Out there is an article on "stuff" that is out there, but not perceived. I could have been an physicist with my B.S in Physics (cleared Properties of Matter in the third attempt). But I am not even an arm-chair physicist as I just do not have the required number of connections in my brain to comprehend papers like that.
But this is an interesting one. Bhagawan once said, "The manifested is knowable and the unmanifested is unknowable." I'm sure the scientists mentioned in the article would agree. But what is this unmanifested?
Rig Veda says - (from Sacred Texts web-site).
1. THEN was not non-existent nor existent: there was no realm of air, no sky beyond it.
What covered in, and where? and what gave shelter? Was water there, unfathomed depth of water?
2 Death was not then, nor was there aught immortal: no sign was there, the day's and night's divider.
That One Thing, breathless, breathed by its own nature: apart from it was nothing whatsoever.
3 Darkness there was: at first concealed in darkness this All was indiscriminated chaos.
All that existed then was void and form less: by the great power of Warmth was born that Unit.
4 Thereafter rose Desire in the beginning, Desire, the primal seed and germ of Spirit.
Sages who searched with their heart's thought discovered the existent's kinship in the non-existent.
5 Transversely was their severing line extended: what was above it then, and what below it?
There were begetters, there were mighty forces, free action here and energy up yonder
6 Who verily knows and who can here declare it, whence it was born and whence comes this creation?
The Gods are later than this world's production. Who knows then whence it first came into being?
7 He, the first origin of this creation, whether he formed it all or did not form it,
Whose eye controls this world in highest heaven, he verily knows it, or perhaps he knows not.
The dark (meaning unknown - not dark as black or negative) energy can manifest itself as identifiable matter or energy. Then the known Physics can take over to measure and explain it. Physics has matured in the past centuries to see that matter can be energy and vice versa; Physics accepts unpredictability and so on. We will be humble enough to say that there exists something that I can't see, feel or measure. We will one day realize that we are not different from "it", but a just manifestation of "it" with some set of properties.
As long as some properties could be defined, we are in the realm of material world where gravity is just natural to try to get back to the oneness from where everything started.