6,000 extrasolar planets found, where will be the 'second Earth'?

In the 30 years since the first exoplanet was discovered, humanity has confirmed 6,000 distant worlds. This milestone not only expands the map of the universe, but also brings us closer to the question: Is there life beyond Earth?

The US National Aeronautics and Space Administration (NASA) has just announced a historic milestone: 6,000 exoplanets have been confirmed - Photo: AI

Exoplanets are worlds outside our Solar System, orbiting other stars. The number of exoplanets is impressive not only in its number but also in the incredible diversity of the universe: from hot planets with lava-covered surfaces, "giant balls of gas" orbiting close to their parent stars, to planets as light as... sponge, even places with clouds made of precious stones.

Interestingly, while our Solar System has a balance of rocky and gas planets, observations of the universe show that rocky planets are much more common. Astronomers have also found unusual cases: planets orbiting two stars, “orphan” planets with no parent star, or even planets orbiting dead stars.

30 years: from number 1 to 6,000

The search for exoplanets began in 1995, when the first planet was confirmed around a Sun-like star. In the past three decades, with the help of numerous space and ground-based telescopes, scientists have turned what seemed like science fiction into concrete numbers: 6,000 distant worlds have been documented, while more than 8,000 more candidates await confirmation.

To detect these planets, scientists mainly use indirect methods, such as observing the phenomenon of a star dimming slightly when a planet passes in front of it (the transit method). Fewer than 100 exoplanets have been directly imaged, because their faint light is often overwhelmed by that of their host star.

Although the James Webb Space Telescope has made it possible to analyze the atmospheric composition of more than 100 exoplanets, studying planets of similar size and temperature to Earth remains a major challenge. This is because the host star is often billions of times brighter than the planet.

To overcome this barrier, follow-on projects such as the Roman Space Telescope and the Habitable Worlds Observatory are being developed, which will feature advanced coronagraph technology that will “filter” the bright light of the star to reveal the tiny planets nearby.

Scientists expect that in the next few decades, we will be able to detect and analyze the atmospheres of Earth-like planets, finding biosignatures, factors that show that life may exist.

The significance of the 6,000 milestone

The number 6,000 is not just a dry statistical milestone, but a mark showing that mankind's journey of space exploration has come a long way.

Each confirmed exoplanet is like a new piece in the vast cosmic puzzle: there are hot planets covered in lava, planets as light as foam, or worlds that float without a parent star.

This diversity helps scientists better understand how planets form, evolve, and interact with their environments.

In particular, the discovery of many small, rocky planets in the "habitable zone" opens up hope that somewhere out there, there are worlds with conditions similar to Earth.

Each step forward in the process of discovery not only enriches scientific knowledge, but also touches on mankind's greatest aspiration: finding the answer to the eternal question: "Are we alone in the universe, or has life flourished elsewhere?".

MINH HAI

Source: https://tuoitre.vn/tim-thay-6-000-hanh-tinh-ngoai-he-mat-troi-noi-nao-se-la-trai-dat-thu-hai-20250921234451002.htm