Quasars are named because they appear star-like but emit energy in which part of the spectrum?

Quasars are named because they appear star-like but emit energy in which part of the spectrum?

• A. Radio
• B. Ultraviolet
• C. X-ray
• D. Infrared

Answer: (A)

Quasars look like stars in optical images, but they are powered by supermassive black holes at galaxy centers and shine incredibly brightly across many wavelengths. They were first identified as point-like sources that were strong in radio wavelengths, so the name comes from this radio emission—quasi-stellar radio sources. That historical clue makes Radio the best answer. Keep in mind that quasars do emit across ultraviolet, X-ray, and infrared as well, but the defining feature tied to their naming is their radio emission.

Quasars look like stars in optical images, but they are powered by supermassive black holes at galaxy centers and shine incredibly brightly across many wavelengths. They were first identified as point-like sources that were strong in radio wavelengths, so the name comes from this radio emission—quasi-stellar radio sources. That historical clue makes Radio the best answer. Keep in mind that quasars do emit across ultraviolet, X-ray, and infrared as well, but the defining feature tied to their naming is their radio emission.