Well, we do know for sure it'd take more than this. We don't know what it would take, but this is far beyond the minimum it could take. If that's all it is then almost every form of life on Earth would have to be assumed to be conscious.
(Sentience is actually the word we are talking about).
Space is BIG. Even if your asteroid idea happened, I can confidently say it won't hit us, because the numbers are so much in favor of them not. Earth is a ridiculously small target compared to the space in the solar system, and we have Jupiter that throws everything out and protects us. It's not happening, and even if it did it'll likely hit water, and even if it hits land it likely won't be near you.
Prepare for a car accident. Don't prepare for asteroid impact. Youre wasting your time and money in the later and, though the former is relatively unlikely to be needed, it's actually realistic that it may happen to you. Until you're prepared for that, for a house fire, for a break in, for a medical emergency, and for anything else that's relatively likely, you're wasting your resources.