Large numbers are numbers significantly larger than those typically used in everyday life (for instance in simple counting or in monetary transactions), appearing frequently in fields such as mathematics, cosmology, cryptography, and statistical mechanics. They are typically large positive integers, or more generally, large positive real numbers, but may also be other numbers in other contexts. Googology is the study of nomenclature and properties of large numbers. Scientific notationLogarithmic scaleOrders of magnitude and Names of large numbers Scientific notation was created to handle the wide range of values that occur in scientific study. 1.0 × 109, for example, means one billion, or a 1 followed by nine zeros: 1 000 000 000. The reciprocal, 1.0 × 10−9, means one billionth, or 0.000 000 001. Writing 109 instead of nine zeros saves readers the effort and hazard of counting a long series of zeros to see how large the number is. In addition to scientific (powers of 10) notation, the following examples include (short scale) systematic nomenclature of large numbers. Examples of large numbers describing everyday real-world objects include: The number of cells in the human body (estimated at 3.72 × 1013), or 37.2 trillion The number of bits on a computer hard disk (, typically about 1013, 1–2 TB), or 10 trillion The number of neuronal connections in the human brain (estimated at 1014), or 100 trillion The Avogadro constant is the number of “elementary entities” (usually atoms or molecules) in one mole; the number of atoms in 12 grams of carbon-12 - approximately 6.022e23, or 602.2 sextillion. The total number of DNA base pairs within the entire biomass on Earth, as a possible approximation of global biodiversity, is estimated at (5.3 ± 3.6) × 1037, or 53±36 undecillion The mass of Earth consists of about 4 × 1051, or 4 sexdecillion, nucleons The estimated number of atoms in the observable universe (1080), or 100 quinvigintillion The lower bound on the game-tree complexity of chess, also known as the “Shannon number” (estimated at around 10120), or 1 novemtrigintillion Note that this value of the Shannon number is for Standard Chess.