Published On 11/6/2026
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Last update: 19:15 (Mecca time)
In the 1970s, finding planets outside the solar system was just a scientific dream, but today astronomers have discovered thousands of planets around other stars.
As humanity approaches a new stage in the search for life outside Earth, the US space agency NASA is working to develop a giant space telescope called the Habitable Worlds Observatory (HWO), which is an ambitious project that aims to achieve an unprecedented achievement: directly photographing Earth-like planets and analyzing their atmospheres in search of signs of life.
In this context, a new scientific study published on the arXiv platform, which has not yet been subject to peer review, revealed one of the most important technical challenges that will determine the success of the mission in the future, which is the telescope’s ability to analyze the light coming from these distant worlds with sufficient accuracy to distinguish between living and dead planets.
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How will the telescope search for life?
The Habitable Worlds Observatory project is based on studying light reflected from Earth-like planets around nearby stars. When light passes through a planet’s atmosphere, different gases leave distinct fingerprints in the light spectrum, allowing scientists to determine the components of that atmosphere.
Oxygen, ozone, methane, and water vapor are among the most prominent “biosignatures” that may indicate the presence of biological activity. But the detection of these gases depends not only on the sensitivity of the telescope, but also on what is known as “spectral analytical ability,” that is, the device’s ability to distinguish between very close colors in light.
The greater the spectral resolution, the greater the amount of information that can be extracted from the planet’s atmosphere, but this requires a longer observation time and more complex devices.
Ancient Earth is a model to test the mission
To test the capabilities of the future telescope, the researchers simulated how the Earth would appear if it were observed from long distances during different stages of its geological history.
In the Archean era, before the appearance of plants and oxygen-producing organisms, the Earth’s atmosphere was almost devoid of oxygen. During the “Proterozoic” era, limited amounts of oxygen began to appear. While the “Phanerozoic” era witnessed a rise in the percentage of oxygen to levels close to the current percentage after the spread of complex life.
Each of these stages leaves a different spectral signature, which means that the telescope must be able to identify signs of life, even if they are primitive or limited, as they were on ancient Earth.
What specifications are required?
The study showed that monitoring oxygen, which is one of the most important indicators of life, requires a spectral resolution of about 140 in the visible light range. Ozone can be detected with a much lower accuracy of only about 7 in the ultraviolet range.
In the near infrared range, the task becomes more complicated. Carbon dioxide and carbon monoxide leave similar signals that may lead to an incorrect interpretation. Therefore, the researchers concluded that the minimum required to distinguish between them is a spectral resolution of 40, while a value of approximately 70 is recommended to study Earth-like planets through various stages of their evolution.
To reach these results, scientists created thousands of synthetic spectra of planets and then analyzed them using advanced algorithms, taking into account the effects of instrument noise, exposure time, and factors that might falsely suggest the presence of life.
The path towards discovering extraterrestrial life
Despite the optimism of these results, researchers caution that the discovery of oxygen, ozone or methane does not necessarily mean that life has been conclusively discovered. Nature possesses non-biotic mechanisms that can produce some of these gases without the intervention of living organisms.
However, the telescope’s mission will not be to announce the discovery of life directly, but rather to identify the most promising planets that deserve detailed study in the future.
The study presented clear technical goals for NASA engineers: achieving a resolving power of 140 in visible light, 7 in ultraviolet light, and 70 in near-infrared light, while reducing electronic noise to a minimum.
In the end, this project reflects one of the deepest questions that man has asked himself since the dawn of civilization: Are we alone in the universe? The answer may be hidden in a faint ray of light coming from a distant planet orbiting another star. Every technical advance we achieve today brings us one step closer to knowing our true place in this vast universe, and confirms that scientific curiosity is still the greatest engine of human discovery.
