The gates in the X-Universe are the "current" means of traversing the universe. They allow great distances between star systems (sectors) to be travelled at a fraction (seconds) of the time it would take to do this using conventional means.
Nobody knows for sure why they are there or more importantly, who put them there. They seem to have been left by some ancient civilisation. There are literally hundreds (if not thousands) of gates and only part of these have so far been found and mapped by the current six races.
A gate acts as a portal to another gate at another destination. These are not necessarily "close" to each other. For example when viewed in the two dimensional plane a sector may appear next to another with adjoining gates, but in reality there could be many star systems in-between.
Entering a gate has to be done at a speed that bears an exact calculable equation with the mass of the object. For example a large cargo ship or carrier class military ship has to enter at a very low speed, whereas a small ship can enter faster. Missiles or rockets can enter at full speed if such an event was to happen. Message drones which are minute, near light speed objects are small enough to enter at their full speed.
Physically the gates themselves are made up of an unknown material. Many attempts have been made by all races to understand this material but so far it has proven to be impenetrable. The gates "appear" to be indestructible. The races themselves have attached the navigation lights that adorn the gates and these draw power from self-contained solar energy devices.
With the creation of the self contained "jump drive" technology first discovered in the X-Shuttle from Earth it is possible to create a temporary "gate" or "jump tunnel" anywhere in space. However, this device is still required to "lock" on to another gate for the jump to be successful. The ability to create a second temporary jump tunnel at the receiving end has so far proven to be impossible.
After years of study (specifically by the Boron Mi Ton) it has been found that the gates emit an amount of negative energy in the opposite direction to the one they are linked to when they are used. This negative energy is countered by the positive energy of the object using the gate (i.e. the ship). All of this energy can be measured and this has been used by various military organisations for a number of years.
Importance for science
With the possibility that the gates present (i.e. being able to travel to another sector) it is quite feasible to not only track what "is" happening but also to look back at a system from afar and see what "has" happened in the past. Much like we do today on Earth. We only have the ability to see the universe how it was but in the X-Universe they have not only that ability, but the ability to be there as well.
By looking at the same point in space from many different directions and therefore points in time, it is possible to "paint" a picture of what has happened. This is exactly what Mi Ton achieved and his findings showed an increase in negative energy in certain areas that coincided with the gate shift approximately 600 years ago.
By studying the current position he comes to the conclusion that another gate shift is imminent and is partially convinced that Earth may once again come within the "loop" that is the X-Universe.
Whether any of this will happen or not remains to be seen...