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SOFIA: Jump on it


by Sarah Scoles

It’s really hard to do infrared astronomy from the ground, no matter how big you make your telescope mirror or how high a desert mountaintop you set it on, and at some infrared wavelengths, observations from Earth are impossible. The atmosphere, which has lots of water vapor (which is good for us), absorbs many infrared waves and keeps them from reaching the planet’s surface.

(For a review of the electromagnetic spectrum and the differences between radio, infrared, visible, X-ray, and gamma ray photons, see this post.)

That’s why some crazy dreamer astronomers and engineers conceived SOFIA, the Stratospheric Observatory for Infrared Astronomy. SOFIA is a modified 747 that contains a 2.7-meter telescope with infrared-sensitive detectors.
In other words, it’s a big plane with a hole in the side out of which you point a telescope.

Told you.
SOFIA flies about 20,000 feet higher than standard commercial airline cruising altitude, which puts it above more than 99 percent of Earth’s atmospheric water vapor, allowing most infrared waves coming from celestial objects to reach the mirror.

This is near-space flight, or near space-flight, and it’s a pretty cool (but hard on the fossil fuels) solution to the astronomical problem of being stuck on Earth.

Why is infrared astronomy important?

Well, like all different kinds of electromagnetic waves, some objects, processes, and phenomena only generate infrared waves or generate infrared waves in addition to other types of light. Either way, infrared waves can tell us something different about these parts of the universe than visible light waves, X-rays, gamma rays, or radio waves can.

Additionally, some places in space can’t be seen at all, with visible light waves. In places where there is a lot of dust and gas, light that you can see can’t get through that dust, so those areas look dark to us, even though visible light may exist there.

Infrared waves, though, are longer and can pass through. So when infrared astronomy was beginning, all these regions where it looked like nothing was happening turned out to be hotbeds of electromagnetic activity.

Some of the questions SOFIA hopes to answer are

  • How is massive star formation different from low-mass star formation?
  • 'Infrared' does not mean 'neon 80s jacket colors.' These are false colors chosen to
    show where different infrared wavelengths (or infrared 'colors') are
    being emitted and at what brightness. Credit: NASA/SOFIA/USRA/FORCAST
    Team/James De Buizer (infrared image), Anthony Wesley (visible light image)
    What are the environmental details of the disks around young stars, and how do planets emerge from them?
  • In what star-forming regions do polycyclic aromatic hydrocarbons (PAHs) exist, and how are they distributed? These are prebiotic molecules that can help us learn more about how life comes to exist.
  • What is up with the center of our galaxy? How do stars, their winds, magnetic fields, fast-moving gas, and that gigantic black hole all interact?
  • What are primitive bodies made of and how do they form? Primitive bodies are not neanderthals, but seriously old things like comets and asteroids. This can tell us more about how the formation of the solar system and the advent of organic stuff here, and how that all might have gone down in other solar systems.
  • Where in the solar system does water exist?

Why am I telling you all this? I’m not citing a specific, timely paper or responding to a press blitz on a popular astronomy topic.

However, I was selected as an “Airborne Ambassador,” which means that I get to fly into the stratosphere on SOFIA. And I get a flight jacket. And I got my picture in a NASA/SETI press release.

Anne Smith, who is a science teacher at Green Bank Middle School, and I are going to create and implement an “invisible universe” curriculum for her middle schoolers, incorporating both radio astronomy and infrared astronomy. As the capstone part of this unit, students will get to use NRAO’s 20-meter telescope to look at SOFIA sources and see how they look different (or, perhaps, nonexistent) in radio waves. Hopefully, the unit can be used in other classes as well. We'll put it on that whole internet thing when it's done.

And, I’m going to take a lot of documentary evidence of Anne and me at 50,000 feet and bring it to the class room and be like, “Hey. Students. If you like scientific research, cool things happen to you.” Which is just a fact.


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