Cosmology: Large Scale Structures, 2 December 2013!NEWS: Comet ISON evaporated. !1.This was one of the things astronomers said could happen to the comet!A.The event was handled by the press fairly well this time. The press usually B.publishes the opinions of astronomers who promise the comet will appear, which can lead to a backlash when it doesn't. All current astronomers said that Comet ISON may or may not appear, so the press had no choice to publish that.!Cosmology deals with the origin and evolution of the entire universe. !2.This unit will start with the structure of the entire universe, and then go A.through several theories, hypotheses, and wondering about the universe's evolution. !The universe is everything that exists. We do not know about anything B.outside of the universe. !Philosophers cannot claim there are multiple universes because if they a.know about these other universes, they are technically inside the universe. !Science may redefine this word in the future. !b.The universe is really big.!3.With today's technology, astronomers have seen light from 13.7 billion light A.years away. !From this, they calculate the universe's age to be around 13.7 billion a.years.!A light year is the distance that light crosses at the speed of light in a year's B.time. It is about ten trillion kilometers. !The universe is a little bit more than 10^10 light years.!C.For comparison, galaxies are around 10^21 meters, but the universe is a.about 10^25 meters.!The galaxies within 30 million lightyears of us are almost all in the direction of 4.the virgo constellation. !Our local group of about 30 galaxies (including dwarf ellipticals, dwarf A.irregulars, and three spirals) is about 3 million lightyears across. !About 55-70 million lightyears in one direction is the virgo cluster of B.galaxies. !It lies beyond the stars of the constellation virgo, which is how it got its a.name.!It is the biggest cluster of galaxies within hundreds of millions of b.lightyears from here. !It is only 1 of thousands of clusters of galaxies in the virgo super cluster c.(which is even farther away).!The virgo super cluster is the biggest structure for hundreds of 1.millions of lightyears.!The milky way galaxy is right on the edge of this cluster. !A.There is only a smattering of galaxies in the other directions. !C.Faint fuzzy nothings:!5.Among clusters of large, bright galaxies you can also discern small blotches A.of light. These are faint galaxies. !Once in a while, this is another galaxy in the background. !a.Most of the time, these are dwarf galaxies in the cluster you are looking b.at. !They are nicknamed "faint fuzzy nothings"(FFNs) by Northern c.Californian astronomers. !Hundreds of "faint fuzzy nothings" are found in all pictures of brighter, more B.noticeable objects. For example: !Stefan's Quintet!a.These are five stars which Stefan thought were associated with each 1.other. Now, astronomers think that only 4 stars are associated, and the fifth is in the foreground. !A cluster of 5 interacting galaxies.!b.The gravity of these galaxies distort each other, so they are patchy 1.and asymmetrical. !A galaxy cluster dominated by giant ellipticals. !c.These ellipticals are probably the result of mergers. !1.Virgo cluster. !d.There is a giant elliptical called M87 at the center of the virgo cluster. !1.It might weigh as much as a trillion suns. !A.It is surrounded by an area of gas which is hot enough to emit x B.rays.!This gas wraps a few other galaxies in with it, which contributes a.to its heat.!There is a supermassive black hole at the core of M87 that is C.actively feeding and emitting jets. !The coma cluster. !e.This cluster is in the direction of the coma constellation.!1.At teh center of this cluster, there is a giant elliptical galaxy 2.enshrouded in hot, x ray emitting gas. !A cluster of galaxies beyond the constellation Hercules. !f.The better the telescope, the more FFNs are visible. !C.To the unaided eye, about 5 FFNs are visible. A couple of these are a.galaxies. !With binoculars, you can see detail on those 5 blotches and more FFNs b.in the background. !Telescopes will allow you to see detail on hundreds of those FFNs, but c.there will be thousands in the background. !So on, until the best telescopes reveal billions of FFNs. !d.At every level of astronomy from amateur to professional, there are e.many FFNs which are each a galaxy containing billions of stars. !FFNs are common, but ignored.!D.They have the same fate as red dwarf stars, dwarf elliptical galaxies, and a.L6 chondrites. !L6 chondrites are called ordinary chondrites because they are so 1.common. !It is impossible to get a grant to study them.!A.Science has therefore not learned much about them in the last a.years, though they are abundant and cheap to study. !This is a phenomena that occurs in whatever subject you become a b.specialist in.!Birding: LBBs, little brown birds!1.Little brown birds are not distinctive or interesting, so A.birdwatchers call them LBBs instead of identifying them. !Mycology: LBMs, little brown mushrooms!2.These mushrooms are common, but not not gaudy or poisonous. !A.Prospecting: LGR, little grey rocks. !3.Wild Flowers: DYCs, darn yellow composites!4.These flowers look like daisies or dandelions. !A.They are not important to wild flower experts, so they are logged B.with a derogatory name.!Achaeologists have a similar phenomena, but no name for it. They are 5.indifferent to shards of pottery that are not from the edge of a pot and do not have a decoration. !Nothing can be learned from these shards. !A.Entomology (study of insects): midges!6.Coin collecting: copper coins!7.Stamp collecting: definitives!8.Antique book collecting: text books!9.Common, but of no value since the information in them is out A.dated.!Literature: Science fiction!10.These objects provide great research opportunities for someone looking c.to get a few papers published: !If you start examining these objects, you will have a whole field all to 1.yourself. !Since the objects are ignored because of fashion that persists over 2.decades, it is likely that new inspection will reveal something interesting. !It is cheap to get the samples to study. !3.You can become the go to person on the subject if it turns out to be 4.interesting. !Though FFNs are not bright or beautiful, it is important to pay attention d.to them.!A few clusters have arcs of light (lensing arcs) around their edges: !6.When this was first spotted it was though to be