On visualizations in science — Part 2

In the last chapter, we had left our lonely neutron to roll away in its space without any destination. As we realised, we couldn’t really visualize it moving even though we had provided it with some velocity. Let’s continue that journey. But before we go ahead, go ahead and clear your mind so that you can visualise the empty space with the neutron we discovered in the previous article.

The reason we could not see the neutron move was because there was no other object in existence that we could compare with. So let’s go ahead and give our neutron a companion — another neutron. What do you see the neutrons doing if kept alone? Are they getting closer? They should be. They have mass and their gravity would be pulling them towards each other. Contrary to the previous article, you would be able to see either both the particles move towards each other or one particle moving towards the other. But wait. How can there be two possibilities to what we can see? Well, you could sit inside one neutron and simply see the other neutron edging towards you. Or you could sit somewhere far away and see both the neutrons getting closer to each other. This is a revisit to the concept of frame of reference. It is quite literally a frame of window that you can look through and see events happen. In the first scenario, the window is inside one neutron. In the second scenario, it is hanging somewhere in our empty space. I’ll stop with gravity for now because it causes acceleration (and related side effects) which will make our visualization complex for now.

So let’s say we have kept the neutrons far away so that the gravitational pull is very weak to cause any substantial movement. Now let’s repeat the same experiment we conducted in the first article — give the first neutron some velocity and then drop your second neutron in the empty space. Earlier, your neutron would appear still even if we gave it high velocities. Stop for a moment and imagine what would happen this time? As soon as we drop the second neutron, the first neutron shoots off with whatever velocity you gave it. This is the most basic intuition regarding motion that we should have in our heads even before we learn about the Newton’s laws of motion. Everything follows from this basic intuition. As an exercise, give the second neutron a velocity either towards or opposite to the first neutron’s direction of motion.

Now, straight motion is quite literally straight-forward. But what happens we decide to go with some other direction. Shift your view so that neutron one is travelling upwards and neutron two is sitting at its place. Now give neutron two some velocity to the left. This is easy to visualize. One neutron moving upwards, one neutron moving to the left. But let’s change your frame. Go ahead and sit inside neutron two and look for neutron one. Where does it look neutron one is going? If you’re thinking of doing vector math in your head to figure it out, stop. Vector math works and is the correct way, but it is also very easy. We’ll go the difficult route. So take two minutes and try to see out your window and figure out which direction you’d see neutron one going. Remember, you’d see yourself sitting still inside neutron two (don’t imagine yourself inside a moving car, there are no trees or roads to act as a frame of reference, the only thing visible is neutron one). If you were able to figure it out, you’d see neutron one going upwards and to the right (now you can go ahead and do the vector math if you feel like it). Now go and sit inside neutron one and look for neutron two. This should be simple now if you got the first one correct. Neutron two would be moving downwards and to the left. If you got to this on your own, congratulations. Now go ahead and challenge yourself with this — neutron two decided to revolve around neutron one. What do both the neutrons see?

Let’s stop here for a second and realize that these are the two most simplest forms of motion and visualizing them takes a certain amount of devisualizing — which is basically ditching our pre-trained intuition so that we are working purely with the laws of physics. As a fun thought exercise, I’d like to challenge you with this question — how were you seeing the neutrons? There is no light. Remember we had designed an empty space which means no electromagnetic fields, no photons, no functioning eyes. So then how do we see the two neutrons? Hint: use other senses to feel something described in paragraph 2.

Also please feel free to point out if I missed visualizing something. Gravity tends to mess things up.