<meta http-equiv="refresh" content="1; url=/nojavascript/"> Special Theory of Relativity ( Real World ) | Physics | CK-12 Foundation
Dismiss
Skip Navigation
You are viewing an older version of this Concept. Go to the latest version.

Special Theory of Relativity

%
Progress
Practice Special Theory of Relativity
Practice
Progress
%
Practice Now
Einstein's Cross

Einstein's Cross

License: CC BY-NC 3.0

Sitting behind ZW 2237+030, the Einstein Cross seen as four images of the same quasar, is an example of a gravitationally lensed quasar.

News You Can Use

Credit: ESO/M. Kornmesser
Source: http://www.eso.org/public/images/eso1122a/
License: CC BY-NC 3.0

Quasars are known to be the brighest objects in the universe [Figure2]

  • The Einstein Cross is an example of a gravitationally lensed quasar. A quasar is an energetic and active galactic nucleus that normally shows a very high red shift. Believed to be powered by the accretion of matter into black holes, quasars are known to be the most luminous objects in the universe.
  • The four images seen in the Einstein Cross is a result of a galaxy in the foreground that is bending the light that is coming from the quasar. The bending of light due to a massive object is one of the concepts involved in general relativity. This means that the light given off by an object on the other side of a massive object will be bent towards your eye like a lens.
  • View an animation of the Einstein Cross at the link below: 

http://www.youtube.com/watch?v=DubRAfJSCrM

  • Learn how quasars are created at the video below: 

http://www.youtube.com/watch?v=qil7bKy1NrQ

Explore More

Using the information provided above, answer the following questions.

  1. What exists at the center of a quasar?
  2. Describe gravitational lensing.
  3. If a star is observed to have a red shift, does this tell you what direction the star is moving relative to you? If so, what direction is it moving?

Image Attributions

  1. [1]^ License: CC BY-NC 3.0
  2. [2]^ Credit: ESO/M. Kornmesser; Source: http://www.eso.org/public/images/eso1122a/; License: CC BY-NC 3.0

Explore More

Sign in to explore more, including practice questions and solutions for Life Cycles of Stars.

Reviews

Please wait...
Please wait...

Original text