Are we alone in the universe? NO to think we are alone in this universe is absolutely ridiculous how naive would one be to think we are the only life form in billions of galaxies!
As for does it matter if there are aliens, I believe so and sooner or later these ET's extra terrestrials who are billions of years more advanced than we are will pay earth a mass visit! I do not believe they will come in peace, I also believe they are already here scouts if you will, I believe aliens have been watching the earth for millenniums we are a food source and nothing more once our planet is over populated we will be like the ripe fruit on a tree ready to eat! When and I do mean when they come they will be so far advanced we will be helpless! There will not be a happy ending like in the movies it will be an annihilation! We will not win!