1

Physics, Astronomy & Cosmology / Re: Does the atomic nucleus have nuclear orbitals occupied by protons and neutrons?

« on: 29/10/2016 11:48:53 »

Lets look at this a slightly different way. Electron orbitals are just the shape that the wave function of the electron takes on when bound to a nucleus. Therefore if the wave function of the electron is real then the electron orbitals should also be real. It would take some serious evidence to show the opposite.

There are certainly reasons to believe that the wave function is real.

At best you can say that according to some interpretations of Quantum Mechanics the wave function isn't "real/physical" but the question is unsettled. Although there is evidence pushing for the real camp.

Additionally,
The phase of a wave function (the complex bit) can have physical effects beyond just participating in the squared magnitude (the extra rotation of the photons in the link).

You can make qubits by exploiting the phase (imaginary) parts of wave functions.

The things above and others like single particle diffraction and tunneling are less strange if you simply accept that the wave function is real.

But to reiterate one should never state as fact that the wave function is not real. At best the question is exactly as unsettled as the question about which interpretation is correct with a bit of evidence pulling for the wave function is real camp.

What is the form of hydrogen used in the experiment? Is atomic or molecular?
If it is atomic, how to prevent them from forming diatomic molecule?
If it is molecular, how can it produce rotationally symmetrical pattern?

It was atomic hydrogen. You can break a fraction of hydrogen molecules apart and keep that fraction constant by adding energy so more are broken at the same rate others reform. Then you can build a trap big enough for only one atom and eventually if you wait long enough you'll have a trapped hydrogen. If you keep the gas dilute enough collisions between things will be very rare.

2

Physics, Astronomy & Cosmology / Re: What is a cyclotron, and how does it work?

« on: 25/08/2016 18:34:05 »

Cyclotron

Essentially it is a very old and by today's standards inefficient method of accelerating charged particles (usually electrons). It uses a static magnetic field to cause the charged particle to go in a circle and two separated metallic half cylinders to which an RF signal is applied to accelerate the particle. As long as the RF signal has the right frequency the charged particle will always enter one of the half cylinders at the right time to be accelerated. Each pass makes the radius of the charged particle's orbit larger and eventually it will be ejected from the machine at high speed. The high speed particle can then be fired at targets to generate X-rays or other accelerated charged particles like at the LHC (though at much lower energies).

Today's particle accelerators work very differently and at much higher energy.   

3

The Environment / Re: If ice takes up more space than water why will melting icebergs cause raising sea levels?

« on: 03/08/2016 21:06:01 »

Yes but the amount of energy required to achieve this temperature change on a colum of water as deep as the oceans is so vast that just by increasing the temperature above the top of the colum by a couple of degrees will not be noticed by the water 2km down for many many thousands of years if ever.

1) Even the top couple hundred meters of the world's oceans is still a heck of a lot of water and even if just that was heated it would still be noticeable. Climate scientists do in fact model the impacts of different depths of the ocean warming differently. (Also you don't even need a couple of degrees of change to have a noticeable change in ocean levels.)

2) The amount of excess thermal energy going into the oceans right now is massive.

For example: http://e360.yale.edu/feature/how_long_can_oceans_continue_to_absorb_earths_excess_heat/2860/

The ocean has been heating at a rate of around 0.5 to 1 watt of energy per square meter over the past decade, amassing more than 2 X 10^23 joules of energy — the equivalent of roughly five Hiroshima bombs exploding every second

To emphasize the point I will reiterate that right now the oceans are on average absorbing thermal energy equal to 5 Hiroshima sized bombs each and every second.

3) Last but not least the sea level rise has been measured: http://climate.nasa.gov/vital-signs/sea-level/



https://www.skepticalscience.com/sea-level-rise-predictions-intermediate.htm <- A more comprehensive look at the impacts of climate change on the oceans

4

The Environment / Re: What criteria would be required to refute man-made climate change?

« on: 21/06/2016 22:46:52 »

The temperature rise since these predictions came out has been below the bottom of these numbers.

You are going to need to source this claim.

http://www.skepticalscience.com/ipcc-global-warming-projections.htm

The figure below from the 2013 Intergovernmental Panel on Climate Change (IPCC) report compares the global surface warming projections made in the 1990, 1995, 2001, and 2007 IPCC reports to the temperature measurements.




IPCC AR5 Figure 1.4. Solid lines and squares represent measured average global surface temperature changes by NASA (blue), NOAA (yellow), and the UK Hadley Centre (green). The colored shading shows the projected range of surface warming in the IPCC First Assessment Report (FAR; yellow), Second (SAR; green), Third (TAR; blue), and Fourth (AR4; red).

Since 1990, global surface temperatures have warmed at a rate of about 0.15°C per decade, within the range of model projections of about 0.10 to 0.35°C per decade. As the IPCC notes,

"global climate models generally simulate global temperatures that compare well with observations over climate timescales ... The 1990–2012 data have been shown to be consistent with the [1990 IPCC report] projections, and not consistent with zero trend from 1990 ... the trend in globally-averaged surface temperatures falls within the range of the previous IPCC projections."

What about the Naysayers?
In the weeks and months leading up to the publication of the final 2013 IPCC report, there has been a flood of opinion articles in blogs and the mainstream media claiming that the models used by the IPCC have dramatically over-predicted global warming and thus are a failure. This narrative clearly conflicts with the IPCC model-data comparison figure shown above, so what's going on?

These mistaken climate contrarian articles have all suffered from some combination of the following errors.

1) Publicizing the flawed draft IPCC model-data comparison figure
Late last year, an early draft of the IPCC report was leaked, including the first draft version of the figure shown above. The first version of the graph had some flaws, including a significant one immediately noted by statistician and climate blogger Tamino.

"The flaw is this: all the series (both projections and observations) are aligned at 1990. But observations include random year-to-year fluctuations, whereas the projections do not because the average of multiple models averages those out ... the projections should be aligned to the value due to the existing trend in observations at 1990.

Aligning the projections with a single extra-hot year makes the projections seem too hot, so observations are too cool by comparison."

In the draft version of the IPCC figure, it was simply a visual illusion that the surface temperature data appeared to be warming less slowly than the model projections, even though the measured temperature trend fell within the range of model simulations. Obviously this mistake was subsequently corrected.

This illustrates why it's a bad idea to publicize material in draft form, which by definition is a work in progress.

2) Ignoring the range of model simulations
A single model run simulates just one possible future climate outcome. In reality, there are an infinite number of possible outcomes, depending on how various factors like greenhouse gas emissions and natural climate variability change. This is why climate modelers don't make predictions; they make projections, which say in scenario 'x', the climate will change in 'y' fashion. The shaded regions in the IPCC figure represent the range of outcomes from all of these individual climate model simulations.

The IPCC also illustrates the "multi-model mean," which averages together all of the individual model simulation runs. This average makes for an easy comparison with the observational data; however, there's no reason to believe the climate will follow that average path, especially in the short-term. If natural factors act to amplify human-caused global surface warming, as they did in the 1990s, the climate is likely to warm faster than the model average in the short-term. If natural factors act to dampen global surface warming, as they have in the 2000s, the climate is likely to warm more slowly than the model average.

When many model simulations are averaged together, the random natural variability in the individual model runs cancel out, and the steady human-caused global warming trend remains left over. But in reality the climate behaves like a single model simulation run, not like the average of all model runs.

This is why it's important to retain the shaded range of individual model runs.

3) Cherry Picking
Most claims that the IPCC models have failed are based on surface temperature changes over the past 15 years (1998–2012). During that period, temperatures have risen about 50 percent more slowly than the multi-model average, but have remained within the range of individual model simulation runs.

However, 1998 represented an abnormally hot year at the Earth's surface due to one of the strongest El Niño events of the 20th century. Thus it represents a poor choice of a starting date to analyze the surface warming trend (selectively choosing convenient start and/or end points is also known as 'cherry picking'). For example, we can select a different 15-year period, 1992–2006, and find a surface warming trend nearly 50 percent faster than the multi-model average, as statistician Tamino helpfully illustrates in the figure below.



Global surface temperature data 1975–2012 from NASA with a linear trend (black), with trends for 1992–2006 (red) and 1998–2012 (blue).

In short, if climate contrarians weren't declaring that global surface warming was accelerating out of control in 2006, then he has no business declaring that global surface warming has 'paused' in 2013. Both statements are equally wrong, based on cherry picking noisy short-term data.

IPCC models have been accurate
For 1992–2006, the natural variability of the climate amplified human-caused global surface warming, while it dampened the surface warming for 1997–2012. Over the full period, the overall warming rate has remained within the range of IPCC model projections, as the 2013 IPCC report notes.

"The long-term climate model simulations show a trend in global-mean surface temperature from 1951 to 2012 that agrees with the observed trend (very high confidence). There are, however, differences between simulated and observed trends over periods as short as 10 to 15 years (e.g., 1998 to 2012)."

The IPCC also notes that climate models have accurately simulated trends in extreme cold and heat, large-scale precipitation pattern changes, and ocean heat content (where most global warming goes). Models also now better simulate the Arctic sea ice decline, which they had previously dramatically underestimated.

All in all, the IPCC models do an impressive job accurately representing and projecting changes in the global climate, contrary to contrarian claims. In fact, the IPCC global surface warming projections have performed much better than predictions made by climate contrarians.

It's important to remember that weather predictions and climate predictions are very different. It's harder to predict the weather further into the future. With climate predictions, it's short-term variability (like unpredictable ocean cycles) that makes predictions difficult. They actually do better predicting climate changes several decades into the future, during which time the short-term fluctuations average out.

That's why climate models have a hard time predicting changes over 10–15 years, but do very well with predictions several decades into the future, as the IPCC illustrates. This is good news, because with climate change, it's these long-term changes we're worried about:


IPCC AR5 projected global average surface temperature changes in a high emissions scenario (RCP8.5; red) and low emissions scenario (RCP2.6; blue).

Intermediate rebuttal written by dana1981

5

Physics, Astronomy & Cosmology / Re: Is orbital data available for s-stars around sag A*?

« on: 20/06/2016 03:56:57 »

So if you don't know about it there is this pretty cool program called Universe Sandbox that lets you either build your own gravitational systems or look at ones like the solar system or the galaxy (naturally at different levels of detail). There's a way to open up simulations other people have made and one of them appears to be at least some the stars around sag A*. Looks like S0-1, S0-2, S0-4, S0-5, S0-16, S0-19 and S0-20. I'm not sure you can get the orbital data out but you can watch the system evolve in time and you can edit the properties of all the bodies (mass, velocity, etc) or add new ones to the system.

http://universesandbox.com/ <- Apparently it has been updated since I last looked at it.

6

Physics, Astronomy & Cosmology / Re: What do you think energy is and why do you believe that?

« on: 13/06/2016 02:57:35 »

Just for the sake of accuracy:

Light is an electromagnetic (EM) wave whose wavelength lies in the range 390 to 700 nm. Most of the energy in an EM wave is in the electric field component. An EM wave cannot interact with neutrons because their charge is zero and are therefore unable to interact via the electromagnetic interaction. I.e. neutrons cannot couple to an EM field.

The energy and the electric and magnetic field components of a photon in free space are equal. Here is a reference:

http://physics.bu.edu/~duffy/PY106/EMWaves.html <- Lecture notes on EM waves

The energy in an electromagnetic wave is tied up in the electric and magnetic fields. In general, the energy per unit volume in an electric field is given by:



In a magnetic field, the energy per unit volume is:



An electromagnetic wave has both electric and magnetic fields, so the total energy density associated with an electromagnetic wave is:



It turns out that for an electromagnetic wave, the energy associated with the electric field is equal to the energy associated with the magnetic field, so the energy density can be written in terms of just one or the other:

http://physics.info/em-waves/ <- Here is another source

For an electromagnetic wave in free space, half the energy is in the electric field and half is in the magnetic field

η =
 
η = +

This gives us this very compact equation for the total energy density of an electromagnetic wave…

η =

or this one, if you prefer to state things in terms of the magnetic field instead…

η =

This is an interesting and simple set of relations, but keep in mind that it only works for electromagnetic waves in free space. Things are different in a media and the electric and magnetic fields can have any values they want if they're static.

http://web.mit.edu/8.02t/www/materials/StudyGuide/guide13.pdf <- Here is an example from MIT

To relate intensity to the energy density, we first note the equality between the electric
and the magnetic energy densities ...

So except from some pretty specific cases in fairly specific materials the energies of the electric component and magnetic component of an EM wave are either identical or nearly equal.

Additionally, while the neutron has no net electrical charge it does have a magnetic field which means it can interact with an EM wave.

http://adsabs.harvard.edu/full/1993ApJ...417...12G <- Neutron-Photon scattering in the early Universe

Now the cross section for neutron-photon scattering is much lower than for proton-photon or electron-photon scattering but it isn't zero.

7

Chemistry / Re: What happens when electrons move between energy levels in atoms?

« on: 29/05/2016 01:12:31 »

http://hyperphysics.phy-astr.gsu.edu/hbase/optmod/lascool.html <- Laser cooling

Of note:

A conceptual problem is that an absorption can also speed up an atom if it catches it from behind, so it is necessary to have more absorptions from head-on photons if your goal is to slow down the atoms. This is accomplished in practice by tuning the laser slightly below the resonance absorption of a stationary sodium atom. From the atom's perspective, the headon photon is seen as Doppler shifted upward toward its resonant frequency and it therefore more strongly absorbed than a photon traveling in the opposite direction which is Doppler shifted away from the resonance. In the case of our room temperature sodium atom above, the incoming photon would be Doppler shifted up 0.97 GHz, so to get the head on photon to match the resonant frequency would require that the laser be tuned below the resonant peak by that amount.

You specifically need to use an absorption event rather than simple scattering (i.e. what happens when the photon energy doesn't coincide with an energy level difference) and you actually need to use light slightly under the energy of the edge in order to selectively excite only the atoms you want to excite (the ones coming towards you that would be slowed instead of the ones going away that would speed up). Using just simple scattering the momentum transfer is generally much much smaller than an absorption event and you lose any hope of selectively interacting with only the atoms you can cool.

8

General Science / Re: How can I strengthen my students' awareness about climate change?

« on: 24/05/2016 22:57:57 »

You need to be very scientific about this.

"Global warming" has been pretty much abandoned as a slogan since none of the predictions has turned out to be correct.

If we're being scientific then we should note that the entire idea that "Global warming" was first adopted and the abandoned by the scientific community in favor of climate change is demonstrably false:

http://www.skepticalscience.com/climate-change-global-warming.htm


Mentions of Global Warming and Climate Change in books published in the US via Google books.


According to Google scholar climate change actually came first and has always been used by scientists more than global warming.

Climate change seems to be inevitable. All the records show that the climate at any point on the planet has changed many times, in geological and in written history.

Largely irrelevant:

http://www.skepticalscience.com/climate-change-little-ice-age-medieval-warm-period-intermediate.htm

There being no consistently predictive mechanism for prehistoric climate change, nor any means of blaming the 11th-century cooling on human activity, the honest answer (and kids need a bit of honesty in their schooling, as they won't often come across it in adult life) is that the earth's climate is inherently chaotic but appears to be bounded, with rapid increases followed by slow decreases in temperature.

Patently untrue. To be more specific there are some parts of the climate that are relatively random but we can easily tell when these things happen because we have relatively good and predictive descriptions of everything else.

http://www.skepticalscience.com/Milankovitch.html <- Milakovitch cycles do a remarkably good job and predicting ice ages

http://www.skepticalscience.com/climate-models-intermediate.htm <- And climate models do a very good job at predicting future climate and even the impacts of events like volcanic eruptions

It's a good introduction to critical thinking to consider any such phrase as "the average temperature of the earth is hotter than it has ever been"  and ask kids "what does that mean?" and "how do they know?" - these are the important questions that must be asked before assigning blame, predicting the future, or even guessing the mechanism: is the data really kosher? Forensic science, the analysis of complex interactive systems, and making inferences from partial data, are all much more interesting than parsing Shakespeare.

http://www.skepticalscience.com/surface-temperature-measurements-advanced.htm <- Climate scientists have put a great deal of effort into answering those questions.





There is remarkably good agreement from several independent sources which includes data analysis performed by people with no professional links (and therefore no way to gain monetarily) to climate science.

But above all you must insist that it is all their fault, otherwise they will object to paying "green" taxes and having an unreliable electricity supply. Never mind the truth, the careers of many politicians and self-styled "climate scientists" depend on the gullibility of the electorate.

Well that's just simply tin foil hat level conspiracy theory thinking without a shred of actual evidence to back it.

9

Physics, Astronomy & Cosmology / Re: Can multiple black holes orbit one another?

« on: 21/05/2016 17:42:33 »

The problem with an anti gravity field is limiting the extent so that it does not cancel the external gravitational field and therefore nullify the sling shot effect.

Just for the sake of clarity the term gravitational slingshot is actually a bit of a misnomer. The extra energy you get doesn't really come from the gravity of the body you use for the slingshot. After all no matter what path you take when passing through a gravitational field it takes exactly as much energy to get out of the field as you gain going into the field and in reality you can actually lose energy due to any drag if there were no other source of energy. The energy the spacecraft gains from a gravitational slingshot maneuver actually comes from the orbital kinetic energy of the larger body used for the slingshot. Luckily planets have so much that they don't notice the very tiny amounts our spacecraft steal. The equations for the speed boost you get from a gravitational slingshot don't actually contain any mention of the gravitational field of the body used for the slingshot. The only thing you really have to worry about is making sure there is enough attraction between you and the large body to make it possible to due the precise orbit you need to do to gain the delta-V you want. This does generally put practical limits on achievable speeds because planets are not points and you can only get so close to their centers (thereby increasing the gravitational attraction) before you hit their atmospheres or surfaces. Thus there is a limit on the orbits and thus the top speed that is possible which is controlled by the mass and size of the object you are using to slingshot.

Further reading including a bit about black hole slingshots at the end:
http://www.mathpages.com/home/kmath114/kmath114.htm

10

The Environment / Re: Are climate skeptics right that there is no link between CO2 levels and temperature?

« on: 01/05/2016 23:49:28 »

I want to know why you think there is something to worry us.

That is why YOU think this.

From there we can try to convince each other of our view. But to just pass the buck and avoid doing this means that I will continue to have my view. I think you wish to change my view. To do so will involve putting yourself into the position of possibly being convinced the other way.

He very clearly stated this already. He understands the scientific processes and therefore trusts the what must be several thousand (if not tens of thousands) of qualified climate scientists that have dedicated their lives to the study of climate. The science behind human caused climate change is well established and widely available. In fact it is well established and supported that anyone that disagrees needs a very good reason for that disagreement (and conversely there is no real need to justify agreement beyond trust in the scientific method). Asking someone to justify their belief in the scientific method and the results derived from it is akin to asking them why they believe in gravity.

But by all means if you have specific criticisms concerning the science I am sure they can be addressed. In fact I've been doing just that for quite some time in this thread. Though it could potentially save as all some time if you simply looked for your question here:

https://www.skepticalscience.com/argument.php?f=taxonomy

As it has probably already been addressed.

It is important to remember that temperature (and in my opinion CO2 level) is the effect, not the cause. The cause is redistribution of water, which is necessarily the essence of life. A small, nomadic population can follow the water, but the migration of a large, urban population will be resisted by other large, urban populations. 

It is demonstrably false that CO2 is not the cause of climate change and that has been fairly well established in this thread.

11

The Environment / Re: Are climate skeptics right that there is no link between CO2 levels and temperature?

« on: 08/04/2016 22:49:08 »

3) As a proponent of climate change weakening your argument in the ways described above weakens the arguments of all proponents of climate change. Deniers will use you as an anecdote to demonstrate the bad science of climate change. That argument is laughably refutable but the point is that it is something a proponent of climate change should never have to address in the first place.

Given that you say you don't like the lying bit would you please point out who has denied any science here.

I ask this as I am sure that I have been part of the group you would describe thus. I feel extremely afronted by the accusation of dishonesty and demand that you either substanciate it or retract it.

Unless of course you choose to do some less than honest stuff yourself.

For starters I've personally never considered the word denier as a pejorative term. Certainly I see no direct connection between the act of denying something and dishonesty. As far as I am aware a denier simply says that some statement is not true and there is nothing beyond that. I also certainly didn't imply anyone here was a denier. If we accept denier as a pejorative term certainly there is room on your side of the debate for those who share your views on climate change but are less than civil just as there is on my side. I certainly didn't mean for anyone to take umbrage at my remarks which should be rather clear from my rather reasoned tone.

Now seeing as you clearly have negative associations concerning the word denier I am willing to make an effort to use the word skeptic. Unless, that is, you have reasons to dislike that word as well. In which case I would have to ask you to provide me an acceptable term as those two words pretty much deplete my thesaural reserves in relation to this particular subject and I am not very keen of proceeding via trial and error.

I do wish to apologize again if I accidently gave you the impression I thought you were being dishonest or lying. That was absolutely not my attention although I do feel the need to point out that your reaction seems perhaps a bit on the harsh side. Not that we all haven't been guilty of that from time to time. It is always good to be reminded that everyone here is a human. That is unless AI has advanced much further than the public has been told.

12

The Environment / Re: Are climate skeptics right that there is no link between CO2 levels and temperature?

« on: 08/04/2016 14:34:14 »

This completely explains the seasonal fluctuations about the mean of the CO2 curve.

Well it would if the CO2 curve peaked in July-August, when sea temperature is maximal, but it actually peaks in May-June. But don't let the facts spoil a good argument!

I apologize for the mistake. Sea temperature changes don't completely explain the seasonal CO2 fluctuations. I neglected the fact that the growth of vegetation in the northern hemisphere (and thereby the world due to a disproportionate area of land being in the northern hemisphere) increases through July and August causing a massive uptick in carbon absorption which is less correlated with temperature changes. Thus shifting the peak CO2 concentrations back a few months remembering the competition between the ocean sink and the plant sink along with general response lag keeps the CO2 concentration from exactly matching to the date any seasonal cycle that drives changes in CO2 concentration.

Please give us a reference to the three independent pre-1900 trans-Antarctic survey records, the corresponding pre-1900 trans-Arctic records, the matching data from the Sahara, Amazon Basin, Manitoba and Gobi, and any three independent data sets from the entire Pacific ocean surface that predate the industrial revolution.

Please cite a temperature proxy that is not also a CO2 proxy.

The links I gave are generally fairly well referenced (especially any that have an intermediate or advanced tab).

For reference there are three major reconstructions of monthly global mean surface temperature and they use data from the Global Historical Climatology Network (GHCN).
https://data.noaa.gov/dataset/global-historical-climatology-network-daily-ghcn-daily-version-3

There are other reconstructions using other data. For example:

https://data.noaa.gov/dataset/global-surface-summary-of-the-day-gsod <-- Maintained by the USAF looking at the station map of the GSOD vs the GHCN (found at the links provided) clearly indicate that the two data sets are independent of each other. As per this link:

http://www.skepticalscience.com/surface-temperature-measurements-advanced.htm

Reconstructions done with the GSOD are mathematically identical (i.e. agree within a relatively small uncertainty) to the reconstructions done with the GHCN. These reconstructions were done by Ron Broberg and Nick Stokes (a software engineer and all I could find about Stokes was that he has a blog). So not in anyway part of organizations that did the major reconstructions nor actually paid for the climate research and therefore have no sane motives fudging the data.

Here is another:

What about satellite measurements of temperatures in the lower troposphere? There are two widely cited analyses of temperature trends from the MSU sensor on NOAA's polar orbiting earth observation satellites, one from Remote Sensing Systems (RSS) and one from the University of Alabama-Huntsville (UAH). These data only go back to 1979, but they do provide a good comparison to the surface temperature data over the past three decades.

and another:

Reanalysis data sets also show the same warming trend.  A ‘reanalysis’ is a climate or weather model simulation of the past that incorporates data from historical observations.  Reanalysis comparisons by Vose et al. (2012) and Compo et al. (2013) find nearly identical global surface warming trends as in the instrumental record (Figure .

Links to the cited papers can be found on the cited page.

http://onlinelibrary.wiley.com/doi/10.1029/2012GL054271/epdf <-- Here is the paper that used proxies. Based on the descriptions of the proxies I'd say a good number of them are either independent of CO2 or dependent on CO2 in a different ways which would average out over the large set of proxies used (173).

Please define "global temperature".

I suppose to be exact I should have said global mean temperature or monthly global mean temperature to be even more precise. It should be fairly obvious how one goes about calculating the mean of all temperatures on the Earth over the period of a month. It takes a lot of addition and some division but computers are good at that.

I do not find it in the least surprising that independent groups, starting  with the same data and the same assumptions, end up with the same model, however dubious the data and assumptions.

As above there are several independent data sets showing the same trend. Additionally different groups approached the GHCN data using different data analysis techniques, assumptions and models. There are even comparisons between adjusted and unadjusted data that show the same trend in both. All of this can be found in the following link:

http://www.skepticalscience.com/surface-temperature-measurements-advanced.htm

However when the model fails by more than its error bars to predict the next finding, or explain the observed historic phase shifts, it does rather cast doubt on the validity of the entire process.

I believe the latter point is now firmly addressed with the correction of my earlier misstatement. As for the former I'm not sure what precisely you are referencing but this may help:

http://www.skepticalscience.com/climate-models.htm

Also I have to point out that the research largely isn't mine as I am using one website.

An interesting mental exercise is to ask the question, what would happen if we took away all the water from the earth. Say we have a waterless earth, but leave the atmosphere with the current CO2. This will allows us to isolate the impact of the water on global climate and weather.

If we took away the water, you would no longer have to worry about hurricanes, cyclones, thunderstorms, floods and any type of storm  event; tornado, that comes from water based clouds. We won't have to worry about El Nino and La Nina affects, which originate in the oceans.

The loss of the water, will alter the thermal capacity of the earth's surface; goes down. This loss will cause higher thermal swings between day and night, as well as summer to winter. Without water in the atmosphere, there are no clouds to reflect the sun or help the earth retain surface heat.

If the surface water was not there to absorb and release heat, less heat would be transferred via oceans based currents. The need for heat transfer will be done mostly by the atmospheres. But the atmosphere can't move as much heat, due to their lower thermal capacity, unless air speed gets super high.

The lack of water, will impact all of life. There will be no photosynthesis, since the two reactants are water and CO2. This means the production of oxygen will stop. The result will be the partial pressure of the oxygen decreasing over time, as oxygen reacts with the surface to form oxides, but is not replaced. With less and less O2 in the atmosphere, we cant form new CO2. We will also lose the ozone layer, allowing more and more UV to enter the earth. CO2 can be broken down wth short wave UV back to CO, O, O2, C. Loss of O2 may shift the CO2 equilibrium back to O2.

I am not sure how one can ignore water, since it is the straw that stirs the global weather drink. The lack of water based disccuson and the fixation on CO2, shows there is a gap in knowledge.

You seem to be laboring under a misconception about what climatologist actually include in their models. As per my citation in the previous post:

http://www.skepticalscience.com/water-vapor-greenhouse-gas.htm

Here are some quotes from the intermediate version of the explanation:

Water vapour is the most dominant greenhouse gas. The greenhouse effect or radiative flux for water is around 75 W/m2 while carbon dioxide contributes 32 W/m2 (Kiehl 1997). These proportions are confirmed by measurements of infrared radiation returning to the Earth's surface (Evans 2006). Water vapour is also the dominant positive feedback in our climate system and a major reason why temperature is so sensitive to changes in CO2.

Unlike external forcings such as CO2 which can be added to the atmosphere, the level of water vapour in the atmosphere is a function of temperature. Water vapour is brought into the atmosphere via evaporation - the rate depends on the temperature of the ocean and air, being governed by the Clausius-Clapeyron relation. If extra water is added to the atmosphere, it condenses and falls as rain or snow within a week or two. Similarly, if somehow moisture was sucked out of the atmosphere, evaporation would restore water vapour levels to 'normal levels' in short time.

Satellites have observed an increase in atmospheric water vapour by about 0.41 kg/m² per decade since 1988. A detection and attribution study, otherwise known as "fingerprinting", was employed to identify the cause of the rising water vapour levels (Santer 2007). Fingerprinting involves rigorous statistical tests of the different possible explanations for a change in some property of the climate system. Results from 22 different climate models (virtually all of the world's major climate models) were pooled and found the recent increase in moisture content over the bulk of the world's oceans is not due to solar forcing or gradual recovery from the 1991 eruption of Mount Pinatubo. The primary driver of 'atmospheric moistening' was found to be the increase in CO2 caused by the burning of fossil fuels.

It should be very clear that water is not being ignored by climatologists and in fact is a large part of their models.

13

The Environment / Re: Are climate skeptics right that there is no link between CO2 levels and temperature?

« on: 08/04/2016 07:16:30 »

For the sake of an actual balanced accounting of the facts:

1. I was first shown the Vostok ice core data about 10 years ago (at an alumni conference of the Cambridge Earth Sciences department, just in case Craig wants to play the academic qualifications game) and immediately noticed that the temperature graph was always ahead of the CO2 curve. Now in my universe, the cause always precedes the effect, so CO2 cannot have been the cause of temperature fluctuations. Subsequent published analyses have confirmed what was visually obvious.

Just to make sure everyone is aware of all the evidence:

http://www.skepticalscience.com/co2-lags-temperature.htm

In particular this video specifically sites a paper that explains the current ice core record:

The simple and brief answer is that historically orbital factors have initiated changes in global temperatures. When an increase in temperature was initiated the decreased solubility of CO2 in the warmer oceans caused a release of CO2 that enhanced the relatively weak orbital forcing. This is why in the ice record the CO2 lags the temperature changes. However, it is well known that the orbital factors are not strong enough to account for the observed temperature changes. In fact because it was known that orbital forcing wasn't enough it was actually predicted that the ice record should show a lag between CO2 and temperature for the reasons above before it was actually observed experimentally. We also happen to know that no such orbital forcing is occurring today thus the current rise in CO2 is not only because of us but is also doing exactly what it was always known to do. It just so happens that this time the instigating cause is different.

2. Notwithstanding point 3 below, we do have some very reliable recent data from a single sampling point - Mauna Loa. The temperature curve shows a smooth continuous upward trend in recent years, but the CO2 curve, whilst its mean follows the temperature curve, shows an annual cyclic pattern that is a very regular sinusoid. Now if this reflected anthropogenic carbon dioxide, as you might expect, you would expect to find the maxima in winter when we burn more carbon fuels to keep warm. But it isn't. The maximum occurs in early summer, every year. This clearly implies that temperature drives carbon dioxide.

http://www.skepticalscience.com/warming-co2-rise.htm

So basically as above it is well known that temperature swings can impact the rate at which CO2 enters and leaves the atmosphere via the oceans. This completely explains the seasonal fluctuations about the mean of the CO2 curve. If anything it supports the fact that climate scientists clearly understand the carbon cycle and how it is related to various climatic parameters.

3. I have always been skeptical of so-called recent historic data on global mean temperature, for reasons rehearsed elsewhere - the fact that nobody had visited the poles,let alone made any serious measurements of arctic and antarctic temperatures before 1900; the fact that nobody has ever defined "mean global surface temperature" when asked; the fact that frankly nobody even cared about accurate land surface temperature measurements before 1920; the increasing paucity of such data between 1945 and 1970; the almost complete absence of temperature measurements of the sea surface (75% of the globe), mountains, or deserts (another 20%), prior to 1970; the increasing heat island effect on what land surface measurements we do have; lack of international standardisation of meteorological thermometers before 1926; the extraordinary correlation of the  NOAA "adjustment" of recent data to the known CO2 concentration.... enough for the moment....In short, most of the "data" looks like guesswork massaged with presumptions.

http://www.skepticalscience.com/surface-temperature-measurements.htm

In short the analysis of global mean temperature has been done by several independent groups using the same data sets as the three main temperature reconstructions, completely independent temperature records, and known temperature proxies that have a well characterized link to global temperature. The results are mathematically identical. Given that independent groups analyzing the same data and completely independent measures of the same quantity came to the same conclusions it is highly unlikely that the warming trend can be ascribed to any non-climatic factors.

4. In my undergraduate days we studied infrared absorption as part of physical stereochemistry and the quantum mechanics of chemical bonds. We learned (and calculated, and measured) that the O=C=O structure is a rigid cylinder with very few infrared excitation modes. At pretty much the same time (the 1960's) we began exploiting the IR transitions of CO2 to make very powerful lasers - simple and powerful precisely because CO2 has such a narrow IR spectrum. Water, by comparison, has an enormously broad IR absorption spectrum even as a monomer, and exists in the atmosphere as monomer, dimer, trimer and possibly hexamer gases, liquid, and several ice phases with different structures and spectra. Given that the hugely powerful greenhouse gas, H2O, comprises around 4% of the atmosphere, and the weakly absorbing CO2 less than 0.04%, and that the latent heat of evaporation and melting of water (both of which take place in the atmosphere) is responsible for almost all of the energy transport that we call weather(still with us, Craig? that's part of the international syllabus for pilots, and I scored 100% in the meteorology exam)  it does not seem at all reasonable to ascribe any significant change in global surface temperature to the IR spectum of CO2.

http://www.skepticalscience.com/water-vapor-greenhouse-gas.htm
http://www.skepticalscience.com/CO2-trace-gas.htm
http://www.skepticalscience.com/empirical-evidence-for-co2-enhanced-greenhouse-effect.htm

Water is a better greenhouse gas than CO2 but crucially it is often at or near its saturation point. The reason we have clouds and rain being specifically that water vapor has reached the saturation point (actually the air is usually supersaturated before clouds form) and precipitated out of the air. More specifically the fact that water is stable as a liquid (or solid) at most temperatures and pressure found to naturally occur on the surface of the Earth the atmospheric concentration is limited via the vapour pressure to somewhere in the 4% range. What this means is that if the atmosphere starts warming for some other reason that increase in temperature is going to increase the saturation point of water which is going to increase the warming effect that water has on the atmosphere. This is called a positive feedback and is well known by climatologists. The flip side of this is that since CO2 is largely not stable as either a liquid or a gas at basically any naturally occurring surface temperatures and pressures on the Earth it is theoretically possible to have an arbitrarily large CO2 concentration. So unlike water vapour concentration which is largely controlled by temperature and pressure CO2 concentration is only limited by the net rate at which CO2 enters the atmosphere.

5. We also learned that the CO2 absorption spectrum is close to saturation at ground level: adding more CO2 will not affect the overall IR absorption or emission of the atmosphere: the "extinction" phenomenon is of course true for all absorbers of radiation and formed one of the bases of my subsequent studies (PhD (Warwick) in case Craig is still with us)  and career (Chartered Physicist, National Physical Laboratory, US Bureau of Standards, and now a few private companies) in radiation measurement of all sorts. Even in our schooldays we learned that warm air can contain more water than cold air, so if water vapor promotes heating or cooling, the effect has an inherent positive feedback until the air is either  desiccated (as over Antarctica) or forms clouds that cut off the solar input - a bounded chaotic oscillator, just like the Vostok record. 

http://www.skepticalscience.com/saturated-co2-effect.htm

So it turns out surface CO2 concentration only actually matters in that it is a sign that CO2 concentration is increasing higher in the atmosphere. Also, while the strong absorption band of CO2 is nearly saturated there are many weaker sidebands which are not and while individually the may be weak together their impact is important. It should also be noted that even in the strong absorption band increasing concentration does still have an impact because the band cutoff is more gaussian than rigid. This means that as you increase the concentration the width of the absorption band over which meaningful absorption takes places increases even if the amount of absorption at the center of the band has saturated.

So I'm just a teeny bit skeptical about any model that begins with the presumption that CO2 is the primary climate agent (particularly when the IPCC said, in its first report, that it isn't) and then tries to fit "adjusted" "data" to the known or presumed CO2 curve. My skepticism is enhanced each year when the dire predictions of those models turn out to be wrong.

The "technical aspects" outlined above can be summarised us: when studied carefully, the data does not support the hypothesis that CO2 is the driver of climate. And that's the historical problem with scapegoats: the goat hadn't sinned, so sacrificing it did not placate the gods.

Meanwhile the world is going to hell in a handbasket, and climate change is going to exacerbate humanity's selfimposed mess, so the sooner we stop bleating about a non-cause and start dealing  with the inescapable effect, the better. But the solution is politically unpalatable, so intergovernmental panels and treaties will continue to ignore the facts and blame the electorate for burning coal.

I am sure answers to any lingering questions anyone might have can be found at the following link:

http://www.skepticalscience.com/argument.php?f=taxonomy

Oh and as an interesting aside there is also this:

http://www.skepticalscience.com/waste-heat-global-warming.htm

Which shows my earlier very crude estimate of human waste heat on global temperatures was at least a factor of 10 too high.

14

The Environment / Re: Are climate skeptics right that there is no link between CO2 levels and temperature?

« on: 03/04/2016 01:09:57 »

From a purely black body radiation standpoint (neglecting albedo and emissivity) without its atmosphere the Earth would have a mean surface temp of 255 K or -18.15 °C/-0.67 °F. This is pretty much 100% from just the incoming solar radiation. The actual measured mean surface temp of Earth is 287 K which is a difference of about 32 K. The sun delivers approximately 783,000,000 terawatt hours of energy to the Earth over the course of the year and all this energy takes us from 3 K (the blackbody temperature of the universe) to 255 K for an increase of 252 K. This means it takes 3,110,000 TWh per year to increase mean global temperature by a single degree K and this is a significant underestimate because the rate at which energy is radiated away increases non-linearly with increasing temperature. So in reality the amount of energy is much higher than this. Now the greenhouse effect has added about 32 K so adjusting for that we get 2,760,000 TWh per year to increase mean global temperature by a single degree K. As of 2011 the world used about 150,000 TWh of energy per year (this counts all possible ways of consuming energy). So even taking into account the greenhouse effect and assuming all of this energy ends up as heat eventually the net increase of Earth's mean surface temperature due to just the actual heat humans produce is on the order of 0.05 K and of course this temperature increase would be basically a one time increase i.e we have to use this much energy each year just to maintain the unnatural extra 0.05 K increase if we stop it goes back to just the plain sun value. Thus, we would have seen the mean surface temperature increase by 0.05 K over pre-industrial values with slight yearly increases tied directly to increases in energy consumption which currently stand at about 3,000 TWh per year or 0.001 K per year.

So the takeaway from that is that if the heat generated by humans was a significant contributor to changes in global temperature than the total change should have been on the order of 0.05 K since say 1880 to today with a change of about 0.001 K per year. (Remembering that we've easily overestimated the impact of energy on temperature.) What we've actually seen is an increase of 0.8 K with yearly increases of about 0.02 K which are somewhere in the neighborhood of 20 times the overestimated values of direct heating by humans. Does human activity directly heat the Earth? Of course it does. Is that effect significant? No it is easily 20 times smaller than the observed changes. Personally I believe the evidence for anthropomorphic climate change but I also understand that the direct heating of the Earth by the human use of energy is not significant.

15

The Environment / Re: Are climate skeptics right that there is no link between CO2 levels and temperature?

« on: 28/03/2016 01:24:14 »

Just to make sure everyone is aware of all the evidence:

http://www.skepticalscience.com/co2-lags-temperature.htm

In particular this video specifically sites a paper that explains the current ice core record:

The simple and brief answer is that historically orbital factors have initiated changes in global temperatures. When an increase in temperature was initiated the decreased solubility of CO2 in the warmer oceans caused a release of CO2 that enhanced the relatively weak orbital forcing. This is why in the ice record the CO2 lags the temperature changes. However, it is well known that the orbital factors are not strong enough to account for the observed temperature changes. In fact because it was known that orbital forcing wasn't enough it was actually predicted that the ice record should show a lag between CO2 and temperature for the reasons above before it was actually observed experimentally. We also happen to know that no such orbital forcing is occurring today thus the current rise in CO2 is not only because of us but is also doing exactly what it was always known to do. It just so happens that this time the instigating cause is different.

16

Physics, Astronomy & Cosmology / Re: How fast can an elevator go without harming the people inside?

« on: 23/03/2016 23:09:23 »

The first thing to remember is that the speed of the elevator doesn't actually matter. What matters is the magnitude of the acceleration the elevator goes through to get to its top speed. For ascent the acceleration phase pushes you against the floor making you feel slightly heavier. This is usually not too uncomfortable for the passengers. For the descent the acceleration phase actually reduces your weight (you push against the floor less) and if the magnitude of the acceleration is too high you'll become weightless or even be pushed against the top of the elevator. Reductions in weight tend to make people feel sick to their stomach and clearly you can't make people feel weightless or hit the ceiling without causing significant discomfort.

Basically when going up you can usually tolerate a greater acceleration than when going down because the acceleration going down feels an awfully lot like falling to the human body and people generally don't enjoy that when they aren't expecting it.

17

That CAN'T be true! / Re: TheBox on black holes

« on: 01/03/2016 16:28:25 »

Second of all, look up "binding energy." When a photon is absorbed by an atom, its energy becomes mass, plain and simple.

A free traveling photon has a mass given by m=E/c². The mass of an absorbing atom changes by exactly that amount. Energy does not become mass.

Third of all, mass/energy "equivalence" means exactly that. Mass can be converted to energy, and energy can be converted to mass. They are the same thing in different states.

Equivalence means things are the same not that one thing can be converted into another. For starters mass and energy are properties and properties can't be in states. Beyond that we know that photons have a mass associated with their energy content it simply isn't an invariant mass.

Did you know that when matter and antimatter annihilate each other, you get energy? Sounds to me like "matter" is probably made of energy ...

When matter and antimatter annihilate you usually get photons that have the property of energy. The energy of the photons (or whatever comes out) is exactly equal to the energy of the particles that annihilated. It just so happens that some of the energy property of the particles was invariant and is generally known by us as the property mass. The particles that annihilated were not made of photons. There annihilation caused a coupling between their particle field and the electromagnetic field (assuming photons were created) and that coupling lead to the destruction of the particles and the creation of brand new never existed photons.

So stop arguing with me for saying the same damned thing.

Except you are not saying the same thing at all.

Electrons don't flow. They oscillate. It's the energy that travels. A good mechanical analogy is dominoes. Stand them up in a row next to each other. Push the first one over, and they all fall down one by one, but it is the energy that travels from domino to domino. No dominoes actually travel from one end of the line to the other. They stay in a row, in order, as the energy travels from one to the next. Another example would be one of those desktop kinetic sculptures with a row of suspended stainless steel balls, bounce one at the end, and the two end balls bounce while the ones in the middle stay in place.

In a DC current given enough time an electron will travel from one end of a wire to the other. The only thing that keeps this from happening in AC current is the fact that the voltage and thus current switches directions. It has nothing to do with you dominoes analogy. Electrons do scatter in most metals but they scatter off impurities, phonons, grain boundaries, imperfections, etc. Electrons in a metal do not in general scatter off other electrons. I know it sounds weird but basically all of our current scientific understanding of metals relies on single particle approximations that treat the electrons as moving in an average field created by all the other electrons in the metal and hence no electron-electron scattering. They certainly do not oscillate unless driven by an AC current. When you move to superconductors the electrons just don't scatter at all which is why the resistance is zero.

A photon is a carrier of the electromagnetic force. When a photon is absorbed, its electric and magnetic components tell the particle that absorbed it to oscillate faster. There is no "flow" of electrons.

Electrons in atoms do not oscillate in the manner in which you believe they do. The charge distribution around an atom is static before the interaction with the photon and then static again after the interaction with the photon. There is no faster oscillation in the atom after the absorption of the photon. There is no time varying electric or magnetic fields in the atom after the absorption. Further, this is a clear misunderstanding of how solar cells work. In a solar cell an electron in a solid is promoted from what is generally called the valence band to what is generally called the conduction band. Then clever engineering causes that electron in the conduction band to leave the solid and enter a wire where it can do work. Thus there most certainly is a flow of electrons. There is also a flow of things called holes which are basically the absence of an electron that should be in the valence band from the valence band. These holes behave a lot like the antiparticles of electrons. The holes are made to flow the opposite direction. The net effect is a current through the solar cell and an outside circuit. Both the conduction and valence bands are special bands of states that exist only in the solid and are delocalized (that is to say they don't belong to any one atom).

Energy is equivalent to mass times the speed of light squared. When a photon is absorbed, it stops travelling at the speed of light and contributes a tiny amount of mass to the system that absorbed it.

When a photon is absorbed it ceases to exist period.

18

Physics, Astronomy & Cosmology / Re: How do we measure extremely low temperatures?

« on: 24/02/2016 22:16:07 »

Evan - using your unique skills in clarity and brevity, can you please explain what that impenetrable page on Wikipedia is actually trying to say about laser cooling please? Maybe I was being impatient, but I didn't find it at all accessible.

I can give it a try if you don't mind. So basically as we should all know photons carry linear momentum as well as angular momentum. The angular momentum is conserved in the absorption process through the selection rules. The linear momentum is conserved in the absorption process through the atom recoiling in a direction opposite the direction of the incoming photon. When the atom then decays to the ground state and emits a photon spontaneously that emission happens in a nearly completely random direction. So if you can figure out a way to make sure only atoms that are traveling toward your photon source can absorb photons they will lose a bit of momentum in a specific direction through the absorption recoil and will gain the same amount of momentum in a random direction through the emission recoil. The differences in direction are important and over many interactions the overall momentum of the atom decreases (i.e. the emission recoil doesn't always cancel the absorption recoil because of the differences in direction) especially in the direction toward the light source.

So if you use photons with an energy slightly less than an absorption transition the doppler effect means that only atoms moving toward the source can absorb a photon (because the atom moving at the source sees the photons has having slightly higher energy) and thus you get the situation described above. That is to say only atoms moving in a specific direction absorb the photons. Now in general you want atoms to lose momentum in more than one direction so you fire a couple of lasers from many directions.

19

Physics, Astronomy & Cosmology / Re: How much time does it take for an electron to emit a photon?

« on: 06/02/2016 00:14:13 »

I can't give an active link but here are some urls (a direct copy paste should work):

www3.uji.es/~planelle/APUNTS/ESPECTROS/jce/JCEphoto.html - This is a very thorough explanation of absorption of photons with quicktime videos.

madsci.org/posts/archives/2004-04/1082128751.Ph.r.html - This is a more direct answer to your question.

webpages.ursinus.edu/lriley/courses/p212/lectures/node40.html - This is another explination of the absorption process.

The gist of the above is that in order for an electron to transition from one state to another it has to enter a supposition of the initial and final state. The resulting supposition is no longer time independent and evolves over a finite amount of time from being more initial state to being more final state with significant oscillations. The result for an electron in an atom is that the electron cloud changes shape in an oscillatory manner with a frequency that matches the light being emitted or absorbed.

The reason most physics courses don't talk about this processes is because it requires some pretty complicated mathematics (even by Quantum standards) and in general you can calculate everything you are likely to need to know about the absorption of a photon without ever detailing the processes. Most physical observables of interest like the energy of the photon can be calculated from the time independent stationary states so there is no reason to bother with the more complicated stuff.

20

Physics, Astronomy & Cosmology / Re: Gravity waves and faster time?

« on: 11/11/2015 21:16:18 »

You may find the following pdf to be of interest:

arxiv.org/pdf/1501.00996v2.pdf

The short answer is yes a passing gravity wave is expected to distort time just like it distorts space.