What is Dark Matter?
Dark matter certainly sounds like a bizarre structure, and many of its references in movies and books give it strange qualities, which it does not posses. Essentially, it is an unseen force that is observed not through radiation, but instead through its effects on gravitation of large objects, mainly galaxies. It is believed the particle makes up for almost a quarter of the mass in the universe, which is huge as stars and planets compose less than a percent of the universe’s mass.
Much on the subject is highly speculative. Since it can’t be directly observed, it is difficult to determine its properties and effects on the rest of the universe. A few things are, at the very least, defendable. One of the more distinct instances of identifying the properties of this unknown substance was observed in August of 2006 when, through gravitational lensing, the light bending properties of the matter were observed. This process is accomplished through predicting how light should move through the galaxy and notices the changes as it passes through space or near large bodies.
Another such observation is the shape of spiral galaxies and the speed in which they spin. Generally speaking, from what scientists know of gravity and matter, these galaxies (like our own) should be shaped and spin differently than they actually do. Therefore, some other effect is influencing these attributes and dark matter is believed to be the cause. Just like the weight of the sun causes our earth to spin around it, the weight of this invisible mass causes other bodies to alter as well.
Dark matter is believed to influence the way the universe is transforming over time. Through the influence of its mass, galaxies are moving steadily faster away from each other over time. Meaning there is more space between each individual galaxy than in the past. There is something that is pushing these objects and that something is this mystery mass.
There are many other components to this problem. Theories of dark energy and dark galaxy certainly sound fun, but they are also the core of understanding what makes up all the space in between all the glowing parts of the universe. There are many scientists from a variety of fields working to better understand this problem. Much of the work is aimed at confirming this hard to pin down matter through direct and indirect detection. It’s very possible that what we now think we know of this illusive object may be totally reversed in a few decades time.