On August 25, 2012 Voyager I passed through the heliopause to become the first manmade object to enter interstellar space. Last week I read Einstein’s The Theory of Relativity and Other Essays. Saturday Treva and I viewed the WONDER exhibition at the Renwick Gallery in Washington, D. C.
How do these events connect? Reading Einstein set me thinking about Voyager I because he claims real physics only applies in interstellar space—far from the interference of stars and the debris fields (including planets) which orbit them. Reflecting on questions of weight versus inertia, and reality versus theory, and art, I came to realize how little we know—about ourselves, about everything.
Avoiding math that would hurt my head, I understand that the great physics question of two last centuries was reconciling gravity and inertia. Einstein says the force that keeps an object at rest (or continuing in the direction it’s already going) is not the same as the force that apparently is pulling it downward from the surface of the earth. Yet they act simultaneously on everything.
Out beyond Voyager it’s empty and cold, but not dark. If you were riding on Voyager, you’d see all the stars we see—probably better. How does the light get there? Photons? Even way out there the mass of our Sun and other stars would tug on you. How? We don’t know.
Until late in the nineteenth century, scientists still referred to aether (not the chemical diethyl ether) as the material which filled space and carried light, gravity, etc. because they couldn’t figure out how light and gravity could cross nothing. Think about it. Before the concept of the photon as a massless carrier of light energy, scientists had no way to explain a phenomena we all experience daily. Even still, no one’s seen a photon. We just see the effects of their presence. Very pretty effects sometimes. As Gabriel Dawes’ plexus art at the Renwick or Crystal Bridges Galleries (above) illustrates.
Gravity poses the same problem. Scientists think/hope there may be gravitons that similarly “mediate” gravity. But there are problems with that idea. Too deep for me.
I look up at a night sky. How does light travel through nothing, unmeasurable unless it interacts with something, until it interacts with my retina, which sends nerve impulses to my brain, which presents an image to my consciousness (whatever that is), which “I” see as stars?
I do wonder.