How big is the Universe?

Hello everyone, and sorry for the long time since my last post. Today I'll be giving an in-depth and unqualified analysis of current astronomy and cosmology. What I find interesting is the pace at which our knowledge of the universe's structure has developed.

1)Starting with ancient cultures, we have known or speculated that we live on a sphere ("Earth") nearby some other objects (the sun and planets), which are all surrounded by little twinkly lights (other stars). Assigning a date and person to this discovery is tricky, but a good guess is an African named Eratosthenes in Egypt, who measured the earth's diameter in ~200 BCE. He did this by noting that on the summer solstice, the sun shone exactly straight down in one city, but cast a shadow about 1/50th of a circle in another city. He knew the difference in the distance between the two cities, and using "math" he calculated the diameter of the earth. So the size of the known universe, in our understanding, was the earth's diameter: 12,800 km.

2)It wasn't until Johann Kepler in the 1600s that we were relatively confident that our Earth was not fixed, but was moving around the sun (and not the other way around). This had been hypothesized before, but only at that time had it been proven and accepted. This increased the size of the known universe to the diameter of the major axis of Saturn's orbit (then the furthest known planet): 1.4 billion km.

3)Even then, it wasn't until Frederich Bessel in 1838 that we confirmed that the other points of light in our sky are stars similar to our sun, and found the distances between them. He did this by measuring the angle of a "nearby" star against the background, further away stars as the earth moved in its orbit. Just like the two images from our eyes allow us to tell the distance to something, this parallax allowed us to calculate the distance to the stars. Until then the working theory was that they were unknown lights, possibly infinitely far away. Now the size of the known universe became the size of our galaxy: 950 million billion km.
4)Only in the twentieth century did we realize that our galaxy was not the entire universe, but merely one tiny, tiny piece of it. Edwin Hubble helped us realize this when he observed objects receding away from us much more quickly than the escape velocity of our galaxy, and this was later confirmed by measuring the brightness of certain standard objects (e.g. Cepheid Variables or Type 1a Supernovas) within those galaxies. This inflated our known universe to the distance between these "nearby" galaxies, about 60 billion billion km.

5) At about the same time, we discovered that the universe is expanding. Our perception of the size of the universe expanded with it, until in the 1960s we found the observational limit: a distance so far that the light has travelled for about 13-14 billion years. Wikipedia explains this barrier nicely:

In practice, we can see light only from as far back as the time of photon decoupling in the recombination epoch, which is when particles were first able to emit photons that were not quickly re-absorbed by other particles, before which the Universe was filled with a plasma opaque to photons. The collection of points in space at just the right distance so that photons emitted at the time of photon decoupling would be reaching us today form the surface of last scattering, and the photons emitted at the surface of last scattering are the ones we detect today as the cosmic microwave background radiation (CMBR).

Now, you might think that that means the limit of our observable universe is a sphere of diameter 13 billion light-years. However, because space itself has expanded during that time, the objects we are observing from 13 billion years ago are now much farther away, meaning the diameter of the observable universe is almost one million billion billion km.

5) And only very recently (1998) have we realized that the expansion of the universe is accelerating, a prediction which completely alters our view of the universe's fate. Current cosmological thinking has no estimate for the boundary of the universe. Our observable universe might be a tiny bubble in an infinite volume; the new estimate is literally "infinity until further notice".

Each of these five discoveries monumentally changed our understanding of the universe. Each time, the universe becomes monstrously larger than we had previously thought, and all of our assumptions become completely challenged. I have taken the liberty of tabulating the size of the "known universe" along with the date, for demonstration purposes:

date	size of known universe (km)	note
200 BCE	12,800	diameter of the earth
1600	1,400,000,000	size of our solar system
1838	950,000,000,000,000,000	diameter of our galaxy
1924	60,000,000,000,000,000,000	size of our "local group" of galaxies
1960s	1,000,000,000,000,000,000,000,000	size of the observable universe
1998	"literally infinity"	astronomers give up

I observe that the rate of this growth as a function of time is not governed by any reasonable function, but might be considered to be logarithmic starting in 1600, with our known universe expanding by a factor of 10 every 24 years until recently, when astronomers simply gave up. This rate of growth (in understanding) is, I'm sorry, astronomical.

There are still so many unresolved questions about the nature of our universe. So-called "dark matter" is required to explain why galaxies spin the way they do, and it has been detected indirectly, but we still have no idea about its nature. If it exists, there is postulated to be five times as much of it, whatever it is, than "regular" matter. Things become stranger: in order to explain the accelerating expansion of the universe, astronomers and cosmologists posit a "dark energy", an unknown force that would have to have 20 times as much "mass-energy" as observable mass in the universe. Mass-energy is the unit used because, as Einstein showed, energy can be converted into matter, or vice versa. If we converted all the dark energy into regular matter, there would be 20 times as much of it.

To butcher a quote by Socrates, "A wise man understands that he knows nothing." The more we study, the less we seem to understand. Maybe that's just the nature of the universe.

An unqualified summary of alternative energy

Hey guys! I'm no Energician or anything, but I do have some BS degree from this one school in the south, so I'm going to just go ahead and offer my (in)expert opinion on alternative energy.

When you come right down to it, most of our energy sources are solar energy in disguise. Coal, oil, and natural gas were formed when plants stored the sun's energy in their biomass and then decomposed. Hydroelectricity is available when water is flowing downhill, and we force it to turn our turbines; but that water was transported to the top of the hill when it was evaporated by sunlight, and fell back down from the sky. Wind exists on Earth only because of local variations in temperature, caused (for the most part) by sunlight. And, of course, solar panels directly harvest the sun's energy. In fact, the only sources of power I can think of that don't originate from the sun are nuclear power and (arguably) geothermal.

One very interesting energy harvesting scheme is called "Ocean Thermal Energy Conversion". Essentially you have a huge pipe that goes down into the ocean to a depth of about 1,000 m, where the water is colder, about 5 C. At the same time you use water from the surface, which will be around 22 C. The laws of thermodynamics dictate that the heat will flow from hot to cold, but we put our devices in the way so that, like water falling down a hill, the whole process powers our machinations. And they say that the oceans provide a "limitless" supply of cold and hot water (maybe a dangerous idea).

Direct solar energy has a lot of promise. The above map shows the average intensity of sunlight. The blue dots represent the total area required, with current technology, to completely provide the current global demand for electricity. I think the map looks pretty neat.

However, as time wears on, our energy demands will tend to grow exponentially. Some guy made what's called the Kardashev Scale, which classifies how "advanced" a civilization is based on how much energy it can produce. To quote wikipedia, "a Type I civilization has achieved mastery of the resources of its home planet, Type II of its solar system, and Type III of its galaxy." We are estimated to have a rating of 0.72. Looking at the plot, which is on a logarithmic scale, our energy development over time is a straight line, which indicates exponential growth. Extrapolating from the data in just the last 110 years, it will take another 200 years or more to reach a rating of 1. Let's work on that, everybody.

EDIT: So on the Kardashev Scale, a Type 2 civilization will use roughly the energy output of an entire star. Freeman Dyson imagined what is now called a Dyson Sphere, a shell around a star that collects all the energy from that star. Dyson spheres have a few problems, though: If you build a solid shell around the star, then it wouldn't interact gravitationally with the star, and the two would slowly drift apart until they collided. If, instead, you build a swarm of space ships that orbits the star, then occasionally one would block the sun from the other. As you increase the number of spaceships, this happens more and more, until it becomes almost impossible to harvest all the star's energy.

Mutant Atomic Race of Super Men?

Let me start this like any other good article: by raffirming that I'm not a secret nazi racist. Now that's out of the way. So. I was reading an interesting article on bbc which quotes "Evolutionary theorist Oliver Curry of the London School of Economics" when he predicts that

The human race would peak in the year 3000, before a decline due to dependence on technology. People would become choosier about their sexual partners, causing humanity to divide into sub-species.

An interesting concept. First, let's think about how a species could diverge evolutionarily while being in the same geographical place (i. e. all of earth). Let's say you're some kind of squirrel thing. To get food you could either dig up tubers or you could climb up a tree and get some nuts. Let say right now the population has arms that are okay at climbing and at digging. But if they could just evolve thumbs, they might be able to climb a lot better, but no longer be able to dig. Or they could evolve shovelly-hands which would help them dig a lot better, but they wouldn't be able to climb any more. The species might evolve into two, since the child of a shovelly-arm and a thumb-hand would be bad at both things.

Aren't we starting to "decline" already? By that I mean, if all our technology were removed, we would be less fit than a thousand years ago. Our feet can't handle the rough ground. More of us are born with diseases which are merely inconvenient right now, with medical technology, but would be fatal or very bad otherwise. You might argue that we don't do hardly any real stuff now. Our houses are built by human-operated machines. Our food is harvested by human-operated machines from farms. Most of our transportation is by car, plane, or train. Even birth is increasingly being performed through C-Section. Women with poor birthing hips, who in the past would not have been able to pass on their genes, are now fine. I'm not saying there's anything wrong with any of these things, but it does show our increasing reliance on technology.

However, with the increasing research in genomic technology, there are some quiet murmurings about the possibility of, say, making sure your baby doesn't get a certain gene. If you have sickle cell anemia, for example, you might be able to take your haploid cells to a clinic, and have them filter our the ones without that gene. But would parents always select the most "fit" child? That depends on what we mean by fit, exactly. Right now, in American society, one might say that blonde women are more fit, because they're perceived as more attractive. But other women can just dye their hair. But in the wild, blond hair is less fit for most of the earth. Sunny days require a dark sun-reflector, which black hair (and black skin) do pretty well. No, the parents will choose their children to be the most fit in the framework of the anticipated environment.