000,000,000,000,000,000,000) and assuming that at least one or two planets orbit each of them, we can estimate that there are hundreds of trillions of planets in the universe. This estimate does not take into account orphan planets, which are planets that have been ejected from their star systems and are wandering freely in space.

The incalculable number of planets in the universe highlights the extraordinary diversity of possible worlds, each with its own set of characteristics and conditions. This diversity also suggests that many planets could have conditions conducive to life, in potentially very varied forms.

The search for life beyond our solar system

Combien d'étoiles dans le ciel

These astronomical figures suggest the possibility that other forms of intelligent life exist in the universe. Scientists are continuing to study exoplanets to determine whether any of them could harbor life. Exoplanet observation missions, such as the James Webb Space Telescope, are designed to analyze planetary atmospheres and look for signs of life, such as the presence of biomarkers.

In addition, research projects such as SETI(Search for Extraterrestrial Intelligence) and the Breakthrough Listen project are attempting to detect signals of extraterrestrial communications. Technological advances in astronomy, astrophysics and biology could well help us to answer this fundamental question: are we alone in the universe, or do other intelligent forms of life exist among the countless planets that populate the universe?

Share your passion for astronomy

Combien y a t-il de planètes

If you’re fascinated by astronomy and want to share your passion, there are lots of ways to do so. You can decorate your home with astronomy gifts such as a galaxy projector or our moon lamps. Together, we can continue to explore the universe and perhaps one day discover the answer to the question of the number of planets and life beyond our solar system.


Although it is difficult to give a precise figure for the number of planets in the universe, current estimates suggest that there could be hundreds of trillions of planets. The immensity of the universe and the variety of worlds it harbors suggest the possibility of extraterrestrial life, and raise fundamental questions about our place in the cosmos. Technological advances in astronomy and ongoing research efforts will undoubtedly enable us to learn more about these distant worlds and, perhaps, one day discover whether we are alone in this vast universe. In the meantime, don’t hesitate to share your passion for astronomy and continue to explore the mysteries of the space that surrounds us.