Planet That Turns the Rules Inside Out

A team of scientists used the Cheops telescope to look at a star that is far away, about 117 light‑years from us. The star is small and dim, called a red dwarf, and it has four planets orbiting around it. Two of the planets are rocky like Earth, while the other two are gaseous and look more like Neptune. What surprised the researchers is the order of these planets. The first planet closest to the star is rocky, then two gas giants follow, and finally another rocky planet sits farthest out. Normally, we expect the outer planets to be gas rich because they form in colder places where more gas is available. This system goes against that rule. The star, named LHS 1903, has only half the mass of our Sun and is very faint. All four planets are much closer to their star than Mercury is to the Sun, which is common for planets around red dwarfs.The two rocky worlds are called super‑Earths. They weigh between two and ten times more than Earth. The gas planets are mini‑Neptunes, smaller than Neptune but still larger than Earth. Scientists think the planets did not form all at once. Instead, they may have formed one after another. The last planet that appeared probably did not get much gas left over, so it stayed rocky. Another idea is that it once had a thick atmosphere but lost it later, perhaps because of a big collision. The outer rocky planet is especially interesting. It has about 5. 8 times the mass of Earth and its surface temperature is around 60 degrees Celsius, similar to the hottest place on our planet. This makes it a candidate for studying how life could exist elsewhere. Future observations with the James Webb Space Telescope might tell us more about its atmosphere and whether it could support life.