So, if there were a nuclear blast or something similar on a desert of sand, it would make a sea of glass. When this cooled it would make a mirror. If there were one such mirror in the solar system of a star say four light years away, and we could get it to reflect our light back to us, we could literally see eight years into the past. So, you know how in the bathroom, two mirrors reflect one another in a series? Find two such mirror-planets in different parts of the solar system, and each reflection would be a successive page into the past. So it would be theoretically possible to literally see into our past. We are already seeing into the past, whenever we look at star light.
A riddle: What is not, yet is unchangeable? The past is what it is, or was, living on only in the present. But the light that bounced off our planet years ago is still travelling about somewhere, and the past is what it is. Not so with the future.
When we shine two flashlights in opposite directions, how fast are the ends of each beam moving away from one another? Or when driving 60 mph, do the headlight’s lights travel at 60 + the speed of light?
One of my favorite thoughts is that the rumble of thunder is caused by the difference between the speed of light and the speed of sound. When a bolt goes across the sky, the sound from parts farther away reaches us later, while the light part is mostly instantaneous. There is a ratio of sound to light that is important.
We do not consider, in Astronomy, that we are not seeing what is out there right now at all, but rather what was out there, and at various times according to the various distances. What is out there now may be basically similar, but would have to be deduced from what we are seeing. There is a market for a real time map deduced by computer. I wonder if any living person has even seen an attempt to depict what is now there. And how are our pictures of swirling galaxies skewed by time?
Enough sci fi yet? What if each planet gradually moves out through the sweet spot where it is not too hot or too cold, and the challenge of each civilization, and life on each planet, is to planet hop, as from the old watery Mars to the young earth, then to Venus? We may have to tread water for a while here though, as the weather on Venus is some 800 degrees. I always wanted to write a sci-fi novel about this world where the purpose is planet hopping, but will probably never have time.
P. S. I still don’t believe Einstein if he says space is curved and the same thing as time. Curved relative to what?
And are you guys really sure that gravity is caused by mass and not somehow the opposite of centrifugal force, like the arms of a skater? I’d prob”ly give you’all this one, but I can’t see it.
P. S. S. Nor do I believe the Big Bang thing straight up. What if, as a Russian physicist too famously noted, there were 16 Big Bangs ? How would we know? Or 16 times, everything could have expanded and contracted. Time itself may not be something that can come to be, or it might come to be many times (?). The theory only says this universe began the 13+ billion years ago. The singularity, too, is a nice thought, but it is relative, depending on things said to come out of it in order to conceive it. Really small, was it?
From Genesis, it is sometimes said that the Big Bang confirms the account that the universe had a beginning, as in the creation story. But here’s a question: On which day did water come to be? And on which day did moving, as “over the face of the deep, ” come to be, according to the text of Genesis? But Maimonides, my best teacher on Genesis, disagrees with me. He has me astonished today at many things about this, but especially, that heaven is set aside in I:1, and is described only by default and analogy, until the first three lines of the gospel of John.
It is very hard to see in terms of the Copernican universe when we look out at our sky, as at sunset, or rather “earthrise.”
Do you know that at sunset, if you hold really very still, you can see the earth gracefully move? The same is true of the Moon, if one sits as in October, with the harvest moon behind the branches of an old apple tree. With the branches as a reference, one can see the moon rise, again, if you hold very still and look with patience.
As far as we are from the sun right now, as we look for example at sunset, so far will we be around the other side in just six months. The radius indicates a circumference that makes our heads spin.
It is very hard, from the ground, to see the cause of the seasonal changes in the position of the sun, and the reason for sol-stice, when the sun holds still and then begins to set further South, indicating the coming of summer. And why is the coldest part of winter after Solstice, when the days are getting longer? It is that the earth takes a while to cool off and heat up. So we now suffer the cooling that was occurring in November and December.
It is almost impossible for us to see believing that when we look East to the sunrise, we are looking in the same direction as when we look West at the sunset.
Would it have been possible to figure out the Copernican universe from what is visible? After sunset, when the moon is in the West, it is clear that the phase of the moon is a reflection of the direction of the sun below the Horizon. One can tell how far away the sun is, and see by implication where it is on the other side of the earth at any time of the night. It just occurred to me yesterday how the place of the sun at night is implied by the angle during the day, according to seasons. The curved shadow of the earth on the moon during eclipse is the best clue to the round earth, which many thinkers figured out for themselves in different ways.
We do not know which way is up. First its perpendicular to the ground, then the direction of the North Pole, then 23 degrees off, perpendicular to the disk of the solar system, then to the disk of the galaxy. And what if the Milky Way is sideways?
But for our purposes, the moss growing on the North side of a tree indicates direction. I thought I saw, just the other day, that if one looks closely at both the forest and the trees, one can tell the direction of South by the slight leaning of the trees growing toward the sun. I have to verify this, but we could gain the habit of always being able to see direction if this were so, and a trained soldier or tracker would simply always know or be able to tell direction by looking.
Tribute to the R. E. M. Song Stand! And to the Essay by Jacob Klein called On the Copernican Revolution.