The Earth is the cradle of humanity, but mankind cannot stay in the cradle forever.

Mankind will not forever remain on Earth but, in the pursuit of light and space, will first timidly emerge from the bounds of the atmosphere and then advance until he has conquered the whole of circumsolar space.

All the universe is full of the lives of perfect creatures.

I do not remember how it got into my head to make the first calculations related to rocket. It seems to me the first seeds were planted by famous fantaseour, J. Verne.

My entire life consisted of musings, calculations, practical works, and trials. Many questions remain unanswered; many works are incomplete or unpublished. The most important things still lie ahead.

Men are weak now, and yet they transform the Earth's surface. In millions of years, their might will increase to the extent that they will change the surface of the Earth, its oceans, the atmosphere, and themselves.