Dark matter is a type of matter hypothesized to account for a large part of the total mass in the universe. It cannot be seen directly with telescopes; evidently it neither emits nor absorbs light or other electromagnetic radiation. Instead, its existence and properties are inferred from its gravitational effects on visible matter, radiation, and the large scale structure of the universe. Dark matter is estimated to constitute 84% of the matter in the universe and 23% of the mass-energy.
Dark matter came to the attention of astrophysicists because of discrepancies between the mass of large astronomical objects and their gravitational effects, and mass calculated from the "luminous matter" like stars, gas, and dust. According to consensus among cosmologists, dark matter is composed primarily of a new, not yet characterized, type of subatomic particle. The search for this particle, by a variety of means, is one of the major efforts in particle physics today. Although the existence of dark matter is generally accepted by the mainstream scientific community, several alternative theories have been proposed to try to explain the anomalies for which dark matter is intended to account.
One of the ways scientists are researching it is through the Large Hadron Collider (LHC).
So why is any of this important? Well, it has been determined that even if we found a way to bend space, there would never be enough power required to travel through the universe. And according to scientists it would therefore make space travel impossible, which would make the existence of an advanced alien exploration, improbable.
But, BUT, what if an alien civilization found a way to harness the power in dark matter or dark energy? There is an abundance of it throughout space, again more of it than there is of atom matter. And then, add in the ability to fold space time, to me, makes it all possible. If another species is traveling in space, then they are advanced enough, scientifically, to use these tools. Just because we can't do it and we don’t understand it, doesn’t make it impossible, just unbelievable.