Journey Into The Electromagnetic Spectrum (Astronomy)

Today ends our journey into the electromagnetic spectrum, which has kept you company for eight weeks. Through eight NASA videos in the Italian version, you have deepened your knowledge of electromagnetic waves, their behaviors and the way in which scientists visualize scientific data. And you have discovered that much, not to mention the essential, is invisible to the eye

Our journey in the electromagnetic spectrum ends with today : eight NASA videos that we have proposed to you in the Italian version, with which you have discovered electromagnetic waves, their behaviors and the way in which scientists visualize the scientific data collected thanks to these radiations . Each region of the electromagnetic spectrum has been described and illustrated with different examples, from the astrophysical field to practical applications in everyday life.

In the introduction to the electromagnetic spectrum  we saw how electromagnetic energy travels in the form of waves that cover a very wide spectrum, from very long radio waves to very short gamma rays.

The radio waves – electromagnetic radiation characterized by the longer wavelengths – can carry melodies from a radio station, as well as important information about even distant astrophysical objects.

The microwaves are able to penetrate through clouds, dust, smoke, snow and rain, are ideal for satellites used in telecommunications. Furthermore, we have seen how these waves are also used by scientific instruments – active and passive – which are involved in studying both the Earth and the sky.

We took a look at infrared waves , with wavelengths just beyond the visible spectrum of light: from near infrared, used in remote controls, to far infrared which can be perceived as heat. Scientists can monitor the health of vegetation and soil composition by studying objects that reflect, transmit and absorb near-infrared solar radiation.

Obviously, visible light could not be missing : that very small part of the electromagnetic spectrum that we can see with our eyes.

When the entire spectrum of visible light travels through the glass of a prism, the wavelengths are separated into the colors of the rainbow. Credits: Nasa

The ultraviolet waves , whose wavelength is a little bit shorter than visible light. We have seen how the Sun is a source of the entire spectrum of ultraviolet radiation and how most of this radiation is blocked by the atmosphere. Thanks to ultraviolet waves, scientists study stars, galaxies and the composition of the Earth’s atmosphere.

Much more energetic, the X-rays are fortunately blocked by the Earth’s atmosphere. Scientists therefore use satellites to observe X-ray radiation from galaxies and stars, such as the sun.

Finally, today it was the turn of gamma rays , the most energetic of any wave in the electromagnetic spectrum, produced by the hottest objects and the most violent phenomena in the universe.

All this is the electromagnetic spectrum, without which life would not exist. Humanity has been limited for a long time only by the sensors that nature has given it but now we can say, also thanks to astrophysics, that we can “see” in every band of the electromagnetic spectrum. And discover that much is invisible to the eye.

Watch the playlist with all the episodes on MediaInaf Tv:

Featured image: The electromagnetic spectrum. Credits: Nasa

Provided by INAF

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