Twentieth-century physicist Albert Einstein says that every thing in the universe is a form of energy.
http://www.dictionary.com/browse/e=mc2
Energy is same as dark matter or dark energy in the universe.
https://www.extremetech.com/extreme/234672-found-a-fluffy-galaxy-made-from-99-dark-matter
And Dark Energy is The Biggest Mystery in the Universe
http://www.smithsonianmag.com/science-nature/dark-energy-the-biggest-mystery-in-the-universe-9482130/
What is reality today will not be the same tomorrow - it is all controlled by dark energy.
You Cannot Step Into the Same River Twice - Heraclitus
http://theinvisiblementor.com/you-cannot-step-into-the-same-river-twice/
the universe expanding faster than the speed of light
http://curious.astro.cornell.edu/about-us/104-the-universe/cosmology-and-the-big-bang/expansion-of-the-universe/616-is-the-universe-expanding-faster-than-the-speed-of-light-intermediate
Universe is expanding faster than physics can explain
https://cosmosmagazine.com/physics/universes-excessive-expansion-speed-hints-dark-physics
So how can you define what is reality?