How come everyone is so satisfied with mp3 quality? I can barely listen to music chewed upon by mp3 compression. Bit for bit perfect? As far as copying is concerned maybe, but it certainly will take another type compression to fool my ears.
Or does everybody use lo-fi pc audio anyway nowadays?
In some way it's our own fault and naivity that we have been regarding streaming media as more authentic than printed, for we already knew how to manipulate the latter (although any tv-director could show you in a sec how to manipulate you without actually image processing a live broadcast).
My guess is that when we feel we need to have authenticated live media, we'll develope ways to ensure this, analogous to the way this is possible on the internet.
Good article by a great scientist. I dont understand the fuzz from some people about his predictions. He seems cautious and humble when he talks about the outstanding questions and mysteries.
What surprises me tho from many GU-physicist is that forget to learn from cosmology. They tend to turn it around and look only to the Hi-energy experiments in order to answer the deepest cosmological questions. Analyzing the Relics of the Big Bang and the evolution of the early Universe however can supply constraints on the behaviour and existence of exotic states of matter.
Besides this, it is unclear what is meant by Unified physics. There are some suspicious aspects about the various GUT theories. For example, it might be unrealistic to suggest true Unified physics in the context of our experiences at low energies. Here, almost every decade of energy-interval from the mass of the electron to the mass of the Z-boson contains new particles. One might expect that even higher energies would open up new physical phenomena, and so on indefinitely. The prediction of GUT is that, instead, we encounter a desert of at least 12 powers of 10 in energy in which nothing interesting happens. This would certainly be convenient, given that it is hard to see how the maximum energy of accelerators can affordably be increased much further. 2;-p
Occasionally I code here and there to pay for my university tuition fees. Short projects, freelance, practically without references. Pays about $50/hour. Have some friends actually chained to an IT job or *sigh* career. I come up with this:
- Free lance: $25 and up for kids designing websites, $50-75 for the more demanding stuff, $100+ for experts. - Starting code monkey @ somecompany: $15 @ 1.0 FTE, somewhat higher if part-time, twice as high if on project base. - Experienced IT engineer/manager: $35-$50
Note, many of the IT firms over here try to seduce you with stocks, gadgets, cars, vacations or one-time $10.000 bonuses. IT's a frenzy. Resumes are relatively irrelevant if you are starting out 2;-p. Many will take the chance and give you some time to prove yourself.
Also an important thing to consider if comparing Europe to US is that every state in Europe has a different tax system (usually higher base income-tax and many times a progressive tax system, ie higher income, higher tax rate)
It's difficult to translate the raw dollars/hour to buying power. Living expenses are typically lower in the Netherlands than in the US. But again this may differ from country to country. Sweden for example is known to be the most expensive of the northern-European countries.
Also tax deductions can have a profound influence on your buying power. Morgage deduction, investment-deduction, transportation deduction, college deduction etc.
My guess is that when your desire is to live and work on the other side of the big pool and you want an accurate estimation of your living standards, you will have to dig fairly deep in the specific laws, regulations and habits of that particular country.
I think that as long as the US army is the one benefiting most from hi-tech communications the US governement will be most reluctant on the subject of international regulation.
But with the things are going now it's clear that control over- and rapid reduction and analysis of data of the battlefield will be crucial in any future war. No wonder Russia has tried to gather support for a United Nations resolution calling for new international guidelines, considering the state of its armed forces.
At our institute we have lotza 'puters clustered in subgroups and I think that the naming conventions our sysadmins use are silly but effective. For example, without going into Dutch geography, one group is named after rivers in the Netherlands. The larger the river the more powerfull the machine that is named after it, with the central servers having names like the IJssel and the Rijn (you know the Rhine don't you?) Another group uses the periodic table with the servers named after the first elements Hydrogen and Helium.
Although not entirely consistent it works fairly well. I know intuitively which machine to hit for that extreme resource slurping process.
One problem is that al our foreign scientists (about 30% of the institute is non Dutch) are in the dark, since they dont know any of the Dutch rivers.;-p
DNA IS DATA! Data is NOT patentable, any more than a christmas carol. You can COPYRIGHT data, but you cannot, and should never be able to, patent it.
Can data live? Besides, is reading DNA the same as understanding DNA? I suspect that when the last chapter of the Great Book of Human Genome is finished reading it would compare to reading encrypted Chinese, without the the key or the Dictionary of course.
Come to think of it... considering the fact that DNA was here first and created US, DNA Inc. would make a fair chance patenting humans. Heck, why not all species... ?;-p
Luckily James Clerk Maxwell didn't patent his blueprints on Electrodynamics and Heisenberg, Bohr, Schrodinger and Dirac were dedicated to open source, else we would still be computing with an abacus.
Since you are under the impression that you've provided a counter-calculation, but you haven't produced anything resembling one and have missed the point in several other areas, I think you might have had too many beers already. You began celebrating just a wee bit too soon.
Now that's not so nice...;-( I started out because your initial posting was a wee bit crude in energy budget and wrong in scenario, to my taste. If you think this discussion is tiresome you shouldn't invite me to reply. I've got better things to do but to irritate you, reeeeally.
Especially the dust band is a nice one. The amount of extinction might be 100-300 magnitudes in UV/X-ray. I do not need to remind you what that means to the flux. But to all non-astrophysists: this means that only 0.00000000000000000000000000000000000001% of the radiation gets through. Ofcourse I'm not saying anything about the re-radiated IR radiation hehehheeh.
Ah. So you admit attempting to obfuscate the issue. Sorry, it doesn't win any points (or brew).;-)
Nah, just remembered that something had to happen to absorped energy. First effect is to puff up the dust donut. But after this it will loose energy in intense IR radiation, just as seen in the FIR galaxies.
Another model just occurred to me: the radiation pressure of the growing BH and its polar jets blows the remains of Earth into a boiling, seething mass of iron-silicate vapor...
Funny thing is that I was thinking 'bout the same thing on my way home yesterday. You know it is impossible that the Earth will collaps into the BH. This you must admit (altho you have been as stubborn as I am). Gravitational collaps with the outer matter pushing the inner matter without delay into the BH hole only works at a mass density close the critical value for a body to lie within it's own horizon. Direct formation of small black holes is extremely difficult.
Do you want a calculation? Critical density scales as M^-2 and has the density of 10g/cm^3 for a 10^7Msun Black hole candidate. For direct formation (collapse) of an Earth BH (Mearth = 3.10^-6Msun) you require a core density of roughly 10^24g/cm^3. This cant be obtained, at least not with our type of matter.
Therefore we need to have some sort of accretion scenario. Since we have spherical symmetrical mass distribution the maximum accretion speed is defined by the Eddington limit, where radiation pressure of the infalling inner layer and the pressure of the layer just outside it balance (in this scenario dominated by the pressure of the rest of the Earths mass above it). This effect starts immediately, and will generate the pressure to support the rest of the core and prevent it from collapsing. If you dont believe this, check every standard literature on gravitational collapse, black hole formation and Eddington accretion. Blowing off the outer layers is a possibility, but this requires super-Edington accretion (achievable in highly anisotropic situations), since you need more outward radiation pressure than supplied by the default balanced influx.
Eddington accretion and Lifetime: There exist a maximum luminosity that can be radiated by a gravitating body of mass M. This limit arises because radiation pressure from a central source can not exceed the gravity of the infalling material and the excess pressure from the material above it (then it would starve). Although the actual value for the Luminosity is hard to calculate, because of the complicate environment in the earth's core, it is interesting to note that the lifetime of een object radiating at the Eddington limit is independent of mass. The lifetime (know as the Salpeter time) is proportional to Mc^2/Ledd and for silicate particles this might be anyware between 10^6-10^8 years. 10^8 for free-fall, 10^6 for solid object.
I suppose my story sounds a bit dull compared to the spectacular 'blowing the face of the moon' scenario, but I think that you will study the relevant literature you find that direct collapse is impossible.
I admit that some of my earlier objections were wrong, but hey they came only from the tip of my hat.;-p
The problem is that altho your total total energy budget might be correct (within a factor of 1000 or so), your calculations about the effects on the moon need this energy to be released almost instantly. From the Salpeter lifetime however it is more likely that this will take millions of years. This is supported by all observations of actual BH and AGN canditates. Eye know that the actual accretion scenarios are different, but that is accounted for by taking enhanced isotropic accretion with silicate particles. (else you would end up with typical 10^12 yr lifetimes)
The heat from this melts the remaining artificial satellites and then coats them with molten goo, as well as stealing their angular momentum from gas drag and pulling them in to share the fate of their creators. The entire Moon gets coated in iron, which simultaneously obliterates all traces of Apollo and turns it into a shiny marble for the next several billion years.;-)
Hehe, I must say that IS an actractive and esthethic thought. But again this requires extreme super-Eddington accretion and this is difficult to achieve.
My best guess is that the BH settles in the Earth's core, slowly accreting the mass because of the inevitable balance between radiation pressure and infalling material (pressure by the outer-layer does not change this, only the increases required radiation level and speeds up the lifetime by a million or so). The heat would slowly dissipate through to the Earth crust, making global warming more like global cooking. The seas will evaporate, we will melt. The Earth might resemble Venus within a few 1000 years. However I think that given the fact that the total radiated energy is smeared out over millions of years, the Moon for example will be able to keep kewl, just by thermal equilibrium.
I've been sleeping a lot during Quantum Field Theory last year. But what I understood from their renormalization theory is that they ignored infinite components in the integrals since they were more or less fixed numbers.
not: A/0 = B/0
but: A + infinity = B + another infinity
Therefore A = B.
Just as tricky btw, but certainly not applicable to every other problem.
Nyquist information theory requires factor 2 sampling of a signal to hold all of its information.
pixelsize != resolution
Therefore typically the distortion by the optical train of a telescope (= the effective resolution (diffraction) limit) is oversampled a factor 2 or 3 by the CCD detector.
If you want to have a calculating battle, by all means jump in. I'm willing to fire off numbers at you and take your return fire, winner to collect a pitcher of beer from the loser if they should ever be in the same city. I admit that this wouldn't be much of a prize for you since I am not likely to visit the Netherlands soon and American beer being as lousy as it is, but I can't think of another prize worthy of a friendly competition.
Hehe, noted. You're welcome to have a beer anyway;-p.
But seriously:
That said, the numbers are not just huge. They are many orders of magnitude beyond huge. For instance, the megaton/m^2 flux at Mars is enough energy to blow off an atmosphere as thick as Venus'. 1 megaton = 4.2e22 ergs = 4.2e15 joules
Eye know about huge, I was just disagreeing how huge. Eating off zeros on the way.
Nope. The gravitational energy available goes as 1/r, so a full 50% of the total is available from only 2 radii out. The radius of a 1-earth-mass black hole is about 1 centimeter; everything is going to be falling in from more than twice that!
..assuming the black hole already contains the earth mass, which is not the case. My point is that since it begins small, in a dusty rotating environment, the black hole will end up with only a small fraction of the mass.
1.Even at the equator, an object sitting on the ground has only enough angular momentum to maintain a circular orbit around an earth-mass point at 1/64 of the radius of the Earth. And that's the best an object on Earth can do! Things at the poles would fall straight down if they were suddenly unsupported.
1/64 Earth radius is 10.000.000 Schwarzschild radii of an 1-earth-mass black hole (which does not exist at the time). I fail to see how it would find its way directly to the black hole (without an up-to-date inner-planetary map that is)
2.Conversion efficiency is supposedly up to 50%. All the mass cramming into that accretion disk at a large fraction of c generates a heck of a lot of heat.
Again I disagree. I'm not talking about forming a M-earth BH and subsequently letting testparticles fall into it. Only matter with small enuff angular momentum to hit the Kerr-radius directly will be eaten instantly. The earth will form an accretion disk extending from 100km to lets say a 100m, depending on radiation pressure. Free falling angular momentum carrying mass from 6000km out to 50km (not into the black hole!) speeds up to a small nowhere near a fraction of C. Your free-fall calculation does not include the centrifugal potential. Again our main difference is that I suggest that the accretion disk at the time of creation will contain almost all of the Earth's mass (lemme throw you a number 99.9999998%;-p). You seem to calculate from an existing M-earth BH.
3.The mini-BH would fall from the surface of the earth toward the core (if it could last long enough to get out of the lab, which it could not)...
Ofcuz. In our lively discussion I also forgot to stress that the damn thing would evaporate instantly anyway. This triggers another question, mebbe you can shed some light on this. How big must the progenitor BH be for the inbound mass flux (in the beginning dominated by free fall to the earth's center and the Rschwarz of the progenitor) to balance the evaporation mass flux?
4.Earth isn't very big, and doesn't have a lot of angular momentum compared to a star of far greater dimensions. If something swallowed the core, the rest would fall inward just fine.
Absolute ang momentum is irrelevant. Only the effective potential matters, and centrifugal component plays a crucial role. Earth spins about 30 times faster than the Sun.
The black hole couldn't starve unless the accretion disk could transfer enough angular momentum outward to get the remaining mass into orbit...
Now this is strange. Are you actually saying that angular momentum transfer helps the BH to starve? Or is there some wrong with my English? In standard thin disk accretion theory quasi-viscous ang momentum transfer is the only way to prevent it from starving. Accretion effeciency computed from the marginally stable orbit is only a few %. Bring in mind that the Kerr-radius is ridiculously small compared to the size of the accretion disk.
The jets are driven by radiation pressure. The jets will also be there to scatter the energy radiated poleward from the accretion disk and allow it to hit objects behind the accretion disk. Remember, my calculations only assumed that 0.0001 of the total energy escaped as radiation toward the equator. The same conclusions hold pretty much even if you reduce that to 0.00000001.
Two possibilities of Jet generation have been discussed in literature. The most important being magnetic field line winding and flux freezing wich will tend to make plasma stream along the field lines. It is thought that this dynamo-effect causes the bulk relativistic motion we call a jet. The radiation pressure only provide the initial acceleration to produce the outflow. That scattering on the jet will contriblute significantly to the overall radiation is unsupported by observations of real jets. My point is that given your severe overestimation of the radiated energy (calculated from a unrealistic simple scenario) and the chaotic poorly understood magnetic effects, the acretion scenario, the absorption of the dust band (which will be created) will provide anuff extra "couple of zero's" to topple your argument.
Especially the dust band is a nice one. The amount of extinction might be 100-300 magnitudes in UV/X-ray. I do not need to remind you what that means to the flux. But to all non-astrophysists: this means that only 0.00000000000000000000000000000000000001% of the radiation gets through. Ofcourse I'm not saying anything about the re-radiated IR radiation hehehheeh.
.. but not for artificial satellites;-p. Hokay the numbers are huge, I agree. But anisotropy does much more than dividing the radiation number by x. Besides that there are several important complications to your lucent but very crude calculations.
- since most matter falling into the black hole is cold and already very deep in the potential well conversion effeciency will very much lower than the theoretically infinite distance approach
- all the mass surrounding the earth center carries angular momentum, the accretion disk into which the earth will transform will only on convert some small fraction of the potential energy of the accreting mass. Besides in our scenario we assume the mini black hole to originate at the earth's surface further decreasing the accretion rate and conversion efficiency. We are not talking about a hardly rotating collapsing stellar iron core here...
- the black hole might starve before it can eat all of its food. After accretion disk forming only the inner 3*R(schwarzschild) orbits are unstable. Then angular momentum transport in the accretion disk will dictate the rate of energy production.
- much of the available gravitional energy will be converted into kinetic energy blowing a significant portion of the mass away in opposite jets
- the evaporated mass of the earth will consist of small iron and silicate particles creating a broad inpenetratable dust band on the equator just as seen AGNs. Given the available Si/Fe mass and high density you may happily assume that.01% of your overstimated radiation at the equator might be several orders of magnitude too high. Silicate grains are magnificent UV absorbers, and UV-soft Xray will be the major emission waveband in the accretion disk.
My conclusion is that the earth satellites probably wont survive, but the Moon and Mars will laugh at Earth's misery. Especially since the momentum carried by the rest radiation will be ridiculously small compared to their orbital momentum.
mister attack says: >> The idea that we are going to destroy the world with the RHIC is absolutely ridiculous. I remember reading that a large number of physicists thought the first nuclear weapon would ignite the atmosphere, destroying all life on Earth. Didn't happen. This is a logical fallacy known as post hoc ergo propter hoc. Just because we haven't destroyed the earth in the past doesn't mean we can't do it.
Actually this is a non post hoc ergo non propter hoc which is something logically different.;-p
Given that the collapse of the Earth into a black hole would involve the conversion of perhaps 50% of the total mass into energy in the accretion disk, all the artificial satellites would probably evaporate.
...assuming isotropic radiation, thus accreating according to Eddington. All observed black hole candidates however show jet forming (ie anisotropic 'dynamo-like' effects), from the small to the very large Active Galactic Nuclei in the center of galaxies.
Sure lifespan has been increasing at that 10% rate for the last dicennia, but how about quality of life? You have to be fit for space travel. How 'bout hospitals over there?
isn't actually that difficult if the angle/position of all the shots are identical
That might be a problem, if you require sub-meter pointing accuraty and stability, just by gyro-control, on a spacecraft at 200km height, traveling at say 7000km/hour, minimal exposure time some fraction of second. It might be quite undoable.
...when a human being sees a blurry or distorted image (particularly of the sort produced by satellite), he can usually pick out most of the deviations from an "ideal" clear image. instantly.
How does een human even know the deviation from a 'ideal' image if it can't be seen. (unless you assume what you are looking at)
Damn, we sure could use this in astronomy research. We just need to recognize to protogalaxy in the fuzz;-p. Heck, we dont even need bigger telescopes, since the only difference image-resolution-wise compared to small telescopes is convolving it with a smaller point spread function, which we recognize away anyway.
I agree that temporal filtering of 100-1000 images would do nicely, but even that is bound to diffraction limiting. (at 200km height you need an equivalent of HST's 2.4 mirror.)
Don't worry about the resolution. Ordinary US/RUSSIAN/[INSERT COUNTRY] spy-sats have 1-2 feet resolution, that's about diffraction limited (ie you just need bigger mirrors for improved resolution). Atmospheric disturbance plays a minor role, but even if it did, you cant compute the interference away (because you have to know the exact interference to deconvolve it... basic image processing). Just statistics is certainly not enuff. The solution is active optics, such as used in the new eso VLT telescopes. But bringing active optics into space.... hmmm, think not, for now.
I think you misunderstood. These 1-meter res images will b used to provide a simulation of the environment at which something (accident, murder, whatever) has taken place. It might prove useful to influence jury members by presenting them the surroundings from a certain perspective (probably the defendant's, hehe)
It's been possible for some years now to obtain 2-meter hi-res imaging data via SPIN-2, imagery taken with the russian sat Cosmos gone commercial. Check out http://www.spin-2.com/
Orbimage is also a global provider of satellite-delivered Earth imagery services with a planned constellation of five digital remote sensing satellites. They will launch 2 1-meter res. sats next year.
Hubble's WFPC2 camera has 3 chips with 0.1 arcsec pixels and one chip with 0.046 arcsec pixels. But sinds this wide-field camera undersamples the PSF of the telescope, which is diffraction limited, the actual resolution is higher. A 2.4m diffraction limited telescope, may have.02 arcsecond resolution.
Usually when astronomers say: this object is so-and-so old they are talking about an intrinsic property of the object, independent of distance. On the other hand when they say this-and-that happend so-and-so time ago they mean that, because of the finit speed of light (according to special relativity) the photons now observed by us spent so-and-so yrs traveling the distance between us and the object. Therefore the image you see now, is 40.000 yrs old.
The difference is perspective: are we talking about the image, or the object.
Actually pointing it at an Black Hole candidate is not incredibly spectacular (visually), given that it's resolution is about.5 arcsec.
Although impressive, this means that resolving the X-ray emitting hot gas in the inner orbits around a black hole requires another increase in resolution of about 3000 (for a near BH). Thus it will look like a point source, not nearly as beautiful as the supernova remnants on the Chandra home page.
It is however unique that it is possible to compare the results in this waveband to those obtained in visual frequenties. AXAF (aka Chandra) provides observers with resolution comparable with the best ground-based telescopes. ROSAT only has an imaging Half Power Diameter (HPD ~ resolution) of 5 arcsec (btw 1 arcsec translates to a coin seen at a kilometer distance).
Because the beam is reduced in size this means the background per beam element does too. Ergo, one can observe much fainter sources than before. Besides this, wavelength resolution improves linearly with reduction in beam size. This means high resolution spectroscopy at low energies will become feasible.
This will not only produce great wallpaper, but great science. Especially for stellar evolution.
Sadly: 'The science and engineering team is investigating a degradation in the front-side illuminated CCD chips of the Advanced charge-coupled Device Imaging Spectrometer (ACIS)'
Ooops, I hope they didnt make any calibration mistakes there *snicker*
Slashdot Mirror
Ello? Ello?
How come everyone is so satisfied with mp3 quality? I can barely listen to music chewed upon by mp3 compression. Bit for bit perfect? As far as copying is concerned maybe, but it certainly will take another type compression to fool my ears.
Or does everybody use lo-fi pc audio anyway nowadays?
Djeez.
In some way it's our own fault and naivity that we have been regarding streaming media as more authentic than printed, for we already knew how to manipulate the latter (although any tv-director could show you in a sec how to manipulate you without actually image processing a live broadcast).
My guess is that when we feel we need to have authenticated live media, we'll develope ways to ensure this, analogous to the way this is possible on the internet.
Good article by a great scientist. I dont understand the fuzz from some people about his predictions. He seems cautious and humble when he talks about the outstanding questions and mysteries.
What surprises me tho from many GU-physicist is that forget to learn from cosmology. They tend to turn it around and look only to the Hi-energy experiments in order to answer the deepest cosmological questions. Analyzing the Relics of the Big Bang and the evolution of the early Universe however can supply constraints on the behaviour and existence of exotic states of matter.
Besides this, it is unclear what is meant by Unified physics. There are some suspicious aspects about the various GUT theories. For example, it might be unrealistic to suggest true Unified physics in the context of our experiences at low energies. Here, almost every decade of energy-interval from the mass of the electron to the mass of the Z-boson contains new particles. One might expect that even higher energies would open up new physical phenomena, and so on indefinitely. The prediction of GUT is that, instead, we encounter a desert of at least 12 powers of 10 in energy in which nothing interesting happens.
This would certainly be convenient, given that it is hard to see how the maximum energy of accelerators can affordably be increased much further. 2;-p
Occasionally I code here and there to pay for my university tuition fees. Short projects, freelance, practically without references. Pays about $50/hour. Have some friends actually chained to an IT job or *sigh* career. I come up with this:
- Free lance: $25 and up for kids designing websites, $50-75 for the more demanding stuff, $100+ for experts.
- Starting code monkey @ somecompany: $15 @ 1.0 FTE, somewhat higher if part-time, twice as high if on project base.
- Experienced IT engineer/manager: $35-$50
Note, many of the IT firms over here try to seduce you with stocks, gadgets, cars, vacations or one-time $10.000 bonuses. IT's a frenzy. Resumes are relatively irrelevant if you are starting out 2;-p. Many will take the chance and give you some time to prove yourself.
Also an important thing to consider if comparing Europe to US is that every state in Europe has a different tax system (usually higher base income-tax and many times a progressive tax system, ie higher income, higher tax rate)
It's difficult to translate the raw dollars/hour to buying power. Living expenses are typically lower in the Netherlands than in the US. But again this may differ from country to country. Sweden for example is known to be the most expensive of the northern-European countries.
Also tax deductions can have a profound influence on your buying power. Morgage deduction, investment-deduction, transportation deduction, college deduction etc.
My guess is that when your desire is to live and work on the other side of the big pool and you want an accurate estimation of your living standards, you will have to dig fairly deep in the specific laws, regulations and habits of that particular country.
I think that as long as the US army is the one benefiting most from hi-tech communications the US governement will be most reluctant on the subject of international regulation.
But with the things are going now it's clear that control over- and rapid reduction and analysis of data of the battlefield will be crucial in any future war. No wonder Russia has tried to gather support for a United Nations resolution calling for new international guidelines, considering the state of its armed forces.
At our institute we have lotza 'puters clustered in subgroups and I think that the naming conventions our sysadmins use are silly but effective. For example, without going into Dutch geography, one group is named after rivers in the Netherlands. The larger the river the more powerfull the machine that is named after it, with the central servers having names like the IJssel and the Rijn (you know the Rhine don't you?) Another group uses the periodic table with the servers named after the first elements Hydrogen and Helium.
;-p
Although not entirely consistent it works fairly well. I know intuitively which machine to hit for that extreme resource slurping process.
One problem is that al our foreign scientists (about 30% of the institute is non Dutch) are in the dark, since they dont know any of the Dutch rivers.
DNA IS DATA! Data is NOT patentable, any more than a christmas carol. You can COPYRIGHT data, but you cannot, and should never be able to, patent it.
;-p
Can data live? Besides, is reading DNA the same as understanding DNA? I suspect that when the last chapter of the Great Book of Human Genome is finished reading it would compare to reading encrypted Chinese, without the the key or the Dictionary of course.
Come to think of it... considering the fact that DNA was here first and created US, DNA Inc. would make a fair chance patenting humans. Heck, why not all species... ?
Luckily James Clerk Maxwell didn't patent his blueprints on Electrodynamics and Heisenberg, Bohr, Schrodinger and Dirac were dedicated to open source, else we would still be computing with an abacus.
How can anyone patent the structure of nature?
A trifling amount. Next mystery: What would a decaying mini-BH (say, 1 million tons) do if it happened to be inside a planet when it went boom?>
;-p
I think it would act like my thesis advisor, who was a bit upset that I missed a deadline because of this discussion, hehehe.
That was educational. Pitcher of Heineken?
Agreed. Make that 2
Ivo
Now that's not so nice...
Ah. So you admit attempting to obfuscate the issue. Sorry, it doesn't win any points (or brew).
Nah, just remembered that something had to happen to absorped energy. First effect is to puff up the dust donut. But after this it will loose energy in intense IR radiation, just as seen in the FIR galaxies.
Another model just occurred to me: the radiation pressure of the growing BH and its polar jets blows the remains of Earth into a boiling, seething mass of iron-silicate vapor...
Funny thing is that I was thinking 'bout the same thing on my way home yesterday. You know it is impossible that the Earth will collaps into the BH. This you must admit (altho you have been as stubborn as I am). Gravitational collaps with the outer matter pushing the inner matter without delay into the BH hole only works at a mass density close the critical value for a body to lie within it's own horizon. Direct formation of small black holes is extremely difficult.
Do you want a calculation? Critical density scales as M^-2 and has the density of 10g/cm^3 for a 10^7Msun Black hole candidate. For direct formation (collapse) of an Earth BH (Mearth = 3.10^-6Msun) you require a core density of roughly 10^24g/cm^3. This cant be obtained, at least not with our type of matter.
Therefore we need to have some sort of accretion scenario. Since we have spherical symmetrical mass distribution the maximum accretion speed is defined by the Eddington limit, where radiation pressure of the infalling inner layer and the pressure of the layer just outside it balance (in this scenario dominated by the pressure of the rest of the Earths mass above it). This effect starts immediately, and will generate the pressure to support the rest of the core and prevent it from collapsing. If you dont believe this, check every standard literature on gravitational collapse, black hole formation and Eddington accretion. Blowing off the outer layers is a possibility, but this requires super-Edington accretion (achievable in highly anisotropic situations), since you need more outward radiation pressure than supplied by the default balanced influx.
Eddington accretion and Lifetime:
There exist a maximum luminosity that can be radiated by a gravitating body of mass M. This limit arises because radiation pressure from a central source can not exceed the gravity of the infalling material and the excess pressure from the material above it (then it would starve). Although the actual value for the Luminosity is hard to calculate, because of the complicate environment in the earth's core, it is interesting to note that the lifetime of een object radiating at the Eddington limit is independent of mass. The lifetime (know as the Salpeter time) is proportional to Mc^2/Ledd and for silicate particles this might be anyware between 10^6-10^8 years. 10^8 for free-fall, 10^6 for solid object.
I suppose my story sounds a bit dull compared to the spectacular 'blowing the face of the moon' scenario, but I think that you will study the relevant literature you find that direct collapse is impossible.
I admit that some of my earlier objections were wrong, but hey they came only from the tip of my hat.
The problem is that altho your total total energy budget might be correct (within a factor of 1000 or so), your calculations about the effects on the moon need this energy to be released almost instantly. From the Salpeter lifetime however it is more likely that this will take millions of years. This is supported by all observations of actual BH and AGN canditates. Eye know that the actual accretion scenarios are different, but that is accounted for by taking enhanced isotropic accretion with silicate particles. (else you would end up with typical 10^12 yr lifetimes)
The heat from this melts the remaining artificial satellites and then coats them with molten goo, as well as stealing their angular momentum from gas drag and pulling them in to share the fate of their creators. The entire Moon gets coated in iron, which simultaneously obliterates all traces of Apollo and turns it into a shiny marble for the next several billion years.
Hehe, I must say that IS an actractive and esthethic thought. But again this requires extreme super-Eddington accretion and this is difficult to achieve.
My best guess is that the BH settles in the Earth's core, slowly accreting the mass because of the inevitable balance between radiation pressure and infalling material (pressure by the outer-layer does not change this, only the increases required radiation level and speeds up the lifetime by a million or so). The heat would slowly dissipate through to the Earth crust, making global warming more like global cooking. The seas will evaporate, we will melt. The Earth might resemble Venus within a few 1000 years. However I think that given the fact that the total radiated energy is smeared out over millions of years, the Moon for example will be able to keep kewl, just by thermal equilibrium.
Damn, got a dry mouth. Could use a beer tho.
Ivo
I've been sleeping a lot during Quantum Field Theory last year. But what I understood from their renormalization theory is that they ignored infinite components in the integrals since they were more or less fixed numbers.
not:
A/0 = B/0
but:
A + infinity = B + another infinity
Therefore A = B.
Just as tricky btw, but certainly not applicable to every other problem.
Ivo
Nyquist information theory requires factor 2 sampling of a signal to hold all of its information.
pixelsize != resolution
Therefore typically the distortion by the optical train of a telescope (= the effective resolution (diffraction) limit) is oversampled a factor 2 or 3 by the CCD detector.
Ivo
If you want to have a calculating battle, by all means jump in. I'm willing to fire off numbers at you and take your return fire, winner to collect a pitcher of beer from the loser if they should ever be in the same city. I admit that this wouldn't be much of a prize for you since I am not likely to visit the Netherlands soon and American beer being as lousy as it is, but I can't think of another prize worthy of a friendly competition.
;-p.
..assuming the black hole already contains the earth mass, which is not the case. My point is that since it begins small, in a dusty rotating environment, the black hole will end up with only a small fraction of the mass.
;-p). You seem to calculate from an existing M-earth BH.
;-p
Hehe, noted. You're welcome to have a beer anyway
But seriously:
That said, the numbers are not just huge. They are many orders of magnitude beyond huge. For instance, the megaton/m^2 flux at Mars is enough energy to blow off an atmosphere as thick as Venus'. 1 megaton = 4.2e22 ergs = 4.2e15 joules
Eye know about huge, I was just disagreeing how huge. Eating off zeros on the way.
Nope. The gravitational energy available goes as 1/r, so a full 50% of the total is available from only 2 radii out. The radius of a 1-earth-mass black hole is about 1 centimeter; everything is going to be falling in from more than twice that!
1.Even at the equator, an object sitting on the ground has only enough angular momentum to maintain a circular orbit around an earth-mass point at 1/64 of the radius of the Earth. And that's the best an object on Earth can do! Things at the poles would fall straight down if they were suddenly unsupported.
1/64 Earth radius is 10.000.000 Schwarzschild radii of an 1-earth-mass black hole (which does not exist at the time). I fail to see how it would find its way directly to the black hole (without an up-to-date inner-planetary map that is)
2.Conversion efficiency is supposedly up to 50%. All the mass cramming into that accretion disk at a large fraction of c generates a heck of a lot of heat.
Again I disagree. I'm not talking about forming a M-earth BH and subsequently letting testparticles fall into it. Only matter with small enuff angular momentum to hit the Kerr-radius directly will be eaten instantly. The earth will form an accretion disk extending from 100km to lets say a 100m, depending on radiation pressure. Free falling angular momentum carrying mass from 6000km out to 50km (not into the black hole!) speeds up to a small nowhere near a fraction of C. Your free-fall calculation does not include the centrifugal potential. Again our main difference is that I suggest that the accretion disk at the time of creation will contain almost all of the Earth's mass (lemme throw you a number 99.9999998%
3.The mini-BH would fall from the surface of the earth toward the core (if it could last long enough to get out of the lab, which it could not)...
Ofcuz. In our lively discussion I also forgot to stress that the damn thing would evaporate instantly anyway. This triggers another question, mebbe you can shed some light on this. How big must the progenitor BH be for the inbound mass flux (in the beginning dominated by free fall to the earth's center and the Rschwarz of the progenitor) to balance the evaporation mass flux?
4.Earth isn't very big, and doesn't have a lot of angular momentum compared to a star of far greater dimensions. If something swallowed the core, the rest would fall inward just fine.
Absolute ang momentum is irrelevant. Only the effective potential matters, and centrifugal component plays a crucial role. Earth spins about 30 times faster than the Sun.
The black hole couldn't starve unless the accretion disk could transfer enough angular momentum outward to get the remaining mass into orbit...
Now this is strange. Are you actually saying that angular momentum transfer helps the BH to starve? Or is there some wrong with my English? In standard thin disk accretion theory quasi-viscous ang momentum transfer is the only way to prevent it from starving. Accretion effeciency computed from the marginally stable orbit is only a few %. Bring in mind that the Kerr-radius is ridiculously small compared to the size of the accretion disk.
The jets are driven by radiation pressure. The jets will also be there to scatter the energy radiated poleward from the accretion disk and allow it to hit objects behind the accretion disk. Remember, my calculations only assumed that 0.0001 of the total energy escaped as radiation toward the equator. The same conclusions hold pretty much even if you reduce that to 0.00000001.
Two possibilities of Jet generation have been discussed in literature. The most important being magnetic field line winding and flux freezing wich will tend to make plasma stream along the field lines. It is thought that this dynamo-effect causes the bulk relativistic motion we call a jet. The radiation pressure only provide the initial acceleration to produce the outflow. That scattering on the jet will contriblute significantly to the overall radiation is unsupported by observations of real jets. My point is that given your severe overestimation of the radiated energy (calculated from a unrealistic simple scenario) and the chaotic poorly understood magnetic effects, the acretion scenario, the absorption of the dust band (which will be created) will provide anuff extra "couple of zero's" to topple your argument.
Especially the dust band is a nice one. The amount of extinction might be 100-300 magnitudes in UV/X-ray. I do not need to remind you what that means to the flux. But to all non-astrophysists: this means that only 0.00000000000000000000000000000000000001% of the radiation gets through. Ofcourse I'm not saying anything about the re-radiated IR radiation hehehheeh.
Love them zero's.
How 'bout a beer?
Ivo
.. but not for artificial satellites ;-p. Hokay the numbers are huge, I agree. But anisotropy does much more than dividing the radiation number by x. Besides that there are several important complications to your lucent but very crude calculations.
.01% of your overstimated radiation at the equator might be several orders of magnitude too high. Silicate grains are magnificent UV absorbers, and UV-soft Xray will be the major emission waveband in the accretion disk.
- since most matter falling into the black hole is cold and already very deep in the potential well conversion effeciency will very much lower than the theoretically infinite distance approach
- all the mass surrounding the earth center carries angular momentum, the accretion disk into which the earth will transform will only on convert some small fraction of the potential energy of the accreting mass. Besides in our scenario we assume the mini black hole to originate at the earth's surface further decreasing the accretion rate and conversion efficiency. We are not talking about a hardly rotating collapsing stellar iron core here...
- the black hole might starve before it can eat all of its food. After accretion disk forming only the inner 3*R(schwarzschild) orbits are unstable. Then angular momentum transport in the accretion disk will dictate the rate of energy production.
- much of the available gravitional energy will be converted into kinetic energy blowing a significant portion of the mass away in opposite jets
- the evaporated mass of the earth will consist of small iron and silicate particles creating a broad inpenetratable dust band on the equator just as seen AGNs. Given the available Si/Fe mass and high density you may happily assume that
My conclusion is that the earth satellites probably wont survive, but the Moon and Mars will laugh at Earth's misery. Especially since the momentum carried by the rest radiation will be ridiculously small compared to their orbital momentum.
Ivo
mister attack says: >> The idea that we are going to destroy the world with the RHIC is absolutely ridiculous. I remember reading that a large number of physicists thought the first nuclear weapon would ignite the atmosphere, destroying all life on Earth. Didn't happen.
;-p
This is a logical fallacy known as post hoc ergo propter hoc. Just because we haven't destroyed the earth in the past doesn't mean we can't do it.
Actually this is a non post hoc ergo non propter hoc which is something logically different.
Ivo
Given that the collapse of the Earth into a black hole would involve the conversion of perhaps 50% of the total mass into energy in the accretion disk, all the artificial satellites would probably evaporate.
...assuming isotropic radiation, thus accreating according to Eddington. All observed black hole candidates however show jet forming (ie anisotropic 'dynamo-like' effects), from the small to the very large Active Galactic Nuclei in the center of galaxies.
Ivo
Sure lifespan has been increasing at that 10% rate for the last dicennia, but how about quality of life? You have to be fit for space travel. How 'bout hospitals over there?
Wait a sec! A space home for the elderly!
Ivo
isn't actually that difficult if the angle/position of all the shots are identical
That might be a problem, if you require sub-meter pointing accuraty and stability, just by gyro-control, on a spacecraft at 200km height, traveling at say 7000km/hour, minimal exposure time some fraction of second. It might be quite undoable.
I'll spare the mathematical details,
;-p
...when a human being sees a blurry or distorted image (particularly of the sort produced by satellite), he can usually pick out most of the deviations from an "ideal" clear image. instantly.
;-p. Heck, we dont even need bigger telescopes, since the only difference image-resolution-wise compared to small telescopes is convolving it with a smaller point spread function, which we recognize away anyway.
please don't
How does een human even know the deviation from a 'ideal' image if it can't be seen. (unless you assume what you are looking at)
Damn, we sure could use this in astronomy research. We just need to recognize to protogalaxy in the fuzz
I agree that temporal filtering of 100-1000 images would do nicely, but even that is bound to diffraction limiting. (at 200km height you need an equivalent of HST's 2.4 mirror.)
Ivo
Don't worry about the resolution. Ordinary US/RUSSIAN/[INSERT COUNTRY] spy-sats have 1-2 feet resolution, that's about diffraction limited (ie you just need bigger mirrors for improved resolution). Atmospheric disturbance plays a minor role, but even if it did, you cant compute the interference away (because you have to know the exact interference to deconvolve it... basic image processing). Just statistics is certainly not enuff. The solution is active optics, such as used in the new eso VLT telescopes. But bringing active optics into space.... hmmm, think not, for now.
Ivo
I think you misunderstood. These 1-meter res images will b used to provide a simulation of the environment at which something (accident, murder, whatever) has taken place. It might prove useful to influence jury members by presenting them the surroundings from a certain perspective (probably the defendant's, hehe)
It's been possible for some years now to obtain 2-meter hi-res imaging data via SPIN-2, imagery taken with the russian sat Cosmos gone commercial. Check out http://www.spin-2.com/
Orbimage is also a global provider of satellite-delivered Earth imagery services with a planned constellation of five digital remote sensing satellites. They will launch 2 1-meter res. sats next year.
Hubble's WFPC2 camera has 3 chips with 0.1 arcsec pixels and one chip with 0.046 arcsec pixels. But sinds this wide-field camera undersamples the PSF of the telescope, which is diffraction limited, the actual resolution is higher. A 2.4m diffraction limited telescope, may have .02 arcsecond resolution.
Usually when astronomers say: this object is so-and-so old they are talking about an intrinsic property of the object, independent of distance.
On the other hand when they say this-and-that happend so-and-so time ago they mean that, because of the finit speed of light (according to special relativity) the photons now observed by us spent so-and-so yrs traveling the distance between us and the object. Therefore the image you see now, is 40.000 yrs old.
The difference is perspective: are we talking about the image, or the object.
Ivo
Actually pointing it at an Black Hole candidate is not incredibly spectacular (visually), given that it's resolution is about .5 arcsec.
Although impressive, this means that resolving the X-ray emitting hot gas in the inner orbits around a black hole requires another increase in resolution of about 3000 (for a near BH). Thus it will look like a point source, not nearly as beautiful as the supernova remnants on the Chandra home page.
It is however unique that it is possible to compare the results in this waveband to those obtained in visual frequenties. AXAF (aka Chandra) provides observers with resolution comparable with the best ground-based telescopes. ROSAT only has an imaging Half Power Diameter (HPD ~ resolution) of 5 arcsec (btw 1 arcsec translates to a coin seen at a kilometer distance).
Because the beam is reduced in size this means the background per beam element does too. Ergo, one can observe much fainter sources than before. Besides this, wavelength resolution improves linearly with reduction in beam size. This means high resolution spectroscopy at low energies will become feasible.
This will not only produce great wallpaper, but great science. Especially for stellar evolution.
Sadly: 'The science and engineering team is investigating a degradation in the front-side illuminated CCD chips of the Advanced charge-coupled Device Imaging Spectrometer (ACIS)'
Ooops, I hope they didnt make any calibration mistakes there *snicker*
Ivo