dipper@utastro.UUCP (Debbie Byrd) (03/25/85)
A new telescope is being designed to look at warm objects in the universe. More on SIRTF -- after this. March 25 Space Infrared Telescope Facility Objects like planets -- or moons, or rocks, or dust -- aren't hot enough to shine as stars do -- with their own visible light. Nevertheless these cooler objects DO emit radiation -- invisible to our eyes -- but very real. This radiation comes from their own heat. It's called infrared. It's really a form of light, which lies beyond the red end of the visible spectrum -- redder than red! From the surface of the Earth, we can detect only the brightest infrared sources. Water vapor in Earth's atmosphere interferes -- and also things on Earth, even telescopes themselves, radiate infrared energy. But it's possible to observe faint infrared objects from space -- and in fact an infrared telescope orbited Earth for much of 1983 -- the Infrared Astronomical Satellite, or IRAS -- whose discoveries, and whose infrared map of the sky, are still being talked about. Now a new infrared space telescope is being designed -- the Space Infrared Telescope Facility -- SIRTF. SIRTF will be cooled to nearly 460 degrees below zero Fahrenheit -- less than two degrees above absolute zero! It'll orbit above the Earth's atmosphere -- looking in detail at objects seen only briefly by IRAS. It's expected to make some interesting revelations about the universe. Just a couple of examples -- SIRTF may discover some of the so-called "missing mass" of the universe -- possibly halos of faint red stars surrounding some of the galaxies. And it'll explore the coldest parts of our own solar system, which may still contain original ingredients of the primordial cloud from which we here arose. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin