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Brian Mendez Lecture

Brian Mendez discussed infrared astronomy and the Wide-Field Infrared Survey Explorer launching in 2009. The introduction included the discovery of infrared light by Willliam Herschel in 1800, a brief description of the electromagnetic spectrum, and the physics of light.  Infrared light is a small fraction of the electromagnetic spectrum with slightly longer wavelengths than the visible portion. It is generally broken into 3 main spectral regions: near-infrared, mid-infrared, and far-infrared.  These different regions correspond to specific wavelength and temperatures ranges, which make them very useful for imaging different types of objects in astronomy.

Objects that would be dark in the visible spectrum such as clouds of dust, nebula, and asteroids are often magnificently detailed in the infrared.  Contrasting pictures of the constellation Orion in the visible range versus the mid-infrared range were shown, and they revealed immense clouds of dust and stars that are invisible to optical telescopes. Some cool objects like these must exclusively be studied in the infrared spectrum.

There is a major problem in infrared astronomy:  the earth’s atmosphere absorbs most of the incoming infrared light, which requires many infrared telescopes to be placed above the Earth’s atmosphere.  NASA’s major infrared missions including the Spitzer Space Telescope, WISE, SOFIA, and the James Webb Space Telescope were presented.  The 40cm WISE telescope will orbit the Earth while delivering over a million images in 4 different infrared wavelengths.  These images will survey as far as 6.7 billion light years away and help cosmologists map large-scale structures. This new data will bring in new knowledge not only about the Milky Way galaxy, but also about all nearby galaxies as well as ultra-luminous infrared galaxies.

WISE will also map the entire sky to a higher resolution and be able to detect many large near earth asteroids and their movements.  The satellite will also completely map all large asteroids in the main belt and define most of their orbits.  Infrared asteroid detection is much less reliant on albedo, making observations of very dark asteroids finally possible.  Detailed information about the composition and masses of asteroids will be created from comparing both optical and infrared telescope data.  The value of archiving this asteroid data will be to determine possible asteroid impacts and assess their hazard to our planet prior to an impact.  The lecture concluded with the potential of infrared astronomy, and Dr. Mendez hosted a long question and answer session about topics in physics and astrophysics.