Short for Stratospheric Observatory for Infrared Astronomy, SOFIA will change the way we view the universe. The 17-ton and 9-foot wide telescope is situated into a Boeing 747 which is going to glide through the stratosphere at 45,000 feet, when the operations begin next year.
The Stratospheric Observatory for Infrared Astronomy's 747SP sits on an aircraft ramp during nighttime testing and operation of the SOFIA's German-built telescope assembly. The aircraft is based at NASA's Dryden Aircraft Operations Facility in Palmdale, Calif. 24 September, 2009 NASA Photo, Credit: Tom Tschida
SOFIA will be the world’s greatest airborne observatory for the infrared (IR) spectrum. The infrared spectrum is the spectrum that is beyond the visible spectrum that means outside the range we can see with our eyes. It is a different way for astronomers to look at the cosmos, watching the light and the heat radiation coming out of the stars rather that the stars themselves.
The galaxy teems with planetary systems, but astronomers don’t know exactly how they form because ordinary telescopes can’t see through the giant, dense clouds of gas and dust that spawn planets. Using infrared wavelengths, SOFIA can penetrate these hazy regions of space and reveal images of the molecular clouds that come together to construct stars – the birthing process of making worlds. The telescope has actually the potential to help scientists understand how planets form.
As a mobile observatory, SOFIA can fly anywhere, anytime. It can move into position to capture especially interesting astronomical events such as stellar occultations – when the light from a star is blocked by an intervening body, i.e. a planet or an asteroid. Ground-based telescopes usually miss these events because they are fastened to the “wrong” geographic locations on Earth’s surface.
The 3 metre (10 feet) mirror that collects the light from the stars is one of the most impressive parts of the German-built telescope. It is largely composed of carbon fibre reinforced plastic or CFRP, a material commonly found in tennis racquets and modern sailboat hulls. These types of composite materials provide the light weight and stiffness required for precision airborne optical components. The mirror can move from 20 to 60 degrees, so it can rotate up and down and move from one side to the other.
This close up of SOFIA offers a view of both the primary and secondary mirrors, the latter a small black circle in the center supported by three braces. NASA Photo, Credit: Tom Tschida
SOFIA will be also able to locate the ‘planetary snowline,’ the region where, as astronomers think, gas giants are born. As the star contracts at constant temperature, the snowline which separates regions of rocky planet formation from regions of icy planet formation moves inward. This process enables rapid formation of icy protoplanets that collide and merge into super-Earths, planets that each has more mass than the Earth.
One of the telescope’s key strengths is its ability to complement other infrared observatories. With a 20-year lifetime, it can do follow-up studies on objects shorter-lived infrared scopes don’t have time to hone in on. If, for example, orbiting observatories like WISE spots something deserving of more attention, SOFIA can move in for a long, slow look, while WISE continues gazing at the rest of the sky. SOFIA can also do follow-up science to reap the full benefits of discoveries from Herschel‘s deep spatial surveys when it will run out of its 3-year supply of coolant, and complement James Webb Space Telescope (JWST) investigations, when it will launch in 2014.
To illustrate how infrared sensors can see things the human eye cannot, project scientist Pamela Marcum offers these white light vs. IR images of a warm-blooded dog and a cold-blooded lizard. Image Credit: Science@NASA
Sources and further reading,
Dryden Flight Research Center, NASA, Science@NASA, Discovery channel
Dryden Flight Research Center News Release, 2008 July 2,
Grant M. Kennedy, Scott J. Kenyon, Benjamin C. Bromley, “Planet Formation Around Low-Mass Stars: The Moving Snow Line And Super-Earths”, The Astrophysical Journal, 650: L139–L142, 2006 October.