Astrobiology Glossary T – Space

Term Definition
T-Tauri Star A class of very young, flaring stars on the verge of becoming normal stars fueled by nuclear fusion.
Telescope An instrument used to observe distant objects by collecting and focusing their electromagnetic radiation. Telescopes are usually designed to collect light in a specific wavelength range. Examples include optical telescopes that observe visible light and radio telescopes that detect radio waves.
Temperature A measure of the amount of heat energy in a substance, such as air, a star, or the human body. Because heat energy corresponds to motions and vibrations of molecules, temperature provides information about the amount of molecular motion occurring in a substance.
Terrestrial Planets whose density and chemical makeup are similar to those of Earth.
Terrestrial Planet Rocky planets such as the Earth and other inner planets, as distinct from the Gas Giants.
Terrestrial Planets The four planets of the inner solar system (Mercury, Venus, Earth, and Mars) are called terrestrial planets because they are made up mostly of rock.
Thermal Radiation Radiation released by virtue of an object’s heat, namely, the transfer of heat energy into the radiative energy of electromagnetic waves. Examples of thermal radiation are sunlight, the orange glow of an electric range, and the light from in incandescent light bulb.
Thermophile An organism adapted to life at high temperatures.
Tracking and Data Relay Satellite System (TDRSS) A network of four communication satellites used to relay data and commands to and from U.S. spacecraft, including the Hubble Space Telescope. The Goddard Space Flight Center provides the day-to-day management and operations of TDRSS, the first space-based global tracking system.
Tree of Life A phylogenetic tree covering all groups of life on Earth. The term is commonly used for the tree derived by molecular phylogeny using small sub unit Ribosomal RNA as pioneered by Carl Woese in the 1970s.
Triton The largest of Neptune’s satellites. Triton has an atmosphere and is roughly the size of Earth’s moon. It has an ‘ice cap’ of frozen nitrogen and methane with ‘ice volcanoes’ that erupt liquid nitrogen, dust, and methane compounds from beneath its frozen surface.
Turbulence Unstable and disorderly motion, as when a smooth, flowing stream becomes a churning rapid.