Topic Tuesday #53 2013/07/23 - "Climate Cycles"

If we are to be skeptical and honest with ourselves about the world we live in, we need facts. LOTS of facts.
I am going to highlight some facts that are not often brought to the table when discussing climate change. I am only going to present the items. In general this is all from the field of applied mathematics and earth sciences known as Geodesy.

Earth's Path

The earth's orbit is not circular. It is elliptical, an oval.
We are closest to the Sun around January at a distance of 147,098,290 kilometres (91,402,640 mi) [0.98329134 AU] and farthest from the Sun around July at 152,098,232 kilometres (94,509,460 mi) [1.01671388 AU] Nearly 3 million miles difference.

The reason we have seasons is due to the Earth's axial tilt. The Earth wobbles a little. Over 41,000 years, the tilt fluctuates from 22 to 24.4. The average tilt today is about 23.5 degrees, roughly in the middle of a diminishing tilt trend. The more perpendicular the planet to the Sun, the more uniform the heating, and the higher the average temperatures. Based on the current figures, the Earth will be at 22.6 degrees tilt in 8,800 years.

Rotation (green), precession (blue) and nutation in obliquity (red)

The tilt undergoes an irregular motion known as nutation with a period of 18.6 years.
The orientation (rather than the angle)of the axis changes over time following a circle with a cycle of 25,800 years. This is the determining factor between sidereal and tropical years.
These changes are known as Axial precession.

The poles also migrate (Polar Motion). The collective term for all the factors in its movement is "quasiperiodic motion". There are several periodic affects. A circular motion occurs annually while others have longer periods, one of which is the Chandler wobble with a 14 year cycle but a period of 435 days.
The rotational velocity along the axis is variable. The phenomenon is known as the length-of-day variation. Think of an ice skater, spinning with their arms in tight and then to stop they put their arms out. As the earth bulges out in the middle more, be it from continental drift or from glacier melt raising the sea level, the planet will spin slower, increasing the day.

Temporal Changes - Surface changes, and things over time.

Plate Tectonics
Episodic fault-line events.
Tidal shifts
Postglacial land uplift
Temperature cycles: Ice age

Human interaction

Material extraction
Material relocation
Teraforming
Directed phase change of material. Fuel consumption

There are thousands, if not millions, of data points that go into climate science, and I don't want to blowup a single thread with all of them. Some of them, nay, most of them are deserving of a day in the sun and I will revisit them in time. Knowledge of your current situation is not enough to determine any kind of model for the future. We must study the rich past.
I hope that this has opened your eyes a little to the nature of our home planet. It is ever changing. Dynamic. Chaotic. Fragile- but only for us. It will go on spinning. The thing to remember is perspective.

"Let's be clear. The planet is not in jeopardy. We are in jeopardy. We haven't got the power to destroy the planet - or to save it. But we might have the power to save ourselves." - Ian Malcom - Jurassic Park

Topic Tuesday #49 2013/06/25 - "The Middle Mind"

I was chatting with an older Hungarian immigrant about cosmology, and he started to get visibly uncomfortable. I recognized this, and it redirected the conversation. We were outside of his comfort zone. This is a reasonable thing to have happen. Thinking about very big things, and very small things, can make your head hurt. These are realms that do not make sense to us, as we are of the middle. To our middle oriented mind, things appear smooth, water appears as a fluid, the sky appears blue, and pin points of light in the night sky appear as single stars.

If we venture to the level of insects the surface tension of a drop of water is as solid, and likely very bizarre, in comparison to soil or plant material. Further into the microscopic, we find that nothing is very smooth, not even our beloved nonstick pan coatings. If we go further still, the very components of what we are made of appear and behave in ways that are completely counter intuitive to our observable reality. The fundamental building blocks of even atoms has yet more structure.

Everything, everywhere, is made up of 12 building blocks (6 quarks and 6 leptons) and 4 force carriers that hold them together and 'guide' their interaction with each other. This may change as the standard model adjusts for new discoveries, but right now, it's the best we have, and it works (albeit in not quite as elegant a way as would be preferred).

Now, up to bigger things. It is hard for us to comprehend the immense nature of the world around us. We may stare at a desk globe and see all the geopolitical dividing lines and vast expanses of blue, but that is only a pale resemblance of what this planet is. With the circumference of the earth, at the equator, being 24,901.55 miles (40,075.16 kilometers) [more or less...] the farthest away you can be from anyone of your fellow human beings is around 12,450 miles, 8,000 or so if you could go through the rock beneath you.
While talking about going through things, let's consider the atmosphere. Easy for us to move through, yet it has a density. There are just as many molecules in a since centimeter of air as there are in a centimeter cube of titanium. Everything around you has something in it. We breath air to consume the nutrients it provides. It is colorless. Or is it? The sky is blue, but the air in the room around us is clear, what gives? Perspective. A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the Sun, more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight. From space, we see our oceans reflecting blue light, giving our world its pale blue appearance.

The structure of the world is amazingly large compared to ourselves. However, Earth isn't that big, all things considered. When we examine our bright neighbor, the Sun, is roughly 109 times the size of the Earth; 865,374 mi (1,392,684 km) in diameter. It is so massive that it makes up 99.86% of the total mass of the Solar System.

The Sun is also a relatively small main sequence star. There are others in the sky that are much much larger and could swallow up our star like the Sun could gobble up any of our neighbor planets.
If we keep looking outward with a modest telescope we find that the pin holes of light in our sky is almost never a single star but a cluster of hundreds. Get curious enough and we up the magnification, and we find that those may well be more galaxies. When you look up, you see trillions of stars, you just can't tell. You are also time traveling... sort of. These points of light are so far away, that in the time it has taken for that glimmer of light to reach you, the source may no longer be there. Distances are the trickiest part of cosmology. Just consider the fastest thing in the universe, light, still takes 8 minutes to make the trip from the Sun to the Earth.

These are just numbers... They are unnervingly difficult to relate in your head, since we are of the middle realm of reality. (Maybe not even the middle, but that is my artistic license.) All we have is the math to even try and comprehend the vastness of the universe and the infinitesimally small nature of the things that it is made of. As Richard Feynman said, "If anyone tell you they understand quantum mechanics, they don't understand quantum mechanics." It's easy to say, "Don't be afraid of the vast unknown. Don't let it make you terribly uncomfortable." The truth is we are not built to interact with these scales. We can only do so with tools and not everyone swings a hammer with the same skill. If you feel dizzied by the world around you, be it large or small, take heart. You are not alone. For all those of the middle mind, water is wet, glass is smooth, and the sky - a wonder.