Question

PHYS 1403 (stars and galaxies.

As you have read the text book and course notes you realize how important words are to describe ideas clearly. But a picture lends so much more interest and clarity! For this forum we want you to use both skill sets – the ability to describe in words and choose a picture. Go to the Glossary of the text book and pick any word you want to learn about. Quote the definition in the book and rewrite it in your own words. Next go to the Astronomy Picture of the Day (APOD) website, and search through their vast archives to find an image related to your chosen word. Embed the picture in your post, give its date and explain it in your own words.

Answer 1

For this question, you can choose any word and describe it... I chose Horsehead as it is Astronomy Picture of the Day (9th march 2018). There is so much data and facts about this nebula along with some people's personal experience.

Horsehead Nebula

  

The Horsehead Nebula (shown above) is around 1,500 light years from Earth and is located in the constellation of Orion. As we can see, It is a dark nebula composed mainly of hydrogen gas and high levels of dust blocking out background light. The heavy concentrations of dust in the Horsehead Nebula region and neighbouring Orion Nebula are localized, resulting in alternating sections of nearly complete opacity and transparency The Horsehead is in fact a small segment of the immense Orion Molecular Cloud, formed from a tendril of gas and dust​ The height of this nebula is around 3 light years with spanning across 2 light years.

However, The Horsehead Nebula is one of the most challenging objects to view in the night sky. To actually get a clear view of the nebula you will need a dark sky away from light pollution, a telescope with at least a 10 inch aperture, a filter and a good deal of perseverance. Even with all the right conditions and equipment a beginner may find it extremely difficult to see.