EM radiation does have energy and by Einstein has an effective mass. In the very early universe, there was enough radiation to contribute significantly to the mass budget of the universe, but today we estimate it to be roughly 1 part in 10000 of the total mass in the universe.
We can (relatively) easily measure gamma rays with a few MeV in energy. Once you get beyond a few MeV, single photons will interact with Cosmic Microwave Background photons and via pair production create pairs of particles like e+,e-. As energy goes up, these processes get really efficient so really high energy photons don't live very long (~10-100 kyr).
Even in physics circles, they are both are refered to as cosmic rays. The muons, high energy electrons and other particles created in the atmosphere are refered to a "secondary" cosmic rays and the stuff traveling through space are refered to as "primary" cosmic rays, but everything gets called "cosmic rays".
The lake is believed to have formed when the bottom of the glacier melted, so the only life that could be there are microbes that could exist in the dirt or in the ice before that happened.
Actually 500,000 years maybe a significant understatement. Antarctica has been continuously glaciated for the last ~40 million years. We know that the lake is at least 500,000 years old because that is roughly the age of the ice directly above it. However, as with all glaciers, the ice slowly creeps from the central domes where snow accumulates out the ocean where icebergs form and the edges melt. Hence, it is pretty certain that the ice above Vostok today is not the ice that was there when the lake first formed.
This opens the possibility that the lake may have existed continuously under the ice for 20 or 30 million years. Till we crack her open and look inside it will be hard to say.
The average height is ~8,000 ft above sea level (far higher than any other continent). The weight of the ice depresses the ground so that most of the bedrock is technically below sea level.
Your guess is basically right. The lakes under Antarctica exist because of a balance between the slow trickle of geothermal heat and the insulating qualities of kilometers of ice.
You may be aware that as one digs down into the Earth it starts to get hotter. This is because everywhere on the Earth there is a slow trickle of ambient geothermal energy being dissipated from the hot core out to the much cooler surface. This should not be mistaken for much more intense geothermal phenomena like volcanos and hot springs as they have nothing to do with most subglacial lakes.
Since everywhere on Earth a little bit of geothermal heat is being released (roughly 1% of the power/area of sunshine) this includes the bottoms of glaciers. This causes the bottoms of ice sheets to always be warmer than their tops. For most glaciers this is only a few degrees, and no cares, but as the ice sheet grows, the ice can eventually become so thick that it can't dissipate the geothermal energy effectively and the bottom will melt. This is responsible for the majority of subglacial Antarctic lakes.
Actually lakes like this aren't so rare. Radar mapping through the Antarctic ice has identified some 250 lakes under the ice cap. Most are small. Lake Vida is important because it is so near the surface, while Lake Vostok is important because it is huge (far larger than any other) and plausibly has remained liquid and isolated for ~40 million years.
And, quite frankly, I'm surprised that there isn't much more VC and grant money available to go and do research on stuff like this. Afterall, these projects are quite prestigious.
If it takes $100 million to find mistakes in the theory, there is very little practical incentive to research it, since more than likely it will take many times $100 million to exploit any of those newly discovered differences for practical gain. Put another way, if existing theories are good enough for all but the most precise applications then only a small number of people working at the very cutting edge are going to care about testing the theory to it's limits.
While it is good for science to check these things out and research foundations do provide money for these types of things, there will always be limited funding when it comes to projects that have no apparent practical value to anyone.
It sounds more complicated than it is because it is usually phrased in geometrical language.
You may be aware that elctricity and magnetism are intimately connected. In one sense magnetism is an extra force that moving electrical charges exert on other moving electrical charges.
Einstein discovered that gravity can work much the same way. Moving gravitational charges (i.e. masses) generate an extra force on other moving masses. This extra force is sometimes refered to a gravito-magnetism and is usually very weak except when high velocities or enormous masses are involved.
Gravito-magnetism works like ordinary magnetism in that the force is exerted tangetial to the direction of motion of the object. So if you are falling into towards a massive rotating object, then the net effect of all of the moving mass in the rotating body is to give you a little kick sideways, towards the direction of rotation. This makes in look like the straight paths near the rotating body have been twisted around and people refer to this effect as "frame dragging", like the massive body has put a twist into space.
Don't forget the theories about an ecosystem being present in Lake Vostok, several miles below the surface of Antarctica.
As cool as it would be to find out (along with the scientific significance of the data), should we really contaminate that ecosystem if it exists? As much as we try not to, any intervention would upset a potentially fragile system.
Something most people don't know is that Vostok is not one of a kind. It is merely the largest of approximately 70 lakes under the primary Antarctic ice sheet, identified by radar imaging. Because it is so large, it is likely that it has been liquid for a large portion of the 40+ million years that Antarctica has been glaciated, thus giving plenty of time for evolution and the development of a novel ecosystem. Whether that ecosystem is "fragile" is anybody's guess, but whatever bacteria live down there do so in a very large (one the largest lakes on Earth) and unfriendly swimming pool.
Incidently there will be no fish in Lake Vostok. Subglacial lakes of this kind form under mature ice sheets. When an ice sheet grows to around 3 or 4 km, it becomes so thick that it can no longer effectively dissipate the slow outflow of heat from the Earth's interior. The result is that the ice sheet actually melts from the bottom. This water, combined with melt from friction as the ice sheet overruns rock, provides the source of the water that accumulates in low spots and forms subglacial lakes. The lubrication such water provides greatly enhances ice flow rates and limits the maximum thickness of glaciation.
Anyway, this means that any life that is present in Vostok today must have survived in the soil underneath a growing glacier for millions of years until the ice sheet was large enough to trap sufficient geothermal heat that liquid water could occur and pool into the form we see today. Hence it is very unlikely that we would find anything more advanced than bacteria down there, though it certainly would be interesting if there was more advanced life down there.
The more we fear, the more we consume. As a whole our society has seen millions of dollars spent on research on a disease that has only killed 295 people out of over six billion. When diseases were feared in the past it was worth fearing them: Justinian's Plague (541-544AD) killed 40% of the population of Constantinople; In the 14th Century we saw as many as 800 people a day dying of the Bubonic Plague -- 30% of Normandy's population was decimated. By comparison, SARS has managed to destroy less than 0.0000005% of the world's population, infecting a mere 0.000077% of the population.
I've been following the statistics published by the WHO. You realize that despite all the attention that has been leveled against SARS, that it still has an accelerating growth rate? The number of deaths have been more than doubling every two weeks. From six deaths in early March to 293 at present. It fits a very nice exponential, with little sign that containment efforts have slowed it down.
But let's all just ignore SARS till it's killed it's first million people. If containment truly fails we could see that by the end of the year. Frankly I think we can do better than that, and that we do have a chance to beat this thing before it settles in for the long haul, but not if people like you whine about how little impact it has had, while ignoring the impact it could have.
That it is part of public record wouldn't bother me (much), though I would certainly like to have a disclaimer saying that listed somewhere on the form.
Even so, that would imply millions of records, in CA alone. I would be very upset if someone could go up and request a copy of all of the email addresses contained therein in a nice electronic format. If a spammer wants the info, let them process a million pieces of paper. Not impossible, but I'd at least like to know that the spammers had to put in a little effort at this. If CA makes it easy for them, then they are an accessory to the crime in my book.
I operate a domain, so it is easy to substitute a unique email address when I register for some suspect activity.
To my shock, one of the single greatest sources of spam that I have gotten is from an email address placed on a CA voter registration form. I've never actually used that address or given it out for anything before or since, and yet a year later I am still getting 3 or so emails a day showing up in my spam filter from that address.
To my knowledge not one of these spams actually came from the CA governement, but I can only infer that either they sold it, or there is some big public list of voter registration emails that spammers know about.
The Earth has a much thicker atmosphere than Mars, and atmospheric drag would be sufficiently large to vaporize all of the cable falling from more than 25 km or so. This effectively sets the distance you need to be from the shore in order to guarantee that the cable won't fall on someone in case of an accident.
The Cretaceous extinction where an impactor killed the dinosaurs (and perhaps 50% of all species alive at the time) was only 65 million years ago. In the media it is widely quoted that events like that happen every 100 million years, though scientists now believe that such impacts are probably more like once in 500 million years. Other than being short on facts, your conclusion is essentially correct, we are quite unlikely to have an extinction level impact in the near future.
Of course, we expect to have an impact capable of leveling a city block once a century. The odds of it actually hitting a city block depend on what portions of the Earth is occupied by us. Of course if we know about it, it would also give us a chance to get out of its way.
In general, I don't think geeks are any more or less righteous than the average individual, but the hoardes of lustful geeks desperately trying to get laid probably wouldn't be helping themselves get into "techno heaven".
I seriously considered getting a.name address for my personal site. The thing that killed my interest was that while they promoted the convenience of the URL (firstname.lastname.name) and personalized email (firstname@lastname.name) as a set, they then turned around and said that the email is a substantial add-on cost. Plus the.NAME people insisted on at least a two year commitment. All told, the minimum price I could find from any seller was $90.
That's a lot of money to register a personal site that has no possibility of ever earning income. So instead I registered a.com based on my name, which included free email forwarding, for only $15 a year. In short, I think that the.NAME folks have an interesting product, but their pricing is way out of whack for something that is inherently targetted to individuals.
PS I haven't checked recently to see if they have changed the pricing requirements, but after they messed up the launch so badly I wouldn't buy now even if they had.
Some others have noted that there are theories where energy and/or matter are spontaneously created in empty space. These can coexist with the heat death fate if the new energy is also evenly spread, which it probably would be in such a uniformly boring heat-dead universe. Still no way to create a new free energy gradient.
The lack fo a free energy gradient doesn't neccesarily follow. Keep in mind that the whole universe (after the first million years or so) condensed out of a virtually uniform distribution of energy, in the form of hydrogen and helium atoms, that gravitationally collapsed into ever larger concentrations starting from only the weakest of quantum fluctutations in the density field.
It's possible that any matter or energy that gets spontaneously created in empty space could be self-concentrating in a way similar to the gravitational concentration of hydrogen, leading to the spontaneous creation of new energy gradients.
In order to have a do-not-email list you have to have an accessible list of valid email addresses. Okay so company A looks at the list and agrees not to email any of the people on it, and then turns a big profit by covertly selling the list to other companies comfortably located outside of US jurisdiction.
Email is global, it's hard to believe that any state is going to come up with a way of significantly controlling spam.
The "Ross Ice Shelf" is actually a misnomer for a sizable portion of it's expanse. Much of it is actually a marine ice sheet, or in other words, an ice sheet of sufficient weight and thickness that it is resting on bedrock that just happens to be below sea level. As such it is much more stable than an ice shelf, though admittedly a little less so than a continental ice sheet.
Not knowing anything definite about the route they are taking, I couldn't say whether they are building over the part grounded at the bottom of the bay or not, but I would assume so. Besides which, it is not like they are pouring lots of concrete or anything.
While there certainly are many other important contributors to the science of chaos theory, I find it hard to fault Yorke as a choice.
He basically defined (literally) the mathematical foundation for chaos theory as small variations in initial conditions leading to arbitrarily large variations in final condition. Not to mention coining the word "chaos". He's been working in the field since the beginning and still does. Now adays he informally heads the theoretical branch of the interdisciplinary chaos research group at UMD.
Of course the poor reporting is a different issue.
Perhaps a lot of scientists do donate the money. After all, Nobel Laurettes don't generally have problems getting grant money.
If you read Nobel's will, it seems he wanted the prizes to be awarded to people that "conferred the greatest benefit on mankind", and it is generally believed he excluded mathematics on the ground it wasn't practical enough.
That isn't true. You're forgetting about the mini ice age -- which many believe to be what knocked off the vikings.
The so called mini ice age which was a very big deal in Europe is believed to have been connected with a local reorganization of the Atlantic currents. There is no local record of this cold period in Asia or most of the Southern Hemisphere. At the global level, this period (1450-1750) represents a drop of less than 0.5 degree C from established averages.
The quoted value of 10-20 meters come from a colloquia by Prof. Stephen Schneider which I attended a few months ago. A naive calculation of thermal expansion using a coefficient of 2.1e-4 per degree C and an average ocean depth of 3.7 km comes out with an increase of about 1 meter per degree C. But because the coefficient actually depends on both pressure and temperature, the value quoted above (for room temperature and 1 atm) is too low. Not being an expert in this area I'm not sure how to arrive an appropriate coefficient, but I do respect Dr. Schnieder's judgment in that matter.
Another issue that people neglect to bring up is the enormity of the task of melting the great land-based ice shields. First, the temperature has to be above freezing for the ice to even start to melt, and it has to be well above freezing for the ice to melt fast enough to keep from being replaced by next winter's snow. One hundred years isn't going to do the job.
Keep in mind that for an ice sheet to maintain a constant size the edges must be melting at exactly the same rate that the pressure of new ice in the center is pushing it out. Hence at the edges the temperatures already get warm enough to melt significant amounts of ice. If the temperatures get warmer the place where equilibrium occurs get pushed inward and ice sheets shrink. Will we melt all of the antartic ice sheet, probably not, but we can easily shrink it a good deal.
Slashdot Mirror
EM radiation does have energy and by Einstein has an effective mass. In the very early universe, there was enough radiation to contribute significantly to the mass budget of the universe, but today we estimate it to be roughly 1 part in 10000 of the total mass in the universe.
We can (relatively) easily measure gamma rays with a few MeV in energy. Once you get beyond a few MeV, single photons will interact with Cosmic Microwave Background photons and via pair production create pairs of particles like e+,e-. As energy goes up, these processes get really efficient so really high energy photons don't live very long (~10-100 kyr).
Even in physics circles, they are both are refered to as cosmic rays. The muons, high energy electrons and other particles created in the atmosphere are refered to a "secondary" cosmic rays and the stuff traveling through space are refered to as "primary" cosmic rays, but everything gets called "cosmic rays".
The lake is believed to have formed when the bottom of the glacier melted, so the only life that could be there are microbes that could exist in the dirt or in the ice before that happened.
Actually 500,000 years maybe a significant understatement. Antarctica has been continuously glaciated for the last ~40 million years. We know that the lake is at least 500,000 years old because that is roughly the age of the ice directly above it. However, as with all glaciers, the ice slowly creeps from the central domes where snow accumulates out the ocean where icebergs form and the edges melt. Hence, it is pretty certain that the ice above Vostok today is not the ice that was there when the lake first formed.
This opens the possibility that the lake may have existed continuously under the ice for 20 or 30 million years. Till we crack her open and look inside it will be hard to say.
The average height is ~8,000 ft above sea level (far higher than any other continent). The weight of the ice depresses the ground so that most of the bedrock is technically below sea level.
Your guess is basically right. The lakes under Antarctica exist because of a balance between the slow trickle of geothermal heat and the insulating qualities of kilometers of ice.
You may be aware that as one digs down into the Earth it starts to get hotter. This is because everywhere on the Earth there is a slow trickle of ambient geothermal energy being dissipated from the hot core out to the much cooler surface. This should not be mistaken for much more intense geothermal phenomena like volcanos and hot springs as they have nothing to do with most subglacial lakes.
Since everywhere on Earth a little bit of geothermal heat is being released (roughly 1% of the power/area of sunshine) this includes the bottoms of glaciers. This causes the bottoms of ice sheets to always be warmer than their tops. For most glaciers this is only a few degrees, and no cares, but as the ice sheet grows, the ice can eventually become so thick that it can't dissipate the geothermal energy effectively and the bottom will melt. This is responsible for the majority of subglacial Antarctic lakes.
The Earth's magnetic field is maintained by dynamo processes that dissipate about 1 TW of power.
As with so many rare finds ...
Actually lakes like this aren't so rare. Radar mapping through the Antarctic ice has identified some 250 lakes under the ice cap. Most are small. Lake Vida is important because it is so near the surface, while Lake Vostok is important because it is huge (far larger than any other) and plausibly has remained liquid and isolated for ~40 million years.
Oops.
You are right. The gravito-magnetic force acts perpendicularly not tangentially.
And, quite frankly, I'm surprised that there isn't much more VC and grant money available to go and do research on stuff like this. Afterall, these projects are quite prestigious.
If it takes $100 million to find mistakes in the theory, there is very little practical incentive to research it, since more than likely it will take many times $100 million to exploit any of those newly discovered differences for practical gain. Put another way, if existing theories are good enough for all but the most precise applications then only a small number of people working at the very cutting edge are going to care about testing the theory to it's limits.
While it is good for science to check these things out and research foundations do provide money for these types of things, there will always be limited funding when it comes to projects that have no apparent practical value to anyone.
It sounds more complicated than it is because it is usually phrased in geometrical language.
You may be aware that elctricity and magnetism are intimately connected. In one sense magnetism is an extra force that moving electrical charges exert on other moving electrical charges.
Einstein discovered that gravity can work much the same way. Moving gravitational charges (i.e. masses) generate an extra force on other moving masses. This extra force is sometimes refered to a gravito-magnetism and is usually very weak except when high velocities or enormous masses are involved.
Gravito-magnetism works like ordinary magnetism in that the force is exerted tangetial to the direction of motion of the object. So if you are falling into towards a massive rotating object, then the net effect of all of the moving mass in the rotating body is to give you a little kick sideways, towards the direction of rotation. This makes in look like the straight paths near the rotating body have been twisted around and people refer to this effect as "frame dragging", like the massive body has put a twist into space.
Don't forget the theories about an ecosystem being present in Lake Vostok, several miles below the surface of Antarctica.
As cool as it would be to find out (along with the scientific significance of the data), should we really contaminate that ecosystem if it exists? As much as we try not to, any intervention would upset a potentially fragile system.
Something most people don't know is that Vostok is not one of a kind. It is merely the largest of approximately 70 lakes under the primary Antarctic ice sheet, identified by radar imaging. Because it is so large, it is likely that it has been liquid for a large portion of the 40+ million years that Antarctica has been glaciated, thus giving plenty of time for evolution and the development of a novel ecosystem. Whether that ecosystem is "fragile" is anybody's guess, but whatever bacteria live down there do so in a very large (one the largest lakes on Earth) and unfriendly swimming pool.
Incidently there will be no fish in Lake Vostok. Subglacial lakes of this kind form under mature ice sheets. When an ice sheet grows to around 3 or 4 km, it becomes so thick that it can no longer effectively dissipate the slow outflow of heat from the Earth's interior. The result is that the ice sheet actually melts from the bottom. This water, combined with melt from friction as the ice sheet overruns rock, provides the source of the water that accumulates in low spots and forms subglacial lakes. The lubrication such water provides greatly enhances ice flow rates and limits the maximum thickness of glaciation.
Anyway, this means that any life that is present in Vostok today must have survived in the soil underneath a growing glacier for millions of years until the ice sheet was large enough to trap sufficient geothermal heat that liquid water could occur and pool into the form we see today. Hence it is very unlikely that we would find anything more advanced than bacteria down there, though it certainly would be interesting if there was more advanced life down there.
The more we fear, the more we consume. As a whole our society has seen millions of dollars spent on research on a disease that has only killed 295 people out of over six billion. When diseases were feared in the past it was worth fearing them: Justinian's Plague (541-544AD) killed 40% of the population of Constantinople; In the 14th Century we saw as many as 800 people a day dying of the Bubonic Plague -- 30% of Normandy's population was decimated. By comparison, SARS has managed to destroy less than 0.0000005% of the world's population, infecting a mere 0.000077% of the population.
I've been following the statistics published by the WHO. You realize that despite all the attention that has been leveled against SARS, that it still has an accelerating growth rate? The number of deaths have been more than doubling every two weeks. From six deaths in early March to 293 at present. It fits a very nice exponential, with little sign that containment efforts have slowed it down.
But let's all just ignore SARS till it's killed it's first million people. If containment truly fails we could see that by the end of the year. Frankly I think we can do better than that, and that we do have a chance to beat this thing before it settles in for the long haul, but not if people like you whine about how little impact it has had, while ignoring the impact it could have.
That it is part of public record wouldn't bother me (much), though I would certainly like to have a disclaimer saying that listed somewhere on the form.
Even so, that would imply millions of records, in CA alone. I would be very upset if someone could go up and request a copy of all of the email addresses contained therein in a nice electronic format. If a spammer wants the info, let them process a million pieces of paper. Not impossible, but I'd at least like to know that the spammers had to put in a little effort at this. If CA makes it easy for them, then they are an accessory to the crime in my book.
I operate a domain, so it is easy to substitute a unique email address when I register for some suspect activity.
To my shock, one of the single greatest sources of spam that I have gotten is from an email address placed on a CA voter registration form. I've never actually used that address or given it out for anything before or since, and yet a year later I am still getting 3 or so emails a day showing up in my spam filter from that address.
To my knowledge not one of these spams actually came from the CA governement, but I can only infer that either they sold it, or there is some big public list of voter registration emails that spammers know about.
The Earth has a much thicker atmosphere than Mars, and atmospheric drag would be sufficiently large to vaporize all of the cable falling from more than 25 km or so. This effectively sets the distance you need to be from the shore in order to guarantee that the cable won't fall on someone in case of an accident.
The Cretaceous extinction where an impactor killed the dinosaurs (and perhaps 50% of all species alive at the time) was only 65 million years ago. In the media it is widely quoted that events like that happen every 100 million years, though scientists now believe that such impacts are probably more like once in 500 million years. Other than being short on facts, your conclusion is essentially correct, we are quite unlikely to have an extinction level impact in the near future.
Of course, we expect to have an impact capable of leveling a city block once a century. The odds of it actually hitting a city block depend on what portions of the Earth is occupied by us. Of course if we know about it, it would also give us a chance to get out of its way.
In general, I don't think geeks are any more or less righteous than the average individual, but the hoardes of lustful geeks desperately trying to get laid probably wouldn't be helping themselves get into "techno heaven".
I seriously considered getting a .name address for my personal site. The thing that killed my interest was that while they promoted the convenience of the URL (firstname.lastname.name) and personalized email (firstname@lastname.name) as a set, they then turned around and said that the email is a substantial add-on cost. Plus the .NAME people insisted on at least a two year commitment. All told, the minimum price I could find from any seller was $90.
.com based on my name, which included free email forwarding, for only $15 a year. In short, I think that the .NAME folks have an interesting product, but their pricing is way out of whack for something that is inherently targetted to individuals.
That's a lot of money to register a personal site that has no possibility of ever earning income. So instead I registered a
PS I haven't checked recently to see if they have changed the pricing requirements, but after they messed up the launch so badly I wouldn't buy now even if they had.
Some others have noted that there are theories where energy and/or matter are spontaneously created in empty space. These can coexist with the heat death fate if the new energy is also evenly spread, which it probably would be in such a uniformly boring heat-dead universe. Still no way to create a new free energy gradient.
The lack fo a free energy gradient doesn't neccesarily follow. Keep in mind that the whole universe (after the first million years or so) condensed out of a virtually uniform distribution of energy, in the form of hydrogen and helium atoms, that gravitationally collapsed into ever larger concentrations starting from only the weakest of quantum fluctutations in the density field.
It's possible that any matter or energy that gets spontaneously created in empty space could be self-concentrating in a way similar to the gravitational concentration of hydrogen, leading to the spontaneous creation of new energy gradients.
In order to have a do-not-email list you have to have an accessible list of valid email addresses. Okay so company A looks at the list and agrees not to email any of the people on it, and then turns a big profit by covertly selling the list to other companies comfortably located outside of US jurisdiction.
Email is global, it's hard to believe that any state is going to come up with a way of significantly controlling spam.
The "Ross Ice Shelf" is actually a misnomer for a sizable portion of it's expanse. Much of it is actually a marine ice sheet, or in other words, an ice sheet of sufficient weight and thickness that it is resting on bedrock that just happens to be below sea level. As such it is much more stable than an ice shelf, though admittedly a little less so than a continental ice sheet.
Not knowing anything definite about the route they are taking, I couldn't say whether they are building over the part grounded at the bottom of the bay or not, but I would assume so. Besides which, it is not like they are pouring lots of concrete or anything.
While there certainly are many other important contributors to the science of chaos theory, I find it hard to fault Yorke as a choice.
He basically defined (literally) the mathematical foundation for chaos theory as small variations in initial conditions leading to arbitrarily large variations in final condition. Not to mention coining the word "chaos". He's been working in the field since the beginning and still does. Now adays he informally heads the theoretical branch of the interdisciplinary chaos research group at UMD.
Of course the poor reporting is a different issue.
Perhaps a lot of scientists do donate the money. After all, Nobel Laurettes don't generally have problems getting grant money.
If you read Nobel's will, it seems he wanted the prizes to be awarded to people that "conferred the greatest benefit on mankind", and it is generally believed he excluded mathematics on the ground it wasn't practical enough.
That isn't true. You're forgetting about the mini ice age -- which many believe to be what knocked off the vikings.
The so called mini ice age which was a very big deal in Europe is believed to have been connected with a local reorganization of the Atlantic currents. There is no local record of this cold period in Asia or most of the Southern Hemisphere. At the global level, this period (1450-1750) represents a drop of less than 0.5 degree C from established averages.
The quoted value of 10-20 meters come from a colloquia by Prof. Stephen Schneider which I attended a few months ago. A naive calculation of thermal expansion using a coefficient of 2.1e-4 per degree C and an average ocean depth of 3.7 km comes out with an increase of about 1 meter per degree C. But because the coefficient actually depends on both pressure and temperature, the value quoted above (for room temperature and 1 atm) is too low. Not being an expert in this area I'm not sure how to arrive an appropriate coefficient, but I do respect Dr. Schnieder's judgment in that matter.
Another issue that people neglect to bring up is the enormity of the task of melting the great land-based ice shields. First, the temperature has to be above freezing for the ice to even start to melt, and it has to be well above freezing for the ice to melt fast enough to keep from being replaced by next winter's snow. One hundred years isn't going to do the job.
Keep in mind that for an ice sheet to maintain a constant size the edges must be melting at exactly the same rate that the pressure of new ice in the center is pushing it out. Hence at the edges the temperatures already get warm enough to melt significant amounts of ice. If the temperatures get warmer the place where equilibrium occurs get pushed inward and ice sheets shrink. Will we melt all of the antartic ice sheet, probably not, but we can easily shrink it a good deal.