Rectangular telescope design could usher in Earth-hunting 2.0

DNVN - Scientists are developing a rectangular telescope model, promising to open a new era in the journey to find "Earth 2.0" (a term referring to planets outside the Solar System that have similar conditions to Earth and are capable of supporting life).

The search for Earth-like planets has long been a major challenge in astronomy, because the overwhelming brightness of stars makes them almost completely obscured. Traditional telescope designs are not up to the task. However, a bold idea for a rectangular infrared telescope has just been proposed, promising to overcome this barrier and help humans reveal dozens of potential planets within 30 light years, paving the way for the search for signs of alien life.

Earth is the only planet we know of that supports life. All life on this blue planet depends on liquid water to sustain essential chemical reactions. Simple single-celled organisms appeared at about the same time as Earth, but it took about 3 billion years for more complex multicellular life to evolve. Humans, meanwhile, have existed for only a tiny fraction of the planet’s history, less than one ten-thousandth of Earth’s age.

This timeline suggests that life may not be rare on planets with liquid water. However, intelligent beings capable of exploring the universe may be extremely rare. If humanity wants to search for life beyond Earth, the most likely approach is to approach it directly through planetary observations.

Conceptual design for a rectangular space telescope, modeled after the Digital Interferometer Refractive Space Telescope (DICER), a hypothetical infrared space observatory, and the James Webb Space Telescope. Credit: Leaf Swordy/Rensselaer Polytechnic Institute.

Space is vast, and the laws of physics prevent travel or communication faster than the speed of light. Therefore, only the stars closest to the Sun can be studied within a human lifetime, even with robotic probes. Of these, the most promising targets are stars similar in size and temperature to the Sun, because they are long-lived and stable enough for complex life to develop.

Astronomers have now identified about 60 sun-like stars within 30 light years of Earth. Planets orbiting them that are similar in size and temperature to Earth — and could support both land and liquid water — are considered the best candidates for finding life.

Separating the image of an Earth-like exoplanet from the glare of its host star is a major challenge. Even under ideal conditions, a star is a million times brighter than a planet. If the two are mixed, detecting the planet becomes impossible.

According to optical theory, the maximum resolution of a telescope depends on the size of the mirror and the wavelength of the light. Planets with liquid water emit light most brightly at a wavelength of about 10 microns – about the width of a thin strand of hair and 20 times the wavelength of visible light. At this wavelength, a telescope needs to collect light over a distance of at least 20 meters to have enough resolution to separate the Earth from the Sun, which is 30 light years away.

Furthermore, telescopes must be placed in space, because the Earth’s atmosphere blurs images. The largest space telescope today – the James Webb Space Telescope (JWST) – has a 6.5-meter mirror, but launching and operating it has been extremely difficult.

Since deploying a 20-meter space telescope is currently beyond the technological capabilities, scientists have tried several options. One solution is to launch multiple small telescopes and maintain precise spacing between them to simulate a giant mirror. However, maintaining precise positioning down to the size of a molecule is currently impossible.

Another approach is to use shorter wavelengths of light, allowing for smaller telescopes. But in the visible range, a Sun-like star is 10 billion times brighter than Earth, making it impossible to block out enough starlight to reveal the planet, although the resolution is possible in principle.

Another idea is to use a “star shield” – a spacecraft tens of meters in diameter, flying tens of thousands of kilometers away from the telescope to block starlight but let planetary light through. However, this would require launching two spacecraft, and would also require huge amounts of fuel to move the shield to new locations.

In the new study, the scientists propose a more feasible design: an infrared telescope with a rectangular mirror measuring 1 x 20 meters, instead of the 6.5-meter circular mirror of JWST. Operating at a wavelength of 10 microns, the instrument would separate starlight and planetlight along the long axis of the mirror. By rotating the mirror, astronomers could observe planets at any position around the host star.

The design is estimated to be able to detect half of the Earth-like planets orbiting Sun-like stars in less than three years. While further technical improvements and optimizations are needed, the concept does not require technologies beyond current capabilities – a departure from many other pioneering ideas.

If on average each Sun-like star has one Earth-like planet, then with this telescope design we should be able to detect about 30 promising planets within 30 light years. Further research will focus on scrutinizing their atmospheres for signs of oxygen – an indicator of photosynthetic life.

For the most promising candidates, exploration missions could be deployed to send back images of the planet’s surface. The rectangular telescope design promises to provide the shortest path to finding our “sister planet” – Earth 2.0.

La Khe (According to ScienceAlert)

Source: https://doanhnghiepvn.vn/cong-nghe/thiet-ke-kinh-vien-vong-hinh-chu-nhat-co-the-mo-ra-ky-nguyen-san-tim-trai-dat-2-0/20250902082651458