Ohhh pretty space picture, Patroclus thought to himself.

Raising his hand, he suggested a possible answer, "Sir could the dust be the remnants of meteors and comets, or even gases and space matter left over from the Bing Bang, being drawn to each other by gravitational pulls."
a word kept popping in ando ut of his head, he was unsure whether or not it was right, but he was going to suggest it anyway, "Sir is the correct name of this dust clouds, Nebulas?"

Zane looked at the pictures and timidly raised his hand, "Is it because of the pull of gravity by the planets and stars?"

Gold raised a hand. "I think those might be interstellar concentrations of dust and ionized gases, especially hydrogen and helium, sir," she said. "Usually most prominent within the spiral arms, of a galaxy. In that case, they could be flung away because of the fall of interstellar gases under the influence of gravity; or because of a stellar explosion like a supernova." Known for its production of celestial 'bodies.'

She paused, and then said, "I know we have dust clouds known as 'Bok globules' by the Milky Way, sir," she said. "Dark knot-like, gaseous structures of dust, dependent on energy from a nebula. I was wondering, if they could have anything to do with these dust clouds?"

"Very good! You're correct," Risu said with a nod.

"It is a cloud, that's right, but," Risu corrected with a slight smile, "there is of course no 'air' for the cloud to be suspended in."

He went to point to the next student whose hand was raised, then, before the girl could speak, turned quickly to Alex. "And - excuse me, Miss Greenwell, you can come in in a second - before I say anything imprecise, these clouds are not suspended in any meaningful way of the term either. As everything else in our galaxy, they are orbiting the core due to grav-... " He paused. "You look like you have something to say about that, Miss Greenwell. Go ahead."

Risu nodded. He was doing a whole lot of nodding again, actually - his students were smart. "Planets do not play much of a role on the galactic scale, they are much too small for that, but stars are. And do."

"Correct on the second account, not completely on the first," Risu said after listening to the Head Boy's answer. "Remember, this is the entire galaxy we are looking at. These clouds extend several thousand light-years from the plane, far beyond the reach of any comet."

Risu cocked his head, smiling slightly. "At this scale, everything in space is controlled by gravity."

"There is one element in this image that's left over from the Big Bang," Risu said, "but the gas clouds are not that element. We will get to that in a moment because it is, in fact, the reason why this picture was taken, but for now, focusing on the clouds, you are correct with," he added, "the caveat I discussed with Mr Potter previously. "When we speak of dust, we do mean dust, Mr Hudson. Tiny particles. Nothing as big as chunks of comet. Dust and ionised gas."

Risu nodded slowly. "The general shape certainly is, although I would say that looking at the galaxy as a whole, the most important gravitational factor is the black hole in its centre. These clouds are not being pulled, however, they are being pushed. Flung out of the galaxy."

Risu's eyes lit up. Gold Laksh's answers were worth every point she got for them. "An exceptional answer once again, Miss Laksh," he said, nodding more vigorously. "At these distances from the plane, there is nothing to fall into, but your second idea is correct. Apart from close proximity to a massive black hole, only supernovae produce enough force to fling gas out of the galaxy like this."

His wand indicated the tips of the clouds. "There are, in fact, runaway stars that get flung out of the galaxy when they stray too close to the centre, but these dust clouds are the result of supernova explosions. They are," he added, "not Bok globules, however. Bok globules are found in star-forming regions, and they are much denser and smaller than the clouds on display here. Very impressive amount of knowledge you have, though," he said with an approving smile.

Risu was almost ready to move on when he remembered something else. His gaze returned to the Gryffindor prefect. "Oh, and they are much hotter too. Bok globules, I mean," The dot of light from his wand moved into the centre of the picture, to the galactic disc. "As I said, they are part of star-forming areas of a galaxy. H II regions specifically, if you want to know. As such, the young stars being born out heat up these globules which surround them, and the globules reach temperatures of 8,000 Kelvin and upwards. These clouds, however," Risu pointed at the image again, "are barely above absolute zero. Ten, twelve Kelvin. Very, very cold. Given their movement away into intergalactical space, that is not surprising."

He paused, trying to remember where he had left off. Recollection kicked a neuron. "As, er, as I was saying... The gas clouds here are the result of supernovae which fling surrounding matter - and matter of the exploding stars themselves - out of the galactic plane. A lot of you mentioned gravitational influences. In this case, that gravity, almost all of which is generated by the black hole at the centre of our galaxy, is overcome by the violent forces in the supernovae."

Risu put the wand down on his desk. His arm was getting tired. "But that is only one part of this picture. An important part because it tells a lot about, for example, star formation, supernovae progression and molecular movement within these clouds, but this was merely an exercise, as it were, to show you how much a single image can show as our scientific knowledge advanced. On to the real importance of this image, though."

He picked up his wand again. "This image is a very recent one, only, oh, a week or so old, so before we dig into it, I want to show you another one that shows the exact same thing." He flicked the wand in the direction of the projector. "Only this one is older and less exact. But it might be a little more familiar to you, perhaps. Or some of you," he added, his gaze resting on Gold for a moment.



"Any guesses? Oh, and I should point out that in this image, the galactic plane has been painstakingly removed. This is a long and difficult process which has not been done yet on the newly released picture, but we are looking at the same thing now."

Patroclus wouldn't deny right now he was slightly confused, parts of what the professor had just said went straight over his head, but the boy decided he would not let on, well not yet anyway. Perhaps the next question would help him to understand the last, yes that must be the case, the boy resigned to himself.

Starring at the new image Patroclus found the colours and patterns rather familiar, so thought it best to venture an educated guess! "Sir, the pattern and style of the image reminds me of a thermal image. The image is showing the temperatures of the various sections of the galactic plane."
Well that sounds right to him, even if it wasn't.

"Not a bad first guess at all, Mr Hudson," Risu said approvingly. "You are right, this is indeed a thermal image of sorts. I'm sure you know which is which - yellow and red are warm, blue is cold, and so on." He waved a hand. "The temperature fluctuations we are seeing here are absolutely minute, ranging in fractions one degree, which should give you an idea of the engineering involved." He gazed up admiringly at the picture, the newer version of which, shown just a few minutes before, was even more accurate and impressive.

"But this does not show the galactic plane. The galaxy has actually been removed from this picture, based on complicated calculations and simulations. The background is what's important about it." He smiled briefly. "Background, in fact, is part of the whole thing."

Yes, it was official. Once again. Evelyn was completely lost on what they were talking about. Pretty much all she got was that the thing had clouds. Dust, clouds. Other than that, it went through one ear and right out the other.

However, now that the clouds were gone, she had no idea what they were looking at. Thermal image? What was a thermal image?! Ohh, it shows the temperatures whatever they were looking at. Yellow and red for warm, and blue is cold. Well, that was pretty neat if she were to admit it.

So, now that everything they just talked about was GONE, what in the world was left?! That had, various hot spots in it? "So is this like...our galaxy without the galactic plane part?..." And, that made no sense whatsoever. Was the galaxy THE galactic plane? Or was the plane something totally different? He probably mentioned something about that already too. "Or, I mean, the stuff surrounding the galactic plane?" Baha! If that could be anymore obvious right now. "The..." thing. "...stuff, the extends, or surrounds..." The...aura, the...thing. It did not occur to her, to look in the book. "I guess, you could say, halo? Or...the...uh huuuuh...nevermind."

Yup, Astronomy, was not her subject.

Gold raised a hand. "Sir?" Her voice was timid. "Is it of any consequence that the backdrop is black?" She asked. "Cold. Perhaps... White and black dwarfs, or the Degenerate Era. Or..." She hesitated. There was so, so much on her mind, but she wasn't sure if she should say it.

She was back to shy, really shy, the way she was when she felt she had a lot, lot to say, on her mind; but wasn't sure how to word or it, or even if she should word it, in the first place.

"I'm afraid to ramble," she said simply.

"Not quite. Galaxy and galactic plane are synonymous in this instance as we ourselves are inside one of the spiral arms on the plane. The galaxy has been removed because it is irrelevant in the context of this image."

He waited patiently until the girl's stream of words had become a silence delta.

Risu twisted his neck around to glance up at the image. Then he realised what Gold was talking about. "Oh!" He shook his head, smiling. "No, that's of no importance at all. This is a copy of a picture appearing in a glossy conference round-up I have in my possession. Most of the pages were black to give it a more, er, space-like appearance, including the one this picture appeared on."

He raised his eyebrows. "Black dwarfs? The hypothesised end state of a white dwarf. Hmm. Fascinating but speculative science, to be sure..." He shook his head again. "No, this image shows no dwarfs of any colour. Nor the Degenerate Era, which is something that lies in the future entirely. Er. Possibly. Science has come a long way, but so far we cannot take pictures of things that are going to happen billions of years from now."

Risu wondered briefly just how much Gold knew about his subject. She seemed to be able to come up with far-reaching answers to every question. "This image," he continued, "is of something far removed from our own time, but in the opposite direction. More than 13 billion years in the past." He waved an expansive arm in the prefect's direction. "But please, by all means, Miss Laksh, ramble. Something fascinating will come of it, I am sure." He smiled. "Miss Flores provided some groundwork for you."

Good Lord, she was an idiot! "The Big Bang," Gold breathed, hand still in the air. "The origin and evolution of the universe." Of course. "The cosmic microwave background radiation." How the heck had she strayed? "The space between the stars and galaxies is..." She paused, again. "Dark," she said, briefly.

So simple. Unless she was mistaken.

"... and the remnants of energy. Our 'confirmation' of the Big Bang Model. Is that so, sir?" She raised her lashes, to look at her favourite professor. She could still very well be completely wrong. "Am I..." She hesitated. "Am I still allowed to ramble? I can't always put what I know, into words. I know I might be wrong..." She trailed off.

Was this how he looked like when hit by a sudden flash of understanding, Risu wondered. He was almost able to see the links clinking into place in Gold's mind.

"It is, it is!" Risu said, smacking a stack of journals on his desk for emphasis. "The cosmic microwave background... The leftover glow of the Big Bang, after 13 billion years reduced to radiation just three Kelvin above absolute zero. Not our only piece of evidence for the Big Bang model, obviously, but one of its most accessible and persuasive pieces nonetheless. And it is, as you rightly pointed out, Miss Laksh, certainly very cold and dark in space. This image," he said to the class, pointing upwards, "is a map of this radiation, painstakingly assembled by scientists reading the data of a space probe."

He flicked his wand, and the previous image appeared again.



"This," he continued while the projector whirred away, "is a new version, by a different space-bound telescope. A much more accurate one at that."
He released himself from the desk and began wandering in front of the class once more.

"We will talk about the cosmic microwave background at length in due time. Possibly next term. The point this lesson is not so much the science behind this image. As I said, when we talk about the Big Bang proper, the CMB will come up again. No, as with all the lessons this term, I aim to teach you something about the thinking behind it. But first..." He pointed briefly at Gold. "You wanted to r-... say something?"

He looked around at the rest of the class. "Or anyone else? Any questions or comments?"

Staring at the picture with a blank expression, and then looking down at her desk, noticing that she didn't even have her notebook out, Evelyn sighed and took it out. There was no way she was going to get all this information down now. At least she could just, draw that thermal picture thing and say that it was a picture of radiation or something from a cannon or...something.

Any questions? Yea, could he go slower? And...repeat everything he just said? "Professor?" she asked, raising her hand and looking towards him. What he said about space being cold and dark made her think of something. "Kinda, off topic, but what you said about space being cold and dark... since like, all stars supposedly have some sort of temperature and light, then why is space so cold...and dark?"

Yup, that confused her.

Space probe, yes. "Explorer 80," Gold agreed, with a nod.

You wanted to r-... say something?

Her eyes widened. "Were you really going to say 'you wanted to ramble,' sir?" she asked, green eyes all huuuge. She made a number of cute, big-eyed faces when she was sure he wasn't looking, and then said, "Well, I was. Going to ramble, I mean. Until you said we'll discuss the Big Bang and CMBR properly, in due length."

Listening to Evelyn's question, Gold placed her chin on the back of her left hand, one elbow resting on the surface of her desk, in a contemplative manner -- and then, remembering that Professor Antares had said [in his last class, perhaps. She wasn't sure when, she just knew that he had said something to that effect] that discussion and speculations were more than welcome in his class, raised a small, white hand.

"That would probably be because we have no fixed measure of the vastness of the universe," she offered. Infinite. She didn't use that word. It was a big one. Far, far bigger, in Gold's opinion, than some people considered it to be. "It's like a sprawling city would still be dark and cold, if you lit a dozen lamp-posts in it. They wouldn't be enough."

She fell quiet, for a second. "... and cities are dynamic, like the universe. We can't have an infinite static model of the universe -" Considering the attractive force that was gravity, of course - "And we can't have a static model of cities. Of course," her voice fell, "We may have the power to place curbs on the progress and expansion of a city, but the comparison will do for an analogy. I think."

I think. In the end, that was it. Gold was hardly ever sure of her answers. Astronomy was such a vast subject, it was scary. But she loved it. She loved, loved, loved it; and, if ever a grade had pleased her, it had been the brisk O next to the 'Astronomy,' on her OWL Examination Report. It had made her think that maybe, just maybe, she knew a bit of it, after all. Enough to please whoever had checked her Astronomy OWL, at least. Unless they had decided to go easy, with the grading.

The thought made her feel all disappointed.

Notes.
Taking notes was the one thing Xylon could do in this class.

He wasn't bad at astronomy. He liked it. It appealed to his more artistic instincts. There was a certain enigma about it that pulled him. Maybe that was why he planned to sit the NEWT. But when matters came to rock hard theory he found it hard to actually digest facts, numbers and data.

Images were better. Instant remembrance. So he fixed his attention on those that were a result of the operation of the projector.

Looking at the Professor expectantly, for a moment, she didn't understand why he was answering her question but his lips weren't moving. And he sounded like a girl...

Actually, sounded like...Gold! Not the awesome awesome Gold, but the awesome Gold. Human one!

Right!

Glancing towards the older Gryffindor, Evelyn smiled since, she understood what the girl meant! OMG! Yea, she knew what she meant with the lamp-posts but the street would still be cold. And...

And now she was lost again. Expansion and curbs. Uh huh.

Nodding and smiling anyways, Evelyn slowly turned away and moved her attention back to her notebook, acting like she was taking notes and still paying attention. Yeeaaa. Something about dynamic and static.

Suuure.

Patroclus was sooooo lost, and he needed help, so Raising his hand the boy ventured a question.

"Sorry Sir, but I am completely lost!" Patroclus was a diligent student, but some of this words were blowing his mind, " Is....." the word were lost in his mouth, he hadn't a clue of where to start.....

"The Wilkinson Probe, yes," Risu said with a nod. "The new radiation map has been produced by the Planck space observatory, in case you want to know. There is a question?" He pointed in the direction of the Slytherin, but as he was still assembling an answer, Gold started talking already. Risu stood quiet and listened in amazement, not wanting to interrupt until she was done now that she had worked up the courage to ramble. But coherently.

"Gold is correct once more. The scale and distances we are talking about here are beyond comprehension. For all the billions of stars in our galaxy, there is even more empty space surrounding it. And I do mean empty. The light-years between galaxies, intergalactic space, is almost literally a vacuum, with only a single hydrogen atom per average per many, many cubic metres."

Another hand was in the air. "Yes, please, Mr Hudson?"
Oh. The boy was confused. That was, Risu thought, a danger of spending time in one-on-one discussions with students such as Gold whose knowledge was much more advanced.
"Not to worry, Mr Hudson. No need to apologise, it is likely my fault for going too fast. We are, however, done with this line of discussion for the moment."

Risu leaned against his desk comfortably. "Leaving the technical details aside as they are of more interest in later lessons, I want to ask your opinion on images like these in general. Mapping, for example, the Microwave Background - it gives us a certain view of the Universe. The person in the Flammarion woodcut wanted to peer beyond the sky, something we are actually doing now." He shrugged. "In a fashion. Er... Perhaps a bit of a laboured metaphor."
Risu shrugged again. "Carrying on. My question, to come to the point, is the following: What do you think about this view of the Universe? I have another picture to show you." The projector whirred more loudly for an instant as the image changed.



"This is a simulated view of the Milky Way galaxy. Our own Sun is hidden somewhere in the lower third of the picture, more or less in the middle. This is another view to have on the cosmos surrounding us. But... leaving aside all questions of scientific knowledge and technical details, what is your personal opinion on this?" Risu spread out his hands. "What if someone said, for example, 'I don't want to know about this. It makes me seem small and insignificant.' How would you reply? Or would you share that person's opinion?"

He nodded sharply. "In short, this is less of a scientific than a philosophical discussion. And I would love to hear your views."

"Sir," Gold's voice was thoughtful, hand in air. "There's a quote in the Lankavatara Sutra - 'as a sword cannot cut itself, or a finger touch its own tip, mind cannot see itself.'" The quote rolled off her tongue like something learned by heart - and it was! It was something she knew by heart. She had always lived by that quote. Had, ever since her father had told her his interpretation of it. "Humans like to think of themselves as intelligent. Superior. But it's funny, how even the smallest of our actions are limited, often defined by forces we do not even give a second thought to. Gravity dictates what we can do, and what we cannot do. It gives us the definition of stamina, of rise, of fall, of a lot that we believe is independent of any factors, save our own will. We always think it's us. I tend to believe that, most of the time, it isn't."

"We mean nothing, for the rest of the universe," her voice was quiet, far-offish, like she wasn't mentally here anymore - and in a sense, she wasn't. "Isn't it amazing that, if our palm was the universe, our planet wouldn't even be a tiny dot on it? Not even the tip of our little finger? It means that everyone we've ever known, every person we've cared for, everything we've ever seen, the most majestic mountain ranges, the most splendid waterfalls, the deepest, darkest oceans, they aren't even a thousandth part of a speck. But I also think," her voice grew a tiny bit stronger. "That significance is, in this case, more of an opinion than a fact. How can we define what 'significance' is? We can only measure our 'opinion' against that of other people - humans - and, given that we're all humans in the end, that isn't exactly an objective measurement."

She paused, to give her thoughts some order. "Our bodies. We never think of it that way, but our bodies thrive on - and go back to - the universe. What we are, could very well have been a part of a dust cloud or a frozen bit of the universe, ten billion years in the past. But that part of us, the same that is ancient enough to surpass all imagination, might have been bored as part of a blinding star - at least it's part of a system that can think, reason, judge now. Perhaps that's more exciting than being part of something that likes to burn up, all the time." She half smiled. "Then again, we come back to the point that yes, we can think, we can reason, but the universe places limitations on us that we can not break free of. For all our 'superior' intellect, we haven't been able to defeat gravity. We can work around it, but we can't bid it goodbye, if we want our harmony."

"I think, sir, that the question you've presented is pretty much a circular one, and if we start from the point you've put forward, after all the discussion, even several dozens years of it, we'll come back to it. In the end, we can't objectively say if we're significant, or not - there are as many points to prove that we are, as there are points to prove that we aren't. I don't believe size can be the measure of importance - a split second or a drop of water can be the difference between life and death. If our whole planet was wiped out, that would merely be like a little point of light flaring out, on a cosmic scale. But that doesn't have to mean we're insignificant, because I believe the fate of a good many billion people is far more important than that of a stray knot of dust and gases, aimlessly wandering around in the dark. In the end, it all comes down to what you measure yourself as and against. That stray knot of dust and gases that's wandering around in space, sir? It probably thinks it's very, very important, and I believe that's what matters."

He shouldn't have allowed her to ramble.

He so shouldn't have.


OOC: Apologies for the novel. xD

Xylon raised a hand.

"I would tell such a person to get a bowl of popcorn and watch a good movie sir," he said seriously. "He has no idea what he's missing out on. Or she."

See? That was way simpler than whatever Gold had said.
Though Xylon had a feeling he got what she meant.

"I think we tend to measure signficance by the tangible properties rather than what we perceive to be true value. I share the opinion that in the grand scale of things we look downright insignificant. But I believe intellect is never there without a reason. If we can think of these questions, we can place them in a context we can understand and find answers too." The point?

"The problem as I see it is that it isn't possible to discuss this in rigid terms of true and false and black and white because often concepts such as faith, beliefs and religion come into play."

"I think those are the people that really are insignificant. I mean how can you not want to learn about the universe. There are so many currently unanswered questions. Like about what is dark space, how was it made, what if anything does it contribute to the universe? Is it of any import or just that during the formulative years there was a degeneration of some sort? And then there's the time-space continuum and the dimensions that make up space. And the stars, like how close they are to going out, and what if any effect these stars going out may have for our galaxy." Was he making any sense at all?

Probably not, it was like he was trying to recall everything he'd learnt and it didn't seem to be ending well to him. Maybe it wasn't best to just blurt everything without trying to structure his answer before he spoke. "I believe that the universe is fascinating because there is so much we don't know, so much I believe that we will never know about the universe because as it is we cannot travel out of our own galaxy."

Trixie, for once in her life, was lost in astronomy. What?! B-b-but she never got lost in Astronomy. What the heck were they going on about now? And it just seemed that the prefect was doing all the talking. Ah well, might as well take notes hadn't she So with the pen lid in her mouth and trying to concentrate on what was actually being said, the Slytherin wrote down what she could make out of the Prefects on going ramble about whatever they were learning about. Ah well, Miss Clumsiness as she had been renamed, teehee, would catch up eventually.

Alex put her head down in pure confusion, every long word they were using was way to much, were they trying to confuse her? She didn't like this class much it was too much sitting around and discussing for her liking, she was as smart as any other first year but the Gryffindor prefect was rambling and other Gryffindors was were rambling and was there a Ravenclaw rambling as well.. too much and way to soon Alex thought having to have written everything down.

Wow. This lesson was deeeeeeeep. Kinda mind-blowing, in fact. Which explained the previous silence from Keefer., who was usually fairly vocal.

Both hands timidly went into the air. "Professor, it really does make me feel small. So many stars, so many galaxies.... it makes me feel like this class barely matters in the scope of it all. Not just this class, but a lot of what we're doing here on Earth. But it's all so beautiful, so elegant, so incredibly orderly! It almost makes me wonder how a big bang of matter and energy billions of years ago could've given us all of it. You know? Like, what are the chances? Just think if even one star had been in a different place. That could have made everything else move, and then Earth might not be habitable. Astronomy classes always made him begin to question such things. "Then again, pictures such as the ones you show us seem to give such a good description of that bang..." He trailed off as he sunk into his own thoughts. Though only a third year, he was prone to deep thoughts. He didn't usually share them in classes like this, since it was a controversial topic, but the Professor had asked for opinions.

Eirian blinked as the professor took a turn towards the hypothetical opinions of the students. Gawking slightly, she wondered how a teacher could even ask that without bursting into flames. Let the students speak? Give opinions? It was so broad... She honestly couldn't believe it. Maybe this teacher was... nice... Weird. But, all the same, she valued the chance to not get something wrong...

"I would tell zem zat zeir opinion is very well grounded," she said simply. "It is zeir right to zink what zey want. We are, indeed, small. Very small. There are billions of us on zis very earth, and zere might be life out zere somewhere else. But learning about zis... it does not make me feel small. I believe zat it is only a realization of 'ow we exist in ze universe... a way to find ourselves. We are all unique, every single one of us. We are each extremely special simply because we can all find ways to be different zan ze billions of ozers out zere. Ze world will not stop spinning if we die; zis is true. But ze world will lose a unique person. Zere will never be anozer one like zat person... It is a small extinction in zis world and zis universe. If anyzing, learning zis - learning anyzing - should make one feel bigger because zey know more zan so many ozers, zat zey know what zey exist in... what bigger picture zey are a part of."

Iris sat there and listened to everyone. She tried to make notes but they were talking SO QUICKLY and there was so much to take down that Iris simply couldn't do it. She struggled enough as it was, trying to keep her ears at the same level as everyone else, let alone anything else.

She put her quill down and looked around at the people that were talking. They all seemed to really understand the topic... and Iris, well... She just didn't.