Dark Flow

Dark Flow

Dark Flow

The known universe is about 27.4 billion light years across. It’s thought that the universe is bigger than that, possibly a lot bigger, but we can’t see farther than 13.7 billion light years in any direction. Our knowable universe is limited by the speed of light and how far it could travel since the Big Bang, 13.7 billion years ago. Since light travels one light year per year, that limits us to a radius of 13.7 billion light years.

That’s pretty big. If it’s all we can see with no way to ever see beyond, who’s to say there is anything else? If we’re to be limited to this, admittedly enormous, bubble of space and time, is there any point in wondering if there’s anything else out there? Of course there is. Even if it’s impossibly out of reach we will reach for it. We humans, as soon as we’re shown our boundaries, will try to see beyond them.

Astronomers think they might have done just that. How do they infer that there is more to the universe than we can see? They do it by detecting its effect on what we can see. Two ways of doing that seem to show positive results. One is the motion of large swaths of galaxies and the other is a peculiar imbalance in the symmetry of space.

The flow of galaxies is called Dark Flow by some, in keeping with other great unknowns such as Dark Matter and Dark Energy. It was found in a survey of galaxy clusters, huge gravitationally bound congregations of hundreds or thousands of galaxies, in an area about two billion light years across. They all appear to be moving in the same direction at about a thousand kilometers per second. The implication of that much matter moving at high speed toward the same point is that there isn’t enough matter in the observable universe to account for the gravitational attraction required. It suggests huge concentrations of matter beyond the known universe drawing our galaxies away.

The peculiar asymmetry, the second effect, is found in the cosmic microwave background(CMB) radiation that fills space. The CMB is the cold, fading glow left over from the extreme heat of the Big Bang. It’s observed more or less evenly spread everywhere, with small fluctuations. In theory even the fluctuations should be evenly distributed, but they’re not. They’re about ten percent more numerous on one side of the sky than the other. This suggests that the observable universe’s structure is affected, distorted or sloped in some way, by other structures much larger than everything we can see.

The “whole” universe, of which our observable bubble is just a small part, would have to be very big. So much bigger that there wouldn’t be room in this article to write out how much bigger. It’s no wonder it affects the part we can observe.

rjb

Posted in Uncategorized | Tagged , , | 6 Comments

Screws

Robertson Screws
I believe I’m coming out of my solsticial somnolence now, so it must be time to make a post. It might as well be about something useful.

Some of the first things humans made were likely shelters. Originally they were just fitted together as best as could be. The boughs and fronds, first used for shelter right where they grew, later collected and used elsewhere, had their ways of fitting together. At some point other materials started to be used. Sticks, stones, lengths of vine or root, used as braces, shims and connectors. Then it was possible to construct a shelter that was more than a lean-to, though its form was still largely dictated by the materials used.

When we began to imagine what the dwelling should look like before building it, then we needed to be able to fasten the pieces together in arbitrary ways. And we needed to get systematic about it, instead of always having to improvise. Notches in sticks and logs would help them lock together. They would continue to be tied and notched for ages, then pegs would join the toolkit. It’s known that woodworkers in ancient Egypt used pegs to fasten wood together. It meant drilling a hole with a bow drill, like an archer’s bow with its string wrapped around the drill bit. Pulling it from side to side caused the string to turn the bit.

The Romans improved on that with the auger. They also invented forged iron nails, or at least took credit for it. Until the late seventeen hundreds, all nails were made by hand – forged, beaten or cut to shape. That’s also about the time the metal screw became commonplace, when machines were being developed that could mass produce them. Handmade metal screws first appeared in Europe three hundred years earlier, and wooden ones were used by the ancient Greeks.

robertsonTo turn in a screw takes a screwdriver. Modern screws have specially designed heads to fit a specific type of tool. The most common are the slot, the x-shaped Phillips, the hexagonal Allen and the square Robertson. The best of the bunch is the Robertson. The screw and driver were invented in 1908 by Canadian P.L. Robertson. He got a patent in 1909, but that didn’t help when an English licensee stole his rights. It cost him a lot of trouble and money to get them back and he would never license their production again, even to Henry Ford.

Now Robertson screws are rare in the UK and barely at 10% of the screw market in the US. But in Canada they account for 85% of screws sold.

rjb

Posted in Uncategorized | Tagged , | 10 Comments

Solstice

Newgrange, Ireland – Credit TJP Finn – CC-BY-SA

Thud, son of Thog, stood on The Rock watching for the Sun to go down. Behind him burned the fire, which he had kept going for the last week. It was working just as his father said it would. Although the Sun set further south each day, its retreat was slowing down. It was being drawn back by fire, a spirit of its own kind. Tonight, if Thud was worthy of the trust passed on to him by Thog and held by the tribe, the Sun would reach its lowest point in the southern sky, pause, and begin its long journey back.

Thud gave The Rock a sharp rap with the butt of his staff, as Thog had done before him. The purpose was to ensure that the Sun paid attention and remembered to come back. It couldn’t be allowed to fall asleep and drop over the edge or it might never return. Besides, it was cold and he needed to be doing something. His job wasn’t over until the Sun rose in the morning. He needed to be certain that the ritual worked.

No one knows for sure how long people have been performing rituals at the winter solstice, but we know for sure that many have and many still do. Maybe not as far back as Thud and his father Thog, but certainly at least 5,000 years.

In Ireland there is a stone structure called Newgrange which has been dated to more than 5,000 years before present. This megalith – literally, big stone thing – is built in a circle, like its famous English cousin, Stonehenge. Both of them are built so as to mark the position of the Sun precisely at winter solstice. Newgrange is a few centuries older than Stonehenge, but they served much the same purpose: to provide a place where people could monitor and probably celebrate the passing of the solstice.

Update: Newgrange is also a burial site. The body there presumably belonged to a person of privilege, nobility of some kind. As was apparently not uncommon amongst those people, it is also the product of an incestuous union, either brother and sister or parent and child. Read about it in this Science News article.

There’s another one in Scotland called Maeshowe. There are hundreds of megaliths all over Europe. All of them mark the solstices or the equinoxes or both. Similar structures exist in the Middle East, Asia, Africa and the Americas. The ancestors of the Pueblo people in New Mexico, the Chacoans, built an array of structures across kilometers of land. Not only did the individual parts have seasonal and astronomical features, the whole extended design did, too.

So far, all the archeological evidence for seasonal and astronomical rites is in the neolithic era. Neolithic refers to the latest part of the stone age. It’s when people began farming, domesticated animals for work and to eat and made great advances in pottery and textiles. The growth of settlements and a small population explosion lent themselves to the development of elaborate societies. They also provided the labor necessary to build large stone structures that weren’t strictly required for daily life.

That wasn’t possible in Thud’s time. It was all he could do to get enough wood to keep the fire going. And nobody was going to drag big stones around for him, as much as they might respect him and the memory of Thog. So we don’t have any megalithic evidence of his labors. Hunter-gatherers don’t leave as much of a mark on the ground as farmers do. But the return of the Sun is equally important to Thud and his tribe as it will be to their descendants living in towns. So he raps The Rock again and hunkers down in his furs, ready to stand vigil on the longest night of the year.

rjb

Posted in Uncategorized | Tagged , , | 4 Comments