Describing the universe

The electromagnetic spectrum and telescopes


Astronomy is the study of energy, matter and the universe. Astronomy is important to humans because if they study how stars shine it can improve energy sources or can be a new energy source on earth. Astronomers can also learn how to protect us by learning the collision between asteroids and earth.


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

Describe the electromagnetic spectrum

The electromagnetic spectrum is the arrangement of electromagnetic radiation including radio waves, visible light from the sun, gamma rays, x-rays, ultraviolet waves, infrared waves, and microwaves according to their wavelengths. Both invisible and visible electromagnetic radiation are forms of radiation and travel in waves. Also are forms of energy, used to study the sun, travel at the speed of light and have electric and magnetic fields. Visible light's shortest wave lengths are blue and violet and the longest waves lengths are orange and red. When light passes through a prism each wave length has the same set of colors. In the other hand, invisible waves need special instruments to detect them. The waves that are shorter than violet and longer than red cannot be seen by the human eye. The invisible waves include: infrared waves, microwaves, radio waves, ultraviolet rays, x-rays, and gamma rays.

Refracting Telescopes and Reflecting Telescopes

Telescopes are instruments that collect radiation, They also help you see objects clearly. Even though objects are far away telescopes help you see everything up close. Refracting Telescopes and Reflecting telescopes are optical. Telescopes concentrate on far away objects for better observation. These telescopes also collect far away images. Refracting telescopes contain clear lenses. Refracting telescopes use a set of lenses to gather and focus light from distant objects. Thr objects are magnified by an eyepiece. A problem with the Refracting Telescope is the lenses focus on different colors of light a different distance. Reflecting telescopes ise mirros to gather and focus light from distant objects. The mirrors of a reflecting telescope can be made large without affecting the quality of the image. This telescope gathers more light and can be very large. The largest pair of reflecting telescopes are called Keck telescope in Hawaii.

Invisible Light Telescope

Invisible light telescopes measure radio waves. Invisible telescopes measure a lot of invisible light like gamma rays, x-rays, and infrared rays. A problem with the invisible light telescope is the atmosphere because it acts like a shield against many forms of electromagnetic radiation. Another problem is water vapor because it can prevent gamma rays, x-rays, and most infrared and ultraviolet rays from reaching Earth's surface. Telescopes work best at high elevations, where the air is dry.

Space Based Telescope

Space based telescopes are not bothered by the Earth's atmosphere. Telescopes in space make clear images using x-rays from objects in space, like the remnants of exploded stars. Some space based telescopes can detect gamma rays from objects, such as black holes. Other space based telescopes detect infrared radiation. Space based telescopes are sent to space to detect invisible waves.