Submillimetre astronomy

Submillimetre astronomy studies celestial objects and processes through radiation with wavelengths roughly 0.1–1 millimetre, between far-infrared and microwave radiation.

Atmospheric window: A wavelength range in which Earth’s atmosphere transmits radiation relatively well. Water vapor absorbs much submillimetre radiation, leaving narrow windows for ground-based observations.
Star formation: The process by which dense regions of gas and dust collapse to form stars. Cold dust and molecular gas around forming stars emit strongly at submillimetre wavelengths.
Electromagnetic spectrum: The complete range of electromagnetic radiation, ordered by frequency or wavelength. Submillimetre astronomy occupies the boundary between far-infrared and microwave regions.
Atacama Large Millimeter/submillimeter Array: An observatory of 66 radio antennas in Chile’s Atacama Desert, operating at millimetre and submillimetre wavelengths. Its high-resolution images have resolved disks, molecular clouds, and distant dusty galaxies.
Heterodyne detection: A measurement method that mixes an incoming signal with a reference wave to produce a lower-frequency signal. It preserves narrow spectral features needed to measure gas motions and chemical composition.
Protoplanetary disk: A rotating disk of gas and dust surrounding a young star, where planets can form. Submillimetre maps trace disk dust and reveal structures linked to planet formation.
Far-infrared astronomy: The study of celestial sources through radiation at far-infrared wavelengths. It overlaps submillimetre astronomy in its focus on cool dust and obscured sources.
James Clerk Maxwell Telescope: A 15-metre radio telescope on Mauna Kea in Hawaii, designed for millimetre and submillimetre observations. Its surveys mapped cold dust and molecular gas across the Milky Way and beyond.
Bolometer: A detector that measures electromagnetic radiation through the heating it produces in an absorbing element. Bolometers detect faint broadband submillimetre emission by measuring tiny temperature changes.
Molecular cloud: A dense interstellar region dominated by molecular gas and dust, often a site of star formation. Its cold gas produces submillimetre lines that map cloud structure and dynamics.

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