Arthwr Bass - Astronomy. Guide for beginners

Infrared image of the M82 galaxy. Image: Hubble Space Telescope, Chandra X-ray Observatory, Spitzer Space Telescope. NASA, ESA, CXC, y JPL Caltech.

Astronomy

Guide for beginners

Basic concepts

By: Arthwr Bass

Idea and realization
Arthwr Bass

Design and layout
Digital Creative Publishing

Translation
Digital Creative Publishing
Sandra Lozada

Photography
(Credits to the respective author in each image)
NASA

Satellite images
The National Aeronautics and Space Administration NASA
Hubble Space Telescope HST
Discovery Space shuttle, NASA: OV-103

Arthwr Bass, 2018

digitalcreativepublishing@gmail.com

This book is intended for students and/or beginners.

All rights reserved. The total or partial reproduction of this work is not allowed, nor its incorporation into a computer system, or its transmission in any form or by any means (electronic, mechanical, photocopy, recording, others) without previous and written authorization of the owners of the copyright. Infringement of these rights may constitute an offense against intellectual property.

Dusty Spiral Galaxy NGC 4414 (HST).

Image: NASA and STScI. Hubble Space Telescope.

Antennae galaxies. Collision galaxies discovered in 1785 by William Herschel.

Image: Hubble/NASA/ESA.

The human being, from the moment in which evolution began, has been questioned about the world around him and, as he obtains answers and increases his knowledge, this world seems to be getting bigger and bigger. The teaching of astronomy has been imparted for several centuries in the eagerness to respond to the curiosity of the human being, allowing us to understand our own Universe.

The Universe, despite the fact that we know so many things about it, continues and will remain a mystery due to its vast immensity.

In the past, people tried to give mythological and religious explanations to the Universe going through all kinds of hypotheses. It is until the recent XXI century that has allowed us, by scientific methods and technological advances, to have clear answers and develop more accurate theories about the nature and reality of the Universe.

Still, the way to discover, is very long. The Universe is so wide or we are just so small. On the next pages we will make a journey through the current knowledge in simple and concrete words for the youngest apprentices of astronomy.

The Universe is the compendium of energy, space, matter and time, that is, everything that exists. It is considered that the Universe is not infinite since there is no infinite matter or infinite stars. If we talk about matter, the universe is generally empty space, which is currently considered as dark matter.

The Universe is exactly everything that exists without exception.

It is included in the Universe: the galaxies, clusters of galaxies, superclusters or major structures and intergalactic matter. Also there are stars and planets, not evenly distributed. Despite all these stellar bodies, the largest percentage of the Universe is dark matter that is not observable or perceived. It cannot be detected directly, since it does not emit visible light or other radiation, but it is known to be there for some scientific evidence of its effects on gravitational force.

For every million hydrogen atoms in space, the 10 most abundant elements are: (See table 1).

The magnitude of the Universe is still unknown despite our advanced technology, and according to scientific studies at every moment it is expanding. There are physical and chemical laws that govern the Universe with principles such as: laws about the movements of the planets, universal gravitation, variation of the wavelength of light, electromagnetic radiation and sound of the bodies that informs their distance from the earth and movements.

The Earth, the planet where we live, is tiny compared to the presumed size of the Universe. We are in the Solar System, which is located in an arm of a big and active galaxy that has at least 100,000 million stars and other bodies, this, at the same time, is one of the billions of galaxies that comprise the Universe.

To explain the origin of the Universe, a large number of hypotheses have been generated. The Big Bang theory is one of the most controversial, and until now it could give an accurate answer to how everything started. The Big Bang is an exception that Physics cannot explain. We can know what happened in the first instant, but the moment and size is still unknown.

The Big Bang theory explains that about 15,000 million years ago, matter had an infinite density and temperature. There was a violent explosion and, since then, the universe is expanding and losing density and temperature.

Milky Way.

Image: Spitzer Space Telescope (SST). By: NASA/JPL-Caltech.

From the moment the human being began to evolve, he has dedicated himself to observe the sky. Initially, he did it with a naked eye, then, thanks to the development of the technology, he used increasingly sophisticated instruments.

The ancient civilizations gave names to the stars that grouped forming figures in the firmament, that is how the constellations were called. The well known were invented in the eastern Mediterranean about 2,500 years ago. These represent local animals or myths. Because of the importance they attached to the mysticism of heaven, people believed that celestial bodies directly influenced the lives of kings and subjects. Then, this practice would be known as astrology. The different constellations in which the Sun, the Moon and the planets intervene were called zodiac: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius and Pisces.

The telescopes were developed to observe the sky more accurately. The first telescopes dates from the 17th century and consisted of simple lenses, then mirrors were used to finally create telescopes with the combination of both. Currently there are high-resolution telescopes such as the VLT, consisting of four of these.

As the observation techniques improved with time, the scientists realized that the Earth's atmosphere caused a distortion in the images, so it was decided to develop space telescopes. The Hubble Space Telescope (HST) is a robotic telescope located at the edge of the Earth's atmosphere that orbits circularly around the Earth. It is at least 593 km above sea level and captures and sends images and data to the NASA headquarters in the USA.

Another instrument of vital importance for observing the cosmos and understanding the Universe are radio telescopes that detect radiation of different wavelengths. These radio telescopes work together using the technique of interferometry. Other techniques that contribute to the science of astronomy are photography, information technology and communications.