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Why use X-rays?

Why use X-rays?

Looking up in the sky you can see many objects, including stars, planets, asteroids, shooting stars, & nebulae. Many objects in the sky emit X-rays. The x-rays originate from regions of gas that are at high temperatures. Astronomers are interested in how the gas gets this hot, and what happens when it does. The nearest star to Earth (besides the Sun) is 4.3 light years away (25 trillion miles), far too far to imagine visiting. Luckily we receive much information from the things found throughout the Universe in the form of electromagnetic radiation, or light. This radiation ranges from infrared light, visible light, ultraviolet light and X-rays and Gamma rays. The entire range is called the electromagnetic spectrum, and it is a powerful source of information.

What kind of information can we divine from the electromagnetic spectrum? The three different kinds of data are images, spectra, and light curves. You may already be familiar with images of objects in the universe: planets, stars, galaxies, nebulae, etc. Here are some examples of data in the form of different types of images:

Crab Nebula in Radio Waves Crab Nebula in Visible Light

Crab Nebula in UV Crab Nebula in X-Rays

When we look at the same image in different wavelengths of light we can see different things. Some wavelengths help to show us the energy given off while others can help us to detect elements or compounds that are present. It is good to view objects in different energy levels; otherwise you might miss something!


A service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA/GSFC

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