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Science

How Neutron Stars Get Their Kicks 77

Posted by Hemos from the get-your-kicks-on-route-66 dept.
mustermark writes: "Now we may know why neutron stars zip through space at 1000 times the speed of a normal star. Massive stars have been shown to collapse aspherically, and chunks blown off in this process may recoil the neutron-star remnant in the opposite direction."
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How Neutrons Stars Get Their Kicks More

How Neutrons Stars Get Their Kicks

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  • Holy moly, galactic billiards!

    I'm going to have to get down to the Patent Office and get dibs on that... but first, Tau Ceti in the corner pocket.

  • Well, duh! (Score:3)

    by Kris_J ( 10111 ) on Monday June 19, 2000 @08:18PM (#990995) Homepage Journal
    From the article;
    supernovae are not symmetrical in shape
    Of course they're not symmetrical, because stars aren't symmetrical. There's an article over at space.com [space.com] that dicusses our own sun's "hills and dales". And, I mean, hello - sunspots, flares, magnetic storms, CMEs. Here's a bit of space.com's article;
    The most sensitive measurement ever made of a star's shape shows that our sun is speckled with tiny hills and dales, much like the surface of the ocean, University of Hawaii researchers said.

  • The Dateline (Score:4)

    by paulproteus ( 112149 ) <slashdot AT asheesh DOT org> on Monday June 19, 2000 @08:19PM (#990996) Homepage
    I particularly enjoyed the dateline.

    "Jun 19, 2000 - ROCHESTER, N.Y. -- When a massive star runs out of nuclear fuel something extraordinary happens in the space of a few seconds: The star's core collapses from a radius of 1,000 miles into a tight, dense ball."

    Wow, all that happens here in Rochester?

    Jeez. I really have to get over to the University of Rochester more often then!

  • This is the stuff that makes /. great. The stories that make us geeks get all excited and feed our hunger for knowledge. This is news for nerds, stuff that matters!

    NightHawk

    Tyranny =Gov. choosing how much power to give the People.

  • You sir, give Anonymous Cowards the world around, a bad name.

  • Kind of cool! (Score:3)

    by tie_guy_matt ( 176397 ) on Monday June 19, 2000 @08:26PM (#990999)
    As the star collapses, if one side is less dense than the other gravity will cause the density gradient to increase. This insures that when it expels matter more matter is expelled on one side than the other. I guess it would be possible to have a star that's density is so balanced that no gravitational gradiant will be produced, but the odds of this happening is so insanely low that stars ALWAYS get a density gradient and therefore always get a kick when they are formed.

    Understanding the mechanics of the universe is important because it increases our knowledge of science in general. It may not be clear right now how understanding something that happens thousands of light years away (and therefore took place thousands of years ago) may be useful. But one day it will be useful. After all at first studying the planets didn't seem that useful but Newton used planetary motion when he was fathering classical physics.

  • What about Binary Neutrons? (Score:3)

    by krystal_blade ( 188089 ) on Monday June 19, 2000 @08:29PM (#991000)
    I'm not sure how long ago it came up, but it was theorized that the high rate of speed came from a close binary system where one Nova'd.

    A closely matched binary system would trade accretion until the soon to be Neutron was orbiting a further away, but rapidly falling towards the slightly denser soon to be Nova. If the quasi Neutron star was far enough away when big brother lost his top, the shockwave, and infalling matter would actually push it to "ludicrous speed".

    If the quasi neutron star was too close... well, it would still move (if not destroyed) but its chances of growing into an adult Neutron.

    Any Accretion pulled off of the nova'd star would be stripped while moving, and the star would begin it's decay into a Neutron.

    krystal_blade

  • Yeah, and the Earth is flat! After all, if it were round we would fall off. Constellations do change though quite slowly (when compared to the length of human life.)

    I've got an idea: here is a book -- read it!
  • Gee, all this I just thought that Neutron stars were neurotic (thus causing the other stars to shun them). No, seriously though. Someone above mentioned that stars don't move. Well, that is obviously quite false. However, unbeknownst to whover wrote that, he actually did bring up an interesting topic. Do all stars move? We would say yes, but there is no objective way to say. Theoretically, assuming a central point from which all stars originated, all stars should be moving. However, theory does not a fact make. It is quite possible that some stars are perfectly stationary, and yet we perceive htme as moving based on our own positioning in the universe. Our solar system/galaxy moving, therefore perceived motion elsewhere. Since there aren't really any signs in the Universe that say "I am perfectly stationary, measure from me", we have to just make assumption about everything else's mation. I propose that we use our own sun to measure the motion of everything else. After all, it is the most relevant "mile marker" for us earthlings, isn't it? This system would enable us to measure travel/velocity of all observable objects, and in a way that would be relevant to us here on Earth (or even on Mars, Venus, or any other planet in the system). What do you guys think?

    Jaeger
    http://334.se2600.org
    http://jump.to/jaeger

  • Hydrogen atoms have 1 proton and 2 nuetrons.

    Most hydrogen atoms have merely 1 proton and no neutrons. A small percentage has 1 proton and 1 neutron, and this is called deuterium. An even rarer (the rarest) configuration is 1 proton and 2 neutrons, this is called tritium and is radioactive.

  • Enter the Collector (Score:3)

    by krystal_blade ( 188089 ) on Monday June 19, 2000 @08:51PM (#991004)
    The neutron star is basically the wiseguy of the universe. Small, compact, and BAD AS HELL...

    So, with Cosmic Inflation, coupled with moderate interest levels, people are gonna start lookin for other means of entertainment. (Do you know how much it costs to get a supernova light show?) Plus, there's always the tickets to those special event horizons, that everyone seems so hyped up on. And lets not forget that since the discovery of the Cosmic Background Radiation, everyone wants a microwave.

    Everyone's gotta PAY for that stuff, and some people are being super dense, and writing rubber checks their atomic structure can't cash. Eventually, all those star banks get pissed, and they send in Guido, the Neutron Star to clear things up. He's got the gravity for Repo jobs, and the speed to get things done quickly... He probably carries around one of those Accretion(tm) golf clubs too, just in case.

    There's just no getting around the speed this guy needs to get his job done, since nothing travels faster than a bounced check. And you think those black holes got any money? Hell no... They sucked down both theirs, and a whole lotta other paychecks during "binge week". Give em Guido Neutrono... He'll bust their kneecaps.

    krystal_blade

  • No, I really don't think you want to be around for that. In fact, I'd recommend getting out of the state if that's likely to happen in Rochester, just to be on the safe side.
  • Space is my favorite subject. More space stuff guys! Especially about black holes.

  • Other chunks... (Score:3)

    by pvcf ( 150815 ) <paul@frattaroli. o r g> on Monday June 19, 2000 @09:10PM (#991007)
    OK, this article left me with one question... If these neutron stars accelerate due to matter being blown off the star, and assuming that this matter being blow off is less than the mass of the star, the expelled matter would obtain an acceleration greater than the remainder of the star.

    So, if the neutron star is going so fast, how fast is the stuff it's blowing off going?

    More importantly, where is it going?

    Oops, that's two questions isn't it? DOH!!! Three!

    ....Paul

  • Re:motion of stars (Score:5)

    by mmontour ( 2208 ) <mail@mmontour.net> on Monday June 19, 2000 @09:12PM (#991008)
    Since there aren't really any signs in the Universe that say "I am perfectly stationary, measure from me"

    Actually, there is a pretty good one - the microwave background radiation.

    There is a nice picture here [nasa.gov] which shows the relative temperature of this radiation as seen from earth. It is clearly red-shifted in one direction and blue-shifted in the opposite direction, indicating that the earth is moving rapidly (600 km/s) in the direction of the blue-shift. Some of this velocity is our motion around the sun, some is the sun's motion in our galaxy, but most of the velocity is common to our entire local group of galaxies.

    If we were "at rest" in the universe, the microwave background would be uniform in all directions [more precisely, the dipole component would be zero; quadrupole and higher terms would still be present]. However, distant stars and galaxies would still be moving away from us due to the expansion of the universe.
  • Nope, no cookie for you...
  • This AC is obviously a flame. But...

    What is science but the statment of a theory (hypothesis), testing that theory by observations and rejecting the theory when no longer supported by evidence.

    > If your predictions match reality, thats just a lucky guess.

    Huh? If your prediction matches reality, that means your hypothesis has not yet been rejected by science. You may gain more confidence but until the theory is disproven or superceded, it'll always be a theory.

    Care to offer comment on how physics, chemistry and biology differ?

    I didn't think you would. Another one bites the dust.
  • Are you by any chance a guy named Douglas Adams?

    :)

    Just joking :)
  • Theoretically, assuming a central point from which all stars originated, all stars should be moving. However, theory does not a fact make. It is quite possible that some stars are perfectly stationary, and yet we perceive htme as moving based on our own positioning in the universe

    Unfortunately, this logic seems flawed. The rotation of the solar systems, galaxies, clusters, etc, proves that motion does in fact take place. If an object within a galaxy was in fact stationary, it would have to rotate at the exact path necessary to remain stationary as the rest of the galaxy circled it local group, which is impossible. Whether or not the entire universe is itself moving is, at this point in time, irrelevant.

    I propose that we use our own sun to measure the motion of everything else.

    The problem with the proposal that our sun is stationary causes problems as well. If our sun is stationary, the universe is destined for substantial problems, for it is not massive enough to support the unbalanced rotation (centripetal and centifugal and all those other nice forces that stem from torques and fundamental mechanics), causing a universe that would spiral off, thereby creating a paradox: if it spirals away due to the unbalanced rotation, it is no longer stationary, therefore it can not by the stationary center of the universe, can it?

    But hey, I didn't do too well in physics last semester, I could be really wrong :)
    ============================================== ===
    If ignorance is bliss, wipe the smile off my face
  • and chunks blown off in this process may recoil the neutron-star remnant in the opposite direction

    this theory has more applications than simply explaining the motion of neutron stars. for instance, i've often wondered when i'm bent over the toilet bowl blowing chunks after a huge drinking session, why my head recoils in the opposite direction, and everything else seems to be moving 1000 times faster than i am. now i know thanks to this new theory.
  • And why am i having a hard time believing you've even had sex??? Or am i just associating you with the typical /. reader??? :)
    ============================================== ===
    If ignorance is bliss, wipe the smile off my face
  • This theory has been in place for a long time. It is a well known fact that neutron stars are often moving with high velocities. Many such objects have had their proper motions (angular velocities) measured. It is also known that supernova remnants (the guts of a star after it explodes at the end of its life) are not spherical. This is the topic of research that I work on. To answer a question above I have measured motions in supernova remnants that vary by over a factor of two. That is, one side may be moving at 5,000 km/s and the other may be moving at 2,000 km/s. One can also see much more rich structure in the kinematics of these complex objects. For instance, I have found material moving inwards! Now that certainly is not a spherical explosion!
  • Not that i completely disagree with you, but i tend to stay away from "black holes"
    ================================================ =
    If ignorance is bliss, wipe the smile off my face
  • In his Hitchhiker's Guide to the Galaxy he describes how a little mistake with Galactic Billiards caused billions of deaths when an inhabited planet was accidentally potted into a nearby black hole.


    )O(
    the Gods have a sense of humour,

  • Re:Other chunks... (Score:3)

    by bubbaswank ( 202541 ) on Monday June 19, 2000 @10:08PM (#991018)
    I also answered a bit of this below, but I thought I would elaborate here...

    Very early on in a supernova remnant's life the ejected material is moving very fast, 10-20,000 km/s. Within a few hundred years most of it is decelerated to less than half that. By a few 1000 years the material is moving a few to several 100 km/s. By 10,000 years (or a few times that) the ejecta slows to about 10 km/s, which is the average random velocity of the interstellar medium. At this point the remnant blends with the ISM and vanishes.

    It is mostly going outward. BUT much of it is not going exactly radially outward. In all remnants where this has been measured there exists a significant non-radial component to the velocity. This could be caused by the asymmetric explosion, or the interaction with the surrounding medium.

    True, the ejecta move faster than the neutron star. This is due to conservation of momentum.

  • Re:Other chunks... (Score:1)

    by Anonymous Coward
    Here's a question for you. What is causing the material to decelerate? Friction with other ISM?
  • I don't know who was first between the two, but Grant Naylor also wrote this into an episode of Red Dwarf. (Is it White Hole? I forget...)

    In that episode, they use a solar flare to knock a 'cue' planet out of orbit with the goal of clogging up some space thing (white hole?) with it so it won't suck in the ship.
  • Just thought some of you might like a more in-depth look at neutron stars. I've been doing some reading on neutron stars in the last few days, so I hunted around in my browser's history and found the two articles I had been reading.

    The first one [newscientist.com], by New Scientist [newscientist.com], is a neat article on stars and their hunger for the planets around them.

    The second one [sciam.com], by Scientific American [scientificamerican.com], is a bit technical, but it describes how the X-ray emissions from neutron stars are being used to estimate their size.

    --
  • There was a Dangermouse episode about aliens whacking planets into a black hole too ("So would the moon have counted as 4 points away?" asks Penfold). Not sure if it was before or after the Hitchikers joke. certainly before Red Dwarf though... And yes the Red Dwarf Episode was White Hole

  • Why was London always so deserted in the Dangermouse cartoons? It was like someone had let off an air strike above it, wiping out all of the population except for Dangermouse's HQ under the post box (is that right?). And it was Baron Greenback, Nero and Stiletto right?


    ---
    Jon E. Erikson
  • The most sensitive measurement ever made of a star's shape shows that our sun is speckled with tiny hills and dales, much like the surface of the ocean

    Yeah, but consider how insignificant the hills and dales on the surface of the ocean are relative to the size of the planet. I don't know how accurate this is, but I've been told that if the Earth were the size of an orange, the largest bump on the surface would be smaller than the bumps on the orange.
  • Yes, but during a catastrophic failure the magnitude of a supernova the slightest deviation will result in major differences across the surface. It's like metal fatigue, or basically any other highly stressful condition - a slight inconsistancy will concentrate energy very dramically.

    Anyway, if Supernova were perfectly even every nebula would be a sphere, or some sort of ring thing (how dull would that be).

  • Lad, you don't seem to understand the fundamentals of astronomy. Although a neutron star might seem inert, the core falls in on itself, and it releases its stored heat in the form of ghostlike particles called neutrinos. As the neutrinos zig-zag out of nuclear fuel something extraordinary happens in the magnetic field that surrounds the newly formed neutron star. After that, the core becomes denser than the other side and then, form peculiar objects with properties of binary pulsar systems. Moreover, many recent observations have revealed that supernovae are not symmetrical in shape!Neutron stars, one group of which are called pulsars, are the cause - the accretion process is well known. This is the fundamental reason for the non-inertness with regard to motive frequency.

  • And if he is:

    Wheres the interview?!
  • Actually, I've heard the Earth is smoother and more spherical than a billiard ball, so yeah, those bumps are pretty insignificant (even Mt Everest to Mariana is nothing: what, 25km/6370km?). However, as the above poster stated, even the slighted deformity serves as a stress concentration point. In fact, that's how glass cutters work: the score they make on the glass concentrates the bending stress to that line and so the glass breaks (mostly) cleany along the score. Similar thing for a super dense star core :)
  • They move so fast because they are always farting. In space you can really let loose because no one can here you fart. Discuss.

    Gaelen
  • Not sure if it was before or after the Hitchikers joke.

    Well, since Hitchhiker's Guide was first out in the late '70s to early '80s, I suspect it came before Dangermouse.


    ...phil

  • Riiiiiiight. And the Earth is only 6000 years old?
  • Once over the inital shock and utter rejection of that statement as complete ignorance or a really poor joke, I realized that in fact it is more logically correct to say that stars are stationary. If you first recognize that the concept of not moving only exists as a relative term from a human perspective, then you see that indeed stars do not move.

    What I find interesting is that this points out how the definition of fact changes drastically from one reference frame to another.
  • Just #include in your application and you'll be able to access:

    g_blow_chunks();

    I'm not sure what the memory requirements for a neutron star are though - probably quite high.

  • Exactly! It is interaction with the ISM that slows the ejecta, eventually causing it to merge back into to the ISM out of which the star itself formed. It is actually quite a wonderous cycle.

    What we don't really know is how much of the asphericity is due to the initial explosion and how much is due to the interaction with different densities in the external interstellar medium, since both produce the same effects.

  • I'm not surprised. I know several people from upstate NY, and most of them are pretty dense.

    (duck, run, hide)

    Those fine institutions in Rochester and Troy excepted of course.. Heh.
  • It seems to me that the best you can do with this is to determine (or decree) that a star does not move. Which frame of reference you pick doesn't matter, but you can only have one at a time.
    ..this is, of course, nit-picking.

    But here's a thought: why is time not relative? Everything in the universe (that we know of) travels in the same direction at the same rate through time. Is time the one constant in a relative world?

    --
    Philosophy, like masturbation, is something everyone does, but most of the time it's just too awkward to talk about.

    --

  • I do believe that time is also relative. Does not time changed with speed? Everything moves forward through time (though I almost recall something....), but age at different rates. The famous atomic clock experiment showed that a clock orbiting the earth gained time slower than one sitting at sea level. Go Einstein.

    .sigs are dumb!

  • Douglas Adams is so far ahead of me I've given up trying, frankly. (grin)

    But the original inspiration for my post was the pinball game in the Grateful Dead Movie animation.
  • Blockquoth the poster:
    But here's a thought: why is time not relative? Everything in the universe (that we know of) travels in the same direction at the same rate through time
    Er, no. Photons (the particle for light) do not experience time at all, from our frame of reference. And if you compare your clock to an identical one on a rocket moving (quickly) past, you'd see that the rocket's clock would be running slow compared to yours. This has been empirically verified, both through muon counts and through a careful airplane experiment.

    What's really weird, though, is that the rocket would see your clock as running slow.

  • You're right, of course -- rate of change of time changes with velocity.
    Hrm.. Motion is relative.. there is no motion without a frame of reference.. The difference in the rates at which two seperate observers travel through time is a function of their velocities relative to each other.

    Here's something I wonder.. the idea that the speed of light is a limit on how fast something can travel seems to be at odds with the notion of the relativity of motion.

    Ex:
    (1) - relatively motionless (v = 0 m/s)

    ...(2) - half of lightspeed (v = 0.5c)

    ......(3) -lightspeed (v = c)

    (4)... -1/2 lightspeed the other way (v= -0.5c)

    QUESTION: Isn't (3) exceeding lightspeed relative to (4), but not to (1) or (2)? What happens at this point? Is there a fault in my logic?

    --

  • Quick... drink lots of beer and wave your towel. It's the only way to prepare for space flight...
  • Yeah guys :o) Come on... What the heck? Come on, if you can't handle reading about SCSI and bit addressing then you need to go elsewhere ;o)
  • Hmmm, good way to get points...suck up ;o)
  • "I realized that in fact it is more logically correct to say that stars are stationary"

    Well, it is all about frames of reference. If your frame of reference only includes the earth and one star, and the distance between both is changing, then, you can logically say either:

    1) The earth is moving w/ respect to the star (The star is motionless)

    2) The star is moving w/ respect to the earth. (The earth is motionless)
    Up to now, what you have said can be right.. NOW, if we include 2 stars and the earth in a frame of reference, and star 1 is moving away from the earth (w/ respect to the earth), star 2 is moving towards the earth (wrtte), and star 1 is moving away from star 2 (w/ respect to either star 1 or star 2) , your options now are:
    1) The earth is moving w/ respect to star 1 (star 1 is motionless, but earth and star 2 move)

    2) The earth is moving w/ respect to star 2 (star 2 is motionless, but earth and star 1 move)
    3) Star 1 is moving w/ respect to Earth (Earth is motionless, but star 1 and star 2 move)
    4) Star 2 is moving w/ respect to Earth (Earth is motionless, but star 2 and star 1 move)
    5) Star 1 is moving w/ respect to Star 2 (Star 2 is motionless, but star 1 and the earth move)
    6) Star 2 is moving w/ respect to Star 1 (Star 1 is motionless, but star 2 and the earth move)
    None of the possibilities now have BOTH stars motionless, that's where the problem lies.. unless all stars in the world are glued onto a matt, and some god slides the matt around, you are wrong.. Sorry!

    "Producing satire is kind of hopeless because of the literacy rate of the American public."
  • Yeah, DanBari admits his ignorance, and feels bad that he has trashed the rest of Slashdot's society. Perhaps we should form a monastary of Science and conduct experiments involving stars that travel.
  • I wonder whether it would be possible to detect a neutron star that is moving toward our solar system at a speed of say 2000km/s and the spin of that star is parallel to our viewing point so that the ejection beams can not be detected (the pulse can not be detected), wouldn't it be neat if a neutron star passed by Earth and maybe even hit it, or any other planet, or even the Sun? I defenetely would love to see the special effects!
  • That's where relativity jumps in. I only covered this for about a week in high-school, so i'm not exactly sure about it all =).. but in those cases, to compensate for what may seem like something going faster than "c", time and space distort.

    v = d / t right? right.

    so if d = 2, and t = .5, THEN v = 4.
    now, saw we double v (v = 8), to make the equation valid, we need to make one of 2 possible changes! We can either change d from 2, to 4.. OR, we can change t from .5 to .25 !

    Check it out:
    8 = 4 / .5
    or
    8 = 2 / .25

    See? it works both ways. NOW, since we can't have a speed exceeding c (well, i guess we can, but lets just say, for this case in specific, that we can't) we must change another part of the equation so it remains valid. We can either change the distance in the equation, or the time in the equation. that's how i remember they explained relative velocities that would exceed c. Either space or time changes so that nothing exceeds c, and so that c is always the same (no matter the frame of reference). Hope that helped!


    "Producing satire is kind of hopeless because of the literacy rate of the American public."
  • Cliffton, most of what you say above is not correct.
    the core falls in on itself, and it releases its stored heat in the form of ghostlike particles called neutrinos.
    The core falls in on itself due to runaway gravitational collapse. The huge increase in density and energy density pushes atoms in upon themselves, forcing electrons into protons and forming neutrons. This in turn creates the neutrinos you mention, it also creates the neutron star.
    As the neutrinos zig-zag out of nuclear fuel something extraordinary happens in the magnetic field that surrounds the newly formed neutron star.
    The neutrinos have nothing at all to do with the magnetic field. The magnetic field is amplified because it is compressed due to the fact that the star shrinks from its normal huge size down to a neutron star of about 10 km.
    After that, the core becomes denser than the other side and then, form peculiar objects with properties of binary pulsar systems.
    There has been nothing of this sort ever postulated or observed. Such a configuration would be extremely unstable due to the excessively high gravity on a neutron star. 1 cubic centimeter of neutron star material would weigh millions of tons on earth. This type of gravitation would not allow for much asymmetry in the shape of the star itself.
    Neutron stars, one group of which are called pulsars, are the cause - the accretion process is well known. This is the fundamental reason for the non-inertness with regard to motive frequency.
    Yes, some neutron stars are pulsars, if they have a high enough magnetic field and are rotating fast enough. We would only see them as pulsars if their "pulsar beam" is pointing towards us.

    The rest of the above is gibberish.

  • Stars are a lot more symmetrical than you appear to think! The reason planetary nebulae and supernova remnants look asymmetrical has much more to do with the non-homogeneous medium into which the shell is expanding...

    OTOH, we are talking about tiny, tiny asymmetries:

    • A supernova relases 10^51 ergs in mass motion and optical display, 10^53 ergs if you count neutrino emission.
    • A neutron star has a mass of ~1.4 times our Sun's mass: to make it travel at 700km/second takes only 10^49 ergs.
    So you see, even the fastest neutron stars we know of (the Guitar nebula, for example, is created by a pulsar going ~1600km/sec) use only a tiny fraction of the energy of a supernova.

    And still, even that tiny fraction takes explaining - but if we buy into hypernovae that create Gamma Ray bursts, then this is a trivial problem.
    Sigh - its annoying to reduce your thesis proposal to a trivial problem!

    Learn more here... [cornell.edu]

  • While this isn't completely in line with what you are saying (trying to find a place to measure from) I have always wondered about something and your comment made me think of it again. If moons orbit around planets, planets orbit around stars (for the most part), the stars orbit around the center of the galaxy (I believe this is the case, anyone with other stories?), then isn't it probable that galaxies are actually orbiting around something (somewhere in the midst of the group of galaxies). Possibly, this level of orbits and larger bodies to orbit around continues for infinity, but I would think that somewhere is a central point that all matter in the universe orbits around. While I know it won't happen in my lifetime, I have always wondered if it would be possible to find this central point of orbit. This would be the perfect thing to measure from, as it would most likely be the actual "mile marker".

    Of course, I could be wrong on this. Since no one really knows (at least no one on earth) if the universe is infinite, maybe the universe itself is part of a larger collection of universes all orbiting some other central point. Perhaps somewhere in this multi-verse (in theory) space-time actually plays into the orbits themselves.

    OK, anybody reading this comment must realize that there are reasons that I didn't take up astronomy as a career. I get to thinking in terms of "is the universe really infinite" and "is there a multi-verse based on space-time" and end up driving myself nuts. But, I would still think that there must be a central point somewhere that all matter travels around that is "stationary". And while I took a long time to say it, that is the point I was trying to make.
  • The point that I was trying (unsuccessfully) to make was more philosophical than scientific. I was trying to say that everything is moving in some sense, and that we are left only with a practical interpretation of immobility. And in this, practicality is how directly something relates to a person's perceptions.

    Relative to the distance between stars and the length of time of human observation, stars can be considered immobile, just as we consider the shifting techtonic [sp!?] plates unmoving.
  • *sigh*

    OK, let's put this baby to rest, once and for all:

    Everything in the universe, by definition, moves, simply because it all revolves around me.

  • While it would be "cool" as you say to see this happen, I am wondering:
    If a neutron star were to hit the Earth, or the sun, or even another planet in our solar system, how the hell would you "see" the "special effects" (as you put it)? I'm not an expert at this sort of thing, but my understanding is that with a neutron star the mass is great enough that having it even pass by our solar system very close could be enough to knock planets out of orbit and screw up our sun's orbit in the galaxy and all sorts of other havoc. If this is true, even space travel to a far away place wouldn't really allow you to "see" this as it happened, as you would either be too far away to see it, or be sucked into the resulting ping-pong like action happening between planets and sun. Of course, I could be completely wrong on this.

    I realize you are just joking around, but frankly, I know people that get all crazy when you say something about how fast some things travel in the universe. They start getting all paranoid and stay up nights looking through a telescope trying to see if we are "about to get it". That's really sad, but I suppose those people probably aren't interested in the reality of it. Everyone needs something to worry about. Some people just worry more about things they have no control over than the rest of us. It may seem neurotic, but to each his own.


    DISCLAIMER
    P.S. If you actually get to this point, you really should seek professional help. It's OK to wonder about it, but letting it consume you is way too far out to be good for your mental health.
  • I was just wondering: your "DISCLAIMER" said "If you actually get to this point, you really should seek professional help..." did you mean this point of mental state or this point in your post ? :)
  • If you think about it, all stars must be moving because everything in the universe has been moving since the supposed "big bang". If anything the star would be stationary relative to the observer, but it would still be moving since the universe is perpetually expanding until it either collapses back down on itself or breaks free and continues expanding indefinantly.
  • I sort of half-remember a short story I read when I was a little kid where it turned out that the earth was an egg. Humans figured this out when the mother bird was spotted returning to the nest. They started checking out the interior and realized that all those silly plate tectonic explanations for earthquakes were wrong, its just the chick moving around. Anyhow, they said that the surface features of the earth are about the same as the tiny bumps on a chicken egg...

  • Thank you for the corrections, lad, my specializing field isn't astronomy, it's Bioinformatics. I do know a bit about it, though, and I can assure you that none of what I said was gibberish.

  • I'm an astronomer, and one area I do research in is the asymmetries of SNe. Actually, some supernovae appear to have asymmetries on the order of 30%. This is inferred from polarization measurements that we've done. One of these days I'll write up a story about it for starstuff.org (I am actually the co-creator of the site, though I didn't write this neutron star article), but for now you can see the gory details at: http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bi bcode=1999astro.ph.12033W&db_key=PRE&hig h=3845e365b719527 You can also see signs of SN asymmetries in the fact that man SN remnants aren't round. We've even been able to watch the evolution of the layers blown off of the closest supernova in a long time, SN 1987A. Check out: http://oposite.stsci.edu/pubinfo/PR/97/03.html Hope this clears up that comment.
  • Just finishing my PhD in astrophysics (after far too many years of training) I can tell you that your final sentence (other than the fact that pulsars are neutron stars) is gibberish.

    Accretion does not create pulsars. It is also not thought that supernovae that are ignited by accretion (SN type Ia) create neutron stars at all. They are believed to expire in a massive explosion leaving all guts and no core (thermonuclear deflagration).

    "This is the fundamental reason for the non-inertness with regard to motive frequency." is gibberish

  • ...any theories about the material moving inwards? Secondary explosions? Fascinating, really...

  • As I said above, in my research I have found inward moving ejecta. This has been seen by other researchers too.

    I have explained it as being due to interaction with the external medium. If you have a much lower density on one side of the supernova remant than the other it will set up a pressure gradient within the remnant which pushes material to the less dense side. This has been confirmed through numerical hydrodynamic simulations.

  • As the neutrinos zig-zag out of the hot (hundreds of billions of degrees) neutron star, they interact with the neutron star matter via the so-called weak interaction, the force responsible for radioactivity. Because the intense magnetic field can polarize the matter, more neutrinos will be emitted along the direction of the magnetic field than opposite to it.

    They should rename it to be The Galactic Fart theory

  • I thought you might have meant it in that way.. but I just had to make sure =)

    Oh, and I agree with you, but I thought a scientific approach might be more clarifying than a philosophical-type one.

    "Producing satire is kind of hopeless because of the literacy rate of the American public."
  • I just thought that I'd add something to my message..

    If you have a car moving at 10 m/s (with respect to the ground), with someone on it, and they through a ball at 5 m/s (w/ respect to the car), both the ball toss and the car are going in the same direction, then, with respect to the ground, the ball is moving at 15 m/s (10 + 5).

    Now, this is what confuses people alot. What if you had a flash light mounted on a car going at 220 m/s, and beside the car a flashlight mounted to the ground? If you stood infront of these flashlights, one might think that the light coming from the car is actually travelling faster than the light emitted from the flashlight on the ground.. That is, of course, false! Why? I don't think we really know yet (or that's what they told me in highschool). Light, from any source moving at any speed, will always register as moving with the speed of 'c'. This is why my above message works out. Of course, there are specific equations to work out time/space dialation (the one i used up there isn't correct for finding dialation, it's just an example to show why dialation happens).

    Once again, I hope that was informative, and I welcome any corrections.

    "Producing satire is kind of hopeless because of the literacy rate of the American public."
  • yes, but it's still more spherical than a billiard ball according to my source (fifth form (gr11) chem teacher). Even a 100km bulge is less than 1.6%.

    Interesting thing: the southern hemisphere is actually bigger than than northern hemisphere: the earth is slightly pear shaped (not so you'ld notice by eye:)

  • Who's years are you referring to?
  • As I understand it (IANAP) c cannot be reached by a chunk of mass because you would need an infinite amount of momentum to push anything to c ... it's an asymptope in space-time. Where relativity comes in is when gravity meets c, or meets photons travelling at the speed of light. In relativity, Einstein showed that motion has a gravitational force (relative to the object at rest on the body of motion ... which is only in motion from another frame of reference) and that gravitation bends space-time in such a way that it modifies the path of light but that, from the reference point of the photon, the path has not changed at all and it travels unaffected. The trick is that from both frames of reference, the speed of light doesn't vary.

    Anyway, you might find this website [aip.org] to be of some help to you. The Michelson-Morley experiment is pretty famous for showing that the speed of light is constant and doesn't change with respect to oppositional or parallel motion. This experiment happened before Einstein came out with his theory but it was General Relativity that explained it.

    Well, back to looking for a burger-flipping job. :grumble:
  • Now this confuses me. Didn't Einstein say that there was no absolute reference for speed through space?
  • Either one. I typically find that re-reading my own posts a couple of days later is enough to send my brain into the ground.
  • AUUUGGH! I was waiting for someone to mention this! I'd like to offer, and believe whole-heartedly that there is NO such thing as the "Big Bang" (I even hate the sound of that!) Space is infinite insofar as the human race can understand. To even think that we can grasp this concept with our very limited five senses (look at what band of wavelength we can "sense" compared to how much we've been able to detect with instruments) would be extremely inane! To try and think that everything started as one gigantic clump of matter and at a single moment, exploded with such force, expelling fragments to far reaches of space... It just sounds so stupid! What was in space before the matter "ball" exploded? Something had to occupy it, otherwise it wouldn't exist, correct? No, there's just too much error in that theory to support. I'm sorry, but to me, space has always been there and will always be there, stars and galaxies in a never-ending dance, birthing and dying in million year cycles, minute life forms on tiny planets living a ten thousand year evolution to finally die off, either to be replaced after a few hundred thousand years with new species, or the planet finally giving in to the pull of it's parent star or stars and plunging into the fiery mass, only to be reborn again after a million years... -but the human race think they have it all figured out! The usual attitude that everything is made for their existence.... Sorry, had to vent, I just get so pissed when I hear or see those two "B" words. Thanks for letting me bend your eyes.

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