CRATERS

Edited By: Emily Miller Spring 2018

Craters are such intriguing features of planets, moons and other bodies of mass. Craters are roughly circular, excavated holes made by impact events. The circular shape is due to material flying out in all directions as a result of the explosion upon impact, not a result of the impactor having a circular shape (almost no impactors are spherical). Craters are the most common surface features on many solid planets and moons—Mercury and our Moon are covered with craters.
Source From

All of the websites listed below are very helpful in better understanding many aspects of craters! From why they exist, to what exactly they are- there is so much information to be learned.

external image transformers.jpg
Picture


The Moon Project- Craters

http://astronomy.swin.edu.au/~smaddiso/astro/moon/craters.html

This is a very helpful website for information regarding lunar craters. It is filled with great pictures and diagrams so readers can better visualize what is being explained on the page. Includes great

facts and even an animation!

Author:

Dr. Sarah Madison

Overview:
This website was created for students, by teachers to learn about the moon. This page in particular is all about lunar craters. Which are, a very large part of what makes our moon what it is.

Last Updated:
July, 2010

Date Reviewed:
May 14th 2018

Reviewed By:
Emily Miller

Accuracy:
The information seems accurate and up to date. Although this page hasn't been updated for several years, the information included appears accurate.

Readability and Clarity:
This website and article were written for students- so the information is clear and readable. Everything is written appropriately for the target age group.

Ease of Navigation:
The site is easy to navigate, everything is clear, no ads to distract you. One drawback may be that the site is a little out of date, but that only affects the esthetics and not the functionality. There is one picture on the page that seems to no longer be available.

external image 600px-Moon_names.jpg



Impact Features


https://airandspace.si.edu/exhibitions/exploring-the-planets/online/comparing-planets/impact.cfm

Author:

Smithsonian National Air and Space Museum

Overview:
This website was knowledgable not only about impact craters in particular, but in a wide amount of planet related topics. This page about impacts was very well organized and easy to follow. Had clear headings, and the appropriate information followed.

Last Updated:
There was no comment on when this site was also updated. However, taking into consideration that this is a national education site, and that the website itself seemed very modern, I trust that the information is relatively current.

Date Reviewed:
May 15th 2018

Reviewed By:
Emily Miller

Accuracy:
The information seems accurate and up to date. Nothing that I read was questionable material or facts that were wrongly stated. One could learn lots from reading the information found on this web page.

Readability and Clarity:
This website and article were written with education in mind- so the information is clear and readable. Everything is written appropriately, and a wide array of people/ages could read the material and comprehend it.

Ease of Navigation:
The site is easy to navigate, everything is clear, no ads to distract you. One drawback may be that the site is a little out of date, but that only affects the esthetics and not the functionality. There is one picture on the page that seems to no longer be available.


Tycho Crater, Moon
Tycho Crater, Moon


Three images of Tycho crater and its central peak, located at 43 S, 11 W, on the Moon. These pictures were produced by using different filtered images from the UV/visible camera on the Clementine spacecraft.

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Why Does the Moon Have Craters?


https://spaceplace.nasa.gov/craters/en/


Author:

Nasa official- Kristen Erickson


Overview:

This website is so helpful to easily learn complex space subjects! Very colorful, fun and easy to read. Definitely a website that encourages curiosity and exploration. The target age for this site would have to be children in grade school, although anyone could benefit from the great facts listed on the page.


Last Updated:

November 16, 2017

Date Reviewed:

May 15, 2018

Reviewed By:

Emily Miller


Accuracy:

The information seems accurate and up to date. The credibility in the fact that the web page is put out by Nasa is huge! It is a trustworthy site which you know will be accurate and updated frequently, or when any new information is determined.


Readability and Clarity:

This website and article were written with education in mind- so the information is clear and readable. Everything is written appropriately, and a wide array of people/ages could read the material and comprehend it. However, the pictures, colors and animations do allude to the fact that the site is intended for children.


Ease of Navigation:

The site is easy to navigate, everything is clear, no ads to distract you. Many interactive aspects, and different areas to click on and explore.


Flat projections of the surface of the Earth and the moon.
Flat projections of the surface of the Earth and the moon.




Comparing Craters on the Earth & Moon


https://www.space.com/7146-comparing-craters-earth-moon.html

Author:

Space.com Staff

Overview:

This website article answered a question that is important to ponder when it comes to craters. What is the difference in craters found on the earth and moon? Mostly, this site answer the question of why the moon is more crater filled than the earth. The information was easy to read and follow along to! Also included a video which was helpful in explaining the information in a slightly different way.

Last Updated:
August 17, 2009

Date Reviewed:
May 16, 2018

Reviewed By:
Emily Miller

Accuracy:
The information seems accurate although it is about 10 years old. Even though the information has not been updated in a while, the information still seemed acceptable.

Readability and Clarity:

This website and article were written with education in mind- so the information is clear and readable. This is a website which is all about space, so the audience is likely those in school or those who are just interested in astronomy. There were a couple ads on the article page, so that is a bit of distraction when you are just trying to gather important information.

Ease of Navigation:

The site is easy to navigate, everything is clear, despite the ads that are on the page. The video is easy to access and watch, which is a plus.



external image azcrater_lpi_big.jpg



Craters Are Forming on the Moon Faster Than Anyone Predicted

https://www.smithsonianmag.com/smart-news/moon-getting-new-craters-faster-anyone-predicted-180960800/

Author:

Erin Blakemore

Overview:

This website article answered the possible question of craters on the moon increasing rapidly! I like the way the article answered this question by providing recent research and stories proving this idea. It was a factual article, yet easy to read through. Also really enjoyed that there was a crater video included with this article!

Last Updated:
October 17, 2016

Date Reviewed:
May 16, 2018

Reviewed By:
Emily Miller

Accuracy:
The information seems very accurate as well as recent. This was just written two years ago, so readers can trust that the information presented is fairly up -to-date. The author of the article also cited different sources in which she got her facts and information from.

Readability and Clarity:

This article was easy to read, well cited and flowed nicely. This is a website associated with the Smithsonian Magazine so there is a level of quality that I am sure they are trying to reach and maintain. It was certainly evident in this particular article.

Ease of Navigation:

The site is easy to navigate, everything is clear and well presented. However, there are ads, due to the fact that this is a "magazine type" website. However, they aren't too obnoxious where it takes a way from the content on the page.


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CRATERS


What is a crater?

Definition: A crater is a bowl-shaped depression, or hollowed-out area, produced by the impact of a meteorite, volcanic activity, or an explosion.
external image lunar_crater.jpg

What are the major parts of a crater?

  • Floor The bottom of a crater, either bowl-shaped or flat, usually below the level of the surrounding ground.
  • Central peaks Peaks formed in the central area of the floor of a large crater. For larger craters (typically a few tens of kilometers in diameter) the excavated crater becomes so great that it collapses on itself. Collapse of the material back into the crater pushes up the mound that forms the central peak. At the same time, the rock beneath the crater rebounds, or bounces back up to add to the peak.
  • Walls The interior sides of a crater, usually steep. They may have giant stair-like terraces that are created by slumping of the walls due to gravity.
  • Rim The edge of the crater. It is elevated above the surrounding terrain because it is composed of material pushed up at the edge during excavation.
  • Ejecta Rock material thrown out of the crater area during an impact event. It is distributed outward from the crater's rim onto the planet's surface as debris. It can be loose materials or a blanket of debris surrounding the crater, thinning at the outermost regions.
  • Rays Bright streaks extending away from the crater sometimes for great distances, composed of ejecta material.


external image aristarchus1.jpg
Aristarchus, named after the Greek astronomer Aristarchus of Samos, is a prominent lunar impact crater that lies in the northwest part of the Moon's near side.

external image Meteorcrater.jpg
Meteor Crater is a meteoriteimpact crater approximately 37 miles (60 km) east of Flagstaff and 18 miles (29 km) west of Winslow in the northern Arizona desert of the United States

How Many Different Craters are There?

  • Impact Craters
  • Volcanic Craters
  • Explosion crater

Impact Craters:

  • What is an Impact crater?
https://www.nasa.gov/pdf/180572main_ETM.Impact.Craters.pdf
  • The process of an Impact Crater:
http://www.impact-structures.com/understanding-the-impact-cratering-process-a-simple-approach/

Volcanic Craters:
  • What is a volcanic crater?
“It is a bowl-shaped geological formation at the top of a volcano”
http://www.universetoday.com/31143/volcano-crater/
  • How is a volcanic crater formed?
http://geology.com/articles/caldera/

Explosion Crater:

  • What is an Explosion crater?
“An explosion crater is a type of crater formed when material is ejected from the surface of the ground by an explosive event at or immediately above or below the surface”
https://en.wikipedia.org/wiki/Explosion_crater

How to Measure a Crater:

You can click on the link below for a video on how to measure a crater;
http://iopscience.iop.org/article/10.1088/0031-9120/48/4/520/meta

How to Draw different Types of Craters/Features of a Crater:
http://i38.photobucket.com/albums/e140/chelsaenevarez/How%20to%20draw%20a%20crater_zpsylassoum.jpg

Descriptions Of:
1. Flat floored crater;
http://link.springer.com/referenceworkentry/10.1007/978-1-4614-9213-9_440-1#page-1

2. Wrinkled ridge crater;
https://en.wikipedia.org/wiki/Wrinkle_ridge

3. Rille crater;
https://www.britannica.com/science/rille

4. Central peak;
http://physics.stackexchange.com/questions/26091/how-does-the-central-peak-in-moon-craters-form

5. Over lapping crater;
http://www.skyandtelescope.com/observing/take-a-moon-walk-tonight/

6. Round floored crater;http://onlinelibrary.wiley.com/doi/10.1029/JB091iB13p00E75/abstra