Editor: Jacob Haley Spring 2014
Astronomy 10

What are Nebulae?


Nebulae (plural of Nebula), are giant, thinly spread clouds of interstellar gas and dust. Nebulae are either remnants of supernovas or large clouds of concentrated gas and dust that have been pulled together by gravity. In either case Nebulae become the sites for new stars to be born. The two most general Nebulae are bright nebulae, cold clouds that reflect starlight (reflection nebulae) or glow by their own ionized light (emission nebulae), and Dark Nebulae, cold clouds that absorb starlight (absorption nebulae). Nebulae were first discovered in the 18th century by Charles Messier who classified smudges in the sky as "not comets" and believed they should be ignored. Later in 1738 William Herschel, and later his son Sir John, classified and cataloged over 5000 entries of nebulae.


Quick Overview of Different Nebulae:

-Emission: These nebulae are made of hot gasses that are energized by nearby ultraviolet light. Emission nebulae are usually red due to the predominant red emission of hydrogen.

-Reflection: These nebulae are made of clouds of dust that reflect the starlight of nearby stars and have no light of their own. Reflection nebulae are usually blue due the scattering of light.

-Absorption: Also known as Dark Nebulae, these nebulae are made of dust and absorb the light from the surrounding light sources.

-Planetary: These nebulae are made by a dying star. Planetary nebulae are the shells of former stars that have blown off their outer layers of gas in their deaths.

-Others: A Diffuse Nebula is an alternate name for both emission and reflection nebulae. Supernova Remnants are a much larger version of a planetary nebula, created from a massive star exploding and leaving its guts in the vicinity.

external image nasa_-_the_horsehead_nebula__b33__orion_nebula.jpg
The Horse Head Nebula (Dark Nebula): http://lovely-pics.com/img-nasa---the-horsehead-nebula--b33--orion-nebula-8053.htm

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Websites:


Name: Atlas of the Universe
URL: http://www.atlasoftheuniverse.com/5000lys.html ||| atlasoftheuniverse.com
The Lagoon and Trifid Nebulae
The Lagoon and Trifid Nebulae

The Lagoon and Trifid Nebulae, located in the constellation Sagittarius.
http://www.atlasoftheuniverse.com/nebulae/m08m20.html

Author: Richard Powel
Trustworthiness and Accuracy: This is a good site for pictures of famous nebulae a general idea of the map of the Universe. It is maintained by an individual and has not been updated since 2006, meaning some of the data might be outdated, however, this site has a lot of generalized ideas, concepts and pictures of nebulae and more that has been mapped over the universe according to multiple links that Richard has provided. This is a good place to start but I would not rely too heavily on it.
Date Reviewed: 5/9/14
Last Update: 2006
Reviewed by: Jacob Haley
Readability and Clarity: This site is easy to navigate because it is split up into easy to find sections. The information is clearly given through maps and pictures along with an appropriate amount of text. This was written for pretty much anyone who was curious to look at the whole of the universe and what we have mapped out so far.
Navigation: It has no search-bar to find specific entries, but the pages are limited so it does not necessarily need one. There are multiple pages worth of information based on light years away.
Overview: This site is a place to look at the mapped out universe up to what we knew in 2006 (since that was when it was last updated). This gives a lot of information of Nebulae and stars/clusters that are part of our known universe. This is mostly shown in the form of raw data, because we do not have the technology to take pictures of objects more than a certain number of light years away. Most of the information on Nebulae is located in the 5000 Light Year page.


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Name: National Optical Astronomy Observatory
URL: Noao.edu http://www.noao.edu/image_gallery/nebulae.html
[Ghost Nebula]
[Ghost Nebula]

Ghost Nebula (vdB 141)
http://www.noao.edu/image_gallery/html/im1060.html
Reflection type nebula.

Author: Association of Universities for Research in Astronomy (A.U.R.A.)
Trustworthiness and Accuracy: Considering that this site is run by the National Science Foundation, I would give this website the benefit of the doubt. It looks professionally made because it is professionally made. It was last updated on May 1, 2014 which means it is not out of date.
Date Reviewed: 5/9/14
Last Update: 5/1/14
Reviewed by: Jacob Haley
Readability and Clarity: Easy reads, especially if you know any information on the subject. If not it is explained in vague details that most amateur astronomers might get but anyone else probably wouldn't. So the audience is intended for astronomers, not just anybody who stumbles on the page.
Navigation: The Navigation is spot on. There is a search bar, and the information is laid out in a nice grid formation so you can browse as much as you want with little difficulty.
Overview: This site is a place to learn about specific nebulae. There are pictures and information on all of them, and is updated regularly by AURA. It also has news and other related topics on any form of astronomy.


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Name: Kidsastronomy
URL: Kidsastronomy.com
A planetary nebula
A planetary nebula

A planetary Nebula http://www.kidsastronomy.com/nebulae.htm

Author: Kids Know It Network
Trustworthiness and Accuracy: I believe that this website is credible, and while it does not offer the most amount of information as compared to most. This site was made for kids. The information is good, but it is "dumbed down" to help the kids or anyone not familiar with astronomy cope with the information.
Date Reviewed: 5/9/14
Last Update: 2014
Reviewed by: Jacob Haley
Readability and Clarity: This is very easy to read, as it was made for kids to look at and become interested in astronomy without having to know the technical terms.
Navigation: Not much to navigate on, if you are just looking for nebulae because it is one long page. There are links and other pages meant to elaborate further on other topics but the bulk of the website (for nebulae) is all on the page linked above.
Overview: This is a site that can explain hard concepts like nebulae and other space terms to kids and those not familiar with sciences. It uses smaller words and doesn't get to technical in its word choice.



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Name: Discovery News
URL: [[http://news.discovery.com/search.htm?q=nebulae|discovery|Discovery.com]] http://news.discovery.com/search.htm?q=nebulae
external image hubble-nebulae-02-130904.jpg
Butterfly Nebulae: a bipolar planetary nebula : http://news.discovery.com/space/astronomy/hubble-bipolar-nebula-pictures-130904.htm

Author: Discovery Communications
Trustworthiness and Accuracy: There is not much to say about trustworthiness, it is Discovery, enough said. The information is also very convincing, considering their background as one of the most trusted sources of scientific information.
Date Reviewed: 5/9/14
Last Update: 2014 (constantly updating)
Reviewed by: Jacob Haley
Readability and Clarity: This is very clear to understand, and was meant for the eyes of any internet surfing soul. With that in mind, discovery made their site easy to read.
Navigation: This has the navigation of pretty much any professional news site, with a search bar, and different links relating to the topic you are currently looking at.
Overview: This site is for discovering news about Nebulae that is meant to be known to the public. They might not focus on Nebulae in general, but they do have a large pool of information to take from, which makes this site a good source of information to anyone wanting to know the latest.



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Name: Spacetelescope.org
URL: [[http://www.spacetelescope.org/videos/archive/category/nebulae/|Spacetelescope.org]] http://www.spacetelescope.org/videos/archive/category/nebulae/
The Eskimo Nebula
The Eskimo Nebula

The Eskimo Nebula (Planetary) : http://www.spacetelescope.org/images/heic9910a/

Author: ESA/HUBBLE
Trustworthiness and Accuracy: This website is backed by HUBBLE itself, along with the international astronomers of Europe and the US. This is information coming from one of the highest facilities of astronomy. It can't get much better than this.
Date Reviewed: 5/9/14
Last Update: 2014
Reviewed by: Jacob Haley
Readability and Clarity: This is a site for pictures and videos to be put up from ESA/HUBBLE so that the public can learn about the new discoveries that the HUBBLE telescope has found. These videos and pictures are created in a documentary form, targeting the general public for its audience. The videos are informative and the pictures are amazing and legit.
Navigation: This site is a professional website backed by an international organization. It has search bars, easy to browse grids, and other menus that make navigation painless.
Overview: This is a site for videos, pictures and information on anything the HUBBLE picks up. It houses a variety of topics, in this case, nebulae. The videos and pictures give a
perfect visualization for the information that they are trying to get people to understand.

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Videos:

What is a Nebula?
A quick 2 minute video about what a Nebula is and its importance.

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Orion Nebula Flythrough
A virtual look-see through the Orion Nebula.

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Tour of Nebulae
A slideshow of nebulae throughout the universe.


Works Cited:


Odenwald, Sten. "Archive of Astronomy Questions and Answers." Archive of Astronomy Questions and Answers. N.p., 1997. Web. 13 May 2014.


Arnett, Bill. "Types of Nebulae." Types of Nebulae. N.p., 10 Feb. 1997. Web. 13 May 2014.








































catseye_chandra[1].jpg

X-Rays from the Cat's Eye Nebula Credit: X-ray: http://chandra.harvard.edu/photo/2008/catseye/ NASA/CXC/[[http://cfa-www.harvard.edu/sao/index.html|SAO; Optical: NASA/STScI

OriondeepfieldM_gendler[1].jpg

Orion Deep Field Credit & Copyright: Robert Gendler



About different Nebulae


seasky.org
by J.D. Knight

November 24, 2009

I really enjoyed this website it has great composition and was very easy to navigate. The webmaster made it easy to read for comprehension as well as made it visually appealing. I found the information accurate and current as well and it is my favorite resource for those who want to get the general information on what they are about. Furthermore this source goes over in detail the nature of nebulae and why they are useful…”Nebulae is the basic building blocks of the universe”. They contain the elements from which stars, planets and solar systems are built.” Here we can also learn the differences between each nebula type such as; Emission Nebula, Reflection Nebula, Dark Nebula, Planetary Nebula, and Supernova Remnant Nebula. I found this site to be very informative.

Nebula M1-67 around Star WR124. Credit: Yves Grosdidier (University of Montreal and Observatoire de Strasbourg), Anthony Moffat (Universitie de Montreal), Gilles Joncas (Universite Laval), Agnes Acker (Observatoire de Strasbourg), and NASA
Nebula M1-67 around Star WR124. Credit: Yves Grosdidier (University of Montreal and Observatoire de Strasbourg), Anthony Moffat (Universitie de Montreal), Gilles Joncas (Universite Laval), Agnes Acker (Observatoire de Strasbourg), and NASA


fusedweb.llnl.gov
November 24, 2009 Lawrence Livermore Lab
Page contributed by G. Samuel Lightner
In describing the planetary nebula they give a very thorough and scientific explanation of how they are formed…“In this stage, the central part of the star, which is about the size of the earth, consists of a carbon ash core, a shell in which helium is fusing to carbon, and a shell where fusion of hydrogen to helium has temporarily ceased. The rest of the star's envelope has expanded to about 70 times larger than it had during most of its lifetime (almost the size of the orbit of Mars).” The site goes on to explain how the fusion of the star increases until it ejects the outer shell and the star eventually becomes a white dwarf. This site is meant for those who are interested in learning about fusion and the role of nebulae in it. I found it to be accurate and easily read by the regular person looking for the science behind it all.

apod.nasa.gov
November 24, 2009
NASA
This NASA site goes over the various nebulae found in space. Easy to read and scientifically accurate data. You can easily find a specific nebula you are trying to research. Each nebula has an explanation an astronomical alpha numeric assignment, where it can be found in space, how many light years it is from us and how many light years large it is. Additionally it explains how it is illuminated what colors it reflects and what type of nebula it is. When you go to this site just search "Nebula" and an amazing list of nebulae with pictures will pop up along with their specific information.
Following is an example of what their Helix Nebula description is: APOD: 2009 March 3 - The Helix Nebula from La Silla Observatory November 24, 2009 Explanation: Will our Sun look like this one day? The Helix Nebula is one of brightest and closest examples of a planetary nebula, a gas cloud created at the end of the life of a Sun-like star. The outer gasses of the star expelled into space appear from our vantage point as if we are looking down a helix. The remnant central stellar core, destined to become a white dwarf star, glows in light so energetic it causes the previously expelled gas to fluoresce. The Helix Nebula, given a technical designation of NGC 7293, lies about 700 light-years away towards the constellation of Aquarius and spans about 2.5 light-years. The above picture was taken by the Wide Field Imager on the 2.2-meter Telescope at the European Southern Observatory's La Silla Observatory. A close-up of the inner edge of the Helix Nebula shows complex gas knots of unknown origin.
Veil Nebula. Credit to: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration
Veil Nebula. Credit to: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration
The Eagle Nebula. Credited to: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)
The Eagle Nebula. Credited to: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)






Britannica.com

This is straight from the Encyclopedia Britannica with a great source of information. Explains thoroughly and accurately what a nebula is

as well as the different types of nebulae there are and history behind some of the discoveries and observers. Easy and clear to read,

very to the point like a dictionary. Navigating is not bad, easiest using the search bar at the top of the page. It is up to date by John S.

Mathis.


Howstuffworks.com

Dictionary Straight from the Discovery Company, How Stuff Works explains nebulae in great detail. Great source of accurate information.

Can get technical but is very clear and readable. Navigation of the web site is easy although easy to get sidetracked as well, search bar
The Egg Nebula. Credited to:Raghvendra Sahai and John Trauger (JPL), the WFPC2 science team, and NASA
The Egg Nebula. Credited to:Raghvendra Sahai and John Trauger (JPL), the WFPC2 science team, and NASA

makes it much easier. Information needs some updating but William Harris did a good job regardless. The author seems to be Bill Arnett,

and has the information fairly updated.


Nineplanets.org

Excellent source anything with astronomy. Very detailed, accurate and readable. Navigation takes some to get used to, tons of information

to go through. The author Bill Arnett, has the information fairly updated since late 2010. Great source of information regardless.

Universetoday.com

Great website for resent events in the astronomy community. Goes very in depth to what kind of nebulae there are and examples of nebulae.

Very easy to read and understand. Navigation through the website can be tricky so using their search bar is best. It is constantly updated

but nebula information is not too resent.


Silkworm Nebula. Credited to: Sun Kwok and Kate Su (University of Calgary), Bruce Hrivnak (Valparaiso University), and NASA
Silkworm Nebula. Credited to: Sun Kwok and Kate Su (University of Calgary), Bruce Hrivnak (Valparaiso University), and NASA



Videos

Youtube.comJuly 07, 2006
November 24, 2009
A spacey upbeat tempo takes you on a journey of many galaxies and gives the viewer a space telescopes' view of these natural wonders.

Galleries
Hubblesite.org

November 24, 2009

This site is great for downloading beautiful Hubble space images to a background for your computer. Lots of amazing images to choose from!


Orion Nebula. Credit to:NASA,ESA, M. Robberto (Space Telescope Science Institute/ESA) and the Hubble Space Telescope Orion Treasury Project Team
Orion Nebula. Credit to:NASA,ESA, M. Robberto (Space Telescope Science Institute/ESA) and the Hubble Space Telescope Orion Treasury Project Team