The last few centuries have been pretty good for science. In the 17th century, Isaac Newton solved the ancient controversy over the nature of forces and motion with his three laws. In the 18th, Ben Franklin figured out a lot about electricity. In the 19th, Darwin explained the diversity of species, Maxwell revealed the physics of light, Mendeleyev defined the families of chemical elements. In the 20th we had Einstein, who figured out all sorts of stuff, including gravity. No to mention Watson and Crick, who deciphered the molecular foundation for genetics and life. What more do you want?
Well, there are still lots of mysteries left for the 21st century to solve, and it has only 86 years left in which to solve them. So it’s a good idea to put them in a list, just to avoid any danger that everybody will forget to work on them.