Weymann and Wilcox 1 have recently claimed that there is no evidence that the true occurrence of absorption lines in quasi-stellar objects (QSOs) is a function of red-shift. Such a conclusion, if true ...

To learn how planetary spectra can be used to search for life on other worlds and analyze a mystery planet's spectrum for potential signs of life. copy of the "Exploring Spectra" student handout (PDF ...

THE vast work of determining and cataloguing radial velocities has made the slitless spectrograph almost indispensable. A number of stars may then be photographed on the same plate at the same time.

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in ...