Why will your neighbor on the lower floor live longer than you? What color is the mirror? How much does Thor's hammer weigh? Why can't we travel to the past? How many megapixels does the human eye have? To read this book, you will dedicate 0.0005% of your life, from 7,200 to 14,400 seconds. Maybe as much as for Blade Runner 2049 or for the original Star Wars trilogy.

But you know that time is relative, like so many other things. If a long and happy life awaits you, you will live over two billion seconds, even though one third of it will be spent sleeping. The remaining seconds, after some time on the pillow, you will be awake, you will live them, you will enjoy them. Because they can be wonderful. So think about how you will make the most of them.

In a few years, some of the things you will read in this book, which are considered certain today, may have no meaning. Nothing remains the same, nothing is stable. "The only constant is change," predicted Heraclitus 2,500 years ago. It is the miracle of science that progresses relentlessly day by day. 

That is why I want this book to be a source of inspiration for you, to help you seek your own answers to all the questions that concern you, and to search for these answers without resorting to standardized knowledge or unscientific myths.