[editor-surveyor]

What an incredible waste anyway!

There are no ‘Earth twins.’

Earth is unique.

[LibWhacker]

No way it's a waste. Some here would disagree, but Ferdinand and Isabella were right to fund Columbus. We're right to fund this.

Count on it: Earth has innumerable twins By 'twin' they don't mean identical down to the last atom, but a rocky world roughly half to five times as massive as Earth, in a Goldilocks orbit around a stable star, and having water on the surface. Some would require an oxygen rich atmosphere, but even that's not necessary.