A few astronomy questions...

Sorry, I think I'm using the wrong terminology here... what if I replace the word "energy" with "force", then does it make sense? For example...



When an object sits on a surface, a force is exerted counter to, and equal to, gravity. Your coffee cup is further supported by atomic forces which have been bound up in the object since they formed.

The object wants to fall. The space surrounding the objects in question is distorted by their mass, and space is resisting the distortion. The only way to smooth the distortion is to allow them to fall freely toward each other. It is only in this state, of free fall, that the system is neutral, an no forces are in play (assuming a closed system defined only by the two objects, and not measured externally).

G_Day, are you taking time dialation into account in your equations? Remember that as gravity increases, time slows, eventually approaching zero, just as things should become unified.

With zero time span, I'm not sure you can predict such levels of heat due to compression.

Sure. What you said is certainly better if you say "force" rather than "energy".

However, I am a bit uncomfortable with the term "natural state". It seems vague and misleading (and sounds like the philosophy of Aristotle who is a villian in the minds of many physic geeks).

I am also uncomfortable with the term "wants to fall". I asked my coffee cup and it didn't express any such desire. There is no property inherent in the cup that gives it the inclination to do anything accept to accelerate in response to an unbalanced force on it.

Newtonian physics says that gravity is a force that is pulling the cup toward the Earth. The table puts a force pushing the cup away from the Earth. These two forces are balanced and so the cup doesn't accelerate.

Under relativity, gravity is not a force. Even under this view, the terms "natural state" and "wants to fall" don't explain anything and probably cause more confusion for the non physics geeks.

For this discussion, Newton does a perfectly good job at explaining the behavior of the cup or the meteor.

For people unfamiliar with Hamiltonian operators and eigenvalues Newton will have to do. But Newton is perfectly correct in these cases and comes up with the same conclusions as Relativity anyway.

I'm comfortable with your discomfort with these terms

I was trying to keep my answer readable (to prevent headspin), thus the loose terminology.

And yes, I was answering from a perspective outside of Newtonian physics (General Relativity) mostly because I find it more interesting thinking of gravity as something other than a "force".

(a slightly related thread on Inertia)

Best Regards,

rosborne,

No I am not using a relativistic framework at all - because at energy densities well above 100 GeV I don't see the laws of relativity have proven applicablity. A black hole's event horizon is a transition to a domain where the laws of Einstein's relativity not applying. From memory SuSy says within the event horizon mass and spacetime practically swap characteristics for instance. Crazy stuff!

To an Earth observer a lot of things change at the boundary we call the event horizon. For the observer at the event horizon (assume advanced technology allows him to survive with negligible impact on the event horizon) nothing changes at the boundary IMHO (except possibly the options he has for direction of travel) Assume the conditions of my new question "hypothetical black hole" What is the observers orbital speed in a circular orbit at the event horizons radius? Neil

Let' me start of by saying this: I never really studied physics at school, so please forgive me for having to catch up here. I am making very basic mistakes, I kindly ask for your patience.

No mass inside a black hole, only energy?
m =0
e !=0
e=mc²
=> something other than zero = 0 times c²
Ah yes, I also had to repeat the 5th grade because I was horrible at math.

I don't know the correct terminology but I (too) would state that the coffee cup is not in a 'natural' state but it's using 'force' as is your table. Just like leaning against a wall or running into it. The wall isn't using kinetic energy to stop me, but the forces that prevent it from falling into rubble are stopping my kinetic energy from having a serious impact.

It's too bad I don't understand anything g_day's saying because according to his avatar he should be the grandest authority on Einstein, on who's theories I have some very basic (simple ) questions (about i.e. the fabric of spacetime and curvature)

Such as:

If the universe is expanding - I suspect it is, creating 'cooling' which is somehow counterbalanced by universal heating (does entropy or a law of thermal dynamics come into play? I honestly don't remember how this theory worked) - and we use Einsteins theories of a dynamic universe rather than a static model as was used before this indicates that all objects move away from each other. Doesn't this mean that the earth too is moving away from the sun? Then exact distance required for life to exist on earth would change and we'd all die. Or does the fabric of spacetime expand with it thus somehow changing the laws of physics (?! What the hell am I doing wrong here? None of this is right!) applied inside this set of coordinates.

Continuing on this fundamentally flawed logic (of mine, mind you), I'll needlessly complicate matters for you. It dawned on me that maybe I could use a vague theory I read somewhere that because of the density of matter (and dark matter) some things just didn't add up and somebody thought (I love scientists like this, always good for a laugh and a philosophical spin): Hey, let's put our solarsystem right back in the center of the universe. This way, things remain relatively(in the other meaning of the word :p) static. Things still expand, but not as much.

Strange thing is, the other day, I was watching a documentary of hawking concerning, yes what else, the universe. And it stated that because of einsteins theory(dynamic model) and the whole expanding thing, that there is no center. How could there be if the coordinate system keeps shifting? I suppose my vision of a universe expanding in all directions evenly is erroneous...
As is the beautiful quotation based on the 'fact' that the universe is infinite: Realise that we are the center of the universe. Because, is the center not the point from which all borders are equally distant?
It's a shame the universe had a beginning and, unless there's some sort of 2d spiral shaped form of time, an end. Because this includes it's finite. Does it not?

I apologize to anyone who read this. At least most of you know where the mistakes are made. Now please try and explain it to me :/

Hi ReX; These guys are mostly way over my head too. According to mainstream, the universe is expanding like what yeast does to bread dough. The raisins, Earth and Sun are extremely close together compared to the billions of light years dimensions of the Universe, so the distance increases perhaps an inch per century = too little to detect. Worse our measuring tools are also expanding.
In medium size black holes such as in my thread/question "hypothetical black holes" the plasma inside the event horizon likely has properties of matter, photons, quarks, neutrinos etc, so radiation is a confusing term. In any case. it is believed that space time is still curved by the mass that entered the event horizon, so mass equals zero likely is not true.
While many experts think the Universe is several times bigger than the 13.7 billion light years we can see, few think the Universe is infinite.
i'm suspicious that much of what we think we know about the Universe, will be replaced with slightly different theories in a few decades, which will be replaced by new theories in the 22 nd century, which will be replaced by....... Neil

ebrown, does force not require energy? I assumed them to be... I don't know a good word, how about "coactive." What is the relation between force and energy?

To answer your question, I'm very interested in the subject, but don't have any plans of using that interest.

I doubt that the theories of the 22nd century will be replaced by you. But we all have our dreams.

Here is another question that will highlight my ignorance of energy (although I think I'm starting to grasp it a little better). What supplies the energy of a pulsar, or emissions from an accretion disk? I mean, wouldn't there only be so much energy to expend. And doesn't that energy have to come from somewhere? I'm trying to understand how energy is naturally conserved throughout the entire universe system. I don't even understand it on simple levels. I've never put much thought into potential energy. Let's say I use some of my energy to lift up a rock, the rock gains potential energy with in a system with the gravity of earth. But what happens TO the energy I used, is potential energy conserved seperately from other forms of energy, or does it draw on some source? I've always pictured energy as something physical, and therefor it must BE somewhere. Is that inaccurate? I hope someone can understand how I am confused; I can't conceptualize what happens on an energy level, accounting for conservation.

Where relativity rules mass and energy are interchangeable properties of perhaps a more fundamental thing. You can convert from one form to the other using the equation you stated.

However when you impart enough energy to matter it changes from solid -> liquid -> gas -> plasma -> atomic elements -> sub atomic particles -> raw quark / leptons / boson -> something else as relativity breaks down as the four forces unify.

If you look at any picture of the big bang for the first 100 secs energy densities where way too high for atoms to form. In fact it took 300,000 years before space cooled enough to become transparent and a billion years before any complex elements other than hydrogen or helium were formed.

All I was saying is that inside a black hole the energy density is so high I would expect there to be layers - like the Earth's crust, mantle and core. And for all substance sucked in to be converted into pure energy so it could be crushed or compacted more readily.

But relativity stops applying the moment you cross an event horizon. You can't readily say e=mc^2 within a black hole, you dont know what exists there - not time, matter, energy or space - all could be transformed into far more exotic things (or strings) that obey different rules!

* * *

Also not only is space itself expanding, the planets are getting further away from the Sun - as it radiates energy it loses mass -> its gravity decreases -> each year the planets move further away (the current rate is about 2 inches a year I believe).

When the dinosaurs were alive the moon was much, much closer - the moon would have appeared 20x larger to them! I think the moon receds currently about 19 cm a year from the Earth.

Ok, I'll simplify things so you can explain them to me easier

Some things I read, correct them please:

Black holes are about ten miles across (err, sure why not :/)
Black holes have zero volume (ah, that's why not)
Black holes have a lot of gravitational pull (hmm, this requires mass doesn't it? ...Oh crap, please don't make this about inertia.)
Black holes are 'singularity' (no volume right? Just a point. How can anything -exist- WITHIN something we've made so small to fix all our scientific problems with 'bigger things')
Black holes are holes. Holes in space. Holes in the spacetimesystem. It's a rift where nothing should exist, but because there's existence around it, it collapses into nothingness (I admit this one was a conclusion I came up with


Sorry for having to break it down to such a basic level, but too much of what I read was over my head. Ow, and if anybody feels like it can they explain energy to me?

I heard the law of conservation can somehow be broken:
SOMETIMES matter is really destroyed and energy is released(ok that energy already existed, but the matter is actually GONE)

If the topic wasn't named the way it's named, I'd be writing this in the reference section, be assured

I'm sorry g_day, you're still far more read on the matter than me. But I'll try and learn from your post nevertheless. These are the impressions which you're giving me:

-You're saying e=mc² is a formula for converting?
Not for explaining the nature of things(universe). I'm trying to understand nature(all of it), if I somehow stumbled upon a formula for making energy using light and mass, I'm on the wrong track, and I doubt that's the case

-The continuation of adding energy to matter makes it smaller? until the breakdown of relativity because of the unification of the four forces?
There nature remains vague to me. And how something which is finally defined as fundamental keeps being put into question.

-I don't know what you were trying to say when you talked about the beginning of the universe as we know it. But a buddy of mine suggested today that maybe there's an infinite repeat of big bang - existence - implosion.

-Perhaps you could explain your inclination to layers when discussion high densitity? Why would there be a need for that? Can't we just have one point of 'something'? Or some interdynamic relationship within this point if indeed there are serveral things within singularity?

-Yeay, strings. Let's elaborate on that later

-Will earth have cooled down by itself before we're too distant from the sun to experience 'troubles'?

-The dynamic nature of all celestial bodies are due to their gravitational pull? That's it? That's all relativity and the lack of center is about? Things constantly attracting one another? Is this enough to explain the curvature of space?

I hope I have given you something to reply on.

Hi SCoats: I changed "new to "slightly different" It takes energy to establish a force. If losses are very low; very little energy is needed to maintain/ continue a force.
The inner portion of the accretion disk of a neutron star or under 20 solar mass black hole orbits at perhaps 0.9 c. Very high speed collisions occur which convert some of the colliding mass to energy including Xrays and gamma rays. I've forgotten the details of other energy producing mechanisms.
The rock you lifted got some of the energy, most of the rest is low grade heat, which is used to evaporate the sweat= perspiration on your body. The energy source is the food you ate, converted to blood sugar, combined in your muscle cells with oxygen that your blood brought to your muscle cells. Neil

I don't believe this is true. There is no reason that energy is required to establish a force. What are you basing this statement on?

What do you see the relation as, Ebrown? Are they entirely independant?

Rex, E=mc^2 is a conversion equation, if mass is directly converted to energy it will produce the ammount the equation specifies, basically. So mass being "destroyed" and energy taking it's place is a misinterpretation. That's like saying when you heat water it is destroyed and steam somehow takes it's place. It's just a conversion.

If anyone wishes to correct me go ahead.

The relation is well defined matematically. Work is equal to the change in energy. Work is a the ability to exert a force over a distance.

You can have a force without any change in energy.

I don't know what was meant by "establishing" but the statement and the logic imply that force is a function of energy. This smiply isn't true.

Rosborne,

I thought about your theory and I think I understand the problem.

You are rejecting general relativity. Yet, you are using the idea of a "gravity bubble" which is a model that is based on the ideas of general relativity.

I took some time to try to find analogs inside of my somwhat rusty knowledge of relativity. I am pretty sure that there is no way a distortion caused by gravity can either contain energy or create a force (both of these would be required if your idea were true). I don't think you can do this without breaking the fundamental principles of relativity-- "background independence" which says that that you can't base any phenomina on a particular frame of reference.

Are you intending to reject relativity? The website you posted ("commonsensescience.com") seems to be doing just that.

You used Mach's principle to support your theory. But you got it wrong. Mach was a precursor to relativity, his theory involved the problem of establishing a universal frame of reference (i.e. a background).

His theory did not suggest, as you said, that inertia was caused by the force of gravity of "all the objects in the Unverse". This would not make sense under Newton or Einstein. Mach suggested an "interaction" which was not a force and certainly not gravity. He was establishing a frame of reference-- a kind of background dependence.

I think it is a problem that you are rejecting relativity, but then using the model of a warping of spacetime as a key component.

Another question (a friend of mine has, I personally lack any formal education on the matter, perhaps you all know what it's about. I don't.):

The energy in an atom contains mass. So in a chemical(endothermic) reaction energy can be lost without actual particleloss.
Mass has disappeared without particleloss.

Energy does not contain mass, although one can be transformed into the other. I do believe, however, that the weight of the reaction components would be less after the energy release, although the effect will be quite small, since the energy released by chemical reactions is not very great.

Hi EBrown: If the force has always been there, no energy may be required, but from an engineering view point I can't think of a system that has absolutely no loss over time. Can you give me an example of creating a force without using some energy? I'm thinking like an engineer instead of a scientist. Neil