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Astronomy 2e

Key Terms

Astronomy 2eKey Terms
amino acids
organic compounds that are the molecular building blocks of proteins
astrobiology
the multidisciplinary study of life in the universe: its origin, evolution, distribution, and fate; similar terms are exobiology and bioastronomy
biomarker
evidence of the presence of life, especially a global indication of life on a planet that could be detected remotely (such as an unusual atmospheric composition)
DNA (deoxyribonucleic acid)
a molecule that stores information about how to replicate a cell and its chemical and structural components
Drake equation
a formula for estimating the number of intelligent, technological civilizations in our Galaxy, first suggested by Frank Drake
extremophile
an organism (usually a microbe) that tolerates or even thrives under conditions that most of the life around us would consider hostile, such as very high or low temperature or acidity
gene
the basic functional unit that carries the genetic (hereditary) material contained in a cell
habitable environment
an environment capable of hosting life
habitable zone
the region around a star in which liquid water could exist on the surface of terrestrial-sized planets, hence the most probable place to look for life in a star’s planetary system
organic compound
a compound containing carbon, especially a complex carbon compound; not necessarily produced by life
organic molecule
a combination of carbon and other atoms—primarily hydrogen, oxygen, nitrogen, phosphorus, and sulfur—some of which serve as the basis for our biochemistry
photosynthesis
a complex sequence of chemical reactions through which some living things can use sunlight to manufacture products that store energy (such as carbohydrates), releasing oxygen as one by-product
protein
a key biological molecule that provides the structure and function of the body’s tissues and organs, and essentially carries out the chemical work of the cell
RNA (ribonucleic acid)
a molecule that aids in the flow of genetic information from DNA to proteins
SETI
the search for extraterrestrial intelligence; usually applied to searches for radio signals from other civilizations
stromatolites
solid, layered rock formations that are thought to be the fossils of oxygen-producing photosynthetic bacteria in rocks that are 3.5 billion years old
technosignature
any observable evidence of technology from an extraterrestrial civilization
thermophile
an organism that can tolerate high temperatures
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