🌟 These photographs of dark matter stars that intrigue scientists

The James Webb Space Telescope recently detected unusual objects in the Universe. These entities, which could be "dark stars," are sparking significant curiosity among astronomers. If confirmed, they would shine thanks to a mechanism linked to dark matter, an invisible substance that makes up a large part of the cosmos.


If these celestial bodies are not truly dark, their name reflects a rather unique energy source. Unlike classical stars that derive their luminosity from nuclear fusion, they would be powered by the annihilation of dark matter particles (a process explained later). This characteristic makes them colder on the surface but extremely bright due to their immense size, which distinguishes them from ordinary stars observed so far.

Dark matter, which constitutes about 27% of the cosmos, remains elusive because it does not emit visible light. Scientists believe it is composed of electrically neutral particles, which annihilate upon collision, thereby releasing energy. This mechanism could heat primordial hydrogen and helium gases, preventing their rapid collapse and delaying classical star formation, leading to the creation of dark stars.

Let's go back to the early Universe: primitive gas clouds collapsed under the effect of gravity. Normally, this triggers nuclear fusion, but with a high density of dark matter, the annihilation produces enough heat to keep these objects in equilibrium. Dark stars could thus live much longer than standard stars, continuously attracting dark matter to remain luminous.


In order to identify these objects, astronomers are looking for specific signs. They must be very old, with a strong redshift in their light (see explanation at the end of the article), indicating they formed shortly after the Big Bang. Their sizes are colossal, reaching tens of astronomical units (one astronomical unit represents the distance between Earth and the Sun, about 93 million miles / 150 million kilometers), and they contain few heavy elements like oxygen. Data from James Webb has revealed candidates matching these criteria.

At the end of their life, massive dark stars could collapse directly into supermassive black holes. This would offer a clue to understanding the rapid formation of such black holes in the young Universe, like the one observed in galaxy UHZ-1. However, this idea is not unanimous, as some researchers believe these objects could be unusual galaxies, requiring more studies to confirm their nature.

Dark matter annihilation

Dark matter annihilation is a theoretical process where particles of this substance collide and destroy each other, releasing energy. Models indicate that these particles are their own antiparticles, meaning they have opposite properties but the same mass. When they meet, they annihilate by producing photons or other particles, converting their mass into energy according to Einstein's famous equation E=mc².

In the case of dark stars, this annihilation occurs at a high rate if the dark matter density is sufficient. The released energy heats the surrounding gases, like hydrogen and helium, creating pressure that counteracts gravitational collapse. This mechanism allows these objects to shine without resorting to nuclear fusion, offering an alternative to classical stellar processes.

Annihilation also influences the formation of structures in the Universe by affecting the distribution of heat and matter. If confirmed, it could explain why certain regions of space exhibit luminous or thermal anomalies, paving the way for new theories in astrophysics.

Redshift and the ancient Universe

Redshift is an effect observed when light from distant objects stretches towards longer wavelengths, indicating that the Universe is expanding. For astronomers, this serves as a tool to measure distances and the age of celestial objects. The greater the redshift, the older and more distant the object, because its light has traveled longer through expanding space.

Regarding dark stars, this redshift helps identify potential candidates, as these objects are thought to have formed shortly after the Big Bang. The James Webb Telescope uses infrared sensors to detect this shifted light, revealing structures that would otherwise be invisible. This allows the study of the first generations of stars and galaxies, offering a glimpse into the primordial Universe.

Redshift data is combined with other measurements, such as luminosity and chemical composition, to distinguish dark stars from normal galaxies. For example, dark stars should show few heavy elements because they form from primitive materials. This multispectral approach is essential for validating hypotheses about these enigmatic objects.

Understanding redshift also allows the study of the accelerated expansion of the Universe, linked to dark energy. By mapping these effects, researchers can reconstruct cosmic history and predict future evolution.