Eye-popping photos from two cool space-roving telescopes
Brilliant Space Photos From Chandra and Spitzer
Two unsung space telescopes create eye-opening images of the universe from light we can’t see
- By Abigail Tucker
The center of our Milky Way galaxy is even more breathtaking when seen as a composite made of data from three space-based instruments sensitive to different wavelengths.
NASA / CXC / UMass / D. Wand et al.
To human eyes, the night sky is a confetti of stars. Powerful telescopes show us the remote planets and faraway galaxies that our puny retinas cannot see. But even the Hubble Space Telescope can’t reveal everything that’s out there. Many objects—the fizzled stars known as brown dwarfs, for instance—are too cool to give off visible light, which represents only a tiny sliver of the electromagnetic spectrum. They do, however, emit energy in an invisible form: longer wavelengths known as infrared radiation. Incredibly hot objects, like massive exploding stars called supernovas, give off much of their energy in shorter wavelengths that also are invisible: gamma rays and X-rays.
Fortunately, other telescopes trans- late these spectacles into images we can understand. In the 1990s and early 2000s, NASA launched space-based telescopes known as the Great Observatories. The first and most famous, Hubble, specializes in visible light. Lesser-known but equally vital instruments focus on different wavelengths.
“The object was to have a major telescope in each part of the electromagnetic spectrum,” says Giovanni Fazio, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics. “When you look at the universe in different wavelengths, you get a completely different picture. They are all pieces of a puzzle.”
Hubble’s 1990 launch was followed by that of Compton (1991), which observed gamma rays, Chandra (1999), which studies X-rays, and Spitzer (2003), the infrared telescope. Compton fell to Earth in 2000, disintegrating in the atmosphere and splashing down as planned in the Pacific Ocean. (Another space telescope, Fermi, replaced it in 2008.) But Spitzer and Chandra are still up—way up—and running, unlocking secrets of the universe and surpassing the hopes of the people who helped create them.
The telescopes’ pictures of winking newborn stars and gluttonous black holes are composed of false colors that scientists assign to the different wavelengths the telescopes detect. In addition to being data-laden, though, these images are simply wonderful to behold. Pulsing with flamingo pink, indigo and saffron, some are almost psychedelic—a florid galaxy appears to breathe fire—while others recall delicate natural forms: spider webs, windowpane frost, wisps of smoke. A few have an almost spectral quality, particularly “The Hand of God,” Chandra’s portrait of a young pulsar in which ghostly blue fingers seem to caress the heavens.