Lens (or combination of lenses) that brings different wavelenghts within a ray of light to a single focus, thus overcoming chromatic aberration. It was first successfully made by ...
1) Active galactic nuclei are very luminous. Their energy output is in two forms: nonthermal continuum and thermal emission line. 2) Any galaxy which is emitting large quantities ...
1) A process by which a star accumulates matter as it moves through a dense cloud of interstellar gas; or, more generally, whereby matter surrounding a star flows toward it (as in ...
Annual or biennial plant (Raphanus sativus) of the mustard family, probably of Oriental origin, grown for its large, succulent root. Low in calories ...
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