How long have the small comets been bombarding the Earth?

We do not know. But if the present influx of small comets is assumed to be true for the past 4.5 billion years as well, then the small comets may be responsible for all the water in the oceans and in our atmosphere. In the spring of 1999 some scientists concluded that the Earth's water probably did not come from comets.

So how could the small comets be responsible for the water in the Earth's oceans? The possibility that the water in our oceans is due to an influx of large comets during the early history of our planet has been quite popular among many scientists until recently. But things have changed now that we can remotely determine the amount of deuterium, or heavy hydrogen, in these well-known large comets.

These remarkable measurements have shown that the fraction of deuterium relative to that for hydrogen in the large comets is inconsistently high relative to that in our oceans. That is, the large comets cannot be the source of our oceans because this hydrogen "fingerprint" ... more.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.