Perhaps we are making an assumption here, that all stars are at a fixed size when they light up. Is it not possible that the giants and super-giants form at a rate that allows a much larger mass to coalesce before fussion occurs at the core ?
On a somewhat related topic, what do you guys think of the dark matter debate ? Are there non-atonic particles out there, and if so, will we/can we ever detect them ? Perhaps the gravity theory does not apply for the very large, as it does not for the very small ? Interesting stuff!
The Largest Known Star
Moderators: MichelleH, Minimalist, JPeters
Dark matter - who knows but it sure is interesting. A possibly completely off target gut instinct in me suggests reasonably ubiquitous particles (wimps, neutrinos, photinos if there is such a thing) might be dark matter, rather than Machos (unless I've completely misunderstood Machos), then again in some ways I wouldn't be surprised if it turns out that there is no such thing as dark matter (at least not as described above) and there's some other (admittedly convoluted) explanation for the excessive weight of the universe (er... heavy substances inside those 6 higher subatomic (and apparently curly) dimensions which we cannot detect... this is where FM tears me a new arsehole!).
Hydroge IS not universally (no pun intended) dispersed. The giant star forming region in Orion's belt is a great example of a stellar nursery, where for light years in every direction there is literally tons of hydrogen floating around.Digit wrote:Maybe Shark, or perhaps the necessary hydrogen is rarer in some localities than others. Dark matter? Not a clue!
The dark matter debate has been going on for some time now...nearly forty years I think. Someone observed ( an american female astronomer if memory serves me) that the stars in the centre of other galaxies are travelling around the nucleus of said galaxy at the same rate as those at the outer edges! From a gravity prespective, this does not make sense, unless something else is acting on the stars near the galaxy's edges...something we cannot see, hence 'dark matter'.
I recently read that there may be an observational proof of dark matter's existance: gravitational lensing of distant galaxies may be the key.
Like I said, interesting stuff!
The gravitaional lensing is what they use to view where they believe mthe dark matter is. Notice I said view where - not see - because they can't see it directly. It bends the images around it. They have a map of what they think is representative of its locations in space.
Mychio Kaku did a presentation explaining it in one of the either history channels shows or discovery channel.
Mychio Kaku did a presentation explaining it in one of the either history channels shows or discovery channel.
i'm not lookin' for who or what made the earth - just who got me dizzy by makin it spin
I think you've misunderstood me Shark. The early stages of a star's life are spent consuming hydrogen, but in certain areas of the universe it seems sensible that a proto star could consist of non-hydrogen materials, so if it's the mass of hydrogen that fixes when a star lights up then a star could, I'm reasoning, be super massive before sufficient hydrogen to iniate the nuclear reaction is available.
Ah, I see. Well, I'm not sure about a star being created from anything other than hydrogen..but let's assume for a moment this is possible. If say, enough big rocks get together to form a super planet, would there ever be enough pressure to cause nuclear fussion to spark ? No idea, as this is way past my meagre astronomy boundary. From the little I know, I believe this would not happen, unless there were waaay more hydrogen than rock, something like a super-Jupiter.
Is this what you mean Digit ?
Is this what you mean Digit ?
Interesting idea Digit. One idea is that some planets, particularly super-giants with a high carbon content, would have a diamond core! I wonder how many carots that would work out to beDigit wrote:Exactly. The halo around a proto star is supposed to be gases and dust. The dust could be just about anything I guess. If I've reasoned it correctly that would explain the enormous variation we see in sizes.
I wonder what the 'dust' is you mentioned... chunks of solid hydrogen perhaps ?
Much interstellar dust must be the remnants of dead stars according to theory so all elements would be present, including the heavy, non-reactive ones.
So let's take theory further.
A black hole is caused when a supermassive star dies, OK?
So I ask this, why do we need the star? If a sufficiently large mass can accumulate without lighting up inevitably a black hole must form.
It all comes back to what size of star is necessary to light up, and the various sizes seem to me to only be possible if their make up before ignition consists a certain amount of non-hydrogen materials.
(Roy, Senior member of the awkward squad!)
So let's take theory further.
A black hole is caused when a supermassive star dies, OK?
So I ask this, why do we need the star? If a sufficiently large mass can accumulate without lighting up inevitably a black hole must form.
It all comes back to what size of star is necessary to light up, and the various sizes seem to me to only be possible if their make up before ignition consists a certain amount of non-hydrogen materials.
(Roy, Senior member of the awkward squad!)
Hmm...so if enough heavy atoms were around to form a super-massive planet, would it be able to grow large enough to collapse inwardly ? The reason that black holes (seem) to start from super-stars is simply a size thing. I've never heard of a non-hydrogen body, a planet in effect, that could be massive enough to do the same. Probably mainly due to the lack of enough material in the surrounding area.
Now, I've been running with this idea, thinking only of one HUGE rock. What about something akin to a gas-giant, where it certainly can happen. Although Jupiters are mostly gas, they do have a solid core. Add enough gas molecules and poof, a star is born. Does this meet your criteria ?
What about the concept of micro-black holes ? From all the black holes I've seen
they are about the size of a basketball larger. Can a hole form that is microscopic in size, and if so, how would we detect these ?
Now, I've been running with this idea, thinking only of one HUGE rock. What about something akin to a gas-giant, where it certainly can happen. Although Jupiters are mostly gas, they do have a solid core. Add enough gas molecules and poof, a star is born. Does this meet your criteria ?
What about the concept of micro-black holes ? From all the black holes I've seen
they are about the size of a basketball larger. Can a hole form that is microscopic in size, and if so, how would we detect these ?Jupiter has been described in the past Shark as a proto star.
It rather depends I think of what the dust we see in interstellar space consists of, if my reasoning is correct and a bodyforms of pure hydrogen then light up would logically be at the smallest mass that that can be achieved with.
Strt and heavy elements and they must act like control rods in a nuclear reactor, I feel, therefore the mass of hydrogen needs to increase further to overcome the effect.
All that seems to be needed to form a black hole is sufficient mass, the fact that that mass was stellar or not seems irrelevant.
Next point, does the gravity well of a collapsed star act over a greater distance than the star's gravity well?
It rather depends I think of what the dust we see in interstellar space consists of, if my reasoning is correct and a bodyforms of pure hydrogen then light up would logically be at the smallest mass that that can be achieved with.
Strt and heavy elements and they must act like control rods in a nuclear reactor, I feel, therefore the mass of hydrogen needs to increase further to overcome the effect.
All that seems to be needed to form a black hole is sufficient mass, the fact that that mass was stellar or not seems irrelevant.
Next point, does the gravity well of a collapsed star act over a greater distance than the star's gravity well?
My initial thought would be 'no difference', but that is only my best guess. As long as the net mass doesn't change...Digit wrote: Next point, does the gravity well of a collapsed star act over a greater distance than the star's gravity well?
In reality, when a star collapses, mass is lost (stars tend to explode), so you would think the final gravitational force would be less. Now, if the collapse continued to the black hole stage, then I would think the force of gravity would be greater (then the original) and therefore it would extend out further.
I simply do not have the math skills to work this out!