Message #260079

[Paradox]

The planet discovered is the size of Mars (NASA/JPL-Caltech/PA)

Another problem is that the world is probably tidally locked, meaning it always has one face pointing towards the star. Kepler-138b is one of many exoplanets discovered by scientists analysing data from the Kepler space telescope. The technique used to find it, described in the journal Nature, has echoes of the historic discovery of Neptune in the early 19th century.

Victorian astronomers learned that the planet Uranus had slight irregularities in its orbital motions. They suspected these might be due to the tug of another world some distance further from the Sun – and they were right. That world, identified in 1846, was Neptune.

Rowe pointed out that the way the three Kepler-138 planets interfered with each other’s orbits would play havoc with time-keeping.

“Any extra-terrestrials living in these systems would have to be expert watch makers, because the length of their year is always changing,” he said.