This new discovery of scientists is mainly attributed to the data of the now retired Kepler K2 mission. During its lifetime, the Kepler mission scanned the dense center of the Milky Way and collected microlens signals, which can be used to detect objects including planets, even if their light is weak. After analyzing Kepler's data, the researchers found that four of the recorded signals were consistent with those of planets similar in size to Earth. The research results were published in the Monthly Journal of the Royal Astronomical Society.
These signal patterns show that the newly discovered planets have no companion stars, which makes them free to float, or rogue planets. Free floating bodies may be ordinary planets around stars at first, but when their orbits are disturbed by the gravity of other nearby celestial bodies, they will drift.
When looking for planets, especially those without starlight, it is difficult to find those celestial bodies in the dark by filtering out all other noises. McDonald added: "From this noise, we try to extract the tiny and unique brightness caused by the planet, and we only have one chance to see it before the signal disappears. This is as simple as looking for fireflies in the middle of the highway with a hand-held mobile phone. " The author of this new paper writes that there may be more earth-sized interstellar nomads in the Milky Way. Both the Nancy Grace Roman Space Telescope of NASA (scheduled to be launched in the mid-1920s) and the Euclid Telescope of the European Space Agency (scheduled to be launched next year) will use microlens signals to identify free-floating planets. Maybe we will soon make an accurate estimate of how many rogue planets there are.