Sunday, June 18, 2006

Infared Telescope questions?

plz answers if you can

1. what form of energy it detects?
2. what that energy is?
3. how the telescope works?
4. what is it used to detect?
5. how that information is used in modern astronomy?

Answer on Infared Telescope questions?

1. what form of energy it detects?

All current telescopes detect electromagnetic radiation. This means they detect photons of light at various wavelengths/energies, produced by a variety of processes throughout the universe. We *do* have detectors for other particles or fields, e.g. cosmic ray detectors, neutrino detectors, magnetometers, but these are special cases, not generally considered to be telescopes.

Infrared (note spelling) is one "band" of the spectrum representing particles with longer wavelengths (lower energies) than visible light, but shorter wavelengths than radio.

2. what that energy is?

Infrared energy is generally emitted by heat processes in stars, dust clouds, and dark bodies (planets, asteroids, etc). The frequency of the infrared is directly related to the temperature of the body: hotter bodies emit shorter wavelength == higher frequency == higher energy photons.

3. how the telescope works?

The telescope usually has a mirror-based optical system with coatings that are good IR reflectors (e.g. gold) and an electronic detector (often CCD or MOS). These are similar to standard optical telescope components except for coatings and frequency sensitivity

The detector may be for imaging (producing a 2-D picture of the object), spectrography (analyzing the constituent wavelenghts including absorption/emission lines caused by photon-gas interactions) or both.

If the telescope is intended to detect long-wave (low temperature) IR, it will need to be cooled (actively with cryogenics and/or thermo-electric coolers, depending on design) to reduce noise from the optics and detector.

4. what is it used to detect?

IR telescopes observe IR sources, including gas clouds, proto-stars, and solar system objects, at specific wavelengths to do imaging, dynamics, temperature analysis, and chemical analysis.

5. how that information is used in modern astronomy?

Understanding dynamics of gas clouds and proto-stars helps us to understand the evolution of galaxies and stellar systems. IR imaging helps us see through otherwise opaque clouds and lets us calculate motion, mass, and other characteristics of large gas clouds. IR spectroscopy and photometry let us measure temperatures and composition of cold objects, including both clouds and solid masses.

We use IR tools in conjunction with others to understand the origin, evolution, and current state of the solar system, stellar regions, and the galaxy. We extend this understanding with predictions and models to understand other phenomena we may observe throughout the universe, such as intergalactic gas filaments that tell us some details of the early state and evolution of the universe.