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.

A 125 million USD NASA aircraft that had traveled to around 420 million to Mars has vanished under mysterious circumstances. This happened for the second time in the short span of six years that NASA has lost its spaceship on its mission to Mars. The “Mars Climate Orbiter” which was sent to mars to study the planet’s weather and to look for any form of life and water apparently flew too close to the planet and broke apart and burned up, the space agency said. NASA top management ruled out any mechanical problem or technical failure.

Previously in 1993 NASA’s 1 billion USD “Mars Observer Probe” disappeared in the same fashion as this one has. NASA’s goal is to launch such expeditions at least once in every 26 months. However the failure of such missions discourages the funding which it gets from the U.S Congress. NASA boasts that its mission to mars, i.e. “Mars Pathfinder” which was sent in 1997, was a huge success. This pathfinder was a tiny land rover, which even took photos of Mars’s surface. However there has always been a debate on the authenticity of these photos.

The Climate Orbiter was last heard on 2.06 AM just after five minutes after its main engine had fired in order to slow the speed of the aircraft so that it would be captured in the orbit of the planet.

The Orbiter carried instruments which were designed to study the weather pattern on mars. The information was the key to understanding whether some form of life existed or can exist in mars.

In the year 1993 the Mars Observer vanished when its fuel line was pressurized before it reached the orbit of the planet. A panel investigating the matter concluded that the fuel line probably broke because of the large distance traveled by the space craft.

According to Carl Pilcher of NASA's Office of Space Exploration "When you're launching missions at such a vast and rapid rate, there is simply statistically a greater trend that you're going to have a loss".

The failure of such space crafts which are highly sophisticated raises a finger of suspicion. Do they really met with an accident or some external force devastated the orbiters? Even the NASA’s team is trying to figure out what the truth really is. Perhaps the time will tell what the truth exactly is and what the fate of these orbiters was.