Dark Matter, Part 3. Synthesis.

The Scientist by James White

Part 1

Part 2

Okay, in Part 1 I noted that dark matter is not directly observable. The reason scientists know that it's there is because something is affecting objects in our space that are directly observable, in ways and for reasons that are understood—gravity draws together, particles get excited when energy is added to the system, spatial expansion pulls apart, etc.—but there isn't anything visible to account for these effects. Dark matter is the name given to these intangible but very real sources of interaction.

If a star is acting like gravity is pulling it a particular direction but there is nothing where we expect there to be the thing that is pulling on it, the star is still being pulled. We just can't see what's doing it. Now, black holes have been offered as a potential culprit here, but the amount of interaction, the sheer volume of interaction that is otherwise unaccounted for would require a truly unfathomable number of black holes, which would probably also lead to a less densely-starred visible universe. Plus, you actually can detect black holes, and they haven't in relation to this, so there's that.

Now, imagine an analogy. Think about driving a car. When you are driving, you are going (most of the time, unless you are a very unusual driver) toward your destination. You cannot simultaneously go away from your destination, right? Now think about driving on a two-lane road. A car is coming from the other direction. As you pass each other, you hear the car, feel the buffet of wind, and its gone, away behind you, heading the direction you came from as you head the direction they came from. You had a moment of interaction, but it was tangible, and even though they were going the other direction along that axis, that car affected yours in a very real way. Had it been a semi, the effect would have lasted longer. If it had been a train (what are you doing driving there, you lunatic?), the effect would have lasted a lot longer. If you were also in a train, longer and more pronounced still! And again, what the hell?

What if?

What if dark matter is perfectly normal matter, that is moving the other direction in time? It still has mass, not anti-mass or something, perfectly normal three-dimensional mass that is simply moving backward through time. Of course, from the dark matter's point of view it would appear that it is moving "forward" in time, just as the oncoming car is moving "toward" the place you left, but relative to us observers on this side of the temporal road, it is moving backward through time. Our matter would act upon dark matter in the same way—not directly observable from that side, but the effects of gravity and such are very visible.

The idea opens up some interesting possibilities. We will likely one day get to a place where we can peek at that dark matter—we may have already, at the Large Hadron Collider, though it may or may not have been interpreted so—and if we can peek, we may eventually be able to jump between the cars, hitch a ride the other direction for a ways or forever.

Roads? Where we're going, we don't need roads.