they are for non-science, nonscientists. they all are. and i hope that i succeeded in making them clear enough. i certainly tried. >> and then for another nonscientific question to you, is there life similar to what we have here on earth in your view somewhere else in the universe? >> the universe is pretty big. and i think the chances are very strong. but how, i me, it's a big unknown question. how likely is it that if you have a planet that is about the right distance from its stars so that water can be liquid on the surface and has a solid surface and has the right chemistry, how likely is it that life will get started there? nobody has the slightest idea. we know the answer isn't zero. on me, there's some chance, and since the universe as so many planets, so many galaxies, each galaxy having so many stars, most stars having planets, i think the chances overwhelming that there is volume elsewhere in the universe. but whether that is life elsewhere in our galaxy, or in the in the neighborhood of our solar system, that's an entirely diff