THE horizon.

This is going to be a cosmology post. It will take a while to get up.
First some credit to Ned Wright, prof of Cosmology at UCLA. I'm mostly just trying to understand and interpret his excellent tutorial web site.

Ok, here we go. Beginning with a picture from the tutorial...

What we see above is a pitcure of the universe! Time is the up-down dimension and distance is the right left dimension. Each of the (almost) straight black lines is for a different observer, at a different place in the universe. Each of the different observers is moving away at a different speed, harking back to the big bang at the bottom when they were all colocated.

"Moving away from where?" you can ask, and the answer is "From me!" ...or from anyone. All viewpoints in the regularly expanding universe are equivalent. He shows that by skewing the frame of reference in this picture. The observer at "A" feels he is unmoving, so his line of position over time is straight, whereas the line showing "us" has relative motion.

There's a lot more to say by way of explaining this diagram, and I will try to get to it soon, but want to get my questions down first.

1) If it's the same for all observers, then everyone should see the same thing, right? That means both we and A should see the same CMB radiation, though we have dramatically different velocity. It is tempting here to say different absolute velocity but is there such a thing? If there's absolute velocity vs CMB, then there's a center: a preferred location in the universe and the point of this diagram is that that's not so. But (here's the question at last) if there is no preferred center, then there is no absolute velocity, and then seemingly none should be measured, by anyone, vs the CMB. Yet there is a dipole! Why? I think this has to be due to a recent velocity, an acceleration that has us moving relative to our local chunk of space. If it were secular (for all time) then we'd be in a different chunk of space (and seeing uniform CMB).

2) The picture shows "light cones" as little triangles along everyone's timeline. That's how fast a signal would travel if you emitted it. You could imagine adjacent societies communicating by radio, with delays for their successive messages (light cones) to reach each other. This elegant picture shows how the light from the big bang can reach us, after a long journey and an uphill race against the expanding universe wherein it actually loses ground before finally approaching us. That's the red pear shape. This explanation makes perfect sense to me if I think of it as an explosion in air. Everywhere, sound moves at the speed of sound, but the air through which it travels moves at different velocities depending on which part of the explosion each pocket of air is located in. As such the sound speeds up or slows down (in a coordinate frame fixed to the location of the original explosion). This all works perfectly for air, but air is the aether through which sound moves. Is there then aether for light? What if there is nobody there to measure the light as it travels from its source to us, through the intervening universe? Is it still doppler shifted along the way, or is it meaningless to talk about a doppler without an observer? Does it arrive along the same trajectory, covering the same distance in the same time?

I think the answers are: the light behaves the same whether there's someone there to see it or not, there is no way to define redshift without an observer to be shifted "relative to" and so, yes, it covers the same trajectory. This is clearly about relativity, wherein the photons, and their speed, are invariant. The doppler changes depending on who (at what velocity vs the emitter) is observing at any given time. Again I'll mention the sound analogy works well (for me at least), so long as you assume that each timeline on the picture represents a different hunk of air.

Another way to learn something from the sound metaphor is to picture the interaction from the transmitter's perspective. We can speak (continuously!) to a nearby observer who, at the bang, suddenly begins travelling away at a huge speed. Thereafter, they and we hear each other with a huge redshift. We would both be speaking in ordinary time at ordinary rates but not just pitch but (consequently!) the time of arrival of words and sentences would be greatly stretched out. To each observer, the other appears to have slowed down. We can know this 'cause we can observe everyone's lips move at the speed of light. However in space, when the redshift is itself that of light, there is no meaning to the idea of the 3rd party observer in absolute or unmoving space. Also, I can be moving far faster than the speed of sound vs the transmitter, but the sound waves speed up as they refract through intervening blocks of atmosphere, each of which is successively travelling faster, with it's local bits of embedded shrapnel & flotsam. From the listener's perspective (measuring the sound pulse approaching via some kind of laser rangefinder) the sound is speeding up: you may think of the doppler as being applied incrementally and it IS, by the incremental delta velocities by all the air pockets. In space we don't know anything about the intervening observers (they may not be there!), but we "see" the light's redshift (as we would hear the doppler shift of sound) and so time at the observer seems to have been slowed down.

Ok, I love this song. "Furr" by Blitzen Trapper

Everybody seen this show on NOVA? Surpassing Newton & Einstein with 11 dimensions, gravity radio between alternate universal branes (excellent, we can TALK to them by shaking an apple!) and the long struggle to squeeze the universe into one set of equations. I'm a little uncomfortable about how badly we seem to want the un...iverse to unify itself "just" to fit OUR need for order. The freaky-cool thing is that bits of pond scum can actually begin to understand the heartbeat of the big implacable pond. Gives me chills. Gotta look past the glossy popularization though: it takes a LOT of "dumbing down" to render these ideas for TV, and boy do they ever.

track, and bike crash

Well, I'm really enjoying track right now. Once a week for sure, maybe a bit more, and working on about a 1:15 pace (for 400m). This is a speed I can maintain for 6 or8 laps on long rest intervals, like 3 minutes. I can string together 1:30s and will shoot for a 6 minute mile soon. Long term goal is to get more comfortable at 1:15, where I'm very badly out of air, right now.

But, I realized after starting this, now it the right time to write something about the bike crash, so I can remember it later.

It was three weeks ago today, the CU Buffalo Bicycle Classic, a 100 mile ride to Ft. Collins & back. Steve and I were going to do it. I couldn't believe he could just pick up cycling and do 100 mile days, and I was a little apprehensive! Then Steve's knee got worse, or an order not to make it worse maybe, and I was gonna do this race alone. I almost didn't go, just out of boredom, but it is a great course and I thought it looked like good weather so I went. I cruised out of town in the chilly morning, gradually picking up speed as I warmed up. It's all uphill out of Boulder along Hwy 36 until you get to St Vrain road which is a downhill tear all the way to Hygiene. By now I was going pretty fast and had caught up with a pack made up of about 3 really strong guys and a bunch of hangers-on. I took a couple of pulls sort of to show I was able to keep up, and generally settled in towards the front of this group. The pack kept breaking up when someone would fall off the front few guys so I would have to pull back up which was no problem, just explaining that it wasn't a pace line so much as a few of us taking turns and a bunch of people barely sucking along. I remember thinking I'd have to be careful because these guys were not all that experienced, and getting tired. It would be a very different group after another hour, I thought. How true. We were approaching Hygiene.

The ambulance had a guy in it, sitting at my left, asking me impossible questions like what day was it, and where was I going and so forth. I don't remember much more than thinking it was hard and I wasn't answering his questions very well, and that it didn't hurt much.

Next is the hospital, same drill, except it's a couple of ladies asking the questions and Sue and the kids are there and I got two CAT scans and some very fluffy bandages on my knees. Then I was done, we drove to CU to get my bike and I rode it down to McGuckin's, loaded the car and drove home.

I told it that way because that's how I experienced it: in a couple of flashes with a ton of missing time. On the phone a week later, some dean from CU (who's responsible for the race, perhaps) offered condolences and a free entry next year and said he saw me laid out on the side of the road. I should've hit him up for a couple of jerseys! Steve & I didn't even get t-shirts out of it. So anyway, I learned I was unconscious for a while. It's interesting how the memories are gone, even from BEFORE the crash. Near as I can guess, there was from 5 sec to a half minute before the crash where I have no memories. Can't visualize the rear wheel that (I imagine) swiped across my front tire and wiped me out, or the tumble, or the asphalt, or laying there. Nothing.

The next remarkable thing was all the gyro failures. I couldn't call it dizziness, but that's the nearest thing I guess. Sometimes I'd turn my head, and the world would turn but then Just Keep Turning, never stopping. ...as though I'd gotten off a merry-go-round. So I guess that is dizziness. Anyway that kept up for weeks. It became a morning phenomenon. Monday, 15 days after, was the first time I woke up and could walk without lights on or holding on to something. Then yesterday (20 days after) the last of the saucer sized scabs on my knees peeled off. Those hurt a lot & still do. My knees continue to weep blood and pus and I can't wear long pants because of it. That's irrelevant though. My wrist feels sprained, or lower part of my arm maybe, so there are some things like dips and pullups and pushups I can't do yet, but that'll all heal soon enough I suppose. It is good to have it over with. I haven't gone back to "full" workouts yet, mostly because I'm daunted about starting up swimming again: even a 3 day layoff makes swimming hard again. As far as the bike? Well, I haven't had the urge.

Utopia

The loudspeaker blared, “All hands for Ves-3 please report to the cafeteria deck for final briefing at 14:00.”

It was the usual pre-drop announcement, Cindra had heard it a before, three times, but never before like this. This time it was for her. Tomorrow at 14:00 some 6 dozen colonists would be jam packed into reentry capsules along with 5x their mass of support gear (just about anything anybody wanted, subject to the weight limits) the mothership would drop out of hyperspace, and they would be dumped into a hyperbolic orbit guaranteed only to impact the atmosphere at just thus and such an angle. They would all de-orbit together, or perhaps go up in smoke together, if the lander didn't work.

Meanwhile, there would be one final briefing, half review, half goodbye, half ceremony. Sometimes Cindra thought it was how the rest of the crew got to closure on what was basically the same thing as losing 20% of all the people they knew, forever. There had been three groups dropped already, and there would be three more, before this ship continued, empty, on whatever irrelevant ballistic trajectory remained to it before it plowed into some gravity well out there.

The USS Niven was a colonization "seed ship," launced from earth along with 8 others in the last extremity, in the twilight of civilization, and they, Cindra and her peers, were the seeds. People all over the earth could tell that the clocks were running down: out of fuel, out of air, out of ozone and clean water and arable land and trees to cut for shelter and oil, there was nothing left but solar power and the foamed concrete eeked slowly thereby, as though from the sun's very furnace. Precious fuels and metals were squandered on these 9 colonization birds, each the same, each with about 450 souls aboard, and 5 to 8 stops to make seeding hopeful star systems before beginning a final irrelevant leg of their endless journeys. Each ship was named after a fanciful sci-fi author.

Tomorrow they would go down. Cindra's group had drawn a very fertile, friendly planet. It might have fauna and certainly there were a lot of plants: that much was apparent from the telescope surveys conducted from earth. Not much would be needed to eke out a living on the surface. But there was more: long studies had been held to try to give the 60 new societies the best possible toehold in their new worlds, to create, as much as possible, a new world in the image of but better than, the old one. The group would have some special advantages, she thought hopefully of these while drifting off to sleep.

Next day passed quickly, checking and rechecking hear she'd stowed and made sure of a dozen times already. In no time it was 2:00PM and time for the meeting. All the colonists sat together in the front of the caffeteria, wearing dark green acceleration suits they'd not take off until they had landed, while most of the rest of the crew clustered around to hear the last speeches.

First there were the obligatory goodbyes and pronouncements of high hopes and expectations. Soon, their leader, Captain Thomas, took the podium, wearing her own green jumpsuit, and began announcing a private catechism Cindra and her peers already mostly knew.

“As you know," she said, "our group of colonists is not taking piles of lasers and microcomputers with us to the surface. We have the lowest gear mass allotment of any group on the ship, something I expect you all to thank us for while you're eating that extra ration of chocolate ice cream you got budgeted into YOUR drop shipment!” A pause here for applause was effective, though sardonic: groups with higher mass allotments generally had harsher planets to deal with, such as those without oxygen, or worse: nobody was actually dropping with chocolate ice cream, although there was plenty shipboard, and Thomas took a healthy lick as she said this, to dramatize it the fact.

“Instead, we are taking something special, something that will make us only marginally human, really, a tiny improvement.” Thomas was on a roll now. People settled down to hear the rest of her talk.

“The whole idea came from studying Neanderthals, our distant distant dumb stepbrothers. Or so we like to think. Archaeological evidence actually seems to suggest that they were bigger, stronger AND smarter than we were. That's something you may not all know. Why then, (our scientists put themselves this question, I'm told...) were WE the evolutionary winners instead of the Neanderthals? Well the more recent evidence has given us some exciting clues to ponder about this.”

You could've heard a pin drop as Thomas paused to emphasize her grip on the audience.

“The Neanderthals, it turns out had a disadvantage, and it was one you wouldn't thinkof very highly: they were fertile.”

“Fertile? How does THAT get to be a disadvantage, you want to ask! Well consider this: we have a species that is getting successful, and one of its key characteristics is how it cares for its offspring, how WE raise and nurture our young, to make them all they can be, help them even at our own expense. The Neanderthals were this way too. Take this burgeoning success and this devotion to offspring, combine them with fecundity, and what do you get? Overpopulation, that's what. A characteristic that's helpful to a butterfly who simply leaves her young behind becomes an actual burden to a cavemother who absolutely won't. Put it together, imagine having babies every nine months like clockwork, and trying to get all those kids fed, and sheltered, and moved to the new hunting grounds! You get the picture. Add to that that half the people, the women would be incapacitated half the time and nursing the other half, and you get a species competing at half power. Maybe it would work if you lost two of every three kids to the dinosaurs, but add successful nurturing to the recipe, and you've got hardship resulting from success. That's the unfair catch-22 the Neanderthals struggled with.”

“Meanwhile, our ancestors had a relative advantage: sparse fecundity. As you all know all too well, we (well those of us who are female) are fertile just a few days each month and noone can tell (without very close inpection indeed) whether we are or not. A baby's not certain every time you dive under the bearskins, and if you're nursing it's highly unlikely. This fact has not only made it quite easy to tame the less intelligent portion of the species (plenty of guffaws here) pretty handily through sexual manipulation, but reduced the popluation pressure our tribes felt when we were a young species. The low birth rates also equalized a physical disadvantage, and made us really partners with our men. I'd like to think that partnership had something to do with beating the Neanderthals, but the reproductive dissimilarity certainly did. With less kids to take care of, we did better as a species.”

“You could argue the whole thing played out again in the 21st century back home, only cultural preferences and birth control created the advantage when even LESS fecundity was needed in the face of longer lifetimes, greater educational burden and more population pressure. That social pressure worked against those who felt it most though, because others of the same species were meanwhile breeding to beat the band, and that put pressure on us all, arguably the very reason for these seed ships we're riding in now. How can we break that cycle in our next try? This was the problem our planning group chose to focus on.”

“The solution is clear with hindsight: we will take our advantage over the Neanderthals and multiply it. In particular, we will genetically alter ourselves, in fact HAVE already altered ourselves to bear less children. Each of the women you see before you is reproductively fertile only for a few days a year, and only she knows approximately when. This change makes us (we women) more nearly equal in our ability to contribute, we've been chosen for size and strength too, but most importantly, we should bring our tribe an immeasurable benefit, that of not facing an overpopulation problem of our own making!” There were some shocked gasps: this aspect of the fourth drop team's mission had not been overtly known.

“Now you may ask 'why now, in the fragile first stages of colonization?' and my answer would be that you are right: there's no place in the first several generations for limited growth, and in fact for just that reason we have thousands of doses of fertility drugs, which WE must take in order to approach the monthly fertility YOU all take for granted. But those drugs will run out in a few generations, and then we will have our new, utopian society to nurture. Then too, like all of our groups we are preponderantly women, for obvious reasons: we want to breed successfully and often at first (Thomas paused here for lusty cheering from the men and boys) but generations hence our growth will taper. Our computer simulations promise good outcomes from this strategy. Now is the time for you to wish us the same, as we take our turn to try to establish a beachhead for humanity on this new earth, here around the star, our Sun, the star known back home only as VES-3!”

Cheers all around, some light drinking, and Cindra went to bed to await the drop.