A new theory suggests that dark matter could be hiding a "mirror world" that would completely change how we think of the Universe.
"There could be a mirror world where interesting things are going on," James Bullock at the University of California Irvine said.
"It means nature is much richer than we would otherwise know."
They have found potential evidence of dark matter while onboard the International Space Station which includes a surge of positrons. They are now waiting to find out if that burst is from decaying dark matter or if it's from another phenomenon, like a pulsar.
Researchers are hopeful that it provides a key into dark matter.
"That would be terrific, like discovering a completely new continent. It would really open the door to a whole new world," CERN physicist Pauline Gagnon said.
Samuel Ting, a Nobel-winning physicist who is leading the team at the European particle physics laboratory, said he is expecting a concrete answer within months.
"This is an 80-year-old detective story and we are getting close to the end," University of Chicago physicist Michael Turner said. "This is a tantalizing clue and further results from AMS could finish the story."
Physicists say the discovery of what dark matter consists of could open up new areas of research. They even think discovering multiple universes and other dimensions is possible.
"Over the coming months, AMS will be able to tell us conclusively whether these positrons are a signal for dark matter, or if they have some other origin," Samuel Ting said.
Dark matter is an ever-elusive ingredient in our Universe, making up 26.8 percent of the Universe's total density. That's much more than normal matter, which can be seen by astronomers. Normal matter makes up only 4.9 percent of the density.
The rest is an even more mysterious "dark energy" which is thought to have a hand in the expansion of the universe.