As was reported in The Guardian last October, Australian scientists made up part of a team that used the world’s most powerful radio antenna, the Low-Frequency Array (Lofar) in the Netherlands to detect exoplanets, or planets outside our solar system. These new techniques will someday be able to tell us if there is life on other planets. Using Lofar, the scientists were able to detect radio signals from 19 distant red dwarf stars, with four emitting the kind of signals that suggest that they have planets orbiting around them.
Finding humanity in exoplanets
Astrophysicists believe that exoplanets could support human life, and so, this discovery has profound consequences for the future of humanity and our understanding of life on other planets. The research was published by Dr. Ankita Anirban in Nature Astronomy and titled, “Finding humanity in exoplanets”, around the same time that Dr. Benjamin Pope published a second paper confirming the data using a Commonwealth Scientific and Industrial Research Organization (CSIRO) optical telescope in Western Australia.
Dr. Pope highlights the fact that CSIRO began studying the sky using military radars during the Second World War. CSIRO went on to create Parkes Observatory, widely known as The Dish.
Although Lofar is incredibly advanced, it is only a prototype, or what experts refer to as a “pathfinder”, of the Square Kilometre Array (SKA), which, when complete in the next five to ten years, will be the largest telescope in the world, and based in Western Australia and South Africa. SKA will be vastly larger than Lofar.
Lofar uses radio signals to study space using a powerful CB radio antenna, determining how to block out non-exoplanet objects like neutron stars and black holes, so that it focuses instead on red dwarfs. The technology used in Lofar is similar to the technology used in polarized sunglasses.
The team believes that there is a magnetic connection between unseen orbiting planets and the stars, that is causing the signals to be transmitted. The team is confident that they have ruled out other possibilities and that the presence of exoplanets is the most probable conclusion.
There is a huge amount of excitement at the possibilities that SKA will open up, based on inferences from what Lofar has been able to achieve. With SKA, astrophysicists will be able to study hundreds upon hundreds of red dwarfs.
Crucially, red dwarfs have temperatures similar to Earth’s. For now, the team is less focused on the possibility of humans moving to other planets, than the question of whether there is life on other planets.
Astrophysicists are looking for a so-called Goldilocks Zone: they understand that exoplanets could be mild and pleasant, but worn away by radiation, making them incapable of supporting human life. To be habitable, a planet has to have just the right set of conditions. Many of these exoplanets will turn out to be uninhabitable, but With SKA, astrophysicists will be able to play a volume game and increase their chances of finding those few exoplanets that can support life.
When asked if he believed there was life on other planets, Dr. Pope was careful to explain that the search for extraterrestrial life is different from the search for biological life. Dr. Pope believes that we will have an answer within a generation.
Finding a super-Mercury
The search for exoplanets goes beyond Lofar’s efforts. A paper in Science reported that astrophysicists discovered an exoplanet, GJ 367 b, which has half earth’s mass, and a composition similar to Mercury, which has an iron core.
GJ 367 b is one of the lightests exoplanets ever discovered, and orbits its star every 7.7 hours. Like Mercury, it appears to be very dense and made up largely of iron. It has been christened a “super-Mercury” because of its composition and location. It has challenged many planetary formation theories, suggesting that miniature planets exist on a more diverse range than first believed.
GJ 367 b orbits a red dwarf star found 31 light years from earth. It was discovered using NASA’s Transiting Exoplanet Survey Satellite (TESS). TESS looks for nearby planets by assessing how the rate at which their stars fade as the exoplanets move in front of them. Due to this eclipse, there is a small trough in the light transmitted from the star. This allows astronomers to determine the planet’s size.
GJ 367 b is 5,700 miles across, which is around three quarter’s earth’s circumference. The exoplanet’s mass was estimated during a follow-up study using a High Accuracy Radial Velocity Planet Searcher (HARPS) mounted on a telescope at the La Silla Observatory in Chile.
The development of novel technologies and the rate of investment suggests that Dr. Pope’s hunch may be correct and we will have an answer to whether there is life on other planets, within our lifetime. Whether that will be full-blown extraterrestrial life, or biological life, is another question. The odds are that we are more likely to find biological life than full-blown extraterrestrial life.