Bernhard Riemann (1826-1866) was a German mathematician who made significant contributions to various areas of mathematics, particularly in the field of analysis and geometry.

The Doctor of Philosophy (PhD) is a doctoral degree most commonly awarded by universities in recognition of academic research and the culmination of a person's education in a particular field of study.

An electron microscope is a type of microscope that uses a beam of electrons to produce a magnified image of a sample.

Gottlob Frege was a German mathematician, logician, and philosopher who made significant contributions to the fields of logic and philosophy of mathematics.

Johann Wolfgang von Goethe was a German writer, poet, playwright, and natural philosopher during the Enlightenment era.

Mathematics is a branch of science that deals with the study of numbers, quantities, and shapes.

The Moon is Earth's only natural satellite and is the fifth-largest satellite in the Solar System.