Describing the universe
The electromagnetic spectrum and telescopes
WHAT IS ASTRONOMY??
OBJECTIVES
1. Identify the visible and nonvisible parts of the electromagnetic spectrum.
2. Compare refracting telescopes and reflecting telescopes.
3. Explain how telescopes for nonvisible electromagnetic radiation differ from light telescopes.
ASTRONOMY VOCABULARY
Universe
The totality of existence including planets, stars, galaxies, intergalactic space and all matter and energy.
Light Year
The distance that light travels in one year ; about 9.46 trillion kilometers.
Astronomical Unit
The average distance between the earth and the sun; approximately 150 million kilometers (symbol, AU)
Electromagnetic Spectrum
All of the frequencies or wavelengths of electromagnetic radiation.
Refracting Telescope
A telescope that uses a set of lenses to gather and focus light from distance objects.
Reflecting Telescope
A telescope that uses a curved mirror to gather and focus light from distant objects.
DESCRIBE THE ELECTROMAGNETIC SPECTRUM
Each wavelength of the visible lights have a different color. Past light through prism, is broken into a set of colors. The shortest wavelengths are blue and violet, the longest wavelengths are red and orange.
The invisible lights needs a special instrument to detect them. The invisible waves include infrared, microwaves, radio waves, ultraviolet rays, x-rays and gamma rays. Waves that are shorter than violet and longer than red, cannot be seen.