The Third Millennium--what has changed that makes it already different from the past Two Millennia:

We no longer depend on animals for transportation, upholstery or clothing--though of course we still eat them. Most importantly, very few people any more are outright owners of horses or draught animals.

New Study Suggests 36 Alien Civilizations In The Milky Way, But...

The Answer, we hope--that we eventually get (might be vouchsafed)--when we call out "¿Anybody there?" will be: (technical information) How Exactly to control Nuclear Fusion, so as to áccelerate a Spaceship at a constant 1-G for the first half of its Voyage, and to décelerate the said-spaceship at the same force of gravity for the second half of its Voyage--in order that we might travel among the stars and arrive at our destinations within our own lifetimes. I can't figure how else to do it. Though I admit, the stark forêverness of never being able to go back home (or anywhere that I had been) would be stomach-knotting.