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The new SOFIA observatory isn’t your average NASA project. Engineers took a 30-year old 747 airplane, cut a hole in the side and installed a 17-ton telescope. Most telescopes are either on the ground or somewhere in orbit, but SOFIA falls somewhere in the middle, flying around at about 40,000 feet.
I got the chance to hitch a ride on one of its recent research flights as the plane left Moffett Field at the NASA Ames Research Center. It’s definitely not the kind of flight where you get a bag of peanuts and movie.
The researchers take advantage of the nighttime sky, so we left at dusk for 10-hour tour flying zigzags across the Pacific Ocean. Each leg of the journey is carefully calculated so the telescope can pinpoint a faraway star. The plane interior is packed with computers and equipment. It also lacks insulation since much of it was removed to install the telescope, so it’s both cold and loud inside.
At four in the morning, the astronomers are still hard at work. If they’re as tired as I am, they certainly aren’t showing it.
“For me, this is very exciting,” says Ian McLean, a professor at the University of California-Los Angeles. He usually works on the ground. “All my career has been ground-based astronomy. So, it’s only my second flight.”
McLean says there’s a good reason to do astronomy in the stratosphere. The atmosphere is thinner, which means it’s easier for the telescope to see the stars. “It’s almost as good as space,” says McLean. “Not quite, but almost.”
And unlike the Hubble Space Telescope, this telescope lands every day, which means the scientists can update and fix the equipment. “By the time you get a mission into orbit, the technology you’re using is relatively old. Here we can stay state of the art all the time,” says McLean. NASA began developing SOFIA in 1997 and almost cancelled the project at one point. It flew its first science mission in November 2010 and now costs about $80 million a year to operate.
Searching for a “Holy Grail”
McLean says the SOFIA telescope could show astronomers something that’s considered a Holy Grail in their field: seeing a star being born. It happens in huge, dusty clouds – stellar nurseries, as Mclean calls them. “The cloud is huge, light years across and it’s gradually contracting to form a whole nursery of stars.”
But there’s a problem. Astronomers can’t see what’s happening inside the clouds because, once again, they’re made of dust and it’s hard to see through.
“We don’t mean dust bunnies, but we mean little, tiny little grains of solid material. Doesn’t matter how big a telescope you have, you can’t see inside it,” McLean says.
That’s why SOFIA looks at a special kind of light called infrared light. If you look through a telescope on the ground, you’re looking at the visible light from space – the light our eyes can see. Infrared light is invisible to us, but it penetrates space dust, which means the telescope can see through the dust too
“You get to see what you can’t see with your eye. It’s like a window has been opened,” says McLean. They’re looking for exactly how stellar nurseries give birth to young stars. McLean says catching a star as it’s forming can reveal clues about how own solar system formed.
But star birth isn’t the only thing these researchers want to see. They’re also looking at the way stars die.
A Star on the Way Out
As the plane makes as sharp right turn, the telescope focuses on an object called NGC 7027. It’s a planetary nebula – also known as a dying star. Mclean and his team are capturing an infrared image of the nebula, which is about 3,000 light years away. They can also see what it’s made of.
“It has a distinctive shape. It’s oval. There’s a hole in the middle and that’s because it literally is a shell of gas that came off the star,” says McLean.
7027 is dying because the star has run out of fuel – the same fate that our sun will face in about five billion years. As it dies, the star casts off its outer layers, shedding huge amounts of material to form a cloud around it. But it’s not entirely a sad story.
“It won’t be wasted,” says McLean. “The material that was thrown off by that star in its dying phase, somewhere, millions, perhaps billions of years from now, will find its way into a new star and the planets that form around it.”
From dead stars come new stars – and planets like our own. The oxygen and nitrogen in our bodies were once formed inside a star. “The cosmos is within us,” as astronomer Carl Sagan once said. “We’re made of star stuff.”
As sky begins to lighten, we descend towards the Dryden Aircraft Operations Facility in the Mojave Desert, where the plane is based. The SOFIA telescope is now flying twice a week. Astronomers from around the world are lining up to get onboard.
Lauren Sommer is a science reporter for KQED QUEST