Books space Checking in on Our Old Friend, Barnard’s Star In case you’ve been waiting for an update for the last seven years… By James Davis Nicoll | Published on July 18, 2025 Credit: NASA/ESA and G. Bacon Comment 0 Share New Share Credit: NASA/ESA and G. Bacon In the seven years since I last mentioned Barnard’s Star on Reactor (back when it was Tor.com), Barnard’s Star has traversed an astonishing 70 arcseconds across the sky. On a less positive note, the proposed planet on which that article focused turns out to have been spurious1. Bah and also humbug. Science takes, but it sometimes also gives. In this case, the current data support a model in which Barnard’s Star has at least four planets. I shamelessly screenshot the relevant table from Wikipedia: Credit: Wikipedia Yes, it would make sense if b was the exoplanet closest to Barnard’s Star and e the outermost. Exoplanets are lettered in the order they are found. In this case, b was noticed first, then c was spotted farther from Barnard than b, then d turned up closer to Barnard than either b or c, and finally e is currently the outmost world. The new-found worlds range from a fifth of Earth’s mass to a third (which would be two to three times Mars’ mass). Unfortunately, all of them orbit Barnard’s Star within the inner edge of the habitable zone. Currently the data does not rule out a world within the habitable zone2. It also doesn’t support it. All hope is not lost for skiffy authors wanting to set stories on Barnard’s b, c, d, or e. The estimated temperatures for the planets may range from about 70o C to over 200o C3. However, Barnard’s Star is very dim. Any orbit within the habitable zone is therefore very close to Barnard’s Star. All four worlds are almost certainly tide-locked with one face towards the star and one face away. Bad news for the day sides, but the night sides might be considerably cooler. As footnote one points out, Barnard’s Star has fascinated humans since Edward Emerson Barnard measured its parameters back in 1916. It is, after all, the second closest star system and the closest singleton system to Earth. No surprise that it appears in science fiction stories again and again. However, the work that established Barnard’s Star in my imagination was a non-fiction work. Or perhaps “speculative non-fiction” is closer to the mark. Whereas the American Rocket Society judiciously attempted to present a sober, sensible face to the American public4, the British Interplanetary Society flew its freak flag enthusiastically. The BIS sketched out plans for trips to the Moon and the planets in our solar system. It was inevitable that they would turn their gaze to the stars. In 1978, the Journal of the British Interplanetary Society presented Project Daedalus: The Final Report on the BIS Starship Study. Edited by Anthony Martin, it outlined a wonderfully ambitious design for a space probe capable of traversing the distance between Sol and Barnard’s Star in an eyeblink, a mere half century5! Of course, the BIS was well aware that no technology on hand in 1978 was equal to the task. Therefore, they did their best to imagine what might one day be sufficient. The end result: Not merely speculations about the advanced technology necessary to permit a 46,000 ton+ vehicle to deliver a 450-ton payload to Barnard’s Star6, …but also hints about the industrialized solar system necessary to support such a project. This would be a civilization so much more capable than ours that our entire industrial output would be lost in the error bars of their accounting systems. It was very heady stuff back in the Disco Era. No doubt it would be heady stuff today. Alas, fifty-year-old back issues of Journal of the British Interplanetary Society can be hard to come by, and the summary to which I would otherwise point readers, Project Daedalus: Demonstrating the Engineering Feasibility of Interstellar Travel, appears to be out of print.[end-mark] Spurious reports of planets orbiting Barnard’s Star are nothing new, as the late astronomer Peter van de Kamp could attest. This is because planets can be hard to spot, humans are adept at seeing patterns in noise, and because Barnard’s Star, being the second closest star system to ours, is subject to intensive scrutiny. ︎Or rather, astronomers are sure there’s nothing in excess of 0.7 Earth-masses towards the inner edge of the habitable zone, and nothing in excess of 1.2 Earth-masses towards the outer edge. However, that leaves room for smaller worlds. ︎For metric-averse readers, somewhere between a very hot giraffe to an extremely hot giraffe. Presumably these are lower limits, as greenhouse gases would increase the equilibrium temperatures. Although I suppose very high albedos (from salt deposits, say, or chrome plating) might produce cooler worlds. ︎Which didn’t stop American rocket fans from engaging in zany hijinks. Had one of William F. Sykora’s exuberant rocket tests detonated at launch rather than up in the air, the casualties would have included Donald A. Wollheim, and SF would look very different. ︎Or as seventeen-year-old me put it, almost three times as long as I’d been alive. ︎Daedalus would have used Helium-3 as fuel. The proposed source was Jupiter. It was not, regardless of claims inserted into certain Wikipedia articles, the Moon. The idea of mining lunar regolith for Helium-3 didn’t come along for over a decade after BIS pitched Daedalus. In any case, mining regolith for Helium-3 is such a ludicrous idea it has only one application: identifying gullible dupes who might very well appreciate affordably-priced Bre-X stock. ︎The post Checking in on Our Old Friend, Barnard’s Star appeared first on Reactor.