Team Number: 28

School Name: Highland High School

Area of Science: Cosmology

Project Title: Does Dark Matter Matter?

Problem Definition:

It is a well known theory among cosmologists that most of the matter in the universe is made of "dark matter", or matter that influences the universe gravitationally, but can not be seen. There are several who call this theory into question due to what they feel is an inadequate amount of evidence to support it. In this project we hope to use computer modeling to determine if a universe with no dark matter could act as ours does, and in succeeding, disprove the dark matter theory.

Plan for Solving the Problem Computationally:

We plan to use Java to represent planets as point masses using Newton's Law of gravity, dark ma>tter theory, and MOND theory.

Description of Progress Made up to this Time:

In addition to some preliminary research on our topic, our team has produced several working Java models in attempt to perfect the model. The first approach was to build a very basic working model of astrophysical masses and their interactions. The Java programmer initially made two versions of the simple program: one using standard gravitational equations, and the other with Modified Newtonian Dynamics, an alternate gravitational theory to dark matter proposed by Mordehai Milgrom, although both were devoid of dark matter itself and of any realistic parameters, containing no more than 20 masses at once. He then experimented with the graphical rendering of these models, as the masses had a habit of getting too close to one another and zooming off the visible screen. This was an inevitable result of the iteration of the model; the gravitational pull between masses was incremental rather than continuous. So, even when he modified the display to constantly expand the viewing window as needed, the masses would travel so far apart as to make the model meaningless. But he had working models, none the less. Next, he researched some realistic parameters to incorporate into his program, such as realistic masses and distances. This, and smaller movement increments, helped to hold his galaxies together, but still neither model gave realistic galactic behavior, and they worked only with very few masses. And also because he still had no tangible manner of incorporating the effects of dark matter, he put this approach on hold, in order to try something different. He wanted his new model to have the ability to include at least a couple thousand stars, and to accomplish this he rewrote the algorithms in a much more simplistic manner, and used larger increments. Unfortunately, the gravitational discontinuity then caused even worse dispersion. To combat this, his new model allowed for stars within a certain distance of each other to attach rather than fly billions of light years away from the galaxy. However, he is unable to find evidence of any real instances of this happening, and has no realistic value to use for the minimal distance. The new model, at least, can incorporate a thousand stars and still run at a reasonable speed, but if left long enough the stars will all clump together and form one large mass. So, he is currently experimenting with different star distributions and initial velocities, attempting to produce a semblance of reality.

Expected Results:

After much trial and error improvement method of the model, we expect to be able to show that the universe can be stable without the presence of dark matter. In this way, we hope to disprove its existence.

Information Sites:

http://www.astro.queensu.ca/~dursi/dm-tutorial/dm0.html

http://csep10.phys.utk.edu/guidry/violence/darkmatter.html

http://www.calresco.org/cosmic.htm

http://astron.berkeley.edu/~mwhite/darkmatter/dm.html

http://csep10.phys.utk.edu/astr162/lect/cosmology/darkmatter.html

Team Members:

Matt Grohman

Audrey Smith

Sponsor Teacher:

Jeffrey Raloff