Scientists discover four Earth-like planets orbiting Barnard's Star, advancing search for extraterrestrial life

In a groundbreaking discovery for the exoplanetary community, scientists have announced the identification of four new small, Earth-like planets orbiting Barnard's Star, located just six light-years from Earth.

These four planets, named b, c, d, and e, are all smaller than Earth but share a common trait—they are rocky, much like our own planet.

This remarkable find marks a significant leap in exoplanetary science and the ongoing search for extraterrestrial life.

While these planets are unlikely to support life due to their harsh environmental conditions, their discovery provides valuable insights into the types of planets that exist within our galaxy.

This discovery brings humanity one step closer to answering the age-old question of whether we are alone in the universe.

Barnard's Star, a red dwarf and the closest single star to Earth (excluding those in the Alpha Centauri system), has long been a prime candidate for astronomical study.

Its proximity to Earth makes it an ideal target for scientists seeking to understand more about the conditions of stars and planets in our galaxy.

The newly discovered planets orbiting this star are of particular interest because of their rocky composition, which makes them even more intriguing to researchers.

The four planets—designated b, c, d, and e—are incredibly small, with masses ranging from 20% to 30% of Earth's mass.

They are the smallest planets ever detected using the radial velocity technique, a method in which astronomers measure the "wobble" or gravitational pull a planet exerts on its star.

This technique allows scientists to detect the presence of planets by observing the very slight movements of a star caused by the gravitational forces exerted by orbiting planets.

Advanced astronomical tools played a crucial role in this discovery. Two key instruments—the MAROON-X spectrograph on the Gemini North telescope in Hawaii and the ESPRESSO spectrograph on Chile's Very Large Telescope—enabled scientists to detect the minuscule variations in the light emitted by Barnard's Star.

These variations are caused by the gravitational influence of the planets, although the signals are incredibly faint and can easily be overwhelmed by the background noise from the star.

The planets orbit Barnard's Star at closely spaced radii, with the inner planet completing its orbit in just over two days, and the outermost planet taking about seven days to complete one full revolution.

This proximity to the star suggests that the planets are likely too hot to support life, as they are much closer to their star than Earth is to the Sun.

Despite this, the planets' rocky composition is a significant factor to consider. Rocky planets, particularly those within the "habitable zone" of their star—the region where liquid water could exist—are key targets in the search for life.

While these specific planets do not lie within their star's habitable zone, their discovery still contributes to the growing body of evidence that could one day help scientists identify planets that might support life.

The research, which was published in The Astrophysical Journal Letters, was led by University of Chicago undergraduate Ritvik Basant, in collaboration with an international team of researchers.

This discovery is a crucial step forward in understanding our cosmic neighborhood and suggests that in the future, we may find more distant planets that share Earth-like characteristics, such as low mass and rocky composition, potentially harboring the conditions necessary for life.

While these particular planets around Barnard's Star are unlikely to support life due to their close proximity to their star, their discovery is an important contribution to the ongoing quest for understanding planets beyond our solar system.

It strengthens the idea that rocky, low-mass planets—those that may eventually be found in the habitable zone of their stars—are promising candidates for hosting life.