Question

The discovery of what Earth-like planet with the greatest potential for harbouring life found so far, was announced in late September 2010?

Answer 1

Gliese 581 g
It orbits the red dwarf Gliese 581, 20.5 light-years from Earth in the constellation of Libra. Subsequently it was decided that it is most likely to be an artifact of stellar activity rather than an actual planet. In 2020 NASA announced discovery of the first Earth-size planet in its star’s habitable zone, TOI 700 d which is a small, cool M dwarf star just over 100 light-years away in the southern constellation Dorado.