For years, scientists have been fascinated by the idea of rogue planets: worlds that wander through space, untethered to a star. But until recently, they were nothing more than an intriguing thought. Now, thanks to new research by NASA and Japan’s Osaka University, we know that these mysterious objects might be far more common than we ever imagined.The study found that rogue planets far outnumber those that orbit stars, suggesting that NASA’s Nancy Grace Roman Space Telescope could find an impressive 400 Earth-mass rogue planets when it launches in 2027. Even more exciting is the fact that the researchers were able to identify one particular candidate planet.
The findings were gleaned from a nine-year survey conducted at the Mount John University Observatory in New Zealand. It works on the basis of microlensing events: when an object comes into near-perfect alignment with an unrelated background star from our perspective. Here, the nearer object acts as a natural lens, creating a brief spike in the brightness of the distant star’s light. This allows for clues about the intervening object to be discovered.With this technology, the team was able to estimate that our galaxy is home to an incredible 20 times more rogue planets than stars – trillions of worlds drifting alone in space. And because microlensing is the only way to find such low-mass, free-floating planets, these incredible discoveries are only just beginning.
The implications of this research could be revolutionary. Not only does it help us better understand our universe and its many mysteries, but it also gives us the potential insight into planets with conditions similar to Earth’s, which could even be capable of supporting life. Rogue planets are no longer just an interesting thought – they’re real and waiting to be explored! With new technology and further research, who knows what secrets these mysterious worlds have in store?
A team of astronomers has made a discovery of a roughly Earth-mass rogue planet, marking the second finding of its kind. The paper describing the finding is set to be published in a future issue of The Astronomical Journal, alongside another paper that presents a demographic analysis concluding that rogue planets are six times more abundant than those that orbit stars in our galaxy.
What can be the shape of rogue planets?
What is a rogue planet? It is a celestial body that is not gravitationally bound to a star, but instead drifts through space, alone and unseen. Unlike planets that are gravitationally bound to a host star, these rogue planets are not affected by the star’s gravity and thus can form in different ways. This makes them an important part of our understanding of planetary formation mechanisms. The team’s results suggest that rogue planets tend to be “Earth-sized” meaning they have a similar mass to Earth. This means they are much smaller than most of their star-bound counterparts, and also explains why they remain undetected for so long. Planets that are gravitationally bound to stars are tethered more strongly to their host star than roamers are. This means that during the chaotic process of world-building, some of these interactions can end up flinging such worlds off into space.
This discovery may even have implications for science fiction fans everywhere. In one of the early episodes of the original Star Trek series, the crew encountered one such lone planet amid a so-called star desert. They were surprised to ultimately find Gothos, the starless planet, habitable. While such a world may be plausible, the team’s research emphasizes that any newly-discovered rogue Earth probably doesn’t share many other characteristics with Earth beyond a similar mass. When you look up at the night in sky now, you can take comfort in knowing that we’ve made some progress in understanding rogue planets and their role in planetary formation mechanisms. But there is still much more work to be done in this field before we can say with certainty what lies beyond our own solar system!
Will the Nancy Grace Roman Space Telescope be able to spot rogue planets?
Rogue planets, or planets that orbit no star, are believed to be extraordinarily rare – yet they remain intriguingly mysterious to astronomers. How do they form? What are their atmospheres like? Might they one day be home to life? To better understand such questions, scientists need to cast a wider net in search of rogue planets – and that’s exactly what the Roman spacecraft, set to launch by May 2027, will do.
Roman is the latest in a line of missions seeking to uncover the secrets of these mysterious worlds. Equipped with a wide view and sharp vision, Roman will observe from space and be sensitive even to low-mass rogue planets. Previous estimates suggested that it would be able to spot up to 50 terrestrial-mass rogue worlds, but recent research suggests that this could actually rise to around 400.
To make sure astronomers can take full advantage of this data, they will also be making observations from ground-based telescopes such as Japan’s PRIME (Prime-focus Infrared Microlensing Experiment). The 1.8-meter telescope is located at the South African Astronomical Observatory in Sutherland and has been equipped with four detectors from Roman’s detector development program – provided by NASA as part of an international agreement with JAXA (Japan Aerospace Exploration Agency).
Because microlensing events (the phenomenon which allows astronomers to spot potential rogue planets) are one-time occurrences, having simultaneous observations from Earth and Roman will give scientists a second chance to measure the masses of these hidden worlds. This invaluable data could help us understand how these rogue planets form and evolve.
What’s more, PRIME’s wide-area microlensing survey means it will detect objects in near-infrared light – vital for learning about the atmospheres of potential rogue planets. If the conditions on these worlds are similar to those on Earth, then we may be able to find evidence of life.Though there are still many unknowns when it comes to rogue planets, we can be sure that with the help of Roman and PRIME, we will uncover many new secrets about these remarkable worlds. Let’s just hope that they don’t all turn out to be too far away for us to explore – or worse, inhabited by alien lifeforms!
