Searching For Water Worlds

Sep, 2022 - By SMI

It could be tempting to picture these worlds as being fully submerged beneath vast oceans, like something from Kevin Costner's Waterworld. 

These planets are so near to their suns, though, that any surface water would be in a supercritical gaseous phase, increasing the radius of the planets. However, Luque said, "We don't see it in the samples." That implies that the water is not an ocean's surface.

Instead, the water can be present in pockets below the surface or incorporated with the rock. In those circumstances, the moon Europa of Jupiter, which is assumed to have liquid water beneath, would be comparable.

According to Pallé, "the two different methods of discovering planets each provide you different information." Scientists can measure a planet's diameter by observing the shadow that is cast as it passes in front of its star. Its mass may be determined by measuring the minuscule gravitational attraction that a planet has on a star.

Combining the two readings allows researchers to understand the composition of the planet. It may be a large, airy planet like Jupiter that is primarily formed of gas, or it might be a tiny, dense, rocky planet like Earth.

Individual planets have undergone these examinations, but the total known population of such planets in the Milky Way galaxy had been done far less often. The scientists saw a startling pattern developing as they studied the data—43 planets in total.

According to the densities of a substantial portion of the planets, these were too lightweight for their mass to be entirely built of rock. Instead, these planets are presumably made up of a mixture of lighter molecules like water or rock. Try picking up a soccer ball and a bowling ball; they are both about the same size, but one is made of considerably lighter material.