Describing the universe

In terms of time, distance ,and organization

What's astronomy ?

The value of astronomy is important to humans. For example, studies of how stars shine may one day lead to improved or new energy source on earth. Astronomers may also learn how to protect us from potential catastrophes,such as collisions between asteroids and earth.

Objectives

1.Identify the visible and non visible parts of the electromagnetic spectrum.

2.Compare refracting telescopes and reflecting telescopes.

3.Explain how telescopes for no visible electromagnetic radiation differ from light telescopes.

Astronomy Vocabulary

Describe the Electromagnetic Spectrum

The Electromagnetic spectrum is all of the frequencies or wavelengths of electromagnetic radiation.Visible radiation and Invisible radiation both travel in wavelengths for example visible radiation is long wavelength, invisible radiation is short wavelength. Visible and Invisible radiation both travel at the same speed of 300,000 km/s. Also the wavelengths are in the same color and in the same order while being detected by an instrument called electromagnetic spectrum.


Visible radiation is a form of energy that is part of the electromagnetic spectrum. Visible light is a small amount of energy and can be seen by human eye. Invisible radiation are invisible wavelengths that include infrared waves,microwaves, radio waves,ultraviolet rays, x-rays, and gamma rays.invisible radiation are short wavelengths that are blue and violet and cannot be see by the human eye.

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Comparing the Refracting and Reflecting telescopes.

The telescope is an instrument that collects electromagnetic radiation from the sky and concentrates it for a better observation. Reflecting telescopes and refracting telescopes are both used to identify the sky at a better observation. The first invented telescope was optical telescope.


A Refracting telescope uses a set of lenses to gather and focus light from distant objects.Refracting telescopes have lenses that bend in special ways .One problem is that the lenses focuses different colors of light at different distances, also it is difficult to make large lenses if the required strength and clarity.


Reflecting telescopes is a telescope that uses a curved mirror to gather and focus light from distant objects. When light enters the mirror it is reflected to another mirror and the to the eyepiece.Reflecting telescopes are 10 meters in diameter and it can gather more light that refracting telescopes and are easier to make. Astronomers are planning to build an OWL which means Overwhelming Large Telescope which would be 100 meters in diameter .

Telescopes for invisible light

Each type of electromagnetic radiation provides scientist with information about objects in space. A radio telescope detects radio waves. There are also telescopes that detect gamma rays , x-rays, and infrared rays. One problem with using telescopes to detect invisible electromagnetic radiation is that earths atmosphere acts as shield against many forms of electromagnetic radiation. Water vapor can prevent gamma rays, x-rays, and most infrared rays and ultraviolet rays from reaching earths surface. Ground based telescopes that are used to study these forms of radiation work best at high elevation. But the only way to study many forms of radiation is from space.
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Space based telescopes

The Hubble bubble space telescope is an example of a telescope that has been launched to space to collect electromagnetic radiation for objects in space. Chandra x-rays observatory makes remarkably clear images using x-rays from objects in space. The Compton gamma rays observatory is no longer in space but it detected gamma rays from objects such as black holes. The spritzer space telescope was launched in 2003 to detect infrared radiation. Te Webb James telescope will detect Infrared radiation from objects in space.
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