SIGNAL FROM SPACE
A message from Proxima Centauri?
RADIO PROXIMA
A strange radio signal from Proxima Centauri is being “carefully investigated” by a team of astronomers. Researchers from the Breakthrough Listen Project (searching for alien life with radio telescopes) have been studying the radio waves after they were first discovered by the Parkes telescope in Australia in April 2019. Unlike previous radio bursts, the 982.002MHz signal, labelled BLC1 (an abbreviation for the first Breakthrough Listen Candidate event), has not been attributed to any Earth-based or near-Earth human-created source, such as satellites. While it probably has a natural explanation, the Breakthrough team say this is one of the most intriguing radio signals since the Ohio-based Big Ear Radio Observatory detected a short-lived signal emanating from a distant star system in 1977. It was named ‘WOW!’, and was, until now, the best candidate for evidence of extraterrestrial intelligence (see FT157:44).
Proxima Centauri, a low mass star in the triple-star Alpha Centauri system, is not visible to the naked eye due to its size, eight times smaller than our Sun. It is the closest star to Earth after the Sun, being 4.2 light years away, and has at least two planets that we know of. Proxima c is a Jupiterlike gas giant that takes 5.2 light years to orbit round Proxima Centauri, and the smaller Proxima b, a rocky planet discovered in 2016 that takes 11.2 Earth days to circle its host star, orbiting Proxima Centauri in the ‘habitable zone’ – an area where liquid water could be flowing on the planet’s surface rather than being evaporated by the star’s heat. But this habitable zone is very close to the star itself – closer than Mercury is to our Sun – meaning Proxima b is subject to intense radiation as well as solar winds 2,000 times greater than those experienced on Earth. Thus, the planet is unlikely to be home to any alien civilisation – at least on its surface.
Shifts in the radio signal’s frequency detected by the Parkes telescope are consistent with a planet’s movement, and so may be suggestive of a third planet within the system. Researchers say it would be “very unlikely” that the signal’s source is alien technology. Pete Worden, director of Breakthrough Initiatives, said the signals are most likely interference from Earth-based sources. But studies indicate Proxima b may have surface oceans and a thin atmosphere, prerequisites for the development of life. It is hoped that the James Webb Space Telescope, due to come online in 2021, could detect the composition of Proxima b’s atmosphere, and there is also a theoretical mission to send a probe to the planet in 2069. The latter initiative was launched by SiliconValley tech investor Yuri Milner in 2015, and seeks to find stray or intentional alien signals.
Professor Avi Loeb, chair of Harvard’s Department of Astronomy, who has argued that ‘Oumuamua is the first solid evidence for extraterrestrial civilisation (see p16), has poured cold water on the Proxima b theory. He has concluded the transmitter of the signal cannot be on the surface of Proxima b, or else its radio frequency would drift much more than observed based on its known acceleration around Proxima Centauri. He argues in a new paper, co-written with his student Amir Siraj, that the likelihood of another civilisation transmitting such radio waves is exceedingly low, based on the Copernican principle. Terrestrial radio technology arose only in the last century of the 4.5-billion-year history of the Earth, and the Copernican principle asserts that humans on Earth are not privileged observers, unlike in Aristotle’s cosmology, which placed the Earth at the centre of the Universe.
Our current understanding of the physical universe implies that Earth-sized planets reside in the habitable zone of roughly half of all sunlike stars, that tens of billions of sunlike stars reside in the Milky Way galaxy alone, that tens of billions of Milky Way–like galaxies exist in the observable volume of the present-day Universe, and that the Universe has no centre. Therefore, applying the same Copernican principle to the technological universe, the co-authors argue, it follows that the chances of a radio signal appearing now from our nearest star is miniscule. They believe BLC1 most likely originated from a human-built radio emitting oscillator on Earth that contaminated the telescope readings.
They conclude the paper with a curious caveat, asking whether intelligent life on Earth and its nearest star may be correlated. Interestingly, they say, Proxima Centauri became our nearest star around the same time that Homo sapiens appeared on Earth. Is this merely coincidence, ask Loeb and Siraj? D.Mail, 18 Dec 2020; scientificamerican.com, 12 Jan 2021.
TELEPORTING BRAINS
Scientists have developed a technique whereby the brain may be “teleported” by means of lasers. Using mice as experimental subjects, laser beams directed at the hippocampus, the area of the brain responsible for learning and memory, were able to stimulate ‘place cells’. These become active when a sentient organism enters a new environment; the new location is then stored in its memory. Thus, by stimulating cells which do not correspond with a person’s environment and surroundings, people could in theory be mentally teleported to another location which those cells are linked to in memory. University College London neuroscientists placed mice in one location, where they were given a reward of sugar water. The mice were then moved to a second location, and when the laser beams activated their brains’ place cells, the mice attempted to locate the sugar water, believing they were still in their original location. The researchers have claimed their findings may be of use in developing new therapies to help Alzheimer’s and dementia sufferers. D.Telegraph, 7 Nov 2020.