Dim objects called brown dwarfs, less massive than the Sun but more massive than Jupiter, have powerful winds and clouds — specifically, hot patchy clouds made of iron droplets and silicate dust. Scientists recently realised these giant clouds can move and thicken or thin surprisingly rapidly, in less than an Earth day, but did not understand why.
Scientists now have a good estimate for the age of one of the most intriguing planetary systems discovered to date — TRAPPIST-1, a system of seven Earth-size worlds orbiting an ultra-cool dwarf star about 40 light-years away. Researchers say in a new study that the TRAPPIST-1 star is quite old: between 5.4 and 9.8 billion years. This is up to twice as old as our own Solar System, which formed some 4.5 billion years ago.