Astronomers have long had a basic understanding of how stars are formed. But observing and proving the theory has proven elusive. Now, a German-American project, complete with an infrared telescope mounted on an old Pan Am 747, is providing new insights … //
… Clouds Ablaze:
The telescope, called SOFIA (Stratospheric Observatory for Infrared Astronomy), is the largest German-American research project currently running. It took 20 years of development, at a cost about €1 billion ($1.27 billion), before it was ready for prime time — and the project was repeatedly in jeopardy of cancellation.
The infrared telescope is located on board a converted Boeing 747 that was once used on Pan Am’s trans-Atlantic routes. At altitudes of up to 14,000 meters (45,932 feet), high above the flight paths of commercial aircraft, the older jet transforms itself into a convertible. A retractable roof in the fuselage is opened so that SOFIA can gaze into infinity. To offset turbulence and vibration, the telescope, the largest ever to be mounted in an aircraft, floats on a film of oil.
The great effort involved in unavoidable. An earthbound telescope is largely blind to infrared radiation from space, because most of it, with the exception of a few wavelengths, is absorbed by water vapor in the earth’s atmosphere. As a result, the cold gas-and-dust clouds can only be studied from the stratosphere on out.
The effort seems to be paying off. “On the first images, it looks as if the dark clouds were ablaze, because of how intensely they glow in the infrared spectrum,” says Hans Zinnecker, the deputy director of SOFIA Science Mission Operations. “We can now finally recover an incredibly valuable treasure trove of data.”
The clouds of matter aren’t just the raw material from which the stars emerge. They also form cosmic factories in which highly complex molecules are incubated, presumably even building blocks of life, like amino acids. “Complex chemical processes are taking place inside the clouds, processes that we haven’t even come close to understanding,” says Zinnecker.
The astrophysicists are currently evaluating data they have obtained with their flying telescope. And it looks as if SOFIA will indeed provide them with a view into the delivery room of the stars.
Fast-Forward Star Production: … //
… The Next Generation:
The scientists working on the SOFIA project hope to make such a dramatic event, the ignition of a star, visible within the next few years. “By measuring infrared radiation, we’ll be able to observe how a star taps against its eggshell from the inside,” Zinnecker hopes. “And we’ll also be able to watch it emerge from the egg.”
With each birth of a new star, the cosmic cycle of coming into being and passing away begins anew. When a star like our sun is extinguished after a lifetime of several billions of years, it ejects its hot gaseous shell out into empty space. The gaseous remnants of an extinguished sun continue to burn at several thousands of degrees for thousands of years after that. But then the cloud gradually cools off and drifts through the Milky Way, so that the ashes of dead suns furnish the raw material for the next generation of stars.
In the end, perhaps the astronomers will even solve the mystery of why such an astonishingly small number of stars are born in our home galaxy. The Milky Way contains an almost unimaginable number of stars, more than 100 billion, as a photo published by the European Southern Observatory at the end of October impressively illustrates. It shows more than 84 million stars in the center of the galaxy but, oddly enough, hardly any new stars are being added.
The swirling dark clouds should provide enough fuel to allow a new star to flare up in the sky every hour. But star maturation is apparently a sensitive process, one that only begins when the clouds of molecules reach exactly the right temperature and density. This helps to explain why only three new stars are ignited in the Milky Way every year.