Railguns, Plasma, Black Holes and all manner of nonsense.

Discussion in 'Discussions' started by OmniaNigrum, May 3, 2012.

  1. mining

    mining Member

    Uh, you can say the exact same about the electromagnetic force - its just that the gravitational force is really meaningful for large masses, while you never get those large charge distributions for the electromagnetic force to really shine 8).
  2. Aegho

    Aegho Member

    These are in the range of the density of a neutron star or nuclear density of 10E21_kg/m3 inside the nucleus of an atom, as calculated by particle physicists. The density increases as the mass of the black hole decreases up to a limit and then the black hole is seen as a neutron star not a black hole. Less than five solar masses is observable as a neutron star not a black hole. Astronomers say neutron stars cluster around a mass of 1.4 solar masses or 2.8E30_kg, and a calculated radius of 9.6 - 11.0_km which gives a density of between 6.9E25_kg/m3 and 6.0E25_kg/m3. The highest density and smallest mass in energy in orbit black holes is therefore nuclear density. The density decreases as the square of the radius or mass so a larger radius or mass means a lower density. As the mass goes up the density goes down. We have black holes without infinities.

    (Source: http://blackholeformulas.com/files/BlackHoles.html)

    Sorry for font size and such, it's copy/pasted directly from the source

    PS: When I said conventional physics, I was specifically thinking of density. The density of a black hole is higher than what is physically possible. IE: It's greater than if it was all a single atomic core of protons and neutrons in three dimensional space.
  3. OmniaNigrum

    OmniaNigrum Member

    Remember that we have exactly zero idea how large what we would call physical matter is within a black hole. It could be the majority of the visible area that light cannot escape, or it could be a tiny pinpoint of extra-dimensional space that can contain enough matter for the observable effect.

    A black hole is nothing more than the effect. We can just as easily argue that there is *NO* matter in a black hole.

    A neutron star is a definable super dense matter that can be measured by direct observation.
  4. Aegho

    Aegho Member

    If einsteins theories are correct, then a black hole causes an infinite curvature of space, which compresses matter into infinite density. What I was speaking of was the minimum mass of a black hole that remains a black hole. Smaller black holes can exist but are not stable, they either dissipate completely, or cease being black holes and revert into neutron stars. A micro black hole has a lifespan only measurable by the sort of instruments that are used in particle accellerators.
  5. OmniaNigrum

    OmniaNigrum Member

    That is a theory. Not a fact. There may well be environments where a microscopic black hole can exist. And by microscopic, I mean the size of the event horizon.

    Just like most commonly believe that space is defined by hard vacuum, that is already known to only be relative. There are high pressure areas of what we would call space too. And there may be vacuum harder than what we call hard vacuum. As far as anyone can tell, there is no edge to the universe.

    So a trillion AU out there may be an area where micro black holes are not only possible, but common. (And even stable at that.)

    I still say there is no evidence that our star system is normal, nor even that normal exists. We live in a snow globe on a shelf somewhere. That is the heliosphere of Sol. Or perhaps even the universe. When the first man made craft exited the Sol system, it started to slow for reasons simply unknown. We have dozens of theories, but none of them can be proven, and the best evidence suggests that space as we know it is not the same outside the heliosphere of Sol as within.

    Sigh. We are vastly off topic. But that fits the pattern. "...and all manner of nonsense..." Aptly named if I do say so myself. :)
  6. mining

    mining Member

    Arguably all black holes decay, just at varying rates, through hawking radiation.

    Re: Density - all it implies is that gravity (ack, you fiend!) is strong enough to overcome repulsive forces, bringing atoms in really, really close.
  7. Aegho

    Aegho Member

    I'm very sceptic about that. What makes a black hole a black hole is the dense mass that exerts enough gravity to bend the fabric of space, and thus compact that mass even denser into a singularity. Also a micro black hole cannot be stable because of the decay through hawking radiation, it dissipates. For micro black holes to even occur, you need an outside force that temporarily bends the fabric of space, which for example can theoretically be done with a powerful enough particle accellerator. Though I'm sure it can occur naturally as well by particles on relativistic collision courses being spewed out by cosmic phenomena, like quasars.

    Not that I'm an expert on the stretch factor of the fabric of space or anything. Btw, there are (theoretically, but not for much longer) things that can make the fabric of space ripple with waves, but the effect is so tiny that measuring it is difficult. There's a project on the way to do so, and the instruments are so far a factor of 10 from being able to measure it(they measure 10th of a proton difference, and need to measure 100th of a proton, with the ends being measured miles apart).
  8. DavidB1111

    DavidB1111 Member

    I'm a little confused. Because Mining is correct above,
    Aegho, A black hole is also as pointed out above an object whose radius is smaller than its Schawrzchild radius.
    Last time I checked, Hawking Radiation is still theoretical. Until we make black holes anyway. :)

    Also, isn't a Singularity a single point of infinite Mass/infinite Density inside a black hole, surrounded by the black hole, preventing the Singularity from interacting with normal space?
    A Naked Singularity would be a Singularity with no protection from interaction with the universe.

    Also, A Neutron star is basically the size of Brooklyn. :) So, how can a black hole be much smaller size than that, and be considered a neutron star because it lost mass?
    Also, I'm not trying to be annoying, I'm just confused.
  9. Aegho

    Aegho Member

    Ok, let's try this again, and now I'm using the source he referenced: An object at nuclear density(the density of the nucleus of an atom) has a schwarzschild radius of about 3 solar masses. Anything with less mass than that would not have a schwarzschild radius larger than its size, and thus wouldn't form a black hole. After a bit more searching around, seems my original source was wrong on the reverting though. Once it's a singularity, it stays that way until the end.

    Of note though: The smaller a black hole is, the faster it will lose mass through hawkings radiation.

    A micro black hole with a mass of 10 million kilograms will have a life span of 84,072 seconds, a temperature of 12,272,080,823,585,224 Kelvin and a luminosity of 3,563,450,746,089,485,300 watts. It also has a diameter of 7.42 zeptometers.

    If the large hadron collider had created any micro black holes as theorized by some, they would evaporate in absurdly small fractions of a second.

    So for micro black holes to exist out there in the universe for more than fractions of a second, they first had to be regular black holes, that lost mass. They wouldn't be very common if theories are true, because black holes are created by hypernovae(a supernova only creates a neutron star, a regular nova just leaves a gas cloud).
  10. OmniaNigrum

    OmniaNigrum Member

    The theory hypothesis goes something like this:

    When a star is big enough, it eventually collapses into nothing, a black hole, or a neutron star.

    The conditions vary quite a bit and size is only one tiny factor in the outcome.

    A black hole with a tiny mass relative to an average star is generally considered a very unstable one. It is theorized hypothesized that it will spew radiation until it has less matter than required to be a black hole, and then poof it is a neutron star.

    All of this, yes every last sentence, is theory hypothesis. None of it can be proven in any way that Humans could even survive if we somehow had the means to do it, and remember that we absolutely do not.

    There is evidence to support the theories hypothesis above, but there was evidence to support the theory that the Earth is flat too. Bear that in mind. :)

    It is only when we examine the evidence with an open mind that we have any real chance to see that we are wrong. So I think it is best to *Presume* we are wrong in all theories until we have undeniable proof.

    I think even the term "Singularity" can be misleading. For all we know each and every black hole has a single tiny bubble of extradimensional space that allows greater mass than is usually possible to persist there despite all physical laws we currently believe to be static. There may be nothing singular about it. If there are two black holes we can observe, how are either a singularity? (I do not get this side of things at all.)

    But we should probably make yet another thread about this stuff. I cannot think of a way to shoot a singularity out of a railgun... :)

    *Edit* Aegho ninja'ed a post while I was building this wall... :)
  11. Aegho

    Aegho Member

    Anyway, to wrap it up, on the point I found most egregious: There's no evidence, and thus no theory(in scientific terms a theory without evidence is called a hypothesis) of massive amounts of tiny black holes in the universe, or areas of space where they are more easily formed, or where micro black holes stay stable and don't evaporate. While we may hypothetically one day find it to be true, it has as much validity as the hypothesis that there's a china teacup in perfect orbit around alpha centauri(stolen and modified from Bertrand Russel's reply about religion. He used the sun in his version, but modern instruments today would actually be able to detect one, so you have to use something further away).
    OmniNegro likes this.
  12. DavidB1111

    DavidB1111 Member

    Yes, but Hawking Radiation is still not confirmed yet.
    We don't have the technology to actually confirm it's existence.
    Since in order to confirm it, we would have to have the means to artificially generate a black hole of a certain size, that would last long enough for us to determine whether Hawking Radiation actually affects it.

    Something there doesn't make sense. A black hole has no luminosity. Because light cannot escape it's gravitation pull. Also, watts is energy. :)

    Also, 7.42 zeptometers seems a bit too small. A black hole with the mass of the moon is 3 milimeters.

    Also, where did you get those stats? I've never ever heard of anything stating black holes have so much heat/luminosity around them? Even so small.

    A Supernova has a temperature of around 6 billion degrees Kelvin. I doubt any black hole can have a temperature vastly higher than that.
    Especially considering how heat dissipation works. I'm pretty sure if I was within 10,000 miles of a Supernova, and it's 6 billion degrees, I'd be very dead from heat. :)
    Maybe Mining knows how far the safe distance from a Supernova is.

    This is extremely erroneous.
    A Supernova will either leave a black hole or a Neutron star.
    A nova is something involving white dwarf stars and normal stars interacting with white dwarfs. A normal star also collapses into a white dwarf probably 100% of the time.
    A Hypernova can destroy a huge area, up to about 1/6 of our entire galaxy when they go off. :) They're exceedingly rare. We would not be here if they were not rare. :)
    OmniNegro likes this.
  13. OmniaNigrum

    OmniaNigrum Member

    A black hole has hypothesized luminosity. And there *Are* energies that escape a black hole that are later converted by passing stellar gases into what we would call light.
    (Also bear in mind that luminosity does not only mean light, other things qualify for that definition.)

    I too would love to know where so precise measurements of a black hole come from. But I do not want anyone to remove their pants, turn around, bend over and say "here"...

    In a hypothesis, any amount of heat can exist anywhere. But I think black holes have the potential to be immensely more hot than any actual star is, even in the hottest stage.

    I think the idea of a hypernova is potentially only a hypothesis. We still have not had a Human leave this star's heliosphere. It is extremely premature to say we understand the cosmos in any meaningful way. The one (or few) man made craft that have been ejected immediately encountered phenomena we are unable to even begin to explain. (Slowing due to an unknown force that is not magnetic, gravitational, and not exactly matter, but may be similar.)
  14. Aegho

    Aegho Member

    The blog of an astrophysicist.


    In this post: http://vastfrontier.blogspot.se/2009/01/micro-black-holes.html

    Other fun trivia about black holes he's posted:
  15. DavidB1111

    DavidB1111 Member

    To be fair, one astrophysicist doesn't equal all.
    I'm still skeptical about all those numbers you said, I'd prefer it if I got more sources on how they all worked.
    Also, Your blog link earlier says Earth – 17.74 millimeters

    I found one that said it would be 8.9 mms.
    From here, http://library.thinkquest.org/C007571/english/advance/core1.htm
    "The Schwarzschild radius of an object is proportional to the mass. Accordingly, the Sun has a Schwarzschild radius of approximately 3.0 km (1.9 mi) while the Earth's is only about 9.0 mm, the size of a peanut. The observable universe's mass has Schwarzschild radius of approximately 10 billion light years."
    That's from wiki at http://en.wikipedia.org/wiki/Schwarzschild_radius

    So, if I can find a few sources that say he's wrong about the size of a black hole with Earth's mass...I think I'm not going to agree with all he says right off the bat.

    I'll wait for Mining to weigh in. I trust him. If he agrees with you, I'll accept it.

    Also, Ganymede (Satellite of Jupiter) – 0.4401 meters.
    Ganymede is not larger than the Earth. THerefor a same mass black hole could not have a larger size.
    In fact, it's .025 the size of the Earth.
  16. Aegho

    Aegho Member

    I know that, but I figure he knows his shit better than us. ;)
    I'm aware appeal to authority is a logical fallacy btw.

    Also, there aren't all that many astrophysicists in the world(Neil DeGrasse Tyson is fond of pointing out there's only about 6500 of them, or about one in a million people on earth, so if you're ever in the room with one, that's the time to ask your questions).
  17. DavidB1111

    DavidB1111 Member

    Fair enough. Also,

    Neptune – 304.2 meters
    Jupiter – 5.639 meters
    I think something is up with his size/mass calculations there. :)
    Like I said before, I"m not trying to be annoying.
    I hope.
  18. OmniaNigrum

    OmniaNigrum Member

    From the Wikipedia Black Hole page, I am posting this as a link, since the image itself is 12.83MB and would slaughter any dial-up Internet users...

    You will note that there are several observable things of interest in this image. The wave/particle duality is observable. But this is a simulated image, not a real one.

    Also, on the subject of Astrophysicists, if you do ask a question, remember not to attempt to kill them when they start speaking in tongues. They know their shit, s to speak, but half the things they say would be like enduring a lifetime of CSPAN...

    I for one *HATE* mathematics more than any other subject. They live, breath, eat and excrete that shit though. Be kind to those who somehow like that stuff. They mean well, even if they are annoying. :)
  19. OmniaNigrum

    OmniaNigrum Member

    Another thing, starting at post # 38, we have not had one word about the subject. I do not mind one bit, but if you are Daynab and you are reading this, could you kindly move the posts from that point on to the thread I am about to make? Or not. Your call. :)
    (That is the first post that the train left the tracks. I will edit this in a moment after I make the Black Hole thread.)


    And the rest of you, you can easily post there instead. The reason for the move is simply to attract people who may want to read the posts or contribute, but may not know what we are speaking of. Some may want to talk about railguns. Some may want to talk about Black holes. I honestly could not care less where we talk about any of this, and I am not giving out demerits or somesuch.

    Keep on keeping on. But kindly try to post in the right threads when one exists. If one does not, you can always make another thread. I promise you that Daynab can be quoted as saying that he likes new threads. So make them if you want. :)
  20. OmniaNigrum

    OmniaNigrum Member

    Relevant reading materials for anyone who has not read them:

    "A black hole is a region of spacetime where gravity is so strong that nothing that enters the region, not even light, can escape.[1] The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that marks the point of no return. It is called "black" because it absorbs all the light that hits the horizon, reflecting nothing, just like a perfect black body in thermodynamics.[2][3] Quantum mechanics predicts that black holes emit radiation like a black body with a finite temperature. This temperature is inversely proportional to the mass of the black hole, making it difficult to observe this radiation for black holes of stellar mass or greater."

    "A gravitational singularity or spacetime singularity is a location where the quantities that are used to measure the gravitational field become infinite in a way that does not depend on the coordinate system. These quantities are the scalar invariant curvatures of spacetime, which includes a measure of the density of matter."