Harvard University study shows that planets in the center of the Milky Way could be able to harbor life due to their radioactivity.
A new study from Harvard University in the United States shows that a planet can become habitable, with water and other liquids on its surface, if heated by radioactivity. This opens up the possibility that many planets that were once considered hostile to life as we know it, may, in fact, be habitable, according to the research published on The Astrophysical Journal Letters.
The Earth, for example, has radioactive isotopes under its crust and mantle, which are atoms with excess nuclear energy. Among other factors, the presence of uranium-238, thorium-232, and potassium-40 (radionuclides) generates an amount of energy that allows life on our planet. And, according to the new study, some planets, particularly those that form near the center of the Milky Way, also have enough radioactive isotopes to generate heat and prevent their surfaces from freezing completely.
“That gives you the freedom to be anywhere. You don’t need to be close to a star,” says Avi Loeb, an astrophysicist at Harvard University and co-author of the new study, to Science magazine. Loeb and Manasvi Lingam, an astrobiologist at the Florida Institute of Technology, analyzed three heat sources for a planet without a star like the Sun: the heat remaining from its formation, the radioactive decay of long-lived isotopes over billions of years and the radioactive decay of short-lived isotopes over hundreds of thousands of years.
The researchers found that planets with the same mass as Earth, but with about 100 times the abundance of radionuclides (radioactive isotopes), were going to release enough heat to keep the substances liquid for millions of years. However, Lingam says that multicellular life is unlikely to survive this irradiation.
According to Science, the James Webb Space Telescope, scheduled for launch in 2021, could identify a planet with this feature. But the telescope’s cameras will need approximately 10 days to detect it. “There are so many unknowns,” Lingam says. “We haven’t said the last word.”