We’ve heard the term tossed around quite a bit. We’ve seen many depictions, accurate and inaccurate of the stuff, but we probably don’t understand it unless we are physicists. To try and explain dark matter, it must be broken up into two parts. First, why does it exist? And second, what is it exactly?

It is our belief that the Universe is balanced between open and closed. The universe is huge and therefore there needs to be a lot of matter to accomplish its size. By studying the Big Bang theory, we can make an estimation of the baryonic matter of the universe. It is accomplished be connecting the observed ratio of helium to hydrogen (He/H) of the universe today to how much baryonic matter was present during the hot phase when the majority of helium was produced. When the temperature of the universe dropped, neutrons began decaying and becoming protons. If early baryon density was low, then protons were hard-pressed to find neutron mates to create helium before they decayed too far to make the amounts of helium we currently see. So, measuring the He/H ratio, we can estimate the baryon density that was needed to exist shortly after the Big Bang. This in turn makes it possible to estimate the total number baryons today. The resulting estimations show that 1/20 of the universe’s mass is baryonic matter. Our best estimates can only include what we can see, so say the mass of the universe is a whole 100%, and we can only see 1% of the stuff that makes up the universe. Well, where then is the rest of the universe?

There are a couple of conclusions. We see only about 0.01 Mass out of 0.05 Mass baryonic matter in the universe so the rest must be in the dark matter halos surrounding galaxies.

But the other conclusion, for those who don’t trust the Big Bang models, is achieved through more direct paths. The movement of clusters of galaxies suggests that they are bound by a gravitational pull that is five to ten times as much matter that can be accounted for in observation of luminous matter. In individual galaxies you can measure the rate of rotation of the stars around the center. This movement as observed would require about five times more mass than can be seen. Because of the extra mass requirements, we can work under the assumption that galaxies have dark matter halos surrounding them.

So, there are many possibilities to what this dark matter actually is. Nobody really knows anything more than just what they theorize. There are many published suggestions including dark galaxies, brown dwarfs, planetary materials (rocks, dust, etc.), neutrinos or exotica.

These can be placed into two categories: those which are solutions to other problems, but just happen to fit the dark matter problem, and those that have been proposed specifically for the problem of dark matter.

So, although we don’t know yet what dark matter actually is, we are working on solving the case and will no doubt be able to explain it someday.

The concept of space worm holes, rather than its existence was first postulated by Einstein that tells us about the possibilities of traveling through space that would be virtually impossible in the complete life-span of a human being. In short, it is a hypothetical feature that allows ‘time travel’ through it.

Features of worm holes

The existence of worm holes have been explained by the famous theory called ‘The Theory of Relativity’ by Einstein, who said that massive celestial bodies can change both space and time. The physical shape and size of worm holes is still in the realm of unknown. The concept of wormhole can easily be understood by imaging two mouths with a common throat. In fact, the name worm hole is coined from the analogy that a worm by burrowing a hole through an apple along its tapered end on both sides, would reach much quicker than the time it would take by covering the much longer distance through the circumference.

Similarly, the worm holes connect different locations of the universe and through them matter can pass through much faster than the speed of light.

The space worm holes not only connect different regions within a single galaxy, they also connect different parallel galaxies. Such types of inter-universe wormholes are called Schwarzschild worm holes.

Time travel

The theory of relativity says that the distance and time is dependant upon the motion. So, if an astronaut in a spacecraft moves faster than the speed of light into the space and returns after, say a year, by that time a considerable time ( may be some centuries) might have elapsed by then. So, when you cover distance at a considerably less time, you would go beyond the effect of aging. In other words, by time travel or by moving to space at far greater speed than light would, you wouldn’t get old. Although it may sound unbelievable, ‘The Theory of Relativity’, as postulated by Einstein, clearly explains this.

The path through which matters move inside a worm hole are called ‘closed time curve’ as time is thought to be closed, while traveling inside them. Such worm holes are known as ‘time holes.’

The theory of quantum gravity also has a role in ‘time travel.’ It takes into account the dispersion of radiations through the worm holes and researches are going on about its possible effects and impact on ‘time travel.’