Climatologist James Annan has a whole series of blog posts debunking Pielke's claims, e.g. here and here, here, etc. The short answer is that given the large amount of interannual noise present in the data, the 2.5 C "best estimate" trend is consistent with the observed trend, i.e. you can't say with statistical confidence whether the discrepancy is due to statistical fluctuations in weather or is something real in the underlying climate system. Pielke also makes the common mistake of pretending that the model predictions don't have any uncertainty and that you can "falsify" them based on a single best-guess trend. Actually, now that I look at it, he also used the projected 100-year warming rate, ignoring the fact that the warming rate is lower at the beginning of the projection period and higher at the end; this method will overstate the near-term warming projected.
For an actual published comparison of IPCC model projections to observations, try here. (Interestingly, they too ignore model uncertainty except for climate sensitivity uncertainty, although that is the largest uncertainty.)
I find it odd that the IPCC fails to mention that increased underwater volcanic activity under the arctic has been occurring since at least 1999, including a pyroclastic eruption and one that supposedly was as large as Pompei
It's not odd; the heat generated by undersea volcanoes is negligible compared to the heat necessary to melt that quantity of ice. This is noted in other press releases [canada.com]. It would actually make a nice physics "Fermi problem" for students to estimate, back of envelope, the amount of ice that could be melted this way.
or would it be better to go ahead and destroy (or at least tax to ruin) western civilization as a precautionary measure?
... and here we descend from a seemingly honest question into insane political hyperbole.
Clue: "Carbon taxes will destroy the economy" is the conservative scare story version of "global warming will make the human race go extinct". Both are ill informed. You might start by reading A Question of Balance, the new book on climate economics by who is arguably the world's leading climate economist, Bill Nordhaus of Yale.
Note also that the evidence in favor of global warming is based on far more than Arctic ice melt rates.
Yes you're guessing correctly, but there seems to be very little to reply to in your post. Anyway, the PDO doesn't cause global temperature trends, but it has most likely influenced north american temperatures
Duh, any climate process affects temperatures. The point is that the PDO is not responsible for the modern global temperature trend, for reasons I already pointed out and you have twice ignored.
the so called global warming was really northern hemisphere warming,
and has stopped (and is currently likely declining).
On the contrary, there is nothing in the climate trend over the last 10 years which is incompatible with ordinary natural variability. Give it 10-15 more years and you might be able to say something with statistical confidence.
Now let's go find the best matching hypothesis for that data. CO2 isn't it - there's nothing in the climate models predicting a levelling of and the start of a decline while CO2 levels have continued to rise.
You've never looked at the output of a climate model, have you? Go into the PCMDI CMIP3 archive and look at some of the forced transient runs. There are all kinds of transient fluctuations on decadal timescales.
It seems there might be a better match when looking at solar activity
Despite the huge disagreement of solar activity with climate trends over the last 40 years in rate, magnitude, and even sign of the change.
possibly with ocean currents as secondary effects that need to be taken into account when looking for that elusive "perfect match".
Ocean currents contribute, but their contribution cannot account for the majority of the observed climate trends, again for reasons I have already stated.
I find it odd that the IPCC fails to mention that increased underwater volcanic activity under the arctic has been occurring since at least 1999, including a pyroclastic eruption and one that supposedly was as large as Pompei
It's not odd; the heat generated by undersea volcanoes is negligible compared to the heat necessary to melt that quantity of ice. This is noted in other press releases. It would actually make a nice physics "Fermi problem" for students to estimate, back of envelope, the amount of ice that could be melted this way.
or would it be better to go ahead and destroy (or at least tax to ruin) western civilization as a precautionary measure?
... and here we descend from a seemingly honest question into insane political hyperbole.
Clue: "Carbon taxes will destroy the economy" is the conservative scare story version of "global warming will make the human race go extinct". Both are ill informed. You might start by reading A Question of Balance, the new book on climate economics by who is arguably the world's leading climate economist, Bill Nordhaus of Yale.
Note also that the evidence in favor of global warming is based on far more than Arctic ice melt rates.
You get modded up for nothing but a naked assertion?
Go ahead, post a citation into the scientific literature which supports this claim.
P.S. The IPCC doesn't do anything but summarize what's already in that literature. If you think that the science proves something in disagreement with the IPCC summary of that science, cite references.
(Btw, the ice on Greenland is nowhere NEAR melting at a rate causing a raise of 20 feet. Science before alarmism please)
As another poster pointed out, you are confusing rate and amount. If the warming over Greenland becomes large enough to switch the ice sheet into negative mass balance, then it will eventually melt if that forcing is maintained, even if it does so slowly. The open question is whether and when we're going to pass that threshold.
Lomborg details nicely how much good we can do with money with regards to possible GW effects instead of spending it on useless CO2-reducing economic disaster-schemes.
Lomborg's own Copenhagen Consensus found that the optimal climate policy is to include CO2 reducing schemes, as long as it's done in concert with adaptation measures and technology investment. Their recommended carbon tax (or tax equivalent) wasn't even that far from mainstream estimates like Nordhaus's. They also admit that they ignored some of the low-probability but high-impact risks like we're discussing, which traditionally strengthen the economic value of CO2 mitigation policies. Go read their challenge paper and the accompanying perspective papers.
Yes they do, for the northern hemisphere, and no one is claiming there hasn't been any:) It's however not as dramatic as land temperatures would make us believe,
I have no idea what that sentence is supposed to be in response to. What is "they" and "it"?
Guessing at what you're talking about, please note that satellite and surface land temperature trends are in agreement, and land temperature trends are supposed to be larger than ocean temperature trends, due to differing heat capacity.
and it also concides perfectly with what we already know is a warm trend compared to when before satellite measurements began.
What is "it"? The PDO? The PDO does not account for global temperature trends for reasons I already explained.
That warm trend has now been broken, and temperatures are on their way down. This falsifies the CO2 hypothesis.
The CO2 hypothesis does not predict an unbroken warming trend.
Cripes. You think the scientists studying these plumes just might have noticed nearby volcanos when constructing hypotheses? But no, this is Slashdot, where uninformed political ranting is just as insightful as actual scientific analysis. I don't know exactly where the volcanoes are myself, but a little Googling indicates they're in the deep ocean on the Gakkel Ridge, whereas these methane plumes are in shallow permafrost.
Facts are readily available. Interpretations of facts parrotted from skeptical websites instead of based on the scientific literature are, as another poster pointed out, a recipe for disaster.
Claims that global warming comes from the ocean generically fail to account for the observed space/time pattern of heat penetration into the ocean. You claim that the warming since the 1970s can be accounted for this way, but the ocean heat data (see, e.g., Levitus) show a continued penetration of heat from the surface into deeper water. The warming isn't coming from heat already in the ocean; it's just the opposite. Specific causes such as the PDO, in addition to the problems with explaining ocean heat trends, fail in other ways: the spatial pattern of observed warming is far broader than the warming correlated with the PDO index (see, e.g., the review by Mantua and Hare).
It's kind of amusing that you're still claiming that the land temperature record is "hugely biased" due to urbanization. I thought that horse was beat dead some time ago. There are several quantifications of the urban heat island (UHI) effect cited in the IPCC AR4 report, which show the effect is small. But since you don't appear to like getting your science from scientists, I might also note that one of the Climate Audit contributors found that you get similar warming trends if you limit yourself to what SurfaceStations deems "high quality" stations. Furthermore, you get similar warming if you restrict yourself to just rural stations; a related bias correction procedure is done e.g. in the GISTEMP homogenization algorithm. You say that we should look at the ocean and atmosphere readings, but they also show warming since 1970, which is entirely consistent with the land warming.
The warmest global temperature on record was not 80 years ago. You're probably getting confused with continental U.S. temperatures, where 1998 and 1934 were statistical ties.
Well, the only events you see that are comparable in rate to the modern warming are the Dansgaard-Oescher events, associated with a restart of a collapsed thermohaline circulation. The THC is not now restarting, so it does appear something unusual is now going on.
Yes, we are in an "ice age", technically speaking. That's geologically defined to be when there are still large continental ice sheets in both hemispheres, such as Greenland and Antarctica. What we are in right now is an "interglacial" part of an ice age, a period when the ice sheets are not as large as they are in a full glacial period. See Wikipedia.
There is recent evidence that methane clathrate destabilization alone couldn't have caused the PETM, because that scenario doesn't agree with paleo-reconstructions of the ocean lysocline. See Panchuk et al., Geology36, 315 (2008).
Look, now they're just talking about this "Bose supernova", coming out of nowhere after decades of preparation!
Um, no. The submitter is talking about a Bose supernova, as if it's some kind of new unexpected threat. The actual LHC scientists and engineers, who have built such helium systems before, know that they don't explode in Bose supernovas. But because there's some kind of ill-informed speculation about it, they felt compelled to write a paper explaining why they don't explode.
"So is the LHC a Bose supernova waiting to go off? Not according to the CERN theory division, which has published its calculations that show the LHC is safe. They also point out that no other superfluid helium handling facility has mysteriously blown itself to pieces."
So, a "Bosenova explosion" under LHC-like conditions (1) can't happen according to theory, and (2) hasn't happened according to experiment either. Sheesh. I can concoct LHC disaster scenarios that are impossible according to theory and experiment too. Can I get on the Slashdot front page?
1. The age given is 3.8 to 4.28 billion years (why billion, not giga. Dunno.) The scientist favours the oldest possible date, at a guess because that increases funding,
Oh come on. Maybe your first guess could involve something, I don't know, scientific, instead jumping straight to bias? Right or wrong, you don't get published in Science, which is the world's leading scientific journal along with Nature, without at least some plausible if not airtight evidence supporting your interpretation.
If you read the abstract, you find that they get a samarium/neodymium ratio which indicates an age of 4.280 +.053/-.081 million years, which is right at the upper age limit and definitely excludes 3.8 billion years. I don't have access to the full text, but some further Googling says that "conventional dating" gives a date at the lower end of the range (although no error bars are given), and Sm/Nd dating (which applies to particularly old samples) gives a date at the upper end of the range. Given the tight error bound on the Sm/Nd date, it seems that there's something in there that's at least 4.2 billion years old. But one possibility is that there's a mix of materials of different ages; zircon crystals which are even older than this have been found before, embedded in younger rock.
The speed of light limit has some caveats. Wormholes, which Relativity predicts, offer a way out.
That loophole requires exactly the kind of "weird things like negative mass" I mentioned, or else the wormhole collapses before you can use it that way.
If you believe in stable negative matter, feel free...
After all, do any of you really think that the current theories are entirely correct?
No, but that doesn't mean I think they're incorrect in a way that violates relativistic causality. It's like saying, "You don't believe current science is entirely correct, right? So why don't you believe in perpetual motion devices, magic, and invisible pink unicorns?"
The fact is, if you take brane theory into account there could be other universes where our laws of physics dont even apply, and if a wormhole bridge can exist between them, not only FTL but time travel is a real possibility.
The fundamental laws of physics apply everywhere in braneworld scenarios, although different string vacua can have different physical constants and such leading to different "effective laws". In particular, all string solutions obey the usual relativistic constraints on the speed of light, everywhere. String theory is defined to be a relativistic theory.
String theory doesn't offer a magic escape for people who want to believe in FTL and time travel. It requires the same kind of bizarre "exotic matter" that GR does. When you find some, let me know. The only other known examples are unstable solutions like the extended Kerr geometry; as soon as you perturb it by allowing real matter and radiation to mess up the idealized solution, it's no longer usable.
No, gravitational effects travel at the speed of light. If something happened to the Sun, we would feel the gravitational effect at the same time we saw the light from the event, 8 minutes later. You can find somewhat more technical details in this FAQ.
There are some subtle effects due to relativity; the direction of gravitational attraction appears to point toward where the Sun is now, not where it was 8 minutes ago. Actually, it doesn't really point to where the Sun is now. It points toward a linear extrapolation of where the Sun "should be" now based on where it really was 8 minutes ago, which solves the paradox: no information about the Sun's current position is transmitted faster than light. This also happens in electromagnetism with the Lorentz force experienced by a charged particle. There is a somewhat notorious crackpot on MetaResearch.org who misunderstands this point and uses it to argue that gravity propagates nearly instantaneously. (For some reason he doesn't apply the same logic to argue that light travels faster than light, which is what that error implies.)
However, if you're saying it "then expanded so that it is no longer in contact with us in any way", doesn't that also make reference to something which is *now* outside our spacetime?
No, just something which is now outside the observable portion of our spacetime. It can't influence us if light can't reach us, because no physical influence can travel faster than light. It's out of contact with us not because it's outside of spacetime, but just because it's too far away for anything that now happens there to have reached here.
If something is outside our spacetime, is there any way of referencing it conceptually that is logical or meaningful?
Logically you can invent anything you want which is outside our spacetime. But physically, if it can influence our spacetime, then it's usually defined to be part of spacetime itself. Something that logically exists outside of spacetime but which can't influence ours, even in indirectly or in principle, has a physically dubious status. You could perhaps meaningfully speak of it if it were a logical implication of physical laws that apply to our universe — e.g., "the laws of physics predict X and Y which we observe, and by the way also predict other spacetimes which we can't observe. We could never verify the last aspect of the theory, but we could verify other aspects of it, and so perhaps have very indirect physical "evidence" of those other spacetimes.
Which is interesting, as I've heard that information can't travel faster than light (admittedly the radio wasn't very far away from me at the time).
Information isn't traveling faster than light in this scenario.
But here, in effect, we are gathering information on something outside our known universe. Why doesn't the article mention this seeming quandry?
The idea here is that "something" was once within our observable universe, it influenced the motion of some matter, and then expanded so that it is no longer in contact with us in any way. It is not now gravitationally influencing the observable universe. It used to, and we are seeing the remnants of that influence.
It not only implies (proves?) that "gravity information" travels faster than light, but they're assuming that gravity - as a physical property - functions *outside* our spacetime.
They're also not talking about "outside spacetime". "Beyond the observable universe" doesn't mean "outside spacetime", it just means "a part of spacetime so far away that light from it hasn't reached us".
Have they thought about how space and time may not function in quite the same way outside our universe
Part of their theory is that spacetime expanded in a different way (at a different rate and time) outside our observable universe than it did inside.
Is there even any sense in saying "outside spacetime"?
Probably not, if you want to talk about something that can relate in any way to our spacetime.
You're right. That is what these scientists are saying: before inflation, matter was in contact with a region which altered their motion. After inflation, the observable universe is no longer in contact with that region, but the matter became galaxies which still have their altered motion.
Yes, I know about geometric units and the causal structure of spacetime. It's certainly true that gravity propagates at c in GR, but I was talking about when this fact was known to be true. It's kind of obvious in hindsight. My point, though, was that it wasn't completely obvious when GR was first invented. Einstein himself argued as late as 1936 that gravity doesn't even propagate, i.e. gravitational waves don't exist. People were still arguing about that even in the 1950s, when Feynman (via Bondi) finally settled it for most people with his "sticky bead" argument. If you don't even agree that gravity propagates, you're not going to agree that it propagates at c. Still, some people did realize this early on — e.g. Eddington a few years after Einstein wrote down the field equation — even if it took a while to be widely accepted. It's not a totally trivial result for the full nonlinear equations, either. You can get FTL propagation of gravitational effects (a la "warp drives") in GR if you allow some of the energy conditions on the stress-energy tensor to be violated, so rigorously proving propagation speed = c is actually kind of technical.
The speed of gravity has been theoretically calculated to be c almost since general relativity was invented. Observationally, the Taylor and Hulse pulsar observations starting in 1974 gave us an indirect measurement of the speed (how fast the star system was losing gravitational energy).
Dark matter doesn't affect light directly (that's why it's dark). Dark matter "halos" around galaxies due to gravitational lensing have been observed. It's the uneven dense clumps that are easiest to observe, not the background matter.
Slashdot Mirror
Climatologist James Annan has a whole series of blog posts debunking Pielke's claims, e.g. here and here, here, etc. The short answer is that given the large amount of interannual noise present in the data, the 2.5 C "best estimate" trend is consistent with the observed trend, i.e. you can't say with statistical confidence whether the discrepancy is due to statistical fluctuations in weather or is something real in the underlying climate system. Pielke also makes the common mistake of pretending that the model predictions don't have any uncertainty and that you can "falsify" them based on a single best-guess trend. Actually, now that I look at it, he also used the projected 100-year warming rate, ignoring the fact that the warming rate is lower at the beginning of the projection period and higher at the end; this method will overstate the near-term warming projected.
For an actual published comparison of IPCC model projections to observations, try here. (Interestingly, they too ignore model uncertainty except for climate sensitivity uncertainty, although that is the largest uncertainty.)
Should have previewed:
I find it odd that the IPCC fails to mention that increased underwater volcanic activity under the arctic has been occurring since at least 1999, including a pyroclastic eruption and one that supposedly was as large as Pompei
It's not odd; the heat generated by undersea volcanoes is negligible compared to the heat necessary to melt that quantity of ice. This is noted in other press releases [canada.com]. It would actually make a nice physics "Fermi problem" for students to estimate, back of envelope, the amount of ice that could be melted this way.
or would it be better to go ahead and destroy (or at least tax to ruin) western civilization as a precautionary measure?
... and here we descend from a seemingly honest question into insane political hyperbole.
Clue: "Carbon taxes will destroy the economy" is the conservative scare story version of "global warming will make the human race go extinct". Both are ill informed. You might start by reading A Question of Balance, the new book on climate economics by who is arguably the world's leading climate economist, Bill Nordhaus of Yale.
Note also that the evidence in favor of global warming is based on far more than Arctic ice melt rates.
Yes you're guessing correctly, but there seems to be very little to reply to in your post. Anyway, the PDO doesn't cause global temperature trends, but it has most likely influenced north american temperatures
Duh, any climate process affects temperatures. The point is that the PDO is not responsible for the modern global temperature trend, for reasons I already pointed out and you have twice ignored.
the so called global warming was really northern hemisphere warming,
and has stopped (and is currently likely declining).
On the contrary, there is nothing in the climate trend over the last 10 years which is incompatible with ordinary natural variability. Give it 10-15 more years and you might be able to say something with statistical confidence.
Now let's go find the best matching hypothesis for that data. CO2 isn't it - there's nothing in the climate models predicting a levelling of and the start of a decline while CO2 levels have continued to rise.
You've never looked at the output of a climate model, have you? Go into the PCMDI CMIP3 archive and look at some of the forced transient runs. There are all kinds of transient fluctuations on decadal timescales.
It seems there might be a better match when looking at solar activity
Despite the huge disagreement of solar activity with climate trends over the last 40 years in rate, magnitude, and even sign of the change.
possibly with ocean currents as secondary effects that need to be taken into account when looking for that elusive "perfect match".
Ocean currents contribute, but their contribution cannot account for the majority of the observed climate trends, again for reasons I have already stated.
I find it odd that the IPCC fails to mention that increased underwater volcanic activity under the arctic has been occurring since at least 1999, including a pyroclastic eruption and one that supposedly was as large as Pompei
It's not odd; the heat generated by undersea volcanoes is negligible compared to the heat necessary to melt that quantity of ice. This is noted in other press releases. It would actually make a nice physics "Fermi problem" for students to estimate, back of envelope, the amount of ice that could be melted this way.
or would it be better to go ahead and destroy (or at least tax to ruin) western civilization as a precautionary measure?
... and here we descend from a seemingly honest question into insane political hyperbole.
Clue: "Carbon taxes will destroy the economy" is the conservative scare story version of "global warming will make the human race go extinct". Both are ill informed. You might start by reading A Question of Balance, the new book on climate economics by who is arguably the world's leading climate economist, Bill Nordhaus of Yale.
Note also that the evidence in favor of global warming is based on far more than Arctic ice melt rates.
You get modded up for nothing but a naked assertion?
Go ahead, post a citation into the scientific literature which supports this claim.
P.S. The IPCC doesn't do anything but summarize what's already in that literature. If you think that the science proves something in disagreement with the IPCC summary of that science, cite references.
(Btw, the ice on Greenland is nowhere NEAR melting at a rate causing a raise of 20 feet. Science before alarmism please)
As another poster pointed out, you are confusing rate and amount. If the warming over Greenland becomes large enough to switch the ice sheet into negative mass balance, then it will eventually melt if that forcing is maintained, even if it does so slowly. The open question is whether and when we're going to pass that threshold.
Lomborg details nicely how much good we can do with money with regards to possible GW effects instead of spending it on useless CO2-reducing economic disaster-schemes.
Lomborg's own Copenhagen Consensus found that the optimal climate policy is to include CO2 reducing schemes, as long as it's done in concert with adaptation measures and technology investment. Their recommended carbon tax (or tax equivalent) wasn't even that far from mainstream estimates like Nordhaus's. They also admit that they ignored some of the low-probability but high-impact risks like we're discussing, which traditionally strengthen the economic value of CO2 mitigation policies. Go read their challenge paper and the accompanying perspective papers.
Yes they do, for the northern hemisphere, and no one is claiming there hasn't been any :) It's however not as dramatic as land temperatures would make us believe,
I have no idea what that sentence is supposed to be in response to. What is "they" and "it"?
Guessing at what you're talking about, please note that satellite and surface land temperature trends are in agreement, and land temperature trends are supposed to be larger than ocean temperature trends, due to differing heat capacity.
and it also concides perfectly with what we already know is a warm trend compared to when before satellite measurements began.
What is "it"? The PDO? The PDO does not account for global temperature trends for reasons I already explained.
That warm trend has now been broken, and temperatures are on their way down. This falsifies the CO2 hypothesis.
The CO2 hypothesis does not predict an unbroken warming trend.
Cripes. You think the scientists studying these plumes just might have noticed nearby volcanos when constructing hypotheses? But no, this is Slashdot, where uninformed political ranting is just as insightful as actual scientific analysis. I don't know exactly where the volcanoes are myself, but a little Googling indicates they're in the deep ocean on the Gakkel Ridge, whereas these methane plumes are in shallow permafrost.
Facts are readily available. Interpretations of facts parrotted from skeptical websites instead of based on the scientific literature are, as another poster pointed out, a recipe for disaster.
Claims that global warming comes from the ocean generically fail to account for the observed space/time pattern of heat penetration into the ocean. You claim that the warming since the 1970s can be accounted for this way, but the ocean heat data (see, e.g., Levitus) show a continued penetration of heat from the surface into deeper water. The warming isn't coming from heat already in the ocean; it's just the opposite. Specific causes such as the PDO, in addition to the problems with explaining ocean heat trends, fail in other ways: the spatial pattern of observed warming is far broader than the warming correlated with the PDO index (see, e.g., the review by Mantua and Hare).
It's kind of amusing that you're still claiming that the land temperature record is "hugely biased" due to urbanization. I thought that horse was beat dead some time ago. There are several quantifications of the urban heat island (UHI) effect cited in the IPCC AR4 report, which show the effect is small. But since you don't appear to like getting your science from scientists, I might also note that one of the Climate Audit contributors found that you get similar warming trends if you limit yourself to what SurfaceStations deems "high quality" stations. Furthermore, you get similar warming if you restrict yourself to just rural stations; a related bias correction procedure is done e.g. in the GISTEMP homogenization algorithm. You say that we should look at the ocean and atmosphere readings, but they also show warming since 1970, which is entirely consistent with the land warming.
The warmest global temperature on record was not 80 years ago. You're probably getting confused with continental U.S. temperatures, where 1998 and 1934 were statistical ties.
Global temperatures
U.S. temperatures
Well, the only events you see that are comparable in rate to the modern warming are the Dansgaard-Oescher events, associated with a restart of a collapsed thermohaline circulation. The THC is not now restarting, so it does appear something unusual is now going on.
Yes, we are in an "ice age", technically speaking. That's geologically defined to be when there are still large continental ice sheets in both hemispheres, such as Greenland and Antarctica. What we are in right now is an "interglacial" part of an ice age, a period when the ice sheets are not as large as they are in a full glacial period. See Wikipedia.
There is recent evidence that methane clathrate destabilization alone couldn't have caused the PETM, because that scenario doesn't agree with paleo-reconstructions of the ocean lysocline. See Panchuk et al., Geology 36, 315 (2008).
Look, now they're just talking about this "Bose supernova", coming out of nowhere after decades of preparation!
Um, no. The submitter is talking about a Bose supernova, as if it's some kind of new unexpected threat. The actual LHC scientists and engineers, who have built such helium systems before, know that they don't explode in Bose supernovas. But because there's some kind of ill-informed speculation about it, they felt compelled to write a paper explaining why they don't explode.
From the summary:
"So is the LHC a Bose supernova waiting to go off? Not according to the CERN theory division, which has published its calculations that show the LHC is safe. They also point out that no other superfluid helium handling facility has mysteriously blown itself to pieces."
So, a "Bosenova explosion" under LHC-like conditions (1) can't happen according to theory, and (2) hasn't happened according to experiment either. Sheesh. I can concoct LHC disaster scenarios that are impossible according to theory and experiment too. Can I get on the Slashdot front page?
1. The age given is 3.8 to 4.28 billion years (why billion, not giga. Dunno.) The scientist favours the oldest possible date, at a guess because that increases funding,
Oh come on. Maybe your first guess could involve something, I don't know, scientific, instead jumping straight to bias? Right or wrong, you don't get published in Science, which is the world's leading scientific journal along with Nature, without at least some plausible if not airtight evidence supporting your interpretation.
If you read the abstract, you find that they get a samarium/neodymium ratio which indicates an age of 4.280 +.053/-.081 million years, which is right at the upper age limit and definitely excludes 3.8 billion years. I don't have access to the full text, but some further Googling says that "conventional dating" gives a date at the lower end of the range (although no error bars are given), and Sm/Nd dating (which applies to particularly old samples) gives a date at the upper end of the range. Given the tight error bound on the Sm/Nd date, it seems that there's something in there that's at least 4.2 billion years old. But one possibility is that there's a mix of materials of different ages; zircon crystals which are even older than this have been found before, embedded in younger rock.
The speed of light limit has some caveats. Wormholes, which Relativity predicts, offer a way out.
That loophole requires exactly the kind of "weird things like negative mass" I mentioned, or else the wormhole collapses before you can use it that way.
If you believe in stable negative matter, feel free ...
After all, do any of you really think that the current theories are entirely correct?
No, but that doesn't mean I think they're incorrect in a way that violates relativistic causality. It's like saying, "You don't believe current science is entirely correct, right? So why don't you believe in perpetual motion devices, magic, and invisible pink unicorns?"
The fact is, if you take brane theory into account there could be other universes where our laws of physics dont even apply, and if a wormhole bridge can exist between them, not only FTL but time travel is a real possibility.
The fundamental laws of physics apply everywhere in braneworld scenarios, although different string vacua can have different physical constants and such leading to different "effective laws". In particular, all string solutions obey the usual relativistic constraints on the speed of light, everywhere. String theory is defined to be a relativistic theory.
String theory doesn't offer a magic escape for people who want to believe in FTL and time travel. It requires the same kind of bizarre "exotic matter" that GR does. When you find some, let me know. The only other known examples are unstable solutions like the extended Kerr geometry; as soon as you perturb it by allowing real matter and radiation to mess up the idealized solution, it's no longer usable.
No, gravitational effects travel at the speed of light. If something happened to the Sun, we would feel the gravitational effect at the same time we saw the light from the event, 8 minutes later. You can find somewhat more technical details in this FAQ.
There are some subtle effects due to relativity; the direction of gravitational attraction appears to point toward where the Sun is now, not where it was 8 minutes ago. Actually, it doesn't really point to where the Sun is now. It points toward a linear extrapolation of where the Sun "should be" now based on where it really was 8 minutes ago, which solves the paradox: no information about the Sun's current position is transmitted faster than light. This also happens in electromagnetism with the Lorentz force experienced by a charged particle. There is a somewhat notorious crackpot on MetaResearch.org who misunderstands this point and uses it to argue that gravity propagates nearly instantaneously. (For some reason he doesn't apply the same logic to argue that light travels faster than light, which is what that error implies.)
However, if you're saying it "then expanded so that it is no longer in contact with us in any way", doesn't that also make reference to something which is *now* outside our spacetime?
No, just something which is now outside the observable portion of our spacetime. It can't influence us if light can't reach us, because no physical influence can travel faster than light. It's out of contact with us not because it's outside of spacetime, but just because it's too far away for anything that now happens there to have reached here.
If something is outside our spacetime, is there any way of referencing it conceptually that is logical or meaningful?
Logically you can invent anything you want which is outside our spacetime. But physically, if it can influence our spacetime, then it's usually defined to be part of spacetime itself. Something that logically exists outside of spacetime but which can't influence ours, even in indirectly or in principle, has a physically dubious status. You could perhaps meaningfully speak of it if it were a logical implication of physical laws that apply to our universe — e.g., "the laws of physics predict X and Y which we observe, and by the way also predict other spacetimes which we can't observe. We could never verify the last aspect of the theory, but we could verify other aspects of it, and so perhaps have very indirect physical "evidence" of those other spacetimes.
Which is interesting, as I've heard that information can't travel faster than light (admittedly the radio wasn't very far away from me at the time).
Information isn't traveling faster than light in this scenario.
But here, in effect, we are gathering information on something outside our known universe. Why doesn't the article mention this seeming quandry?
The idea here is that "something" was once within our observable universe, it influenced the motion of some matter, and then expanded so that it is no longer in contact with us in any way. It is not now gravitationally influencing the observable universe. It used to, and we are seeing the remnants of that influence.
It not only implies (proves?) that "gravity information" travels faster than light, but they're assuming that gravity - as a physical property - functions *outside* our spacetime.
They're also not talking about "outside spacetime". "Beyond the observable universe" doesn't mean "outside spacetime", it just means "a part of spacetime so far away that light from it hasn't reached us".
Have they thought about how space and time may not function in quite the same way outside our universe
Part of their theory is that spacetime expanded in a different way (at a different rate and time) outside our observable universe than it did inside.
Is there even any sense in saying "outside spacetime"?
Probably not, if you want to talk about something that can relate in any way to our spacetime.
ISTR people working out the minimum quantun of energy to change a bit.
See the von Neumann-Landauer limit.
You're right. That is what these scientists are saying: before inflation, matter was in contact with a region which altered their motion. After inflation, the observable universe is no longer in contact with that region, but the matter became galaxies which still have their altered motion.
Yes, I know about geometric units and the causal structure of spacetime. It's certainly true that gravity propagates at c in GR, but I was talking about when this fact was known to be true. It's kind of obvious in hindsight. My point, though, was that it wasn't completely obvious when GR was first invented. Einstein himself argued as late as 1936 that gravity doesn't even propagate, i.e. gravitational waves don't exist. People were still arguing about that even in the 1950s, when Feynman (via Bondi) finally settled it for most people with his "sticky bead" argument. If you don't even agree that gravity propagates, you're not going to agree that it propagates at c. Still, some people did realize this early on — e.g. Eddington a few years after Einstein wrote down the field equation — even if it took a while to be widely accepted. It's not a totally trivial result for the full nonlinear equations, either. You can get FTL propagation of gravitational effects (a la "warp drives") in GR if you allow some of the energy conditions on the stress-energy tensor to be violated, so rigorously proving propagation speed = c is actually kind of technical.
The speed of gravity has been theoretically calculated to be c almost since general relativity was invented. Observationally, the Taylor and Hulse pulsar observations starting in 1974 gave us an indirect measurement of the speed (how fast the star system was losing gravitational energy).
Dark matter doesn't affect light directly (that's why it's dark). Dark matter "halos" around galaxies due to gravitational lensing have been observed. It's the uneven dense clumps that are easiest to observe, not the background matter.