If the initial position of Conway's game of life is a line of $n \le 100$ cells, then it vanishes completely after some steps iff $n \in \{0,1,2,6,14,15,18,19,23,24 \}$. See below for $n=24$.

Question: Can we prove that such a vanishing is not possible for any $n>100$?

Edit: The sequence A061342 gives the period $p_n$ of the stationary component of the final pattern for an initial line of length $n$. But for $n \in [84,1000]$ we have $p_n \ge 2$, so the pattern must be non-vanishing in this case. But we observe (after Nathaniel Johnston) that for $n=500$, perpetual gliders are produced on the boundaries after $435$ steps, but $435<500$, so this must happens $\forall n \ge 500$.
It follows that the answer is yes.

Improved question: Is the stationary component non-vanishing for any $n > 1000$ ?

Stronger question: Is $p_n \ge 2$ for any $n > 1000$ ?