NetLogo User Community Models

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Download If clicking does not initiate a download, try right clicking or control clicking and choosing "Save" or "Download".(The run link is disabled for this model because it was made in a version prior to NetLogo 6.0, which NetLogo Web requires.)

WHAT IS IT?

This is a demonstration model of the Big Bang. This is a simple model; the stars have constant directions and velocities, and there are no relativistic effects. Stars are not clustered in galaxies, and of course it follows that there are no clusters of galaxies.

HOW IT WORKS

Stars are intialized at the center of the universe, each with its own direction and speed. The motion is followed after the Big Bang. Optionally, stars can be randomly colored, or colored according to their speed.

HOW TO USE IT

Set the switches for how to color the stars, initialize, then go. To "run the (expansion) movie backwards, click on the run-backwards switch after the expansion has run for awhile.

THINGS TO NOTICE

The main point of this model is the demonstration that the faster stars travel further. It also shows the universe getting darker as it expands.

THINGS TO TRY

Set the switch to color stars according to their speed.

EXTENDING THE MODEL

This model could be extended to show relativity, red shift (color each star according to its red shift), show the view from the earth, show inflation, etc. Perhaps most interesting would be to show the cosmic microwave background.

NETLOGO FEATURES

This model uses the run-backwards switch to reverse expansion after it has proceeded for awhile. "Running the (expansion) movie backwards" was the first piece of evidence for the Big Bang. If the microwave background were added, this would illustrate the second piece of evidence.

RELATED MODELS

There are models of the solar system.

CREDITS AND REFERENCES

Wilensky, U. (1999). NetLogo. http://ccl.northwestern.edu/netlogo/. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.