Notes: The Sun

Part of what makes science kinda great is that it's constantly being worked on and improved, tempered in the forges of experimentation. Astronomy is one of those odd sciences, in that we can't exactly go out and do that. Going up to stars and measuring stuff poses certain logistical problems. So instead what we do is look at stuff. A whole lot. And would you believe that looking at stuff is really gorram interesting? Think about it, it's one of the oldest sciences and it still has a pretty massive presence. Something about the vast expanse of unknown is still sparking the old human curiosity...thing.

Ok, so let's explore what we can observe with just our naked eyes. I mean let's face it, not everyone has an awesome 8" reflective equatorial telescope. And while that is a shame, it's not the end of the world.

For starters if you look up during the day, and are not in Wales, then you may see an incredibly bright thing. We call this The Sun, or Sol, if you're the kind of person who calls the Earth Terra in casual conversation. If you give it a while, you may also notice that the sun takes a path across, and further careful observation reveals that the path the sun takes is a little different every day. In fact this happens all year around, the path being a little bit shorter each day at this time of year until the 23rd of December, or the Winter Solstice.

Source

Side note: You may notice that that is a fairly familiar date. That is no coincidence. Fun fact, the Bible doesn't actually give a specific date for Jesus' birth. Thing is that at their most expansionist, the Roman Catholics decided they needed a date to celebrate the event of their saviour's birth, and they also wanted to get rid of the pagan celebrations of the solstice. And as my lecturer so put it, you don't get popular by cancelling parties. So, the logical thing to do was to co-opt the existing "unholy" celebrations for their own righteous and godly one.

Ok, so that's one glowy orb seen, how about the other? During the night, when they sky is arguably at it's most stunning we have the bright white disk we call the Moon, and that's what we shall cover next time.

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Notes: Thermodynamics

Posts with the heading Notes:[subject] are more for my benefit than yours, just a little something to reinforce what I've already written down. There is only so much I can do to make dynamics a source of humour, for instance. But by all means read on, and I'll certainly do my best to spice things up a little.

Kicking things off with a bit of basic classical mechanics. This is the part that deals with the energy transfer of stuff on the macroscopic scale, that is to say, things we can measure easily enough in a lab. Key word in this area is systems.

A system has been defined for me as a collection of matter in a boundary, though truthfully I prefer Wikipedia's disambiguation page's suggestion "the portion of the physical universe chosen for analysis". It makes it sound like we are undertaking something fairly special, selecting a single part of the entire universe to study and observe, when in fact we are just considering energy transfer in engines and what not.

There are, generally speaking, 3 types of system; we have open systems, where matter can cross the boundary, closed systems, where matter cannot cross the boundary, and isolated systems, where both energy and matter are unable to be exchanged.

Generally speaking CT deals with systems in thermal equilibrium.

Extensive and Intensive properties

Extensive depends on amount of matter in a system
Intensive does not.

Well that was easy.

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