Researchers are developing a new telescope designed to observe our own Sun, a novel approach aimed at improving the search for Earth-like planets orbiting distant stars. The project, funded by the European Union, seeks to solve the problem of stellar interference that currently hinders the detection of small, rocky worlds.
Key Takeaways
- A new telescope named PoET will be built in Chile to exclusively study our Sun.
- The primary goal is to understand the Sun's surface activity, or "noise," which obscures observations of other stars.
- Data from PoET will help filter out similar noise from distant Sun-like stars, making it easier to detect small, Earth-sized exoplanets.
- This research is essential preparation for the European Space Agency's PLATO mission, scheduled to launch in 2026.
The Search for Earth-Like Worlds
Scientists have cataloged nearly 6,000 exoplanets, yet a true Earth twin—a similarly sized planet orbiting a Sun-like star at a comparable distance—remains undiscovered. The search is a central focus of modern astronomy, driven by the question of whether life exists elsewhere in the universe.
Finding such planets is extremely difficult. While rocky planets have been found around smaller, dimmer red dwarf stars, detecting them around bright, Sun-like stars is a significant technical challenge. The intense light and surface activity of these stars create interference, or "noise," that can easily mask the faint signal of a small planet passing in front of it.
Why Stellar Noise is a Problem
Stars like our Sun are not static balls of light. Their surfaces are turbulent, with churning plasma, shifting magnetic fields, and features like dark sunspots. This activity, known as granulation, creates fluctuations in the star's brightness that can be mistaken for, or completely hide, the dimming caused by a transiting exoplanet.
A Novel Solution: Observing Our Sun
An EU-funded research team, led by Portuguese astrophysicist Dr. Nuno Santos, is developing an innovative tool to address this issue. The project, named FIERCE, involves building a new instrument called the Paranal Solar Espresso Telescope, or PoET.
Instead of pointing at distant star systems, the 60-centimeter PoET telescope will be dedicated to observing our own Sun. It will be located in Chile's Atacama Desert, operating alongside the European Southern Observatory’s Very Large Telescope (VLT).
"If you look at the surface of the Sun, it looks like a boiling pot of water, speckled with darker and brighter regions," explained Dr. Santos. "The big issue is that we don’’t really understand how to diagnose this noise that comes from the star."
Connecting to ESPRESSO
PoET will work in conjunction with an existing instrument called ESPRESSO (Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations). ESPRESSO is designed to split starlight into its component colors, allowing detailed analysis of distant star systems.
By connecting PoET to ESPRESSO during the daytime, the team will gather high-resolution data on the Sun's surface activity. "By connecting ESPRESSO to solar observations, we hope to understand exactly how the Sun is behaving in different regions," Santos added. This will create a detailed map of the Sun's chemical signatures and how they change with surface turbulence.
The insights gained from studying our Sun will then be used to create models that can filter out similar noise from observations of other Sun-like stars, effectively cleaning up the data and revealing the faint signals of hidden planets.
Project Timeline
- Project Name: FIERCE (funded until September 2027)
- Telescope: PoET (Paranal Solar Espresso Telescope)
- First Observations: Expected by the end of 2025
- Initial Mission Duration: Three years
- Location: Atacama Desert, Chile
Paving the Way for Future Missions
The work being done by the FIERCE team is critical for the success of upcoming exoplanet-hunting missions. Most notably, it will support the European Space Agency's (ESA) PLATO mission, which is set to launch in 2026.
PLATO (PLAnetary Transits and Oscillations of stars) will be a space-based observatory equipped with 26 cameras. Its primary objective is to survey up to a million stars, specifically searching for Earth-sized planets in the habitable zones of Sun-like stars. PLATO will measure the size of these planets, allowing scientists to calculate their density and infer their composition.
For PLATO to achieve its goals, the stellar noise problem must be solved. The precision required to characterize small, rocky worlds from hundreds of light-years away is immense.
"We have to find a way to get rid of this noise to be able to fully exploit the data from the upcoming PLATO mission," said Santos. "Our hope and our expectation are that PoET will learn enough so that we'’ll be able to reduce the noise to the needed level."
A Stepping Stone in Cosmic Exploration
The FIERCE project and the PoET telescope represent a foundational step in the broader search for life beyond Earth. Supported by the European Research Council (ERC), this initiative ensures Europe remains at the forefront of exoplanet science.
If the project timeline holds, PoET could begin delivering crucial data by mid-2026, just as the PLATO mission begins its work. The discoveries made by PLATO will, in turn, provide targets for even more powerful future observatories.
Missions planned for the coming decades, such as NASA's Habitable Worlds Observatory (2040s) and Europe's next-generation large telescope (2030s), aim to directly image potentially habitable exoplanets and analyze their atmospheres for biosignatures—the chemical signs of life.
Before those missions can begin, however, astronomers must first identify the most promising candidates. Projects like FIERCE are essential for building that catalog. As Dr. Santos noted, "The quest for Earth-like planets orbiting other suns is one of the big questions we have." By studying our own star, scientists are taking a critical step toward answering it.