Hypothetical Proton Decay

Some of the models that seek to come up with a Grand Unified Theory of the Universe hypothesize that protons will eventually decay into neutrinos and positrons. Because it violates baryonic conservation, it's by no means a commonly accepted theory. But if proton decay ever ends up being observed, my very rough understanding is that it would mean that at some point in the future, most matter in the universe would become light, because most positrons would annihilate with electrons. In fact, because of the expansion of space, it would eventually become radio waves. When I first worked this out in a General Relativity class years ago, I remember wondering what it would be like to put a radio in that unfathomably distant future, and listen to the radio waves that used to be things: stars, asteroids, bodies, water. I'm still wondering about it, and this song came out of that wondering. Lyrics: I learned That all the matter making our world Might dissolve into neutrinos and dead light Then our bones Could be like channels on a radio Singing through the void where everything once hung In the time of touch My god, my god how beautiful it was The moon at dusk and the stories we made up The birds had hearts and the blossoms swirled like dust Sometimes it hurt and sometimes there was love I'm made of atoms formed within a Big Bang I've been carrying that darkness deep inside Borne a billion times And someday When we're all a bunch of light waves Will it matter still how much I failed to hold? Before the endless cold Because, My god, my god how beautiful it was The moon at dusk and the stories we made up The birds had hearts and the blossoms swirled like dust Sometimes it hurt and sometimes there was love Sand dunes delicate as blood There were worlds inside our guts Asteroids spun round like clocks And there was so much we fucked up My god, my god how beautiful that was The moon, the dusk, all the stories we made up The birds had hearts and the blossoms swirled like dust Sometimes it hurt and sometimes there was love Granite faces dripped with rust Holy words spilled from our tongues What a glory to remember us And those millenia of touch