Barnard's star is a red dwarf, the smallest type of regular star and much smaller and less luminous than our sun. At about 6 light years away, it is the closest single star - one not orbiting with other stars - to our solar system. It is, in cosmic terms, in our neighborhood.

Because of this, scientists eager to study nearby potentially habitable worlds are excited by the discovery of the first confirmed planet orbiting Barnard's star, a rocky one with a mass about 40% that of Earth, Reuters reported.

While this planet, orbiting very close to Barnard's star, has a surface temperature too high to be suitable for life, the researchers found what they called "strong hints" of three other planets around Barnard's star that might be better candidates.

The confirmed planet, called Barnard b, has a predicted diameter about three-quarters that of Earth, so about 6,000 miles (9,700 km).

"It is one of the least massive planets ever found," beyond our solar system, said astronomer Jonay González Hernández of the Instituto de Astrofísica de Canarias in Tenerife, Spain, lead author of the study published this week in the journal Astronomy & Astrophysics, opens new tab.

Among planets in our solar system, only Mars and Mercury are smaller.

Barnard b, with a surface temperature around 275 degrees Fahrenheit (125 degrees Celsius), orbits Barnard's star in just three Earth days at a distance 20 times closer than our solar system's innermost planet Mercury is to the sun.

Planets beyond the solar system are called exoplanets. Scientists searching for exoplanets that possibly could harbor life look at those residing in the "habitable zone" around a star, where it is not too hot and not too cold, and liquid water can exist on the planetary surface.

The researchers used an instrument called ESPRESSO on the European Southern Observatory's Chile-based Very Large Telescope to detect this planet. The three other potential planets orbiting Barnard's star all apparently are rocky and smaller than Earth, ranging from 20-30% of Earth's mass. The hope is that at least one of these may be in the vicinity of the habitable zone.

If confirmed, this would be the only known star with a multi-planet system entirely comprised of planets smaller than Earth.

Barnard's star, in the constellation Ophiuchus, has a mass about 16% of the sun's, a diameter 19% of it and is far less hot. It also is estimated to be more than twice as old as the sun.

"Being so cold and small, it is quite faint, making its habitable zone much closer to the star than in the case of the sun," said Instituto de Astrofísica de Canarias astronomer and study co-author Alejandro Suárez Mascareño. "It also is a very quiet star. While some red dwarfs have been found to flare very frequently, Barnard's star doesn't do it."

The closer that exoplanets are to us, the easier they are to study. It is easier to detect low-mass rocky planets orbiting red dwarfs, the most common type of star in our Milky Way galaxy, than around larger stars.

Only the three stars in the Alpha Centauri system, about 4 light-years away, are closer to our solar system than Barnard's star. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). Two exoplanets have been detected in the Alpha Centauri system, both orbiting the red dwarf Proxima Centauri. One has a mass about equal to Earth's. The other is about 25% Earth's mass.

In science fiction, light speed travel is commonplace. In reality, it is far beyond human capabilities, though research projects such as Breakthrough Starshot are exploring the feasibility of interstellar travel. Barnard's star and Alpha Centauri might be on wish lists of future destinations.

"While they are very close in astronomical terms, they are out of reach for any kind of human technology. However, if projects such as the Breakthrough Starshot are successful, it is likely that these will be some of the first targets," Mascareño said.

SpaceX plans to launch about five uncrewed Starship missions to Mars in two years, CEO Elon Musk said on Sunday in a post on social media platform X.

Earlier this month, Musk had said that the first Starships to Mars would launch in two years "when the next Earth-Mars transfer window opens."

The CEO on Sunday said that the first crewed mission timeline will depend upon the success of the uncrewed flights. If the uncrewed missions land safely, crewed missions will be launched in four years. However, in case of challenges, crewed missions will be postponed by another two years, Musk said.

Musk, known for providing changing timelines on Starship's readiness, said earlier this year that the first uncrewed starship to land on Mars would be within five years, with the first people landing on Mars within seven years, Reuters reported.

In June, a Starship rocket survived a fiery, hypersonic return from space and achieved a breakthrough landing demonstration in the Indian Ocean, completing a full test mission around the globe on the rocket's fourth try.

Musk is counting on Starship to fulfill his goal of producing a large, multipurpose next-generation spacecraft capable of sending people and cargo to the moon later this decade, and ultimately flying to Mars.

NASA earlier this year delayed Artemis 3 mission and its first crewed moon landing in half a century using SpaceX's Starship, to September 2026. It was previously planned for late 2025, NASA said.

Japanese billionaire Yusaku Maezawa in June canceled a private mission around the moon he had paid for, which was to have used SpaceX's Starship, citing schedule uncertainties in the rocket's development, read the report.

Facebook owner Meta said on Monday it was banning RT, Rossiya Segodnya and other Russian state media networks from its platforms, claiming the outlets had used deceptive tactics to carry out covert influence operations online, Reuters reported.

The ban marks a sharp escalation in actions by the world's biggest social media company against Russian state media, after it spent years taking more limited steps such as blocking the outlets from running ads and reducing the reach of their posts.

"After careful consideration, we expanded our ongoing enforcement against Russian state media outlets. Rossiya Segodnya, RT and other related entities are now banned from our apps globally for foreign interference activity," the social media company said in a written statement.

Enforcement of the ban would roll out over the coming days, it said. In addition to Facebook, Meta's apps include Instagram, WhatsApp and Threads.

The Russian embassy did not immediately respond to a Reuters request for comment. The White House declined to comment, read the report.

Meta's move came after the United States filed money-laundering charges earlier this month against two RT employees for what officials said was a scheme to hire an American company to produce online content to influence the 2024 election.

U.S. Secretary of State Antony Blinken said on Friday that countries should treat the activities of Russian state broadcaster RT as they do covert intelligence operations.

RT has mocked the U.S. actions and accused the United States of trying to prevent the broadcaster from operating as a journalistic organization, Reuters reported.

In briefing materials shared with Reuters, Meta said it had seen Russian state-controlled media try to evade detection in their online activities in the past and expected them to continue trying to engage in deceptive practices going forward.