Aaaand it's decided. No more Astronomy. Possibly ever. Because, well... Ellie wasn't sure her brain was the same consistency it was when she walked in. She liked the solidity of it.

It was quickly becoming clear to Kurumi that Astronomy was not going to be one of her better subjects and she was not very happy about that. Her perfect track record ruined?! NEVER! Kurumi frantically wrote down notes on her parchment. Maybe she should have drank a potion to make her understand the subject more...was there such a thing?

Freya raised her eyebrow. Steady State Theory and Big Band model? She thought a moment before answering the question. She raised her hand before saying "Umm..The Steady State Theory said that the galaxies move farther away with a specific and orderly manner. while the Big Bang Model The Big Bang said that the universe comes from a powerful explosion that tossed their bodies in every direction and slow the body lan forming galaxies.." she took a few breath before continue answering the second question "In the beginning The Steady State Theory believed that the universe is constant unchanged, has no beginning and no end but some of the scientist doubt this theory from the observation of the phenomenon of redshift which show that the universe was indeed expanding. But the supporter of The Steady State Theory revised it and said that although the universe expands, but the density remains balanced with the creation of new matter." she sighed. She wasn't very sure with her answer about redshift.

"The Steady State Theroy or the Infinte Universe theroy was an alternative to the Big Bang theroy. In steady state views, new matter is continuously created as the universe expands." she said she loved Astronomy "The Big Bang was an event which led to the formation of the universe, according to the prevailing cosmological theory of the universe's early development. According to the Big Bang model, the universe, originally in an extremely hot and dense state that expanded rapidly, has since cooled by expanding to the present diluted state, and continues to expand today."

Hmm. Rose thought really hard for a couple minutes, racking her brains for any recollection of this Big Bang Theory stuff. She thought of the textbook, and reached for it, but decided that would be cheating. In other words; not good. She wasn't going to CHEAT. Nope. She thought for another minute or so, going over possible answers in her head. And then it came to her in flash. She remembered! Yay! She stuck her hand in the air with a smile.

'Proffessor, the Big Bang Theory, which is currently the most accepted one, implies that the universe exploded from a single point at some time about 13 or so billion years ago. The Steady-State Theory says that... um... whatever-it-is, is it matter? Anyway, that stuff is always being created in empty space as the universe gets bigger, and so it has no beginning and no end. I think' she said happily, glad to finally know the answer to one of these questions. She felt happyyyy!

Fee raised her hand as she spoke up once again.
"Steady State Theory proposes that matter is being continuously created. That means the univers is able to never stop expanding. "

She took a deep breath as she continued talking.

"The Big Bang Theory is the most accepted theory at the moment and says that the universe was created by exploding from a single point."

Humdumdedummm?

"Well.. in cosmology, the Steady State theory (also known as the Infinite Universe theory or continuous creation) is a model developed in 1948 by Fred Hoyle, Thomas Gold, Hermann Bondi and others as an alternative to the Big Bang theory (known, usually, as the standard cosmological model). In steady state views, new matter is continuously created as the universe expands, so that the perfect cosmological principle is adhered to." But how did that differ from the Big Bang?
"But according to the Big Bang model, the universe, was in a extremely hot and dense state that expanded rapidly, has since cooled and thus expanded to the present state which continues to expand today. The original state of the universe is thought to have existed around 13 billion years ago, which is often thought to be around the time the Big Bang occurred."

Chyeah?

"Wasn't the big Bang theory the moment a certin star got too hot, exploded and it's gas and dust created the universe?"Adam said and asked at the same time- he wasn't too sure of his answer but it was better than nothing.

After the Professor said his answer was correct Riley put his quill to his parchment, ready to write down the information that the Professor was about to give them but....

.............................

THOSE. WERE. SOME. BIG. WORDS. Riley just stared at the man infront of the class and could pratically hear his brain sizzling. Who could even understand any of that. He just blinked at the man for practically a whole three minutes before he shook his head, wiped the bit of drool in the corner of his mouth and then tried to make sense of at least one thing he had said.

"Well.....Professor, perhaps the Big Bang Theory happened much quicker and less organized as the Steady theory?" he said, hoping that he even answered the right question. What did this Professor have against Riley Sinclair, he obviously was trying to call him out on his intelligence.

Sidney raises her hand. "The Steady State Theory says the universe does not change over time in a major way. It has existed for millimillennium the way it does now and will continue to do so into the future. On the other hand, the Big Bang Theory says over 12 to 14 billion years ago the universe was much smaller. It was in a hot dense state back then. Over time the universe has expanded and cooled down to the larger size it is today."

"For the Steady State Theory to work, new matter must be created continually using hydrogen to keep the average density of matter equal over time."

"The Steady State Theory suggests that the universe is expanding, but not changing. A certain element...Hydrogen, I think, is used to keep the universe at at steady state. The Big Bang theory meanwhile claims that the universe was once a hot and dense object that exploded....or something of that matter..." Cass said, uncertain of her answer

"Entropy is a concept we will talk more about in the future," Risu said. "It certainly does apply where, for example, the future fate of the Universe is concerned."

Risu smiled. "Good thinking, but both the Steady State and Big Bang models are sound when it comes to the first law of thermodynamics." He eyed the student curiously. "I don't know how much you know about this, of course, so perhaps this will all sound too complicated, but the amount of new matter that the Steady State theory requires is, as you say, very, very low on average. Low enough to be accounted for by, for example, the application of the uncertainty principle."

He saw other students raising their hands, but he wanted to finish first. "As far as the Big Bang model goes, there are a number of explanations. Thermodynamics is a tricky business - the first law only applies to closed systems, and it is certainly possible that the Universe is not a closed system. Think multiverse. You can get less far-fetched than that, of course - quantum uncertainties of the kind I mentioned equally apply to the early Universe as they do to the Steady State theory because of its tiny size. You can only get so far with Einsteinian relativity since it breaks down at the moment of the Big Bang, but if you only argue with relativity, then all energy in the Universe came into existence with the Big Bang, and has stayed the same ever since."

He paused briefly. "Would you like me to expand on that... no pun intended?"

"You must be thinking about a nova or supernova," Risu said kindly. "The Big Bang is something slightly different - but supernovae, while we're at it, are very important as well. Many of the most important elements in the Universe, for example the nitrogen in your body, have come from successive explosions of stars."

"Much quicker, certainly, since we are only really talking about a single moment in time, but the question of how organised the early Universe was is an interesting one. Your classmate over there mentioned entropy, the order or disorder of a system. It's quite possible that the Universe started out in perfect order. This is what our understanding of entropy seems to imply."

Risu wandered back and forth once more. "As you all correctly pointed out, the Steady State theory requires the continuous creation of new matter. This, however," he said, raising a finger, "is not the biggest problem with it. As I explained to Mr Marius here, the amount of matter needed is fairly small and explained easily enough by the application of quantum theory."

He stopped and leaned against his desk. "No, the evidence in favour of the Big Bang model was discovered in the 1960s. For anyone who remembers, we briefly talked about this last term. What I mean will become apparent in a moment. Back to the story. Two physicists by the names of Penzias and Wilson, working on a radio wave detector, found their data full of a faint noise neither of them could account for. This noise was coming from all directions of the sky. Day and night. It was not fluctuating, which is to say changing, in strength either. It had to be from a source outside the Milky Way..." he thought he sounded very mysterious now, and paused for effect, "and when a friend of Penzias' told him about a research paper by another astrophysicist hypothesising about left-over radiation from the very early Universe, he and Wilson realised that they had inadvertently stumbled across this very radiation!"

Risu nodded thoughtfully. "This radiation, which we call the cosmic microwave background, or CMB for short, is something like the afterglow of the Big Bang. After 13 billion years, it has cooled down to only a few degrees above absolute zero, but if you wind back the clock, you end up with radiation that has been on the move through the Universe since less than four hundred thousand years after the Big Bang. The Big Bang model predicted this radiation, and its discovery thoroughly vindicated the model to the point that it is now considered the best explanation of how the Universe began."

Whuuuu?

Eli blinked twice, hard. This class was making his brain strain, for certain. He listened, trying to take it all in, but one thing utterly confused him. He slowly raised his hand.

"Perfesser? What is a 'radio wave detector'? And... radiation, what's that?"

Radiation. CMB. Tiff'd heard of all that. Her father used to talk about it to his friends when she was around. She grinned, glad she'd finally understood something about the Hubble person she didn't know much about. She raised her hand, "Is the CMB radiation harmful?" She asked. She knew it couldn't really be, only being slightly above zero, but she wanted to make sure.

................

Huh? Oh goodness what had she just missed. The Blonde snapped back into attention just in time to catch some information on radiation and the mention of the theory of the bIg Bang. Oops. It appeared she had just missed a load of big long words strung together that sounded incredibly impressive.

Guess she'd have to write a LOT of notes from now on. The older student listened to the others asking question and rolled her eyes at one of Cammys reply. Seemed SOMEONE had turned into a swot.

*Snort*

Emmaleigh gave a small smile. Apparently her guess at the last question had been at least partially correct. And then Professor Risu started to explain things, and the poor little first year was SO confused. When were they going to be able to look at the stars? This radiation stuff confused her, so she raised her hand and asked, "Um, how do they know the s-signal if from radiation?" After all, to her mind there was any number of things it could have been. Like, "How do we know its not the slow-time envelope around the planet Krikkit giving off that signal, or the, the." Her hand shot to her mouth, and her cheeks turned fire red. Did she really just say that out loud?

Pam listened carefully and jotted down important notes. She was so excited!! She couldn't wait to tell her dad all these new things she'd learn!

Whoa. Now Jenny just entered into a whole new world again. She has never heard of a radio wave detector or CMB before; it sounds scary. Quickly she jotted some notes down so that she wouldn't forget. Then a question popped into her mind. Oh! Her hand shot straight into the air. "Professor, does that mean we can feel the CMB radiation too?"

Whoah. SO Cameron had been a tad confused.. but this was soooooo way out of her hemisphere that she was flailing at the words used.

"So... this CMB stuffs.. is it good or bad for us?" Could muggles do stuff with it? And she meant muggles. THEY were usually the ones that took potentially good stuff and made bad stuff from it.

blink blink blink

What happened to studying about constellations and planets? All this was way over Kurumi's head and her frustration was beginning to show on her face as her quill moved furiously across the parchment. "Professor, with proper study of this radiation, could we estimate the exact date and time that the universe was created? What happens if the radiation runs out?"

Those sounded like intelligent and relevant questions...right?

Cass stared at the professor. What did she say? Then with a sigh, she massaged her temples tiredly and stared blankly, oh dear, this is too much for her 11 year old brain...But then, a question popped into her mind, so she raised her hand and asked "Professor, you said that the big bang is sort of an explosion of some kind that formed the universe. I was just wondering, where did it start and if it has cooled down, how is it that it's still expanding?"

Thoroughly vindicated...

Keefer still didn't think it was thoroughly vindicated. After all, it was still called the Big Bang THEORY. After all, where had all the matter come from initially? He scribbled in his notebook.

Underlining these words, he decided to think on this later. Now was not the time to get into that discussion.

"Oh, forgive me if I'm moving too fast." Risu smiled apologetically. "Well, radiation is, very simply put, moving particles or waves. That's all, really. Radio waves are technically electromagnetic radiation, which is to say waves with an electric and magnetic field. If you want to get even more technical, their wavelengths - which we discussed earlier - are longer than infrared. There's a particular importance to astronomy as radio telescopes allow us to 'see', if you will, what regular, optical telescopes can't."

Risu shook his head. "Oh, no. It is so weak now that we need very sophisticated instruments to even measure it. And the Earth's atmosphere does a wonderful job of blocking radiation of all kinds and bouncing it back into space."

Risu opened and shut his mouth a few times. Since when were first-year students into classical literature like that? "Erm... Well," he said with a slight smile - a little confused too - "as I explained to your classmate over there, radiation is simply particles or waves moving through a medium or, in this case, empty space. Even if we didn't know it was the leftover Big Bang radiation, it would still be radiation. As it is, the proposed explanation is the only one that satisfies the observations - that this radiation is coming at us from all sides, unchanging, very steadily, and so forth."

He waved a hand and walked slowly around his desk. "As for your second, er, suggestion..." He opened a top drawer and withdrew a rather dishevelled-looking purple towel. "I'm prepared." He grinned brightly and dropped the towel back into the drawer.

With a creak, the drawer clicked shut again. "No, we cannot," Risu said, leaving his desk and resuming his place in front of the class. "The CMB is very weak radiation of a long wavelength, and while our bodies have evolved to detect certain kinds of radiation very well," he scratched the corner of his eye, "light, for example, "we aren't very good at other kinds. So we need specially assembled satellites and telescopes to catch this radiation for us."

Risu shrugged. "I wouldn't say it's anything for us, Miss Caddock. It just is. If you mean scientifically, of course, then it certainly is good for us in the sense that it's a very important discovery that helped us understand more about the history of our cosmos."

"Very good questions," Risu said, nodding. "There are a number of ways to determine the age of the Universe - which I can go through quickly if you want, but which are fairly technical - some of them relying on theoretical models, some of them on measurements of the oldest detectable structures, such as very long-lived stars." He paused briefly. "Or, of course, a combination of those. The most accurate extrapolations put the Universe at an age of about 13.7 billion years."

Risu wandered. "The CMB is thought to be about 400,000 years younger than that. Until that time, the early Universe was full of a burning hot plasma. It was so dense that it was actually opaque, which is to say, impervious to light. The CMB radiation is made up of a certain kind of particle that was able to decouple from this dense plasma once it had cooled down enough. This happened, as I said, about 400,000 years after the Big Bang. From that point on, the Universe became transparent."

He paused briefly. "As far as your second question goes... Intriguing idea. The radiation can never really 'run out', but it is certainly possible that, as the Universe continues to expand, stretching the wavelength of the CMB further and decreasing its energy and temperature even more, the radiation might become undetectable."

OOC: On the meaning of theory in a scientific context, you should check out the first lesson of last term where we talked about the importance of theories in science. :> 1 2 3

"We-ell..." Risu said slowly. "All questions of time and space in the very early Universe are difficult to understand. In a sense, the Big Bang was everywhere because prior to that, there was no space (if you leave out ideas of a multiverse for a moment) for the where in your question to be. Space itself came into existence with the Big Bang expansion." He gave the girl a questioning look. "Or are you talking about the centre of the Universe today?"

He cleared his throat. Lots of talking... "Well, there are two reasons for the expansion. One is very well-known, one science is still unclear about. The known reason for the continued expansion is simple inertia." He shrugged. "The Universe is continuing to expand because it did so in the past, and there is not enough total gravity to stop and reverse that expansion... The second reason, however, has not been explored yet. We only know that there has to be something else that feeds this expansion. Dark energy, perhaps?"

He glanced at his desk where a small watch was ticking away. "We are nearly out of time, if I see this correctly. We didn't quite get through everything I wanted to, but that's quite alright. Are there more questions before we continue?"

"Oh god, oh go, oh god, I'm going to get yelled at," Emmaleigh thought as the professor kinda stared at her while he did something weird with his mouth. But she was relieved when he seemed to skip that last comment and explain her actually question, with a smile even. "So its not some odd signal that they don't know what it is. They knew that it was definitely radiation, but they just didn't know the source of it?" Em asked.

Oh, know, he as going to bring up her stupid comment about Krikket! "Don't Panic. Em. Don't Panic," she quoted her mantra over and over in her head. OK, so it never seemed to work. She was panicking, that is until she saw Professor Antares pull a towel out of his desk. She turned goggle-eyed in wonder. She grinned at him. "You know where you towel is!" she said maybe a little too excitedly. "I, I have mine," she said as she pulled her largish green bath towel out from her bag on the floor. She carried it with her always, along with food, a first-aid kit, and her dragon hide gloves.

Err, questions? no, Em shook her head in answer the professor's question.

Cameron nodded, "Thanks Professor." That made sense.

Oooh! Continuing. She grinned and nodded. "Sure, sir. Let's continue.." They didn't have much time left, did they?