One does. One. Singular earth. No others are known, and saying there must be others is as wild a speculation as saying there is just one --this one.
One does. One. Singular earth. No others are known, and saying there must be others is as wild a speculation as saying there is just one --this one.
If I go outside at night with my eyes closed and I feel and hear something wet falling on me that sounds like rain, which is more likely - that it is raining, or that a flock of bats happens to be flying over me and taking a group piss? Rationality sides with the probable, not the merely theoretically possible.
Saying that this is the only Earth we are aware of is one thing; saying that this is the only Earth-like planet in the universe is straining probablity far, far beyond what is rational; and saying that we cannot rationally speculate about the probability of other earths is itself, irrational.
The probability that there are other Earth-like planets in the universe, based on what we know so far, is extremely high; the only question is how many of them there are, and where they are. It is irrational to call this rational speculation "wild speculation"; you are taking skepticism far beyond its rational limits, and trying to insist we cannot speculate rationally based on existing evidence. You are wrong; we can.
If you insisted that this was the only Earth-like planet, you would be the one engaged in "wild speculation". If this were true, the universe would be weirder then we thought, and most of our existing scientific theories and the evidence these are built on would have to be thrown out. Smart money is on my side (one or more other earth-like planets in the universe, besides Earth); the only question is when we will discover them, and where, and in what quantity.