Things I learned in physics class
POSTED BY: BadgersHat
UPDATED: Friday, August 12, 2005 15:00
VIEWED: 25158
PAGE 4 of 11
If we are really keeping our minds open, I think that it's a dis-service to say that wormholes can exist. It would be more appropriate to say that, some theories say that they can, and others say that they can't.
Also, with regards to the faster than light thing. The only thing that is stated is that things can't accelerate to the speed of light. It says nothing about things already at the speed of light and/or beyond. Nor does anything state that there isn't another way to get to speed without acceleration. It's just that that is the only way we know how right now.
That being said, there is nothing to indicate that there is another way to get to speed aside from accelerating.
And what about future theories. We've been proven wrong before.
On a note about me by Zoid. I have seen recent interviews with Kaku and I challenge anyone that is sane to say that Kaku is sane. He is clearly unstable. I will also reference the above provided link. Clearly others think so as well, I
did link to Peter Woit, Columbia University.
On a note about String Theory. It has been around for what 30 years or so, and how many predictions? Any serious theory has to make prediction or else people with be highly critical of it (and rightly so). I'm just surprised that it's taken this long to get some serious critisism against string theory.
String Theory right now (as it's always been) is nothing more that pretty math and philosophy.
My wife (Theoretical Physicist) and I (senior mathematics student) watched Brian Greene's infomercial about string theory. Many things that he stated in that thing was blatenly wrong. ie QM predicts that space-time is "bumpy," it does not. It is nothing more than a pop infomercial for the masses so that they are convinced that it is true so that the String theorists get more funding (which they haven't earned).
A note to Zoid about me being a "science troll." The last time I got on you was because you didn't see reason. I also think that people (more that just Zoid) should stop using the term "troll" so often. Using it in situtations where is doesn't belong (like now) weakens the term for real trolls.
In that thread, I let a lot of things go and tried to explain that you didn't really know what you were talking about and tried to explain why (politely at first) that was so, and the reality of the matters. Some time passed and I thought it
was all done with. Then you started on again spouting the same provably false things (and more) to someone else. Even things that were already proven false.
At this point I was fed up and corrected you; pointing to literature that proved you wrong. You didn't take that well and then threatened me with a body cavity search should I enter your airport with that "attitude" (may I assume you still
hold that postion).
So, if you want to avoid another occurance of that, then just accept when you are wrong gracefully instead of freaking out. ie. When someone with a physics degree (in my wife's case a PhD) and/or is holding an actual text book infront of them quoting page numbers says that you are wrong, accept it, move on (when speaking of physics of course). Don't try to prove you point quoting pop literature.
ie Knowing the mathematics of something is very different than having read a poor explination of something through some pop novel. Not that a lay-man would be able to tell the difference of course.
And I never said that you could not understand, just that you didn't, which was clear and proven. Don't blame me if you can't handle that.
Also, saying that I'm just waiting to tell you that you aren't a scientist...
I'm definitly not waiting to tell you you are wrong or any such thing. BUT, I will not hesitate to tell you you are wrong if you are wrong. Which I hope that others here will tell me I am wrong, if that is the case.
This all of course should come with explination and hopefully accepting grace. Zoid, have you learned this quality yet?
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Quote:
Originally posted by ReaverMadness:Quote:
Originally posted by FFFan1:
Actually... the effects of gravity are tremendous in space travel, and extend pretty much forever.
When you get into the space in between the various and drastically weakened gravity wells begin to sort of cancel each other out.
Well... Sort of... But only well outside of a star system (and getting out of our solar system is no mean feat), and even in interstellar space, you're still orbiting around the Galactic Center, being pulled in various directions by other stars, and being accelerated towards the nearest star, etc. Basically, you'd have to plot your course very carefully, and you'd still have to make lots of course corrections.
Quote:Quote:
The rest of your post has been fairly well addressed by others...
Really? I was talking about maintaining course speed and direction, not really talking about "what speed" or how close it gets to the speed of light.
I go for more of the Sleeper Ship or Generational Ship idea anyway.
I didn't mean to say that the rest of your post was wrong or anything like that, just that the ideas you presented had been discussed and expanded on by others. I was responding more to what the others had written than to what you had.
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It is, however, somewhat fuzzy on the subject of kneecaps.
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Quote:Actually there is a little criterion concerning zero mass. To travel at speed of light something must have zero mass, otherwise momentum becomes infinite at the speed of light. And beyond the speed of light, the mass must be negative. If you assume negative mass is meaningful and extant, then a massive objective simply cannot accelerate (or decelerate) to the speed of light.
Originally posted by SigmaNunki:
Also, with regards to the faster than light thing. The only thing that is stated is that things can't accelerate to the speed of light. It says nothing about things already at the speed of light and/or beyond. Nor does anything state that there isn't another way to get to speed without acceleration. It's just that that is the only way we know how right now.
That being said, there is nothing to indicate that there is another way to get to speed aside from accelerating.
So if you don’t rule out magic, a lot of possibilities open up.
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Qui desiderat pacem praeparet bellum.
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SigmaNunki:
Dude.
I never mentioned you by name (except in the case of Michio Kaku and then not in a way that ridiculed your opinion, but that only sought to find if others agreed with your assessment). Only you and I remember this quarrel and I didn't want to get you started again. I really wanted some honest observations and opinions from the 3 working scientists who I saw were writing on this topic.
Yes, I also saw that you were writing on this topic. I know what your opinions are on science, religion and the topic of zoid. But, I have a burning desire to know what others think on the specific subjects I mentioned, so I risked posting on a thread I knew you were following.
So, I apologize for stating that there was a science troll, and for you self-identifying as the troll. Another man might have neatly sidestepped my ingeniously laid 'trap' by realizing that I hadn't mentioned him by name or directly challenged his views. Now can some one else have a chance to answer my sincere questions without any more of your personal assaults on my integrity? I assure you, I bear you no ill will, and wish only to avoid you to the extent possible. My desire to have absolutely no interaction with you is only outweighed by my interest in the opinions of others on this topic.
Respectfully,
zoid
P.S.
As far as the body cavity search thing goes: Your sig at the time was something along the lines of "You can get a really good cross-section of human mental illness in an airport waiting area -Me" or some such (edited, to be nice). Quoting oneself is (edited, to be nice). I then stated that if I ever saw you (or anyone else for that matter) sitting in my terminal casing the other passengers and wearing a tinfoil hat I'd have airport security body cavity search them. I stand by that statement.
I like your new sig much better. Mr. Rogers, Canada, bricks and Jon Stewart. I think it pretty much sums up your personal philosophy, too. Have a nice life...
P.P.S.
Science is a belief system with its own dogma and sects. I mention this because, what the hell? I'm already in trouble with SigmaNunki. How much worse could it possibly get?
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"Mercy is the mark of a great man... Guess I'm just a good man... Well, I'm all right." -Capt. Mal Reynolds, "Shindig", Firefly
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Finn mac Cumhal wrote:
Quote:
...So if you don’t rule out magic, a lot of possibilities open up.
And, since no one else has mentioned it, if one were to accelerate a massive body like a spaceship to a significant fraction of the speed of light in order to make an interstellar journey, running into a chunk of pea gravel with the mass of a dime would prove catastrophic, unless the ship were somehow magically shielded from such collisions. Correct?
Would I also be correct in stating that since everything is relative, as one approaches infinite mass while accelerating to c, every other bit of matter one might encounter (even massive particles) could be seen as acquiring infinite mass instead, from the viewpoint of a traveler who felt stationary on the ship? Hence, you really don't want to come into contact with anything on your sub-10,000 year interstellar voyage at near-light velocities, unless one wants to become intimate with the ramifications of the E part of Einstein's equation...
Respectfully,
zoid
P.S.
I know accelerated motion is different from constant velocity motion; but, I think my observation is valid if somewhat improperly worded. I don't like overediting my posts. I was envisioning accelerating to say 2/3 the speed of light and then maintaining that constant velocity until a turnaround and deceleration. I'd speculate that one could not thus begin accelerating in earnest until beyond the Oort cloud, and must needs be appropriately decelerated before reaching the target system's Ooort-like cloud. That's going to make for a long trip in any case (at least 500 years?), unless we find some "magic"...
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"Sure as I know anything, I know this: I aim to misbehave." -Capt. Mal Reynolds, Serenity, a.k.a. 'the BDM'
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Wow, a lot can happen when one goes to sleep. Let me try to catch up as best I can...
ColdFusion:
You may be right about the wormhole. When I took GR, we didn't talk so much about the creating, only the maintaining. Solving the Einstein equations for a wormhole definitely yeilds a negative energy density, but I'm not sure about actually GETTING there in the first place...
Finn Mac Cumhal:
I'm not so sure I subscribe to the "science will be its own undoing" philosophy you're talking about. But i supposed that that depends onmy mood at the time. It's certainly possible for people to come up with something to exterminate all life on earth, but I tend to hope the universe is better designed than self-implosion if we get too far :-).
Zoid:
I am by no means a String Theorist, and I certainly haven't read the appropriate books to comment well about it. I've heard a few lectures, and a number of seminars on the subject, but that doesn't give me the authority to contradict Brian Greene. But, what I can say, is that I do know a goodly number of other physicists who have seen Brian Greene's show and read his book saying that it's mostly fluff, very hypothetical, and makes it sound a lot more possible and plausible than the mathematics will dictate. As has been mentioned, string thoery is a very pretty mathematical construction, but as for real physics, has made very little progress over the past few years. Possibly more progress than Numerical relativity, but that's another discussion all together.
To the Sigmanunki-Zoid Feud:
Ok, I seem to recall the thread that start this whole thing off, becuase I think I was posting in that one too. (Physics Geeks, Unite!) Let me just say this. Zoid, you can come off as a bit, um, aggressive with some of your posts. I'm not trying to take sides or be beligerent, just calling it as I see it. You don't mean anything by it, but even when you ask questions it can sound like you're attacking the other people...
Zoid II:
You're right, acceleration and speed are different beasts when you're traveling a significant fraction of the speed of light. The universe doesn't get more massive, because acceleration makes things no longer "relative". If you're not accelerating, you have no way of knowing whether you or the rest of space is moving, but when you are accelerating, you are feeling a force (just like if you were in a gravitational field), and that differentiates you from the rest of the universe, therefore only your mass increases. But yes, that still runs into a problem if you hit a pea sized anything, because at that speed, even something small is still likely to do you damage. Also, the Oort cload doesn't have much to do with it. Even in the Oort cloud, the densities of the material out there is quite small. Literally miles upon miles between one rock and the nexk. Granted, this is orders of magnitude more dense than insterstellar space, but still not a really significant issue...
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FourSkys:
Thanks for your replies. By paragraphs:
1. My understanding of wormholes is that we are more likely to create very small temporary ones, than stable ones large enough to travel through. Potential uses for such would include telecommunications.
2. ..."science will be its own undoing": I, as an inhabitant of this planet, am very concerned about the prospect of fusion reactors on Earth. The notion of containing a plasma as hot as the sun within either a magnetic or inertial confinement of Man's manufacture, gives me pause. I'm also not keen on the names 'Shiva' and 'Nova' for an earth-based reactor...
3. So, basically, string theory is mainly popular among authors. This is because it makes no independent predictions which can be experimentally verified; it appears to be a mathematical formulism that agrees with QM without predicting anything new (that can be directly verified) and adds a level of complexity unnecessarily. So, Okham's Razor applies. All correct?
4. Yeah, the feud. It all started when I made an analogy between religion and science (as in my P.P.S. above). Everyone showed me the hate. And I still believe what I said is both logically supportable (as analogies go) and relevant when considering Western society. No offense intended, but I see parallels.
5. Upwards of a trillion cometary nuclei in a spherical shell around our (and possibly every) solar system, none of which are astrogationally plotted would pose a problem in risk analysis for a ship moving at near-light speeds. Launching the ship out of the plane of the ecliptic would avoid most of the matter in our system; but, if http://www.windows.ucar.edu/tour/link=/headline_universe/solar_system/
stories_2004/sedna_planetoid_march2004.html> Sedna truly indicates the existence of an "inner Oort Cloud", the interstice between inner and outer solar system may be relatively small. (NB: Sedna resides at 900 AU; Oort cloud suspected ~50,000 to 100,000 AU.)
Again, thank you for your insights. I truly value them. Do you ever contemplate the implications of your investigations, or are you more of a "just calculate" guy? It seems somehow unnatural to me not to question underlying fundamental frameworks as an article of 'faith'; but, QM says you can't know, so don't bother asking. Yikes.
Respectfully,
zoid
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Quote:
Originally posted by zoid:
1. My understanding of wormholes is that we are more likely to create very small temporary ones, than stable ones large enough to travel through. Potential uses for such would include telecommunications.
While of greater plausibility than transport, I still hold many a reservation. We're just not at the stage where something like that is even remotely possibly...
Quote:
2. ..."science will be its own undoing": I, as an inhabitant of this planet, am very concerned about the prospect of fusion reactors on Earth. The notion of containing a plasma as hot as the sun within either a magnetic or inertial confinement of Man's manufacture, gives me pause. I'm also not keen on the names 'Shiva' and 'Nova' for an earth-based reactor...
So, yeah, having something go wildly wrong witha fusion reactor poses an immense problem. But there are many other ways to destroy most if not all life on earth that are a lot easier and the technology has already been developed. We just haven't done it yet. What can I say, I'm an optomist.
Quote:
3. So, basically, string theory is mainly popular among authors. This is because it makes no independent predictions which can be experimentally verified; it appears to be a mathematical formulism that agrees with QM without predicting anything new (that can be directly verified) and adds a level of complexity unnecessarily. So, Okham's Razor applies. All correct?
I'll agree to that.
Quote:
5. Upwards of a trillion cometary nuclei in a spherical shell around our (and possibly every) solar system, none of which are astrogationally plotted would pose a problem in risk analysis for a ship moving at near-light speeds. Launching the ship out of the plane of the ecliptic would avoid most of the matter in our system; but, if http://www.windows.ucar.edu/tour/link=/headline_universe/solar_system/
stories_2004/sedna_planetoid_march2004.html> Sedna truly indicates the existence of an "inner Oort Cloud", the interstice between inner and outer solar system may be relatively small. (NB: Sedna resides at 900 AU; Oort cloud suspected ~50,000 to 100,000 AU.)
Problematic? Yes. An issue? Sure. But if you could get a spacecraft out that far in a reasonable amount of time, you've already solved problems that are a lot harder than that. We're talking a trillion cometary nuclei, a few miles in diameter, over a spherical shell thats, oh, 4PI*(R1-R2)^2 that's... a really big number. It's not un navigably dense out there...
Quote:
Again, thank you for your insights. I truly value them. Do you ever contemplate the implications of your investigations, or are you more of a "just calculate" guy? It seems somehow unnatural to me not to question underlying fundamental frameworks as an article of 'faith'; but, QM says you can't know, so don't bother asking. Yikes.
So I'm bipolar when it comes to science. I really don't think that religion and science have much to say to each other. Philosophical speculation in many ways can hinder science and gets in the way. You start doing things becuase you expect them, not because the theories and math lead you there. Science really should leave the religion out of it's processes.
That said, I'm a fairly religious person. I belive religion has something to say about everything. But that doesn't mean that I confuse the two. I can contemplate the Truths about existence and stand amazed at the incredible creation that is the world, and philosopically contemplate the end products and goals of scientific persuit. I love to philosophize (took a number of philosophy courses for fun in undergrad). But questioning the underlying framework from that perpsective doesn't lead to good science. It leads to good discussion, good philosophy, but not good science. Philosophy/Religion ask Why, whereas Physics asks How. They're fundamentally different persuits, and I think they should pretty much stay that way...
(granted there are argum
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FourSkys wrote:
Quote:
...So I'm bipolar when it comes to science. I really don't think that religion and science have much to say to each other. Philosophical speculation in many ways can hinder science and gets in the way. You start doing things becuase you expect them, not because the theories and math lead you there. Science really should leave the religion out of it's processes.
That said, I'm a fairly religious person. I belive religion has something to say about everything. But that doesn't mean that I confuse the two. I can contemplate the Truths about existence and stand amazed at the incredible creation that is the world, and philosopically contemplate the end products and goals of scientific persuit. I love to philosophize (took a number of philosophy courses for fun in undergrad). But questioning the underlying framework from that perpsective doesn't lead to good science. It leads to good discussion, good philosophy, but not good science. Philosophy/Religion ask Why, whereas Physics asks How. They're fundamentally different persuits, and I think they should pretty much stay that way...
My last stab at clarifying my position on this issue: Yes, I am a deist and a Christian. But, I don't expect to find God's handiwork through science. I believe God created the universe and likewise made it a whole puzzle for the mind of Humankind. You will never lift some corner of the universe's 'carpet' and find a tag reading, "Made by God, (c) 4000 B.C. Do not remove under penalty of The Law."
As such, Science is on its own, as are we all. There are no given answers; we must find them on our own or not at all. Hell, maybe there are no answers, only questions and hints.What I was trying to say -- and was soundly spanked for even suggesting it -- is that science is like a religion in that it has basic tenets of 'faith' (things it believes even though these haven't and possibly may never be proven), and uncomfortably coexisting sects (differing schools of thought based on the same principles). I'd like to refer the reader to http://en.wikipedia.org/wiki/Interpretation_of_quantum_mechanics and specifically the section on that page entitled "Comparison". Even though the most commonly believed (there's that word again) 'interpretations' hold the same basic principles to be inviolable, their adherents come to some radically differing conclusions (unless you don't think a single universe v. an infinity of universes is a radical divergence). Likewise, even though most scientists engaging in these endeavors adhere to Dirac's commandment, "Just shut up and calculate", they nonetheless wind up falling into one of these schools of thought; wackiness and occasional name-calling ensues. I cannot help but see a parallel between this and Franciscan v. Dominican v. Benedictine, as one of many examples in religion. And then of course, you have those who adhere to ('believe in') wildly variant fundamental principles, and careers (and research grants) may hang in the balance.
To sum up, I'm not saying science is a religion that replaces God in the mind of scientists, per se; but rather that it has a lot in parallel with religion, in terms of its framework. That was all I was trying to say then (although that discussion escalated beyond reason), and that's all I'm trying to say now. I'm not saying science should try to find God or be somehow informed by a belief in Him. I'm not trying to say Science is trying to replace God. (NB: ...And good luck to It, if It is. Religions have been trying to replace each other for millenia, and we can all see how that's working out.) I do not read my little science books trying to debunk science or find the hand of God in the universe. I read them because I'm genuinely interested in what we as humans know about our universe and our place in it, and what remains to be known and what roads we are taking to get there (I'm also fascinated by the spontaneous generation of complexity, vis-a-vis an explanation of the 'staccato' fossil record). I find it
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Quote:
Originally posted by zoid:
P.S.
As far as the body cavity search thing goes: Your sig at the time was something along the lines of "You can get a really good cross-section of human mental illness in an airport waiting area -Me" or some such (edited, to be nice). Quoting oneself is (edited, to be nice). I then stated that if I ever saw you (or anyone else for that matter) sitting in my terminal casing the other passengers and wearing a tinfoil hat I'd have airport security body cavity search them. I stand by that statement.
If you're going to quote me, then quote me. By stating this I will assume that you don't actually have the quote. And you never stated that "if I ever saw you ..." prefix in your reply to me, you just stated if I ever saw you...
So, if you have time to look up the thread and prove me wrong, go right ahead. I don't have the time to waste.
Quote:
Originally posted by zoid:
I like your new sig much better. Mr. Rogers, Canada, bricks and Jon Stewart. I think it pretty much sums up your personal philosophy, too. Have a nice life...
I find it funny at this point that you are pointing out to me my personal philosophy having never met me nor have you ever really had a meaningful conversation for me. Tad arrogant are we?
So, why don't you enlighten us by what my personal philosophy is? Because, quite frankly, I just found it funny (by the way, I am Canadian).
Quote:
Originally posted by zoid:
P.P.S.
Science is a belief system with its own dogma and sects. I mention this because, what the hell? I'm already in trouble with SigmaNunki. How much worse could it possibly get?
Please read:
http://dictionary.reference.com/search?q=belief%20system
Belief system does not have anything resembling sect (read: orgaization).
Also, in it's colloquial meaning, it does refer to something of a religion. Which we all know that science is definitly not (provable).
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"Canada being mad at you is like Mr. Rogers throwing a brick through your window." -Jon Stewart, The Daily Show
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