Echo, a repeated sound. The term is usually used to refer to sound that is reflected from a surface and returned to its source after a noticeable delay. A person can typically hear his or her own echo where a hard surface, such as the side of cliff, reflects sound waves directly back to the person. The use of echoes to locate objects is called echolocation.
Some scientists believe that space is infinite. But is it? If it isn't, what form does space take? Is it a dodecahedron or a triple torus?
How cool would that be to stand amongst the company of fellow laureates like Mother Teresa or Albert Einstein? We have some ideas for scoring you one (nominating yourself isn't one of them).