The Mystery of Missing Matter

And, Now for something completely different.

Some of the best mysteries are scientific mysteries and the more scientists discover about missing matter in the universe the more amazing this all gets.

One of the most baffling mysteries of the last century is found in the field of Astrophysics and has to do with a paradox in the rotation of galaxies. The problem is that the stars on the outer edge of all galaxies are moving too fast to be constrained by the gravitational pull of all of the material in their galaxies. Those stars should be just shooting right into space.

To understand this, think about swinging a ball on a string above your head. When you swing it and pull the string tighter, the ball will move faster. When you loosen the string, the ball will move more slowly.

This same principle is in place when planets orbit the Sun. Planets closer to the Sun experience a higher gravitational pull and have to move faster in order to maintain their orbit. So Mercury needs to travel faster than the Earth and both planets need to travel faster than Pluto, otherwise they would be pulled into the Sun. If Pluto spun around the Sun as fast as the Earth it would just fly out of the solar system.

According to astronomical observation, the outer stars in every galaxy rotate so fast that they should fly away too. This problem forces astrophysicists to propose another idea; The Dark Matter Theory. According to this theory, every galaxy is surrounded by a halo of  unseen matter that has a mass many times greater than the entire mass of the observed part of the galaxy.

Astrophysicists have tried to determine just what might qualify as dark matter and they have ruled out things such as black-holes, dust, interstellar planets and burned out stars. Even though some of these things can’t be directly observed, their localized gravitational effect can be. So dark matter probably isn’t made up of big objects, and astrophysicists now consider the possibility that dark matter might be predominately made up of subatomic particles which are objects that are smaller than atoms.

Unfortunately, the presence of most standard subatomic particles such as electrons and protons could be observed, even in a distant galaxy, so they probably aren’t the solution to the dark matter problem. As a result the search moves to hypothetical subatomic particles or WIMPs; with the prime suspect being a hypothetical particle called a Neutrolino. Theoretically there is a gigantic quantity of Neutrolinos floating around you right now. You can’t detect them because they contain no charge and their gravitational effect can’t be localized.  These hypothetical particles have never been observed but are predicted by physicists using the Supersymmetry Theory.

So the upshot of all of this is, as of now the rotation of galaxies can only be explained by a theory that involves hypothetical particles and something unseen is holding it all together.

The more that topics like this are studied, the more interesting and mysterious it all gets. We humans really know very little about what is going on around us and we need to use extreme humility when estimating our own observational skills. I become more religious when I try to understand ideas like this, it seems that God always has a new wrinkle for us and invites us to continue to find that something that lies just beyond our grasp.