Welcome to AP Biology's summer reading forum. In this post, please feel free to ask any questions and make comments that you have for me or other students.
Questions that I have:
1) on page ten it states that in less than a minute that the universe is over million billion miles across. How can this be expanding faster than the speed of light? Do we just ignore Einstein's Theory of Relativity that nothing can travel faster than the speed of light?
2)On page 17 it states that we cannot find the center of the universe. If the universe is expanding at a set rate, don't you think that we would be able to trace it back to a center point, or at least close to it?
3)On page 25 it talks about the Oort cloud being the edge of our solar system. Does the Oort cloud orbit the sun, thus making it the edge of the solar system?
Please feel free to comment, keep it professional and let me know what questions you have as we progress through summer.
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37 comments:
To answer Mr. Wallace’s initial question, the expansion of the universe does not contradict Einstein’s Theory of Relativity since it is space itself that is expanding. The expansion of space is conceptually different from other kinds of expansions and explosions witnessed in nature. In the universe space, time and distance are not absolutes. It is the space that contains the objects which is itself changing and somehow growing in between them. Because it is the metric defining distance that is changing rather than the objects themselves, this expansion is not restricted by the speed of light that results from special relativity.
The author seems to confirm the question raised by Mr. Wallace in #3. On page 26, the author states that: "...It is a remarkable thought that that distant tiny twinkle (the sun) has enough gravity to hold all these comets in orbit. It's not a very strong bond, so the comets drift in a stately manner, moving only about 220 miles an hour...". So I assume, by this statement, the author seems to believe that if the Oort cloud, (which as of now is purely theoretical)were confirmed to exist, it would be under the pull of the sun's gravitational forces, and thus, in orbit around the sun. As fascinating as I found the numbers the author provided about our universe and just how vast it really is, the most curiously intriguing section for me (which has been to most of society for quite some time) in the first three chapters came on page 27 when the author introduced the hypothesis of Frank Drake, the 1960's professor from Cornell who engineered a calculation which would compute the chances of other advanced life in the universe. Now finding ourselves 40 years down the road, are there any current professors or organizations working today to try and improve the accuracy behind the probability of other life, and if so through what methods?
1)Einstien's theory of relativity could not have been possible without the initial beginning of the universe. There are exceptions to every rule and the beginning of the universe apperantly is one of them.
2)Although it is expanding at a set rate that doesn't mean we can trace it directly to the point of origin.
On the top of page 17 Mr. Bryson says, "...The reason for this is that the unverse bends, in a way we can't adequately imagine, in conformance with Einstein's theory of relativity...Rather, space curves, in a way that allows it to be boundless but finite...". This proves that the universe is so misconformed that it is pretty much impossible to find the center.
Okay, I'm taking a Stab at #2:
I agree with the author in that there is no way you can locate the center of the universe. I guess in a sense, to me it doesn't seem that the universe just hatched from an egg and then began spilling out infinitely in all directions. I kind visualize the formation as a materialization of the universe, you know how on TV the pictures fade in and fade out--kind of like that. Because of that, everywhere is the center, so it's impossible to locate a center. Plus, much of the universe we know today is based on theory, since we can only reach out so far. The way theory has been going, it seems only logical to say no to the "can we find the center?" question.
On the bottom of page 17, the author writes, "think what [being at the center of the universe] would imply--but that the phenomenon must be the same for all observers in all places." This reminded me of the way that black holes bend time and space. If I saw someone getting sucked into a black hole from very far away, it would be very very different from the experience that person would be having getting sucked up into the hole. Time would have come to a standstill for them and (just for this story) assuming that they would be alive, they would see themselves very differently from how I would see them. Similarly, it's difficult for each person to observe the exact same thing as another person, with interferece of the fourth dimension, implying that in this variance of observation there exists no center to the universe.
The outer perimeter of our continuously expanding galaxy is not contradicted by Einstein's Theory of Relativity like Jacob said. According to Einstein's theory of Special Relativity the laws of physics are the same for all in uniform motion. But since the universe is forever expanding it can be deemed as non-uniform motion. Can't it? I also agree with Bill Bryson in saying that it is impossible to find the center of the universe first off because the universe is so infinitely huge and secondly the universe and it’s space time can’t be understood with time, space, and distance as certanties.
So do we just resign ourselves into saying that the universe is too big, too complex and ever changing that we will never know the answers? Do you remember that old tootsie roll tootsie pop commercial about the boy wondering how many licks does it take to get to the center? The owl takes three licks and then chomps (woo-hoo) and declares that it takes three licks. Is that what we are doing in this case, taking the simplest answer (that we will never know) and calling it good? Have a tootsie roll tootsie pop sometime this summer for me.
I am going to comment on question number 2 and Shamita's comment as well. I don't think there is a definite center to our universe. First of all, like Shamita said, most of what we know about the universe is based off of theory. So how do we know what is really the edge of our universe and what isn't? How do we even know what, if anything, is going on beyond the farthest planet? Yes, there are advances in technology that can help explain all of these things but do we really know what is going on out there? I don't think we do. Is the universe really expanding at a set rate? Does it slow down sometimes and speed up at other times? Like the author said, "Space cannot even properly be said to be expanding ..." (17). Which in turn means that there isn't an exact center to our universe.
Going off of the tootsie pop analogy, doesn't that just emphasize the ambivalence of the this topic? I mean some people will say that the universe isn't expanding and we can find the center, while others will say that the universe is expanding at different rates in so many different ways that finding the center is impossible. Similarly, the owl, could call it three licks to get to the center and hundreds of other people could call it thousands of other numbers depending on how fast or slow, etc.. they lick the tootsie pop. And I guess in both cases, any set of numbers would satisfy this equation, because as Bryson says "the universe bends, in a way we can't adequately imagine, in conformace with Einsein's theory of relativity", everywhere is the center, every answer is acceptable, and therefore no definite answer can be found. It's not that this answer is the easiest way out--I know it sounds like a logical fallacy, but it mostly depends on perspective, which we have a lot of, or maybe in a sense, not enough of.
To me, it's scary and intimidating to think that our world, which seems so huge and inviting of exploration, has basically no importance to the universe in which we are apart of. How can it be that the "number of advanced civilizations just in the Milky Way always works out to be somewhere in the millions" (27 Bryson), and yet there is no limits? Living in the world we do, I can't understand how there is an infinite amount of space. Doesn't it, won't it have to end eventually?
However, after I started thinking about this, how CAN there be one center of the entire universe. For Earth, it's the sun. For our individual universes it's school, or family, or friends. But none of these have any importance in the whole of the universe and so the center, I think would be SO massive, almost incomprehensible, that in truth, we wouldn't be able to comprehend it.
When I was reading the chapter about our solar system and Bryson explains how much space there is in space. The description reminded me of the atom, and how similar our solar system is to the atom. But what I don't understand is why. Why a small dense particle expand into a lot of nothing? Is this state lower energy?
I have a few questions about number 2 to clarify what people are arguing. First of all, I feel like the real question is not where the center of the universe is, but IS there a center to the universe? Also, What would the center of the universe look like? Are we talking like a immeasurable point in space? Or like caylab suggested a massive object that the entire universe is orbiting around? Think back to when Bryson described the birth of the universe. Picture the infinitesimally, compact, virtually dimensionless, singularity; and the literal nothingness surrounding it (Bryson 10). Now imagine trying to find the center of the dimensionless point. Impossible, right? Instead, imagine that the singularity is the center. Ok, now try to keep track of this point as the universe expands. The entire point expands and the whole thing is still the center. If you can't find the center of the singularity, how can you keep track of the center of the universe? I don't think the universe has a center. But I do like what Bryson and some other people said about the center being what you make it in terms of perspective. We see a big sphere around us, so of course, we are the center of what we know.
On page 18, it says, “According to Rees, the number of light-years to the edge of this larger, unseen universe would be written not ‘with ten zeroes, not even with a hundred, but with millions’” (Byson 18). We do not even know exactly how big the universe is, so how can we know exactly where the center is. It seems that we live in one of millions of galaxies. I think that there is a center to the universe somewhere, but right now we do not have the technology to determine where it is.
1) to the best of my understanding, the "faster than light" expansion of the universe does not defy the theory of relativity. this is because the universe is not actually an object, it is more or less all of the space in existance that contains all of the matter that exists. Nothing exists outside of the universe because there is no space outside the universe. The matter inside the univers is subject to Einstein's Theory of Relativity, but no the actual universe, because it is merely space, not actual matter or energy, that is expanding.
2)I don't think that there is a center of the universe. The author states that if you were to travle in a perfectly straight line in any direction in space, you will eventually end up where you started. The universe must have some kind of curve to it making it impossible to reach the edge of it. If this is true then how could there be a center of the universe when it is curved is such a way as mentioned before? shamitap has good insight on this topic also.
3) Yes, if the Oort cloud exists, then it would indeed orbit the sun. In order for something to be considered a part of the solar system, it has to orbit the sun.
One question I had goes back to when Bryson says that if you travle in a straight line in space, then you will eventually find yourself back where you started. If this is true, then would light from a star eventually reach itself again?
When Einstein made the Theory of Relativity he was measuring energy that he could physically test. He was using light which was obviously available to him excessively. When the universe was created an incomparable amount of energy was used to create the earth, one in which we will never see physically. This amount of energy cannot be measured and we merely just estimate the actual amount of energy it took. We can hypothesize that it was more energy than the speed of light can even compare to, and therefore it can travel at a much faster rate. Because we do not see this huge amount of energy nor can create it, the next highest amount of energy with the fastest speed is the bench mark to how fast something can travel, which in our case and in Einstein's theory of Relativity, is light.
Concerning question #1, I am a little confused as to if the universe continuing to expand that quickly or if the universe expanded quickly for one moment and then stopped? If the universe only expanded for a short amount of time Einstein’s theory of relativity may not be applicable. In this context the universe may have expanded before light was formed. On page ten it states “In less than a minutes the universe is a million billion miles across and growing fast.” Then it goes to say “There is a lot of heat now, ten billion degrees of it, enough to begin the nuclear reactions that created the lighter elements-principally hydrogen and helium…” Therefore, going off of what Bryson was saying, the universe was formed before heat, the elements, and light was created.
Responding to Sandy's comment, I have actually thought before about how our solar system seems to be a lot like an atom. The planets serving as electrons orbiting the sun as its nucleus. It's an interesting thought! Additionally, I have a question relating to the shape of the universe. Bryson mentioned that the shape of the universe "curves in a way that allows it to be boundless but finite" (Bryson 17). What kind of dimension is the universe in? What is the shape of the universe if it's not "some large, ever expanding bubble" (As I had always imagined it was)?
In answer to question 2, I think it is not possible to find the center of the universe. If the universe is always expanding at a set rate we can't find the edge of it. And in that case, where would we work back from to find the center?
By the way, http://www.candyfavorites.com/Tootsie-Pop-Lollipop-pr-1002.html says that:
"A group of engineering students from Purdue University recorded that their licking machine, modeled after a human tongue, took an average of 364 licks to get to the center of a Tootsie Pop.
They tried the same licking test on 20 volunteers and found that the average licks to the center were 252 licks!"
So in answer to Mr. Wallace's question, I don't think that we simply accept there is no answer. The problem is everyone has a different theory.
Concerning Jeff's question about the shape of the universe, I also found that specific statement interesting--about how the universe is boundless but finite. I don't exactly know what kind of image Bryson is trying to create, but I kind of thought of an infinitely long cylindrical shape--of course it would have to have an immense finite diameter, but it's also boundless because when you go around, you can head in one direction forever and would always end up in the same spot (according to Bryson's illustration), delineating the curvature of space. Maybe this is why the universe is seen as never-ending, because it curves in such a way that if we were to travel along it forever, we would end up in the same spot like traveling in a circle. That's just what I thought, but I'm sure there are many other different interpretations!
I agree with Annie Lo on number 2... The universe expands in such a way that it is impossible to track it. But Shamita's idea on it is also interesting. Just the fact that the universe is a never ending circle so if you start traveling towards the middle, you will end up in the same place sooner or later.
1- on page 10 it also says that gravity and other forces that govern physics are produced in the first second, and that the universe expanded from a "singularity" with no dimentions at all in a fraction of a second. But if gravity and the laws of physics didnt exist until the first second how much had the universe expanded by then? Isnt it possible that because the forces that governed physics didnt exist even for a second or less that they dont apply? So maybe things could move faster than the speed of light. If not maybe the "dark matter" mentioned on pg 171 and 33- stuff that theoretically composes up to 99% of the universe-had some part to play. Is dark matter governed by the same laws normal matter is governed by?
2- The center of the universe would change depending on the shape of the universe, right? Aside from the practical problems of finding the center (too much space and distance) theoretically we would need to know the shape. is it just a sphere or a blob or what? The book says on pg 17 that "the universe bends in a way we cant adequately imagine in conformance with Einstein's theory of relativity. So maybe the universe is a shape we cannot comprehend because it exists in 4, 5 ,6 or a million dimentions. (This line of thought is also applicable to 1.) The enourmous temperatures and energies during the inflation or big bang could have been so extreme that we dont know how matter -normal or dark- would have followed the laws of physics or dimentions, etc. Do we have any data on this from exploding stars and that kind of thing, when temperatures are really high? Dont black holes supposedly contradict a law of physics?
3) The whole idea behind the oort cloud confuses me bcause Bryson says, "..we don't actually know that it is there. Its existence is probable but entirely hypothetical." Which leads me to another question does the oort cloud surround the solar system making it our circumference? or is is just a chunk? If it is a chunk i can see that it orbits with the sun but at the same time how does the sun have enough gravitational force to hold it in when pluto is only one-fifty-thousandth of the way? i guess to answer the question hypothetically the sun is at least holding it in thus making it part of our solar system even if it does not orbit with our solar system.
Today I read the chapter about Yellowstone National Park, and it really made me think. Since the park is actually a giant volcano which seems due to explode (it erupts on average every 600,000 years, and hasn't for 630,000), I was wondering about the damage the blast would cause. Bryson states, "The last eruption was a thousand times greater than that of Mount St. Helens," (page 226). Of the two eruptions before this, one was much smaller, and the other was much larger, so of the little we know about this volcano, the last eruption seems to be around the average. From the earlier chapter, we know that Mt. St. Helens devastated 230 square miles of forest, and rained enough ash to completely shut down the town of Yakima for three days, which is eighty miles away (page 222). These facts are frightening, but Yellowstone and Mt. St. Helens are two different types of volcanoes, so that could change the effects of a Yellowstone blast.
We live a little over 600 miles away from Yellowstone, so if it were to erupt, how much danger would we actually be in?
Sorry for my absence-- I just got back from a string of vacations!
One question that I keep returning to is the idea of spacetime. On page 126, it related spacetime to a "...mattress, say, or a sheet of stretched rubber-- on which is resting a heavy round object, such as an iron ball. The weight of the iron ball causes the material on which it is sitting to stretch and sag slightly". Bryson later states that gravity is a result of this bend in spacetime. I'm having trouble understanding spacetime. At the simplest level, I understand that it is a model of a compilation of space and time, but beyond that I'm not sure. Does that mean that time operates at a different speed in areas of different gravity? How does an object such as a planet have a noticeable effect on it?
Today I read about chapter 27, Ice Time. What Bill Bryson told the reader was shocking. I knew that Earth had a history with ice ages, but I never knew that they were so frequent. At first I thought, well global warming will fix any up and coming ice ages, but then, like he always does throughout his book, Bryson told it like it was and he explained how it could actually bring on an ice age. It made me ask why we aren't doing more for our world when it comes to these type of situations. We know what is going on, so why not fix it? This book has helped me realize how fragile and remarkable life and Earth are.
In response to the question about Yellowstone National Park; I found an interactive website from the Discovery Channel based off a program they did about the park. According to it, the next eruption of Yellowstone could result in devastating global changes as well as local. (The last slide of this has the most information on the effects of the potential eruption.)
http://dsc.discovery.com/convergence/supervolcano/interactive/interactive.html
In response to the original questions posted by Mr. Wallace, I would like to address question number two, which seems to be the most controversial one so far.
I think one of the main reasons we wouldn't be able to pinpoint the center of the universe, even though it is said to be expanding at a set rate, is because it is most likely expanding in more than one dimension. As Matt R said, the universe could potentially be millions of dimensions. So, how would we technically be able to find the center (if it is even there), unless our knowledge of math can calculate the set expansion through multiple dimensions. In conclusion, how can we calculate the potential center of the universe without even completely knowing every aspect of it?
I am going to comment on Mr. Wallace's comment about tootsie roll pops. I do believe we have taken the easy way out, but I don't think it is necessarily bad. When reading about what Bryson had to say about the universe I was fascinated and very confused. I think that something like the universe, so big and mysterious, is impossible to tackle and find set answers to. I think the quote on page 17, “ ‘The universe is not only queerer than we suppose; it is queerer than we can suppose,’ ” really sums it all up. So how many licks does it take to get to the center of a tootsie pop? Well, the world may never know.
I had a question about a statement Bryson made on pages 256 and 257. He says (at the bottom of 256) that you move from the mesosphere to the thermosphere, the temperature increases from -130 degrees F to 2,700 degrees F. He then explains how at sea level, air molecules are so thick that they constantly colliding and therefore exchanging a lot of heat. But then, he seems to contradict what he just said when he says, that "at the height of the thermosphere, at fifty miles or more, the air is so thin that any two molecules will be miles apart and hardly ever come in contact. So although each molecule is very warm, there are few interactions between them and thus little heat transference." Then why, is the thermosphere so HOT? Does the heat of each single molecule make up for the lack of collisions? Anyone have an answer to this question? thanks!
I don't have an answer to your question Shamita, but i do agree with what you are saying. It doesn't really make much sense that there are so few molecules in the air up there, hardly colliding with each other, yet there is so much heat. I wonder if Mr. Wallace knows? :)
As obvious and easy as an answer this might sound to Shamita's question...wouldn't the temperature be greater at the thermosphere than sea level (or mesosphere) not because of molecular collisions, but because a greater concentration of UV rays/in simple words, it's closer to the sun? On Earth we find a comfortable temperature of 80 Farenheit, but if we were to exist on Mercury or Venus, it wouldn't be thousands of degrees hotter because of the molecular orientation of the air, but because we would be closer to the universe's heat supply, the sun!
I propose this question to those of you who have seen the movie Deja Vu. In the movie, in order to prevent the mass murder of the families on the boat and the murder of the woman, the main characters must "fold the plane of time" in order to shorten the distance and allow them to cross back into time... Does anybody have a more logical explanation of this because I am confused about this theory. And in addition, does anybody see this theory taking ground in the near future?
Thanks Brooks! That makes sense--online, I found this site that explains almost exactly how interestingly hot the thermosphere is. The oxygen and nitrogen absorb radiation from space and convert it to heat! To read a short paragraph about it, explore the link:
http://members.tripod.com/atmosphere_guys/thermosphere.html
Sorry, the link didn't post properly the last part reads:
thermosphere.html
2) Despite today's advanced technology, it is possible that the center of the universe might remain unknown. If the exact size of the universe has not yet been determined then chances of finding its center are, at the moment, slim to none.
On a side note, I found the first chapter fascinating because it stretched the limits of my imagination on creation of the universe. It is staggering to think that in less than sixty seconds something over “a million billion miles” was created. On page 39, the book reads, "Had we not had the benefit of a greenhouse effect, the Earth might well have frozen over permanently, and life might never have gotten a toehold. But somehow life did." This passage further intrigued me because with all the countless research that has been conducted on the creation of the universe, there is still so much to learn and most likely many more discoveries to be made so that at times "But somehow life did" has to suffice.
On page 17 the author explains that you can never reach the end of the universe which would make it impossible to find the center. He states, "...space curves, in a way that allows it to be boundless but finite." If there is no end to the universe how is it possible to find the center? We would think that if the universe was expanding at a set rate we would somehow be able to find the center but how would we even know that the universe is expanding? Steven Weinberg says, "solar systems and galaxies are not expanding, and space is itself is not expanding." This is only a theory but we have no evidence that space is actually expanding. If this theory is true, finding the center of the universe would be impossible.
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