Fly By Night, SOFIA

Artwork of SOFIA with backdrop of
astronomical objects; Credit: NASA/USRA.Soon, the nighttime Bay Area skies may be graced with a new astronomical wonder-- and I'm not talking about a celestial object or event. I'm talking about something that’s a bit of a cross between an astronomical observatory, a stealth aircraft, and a NASA spacecraft...

I’m referring to SOFIA. The Stratospheric Observatory For Infrared Astronomy is the next generation airborne infrared observatory: a 2.5-meter reflecting telescope built into a Boeing 747. SOFIA is a joint project between NASA and the German DLR. Its purpose: to make astronomical observations and measurements of the infrared light emitted by objects in space.

Visible light comes primarily from stars, or objects and material reflecting visible starlight. But there's plenty of stuff out there that emits or reflects little, if any, visible light, but which does emit the lower-energy form of light called infrared. Anything that's even slightly warm emits some infrared light-- and though human eyes can’t see it, we can build detectors that are able to.

SOFIA will observe all sorts of things, from planetary atmospheres to clouds of molecules in space to dust-disks around forming solar systems to regions of our Milky Way galaxy inscrutable to ordinary telescopes but unexplored virgin territory to infrared eyes. It may be possible for SOFIA to measure and analyze infrared emissions from extrasolar planets (exo-planets) and possibly determine the composition and temperature of their atmospheres, and maybe even telltale chemical signatures of possible life.

Why fly an infrared telescope in an airplane, instead of basing it on the ground like conventional observatories? Simple: While Earth’s atmosphere may be transparent to visible light, allowing us to see stars and planets and nebulas and such with our eyes, molecules in our atmosphere-- primarily water vapor-- absorbs most forms of infrared light. To an infrared telescope, the sky appears in a perpetual overcast.

I have a special interest in SOFIA, as I once worked on SOFIA's predecessor, the Kuiper Airborne Observatory (KAO), on which I served as an observing assistant for seven years.

The KAO sported a smaller, 1-meter telescope built into a C-141A "Starlifter" cargo plane, and flew the night skies from 1976 to 1995 observing an invisible universe overhead. As SOFIA will be, the KAO was based at NASA’s Ames Research Center in Mountain View.

I affectionately refer to the KAO as a true fly-by-night outfit-- no metaphor included! At some point in the future, you may be out in your backyard and notice the stealthy passage of what may otherwise appear as an ordinary jet liner. You may wonder if, instead of a plane-load of sleeping tourists, that plane holds a 20-ton infrared telescope and a team of dedicated crew and scientists probing the cold darkness of the universe...

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.