## Wednesday, March 05, 2014 ... /////

### Particle fever: where to see

Particle Fever, the universally praised David Kaplan's full-fledged movie about particle physics, is coming to the movie theaters in the U.S. today.

Lots of news outlets discuss what the movie is all about.

It took 7 years for the movie to be shot, and so on. It is both about theorists and experimenters and the emotions they have been going through

For your convenience, here is a copy of the dates and places where the film will be shown. The film's website also tells you about the film festivals where the movie is participating.

March 5
New York, NY - Film Forum

March 6
Santa Barbara, CA - UCSB

March 7
Los Angeles, CA - Nuart
Toronto, ON – The Bloor
Irvine, CA – University Town Center

March 8
Sioux Falls, SD – Cinema Falls

March 14
Seattle, WA - Landmark
San Francisco, CA - Landmark
Berkeley, CA - Landmark
Bellingham, WA - Pickford Film Center
Scottsdale, AZ - Harkins Camelview
Chicago, IL - Music Box
Naperville, IL – AMC Showplace 16
Nashville, TN - Belcourt

March 16
Sioux Falls, SD – Cinema Falls

March 19
Ithaca, NY - Cornell Cinema

March 21
Cambridge, MA - Kendall Square
Minneapolis, MN - Landmark
Washington D.C. - E Street
Baltimore, MD - Charles
Philadelphia, PA - Landmark
San Diego, CA - Landmark
Denver, CO – Landmark

March 28
Santa Fe, NM - CCA
Columbus, OH - Gateway
Kansas City, KS - Tivoli
Atlanta, GA – Midtown Art
Houston, TX – Sundance Cinemas

March 31
Ann Arbor, MI – Michigan Theater

April 3
Oklahoma City, OK – Oklahoma City Museum of Art

April 4
Boise, ID - Flicks
Charlotte, NC – Manor
Charlottesville, VA – Downtown Mall

April 11
Albany, NY – Spectrum 8

April 15
Portland, OR – Oregon Museum of Science

April 18
Austin, TX – Arbor
Knoxville, TN – Downtown West
Eugene, OR – Bijou Art

April 25
Lincoln, NB – Mary Riepma Ross Film Center

#### snail feedback (26) :

reader Ariel Panelli said...

Sorry to interrupt, but I have a question that after 1 month of search I still can not find an answer.

Why there is so different temperature measurements at 1 bar level on 50km altitude? Some charts mention 100 degrees above earth temperature and other charts like this one mention the same range of temperature than earth.

reader Luboš Motl said...

Hi, 50 km is the stratopause, see graphs

http://eesc.columbia.edu/courses/v1003/images/atmprofile.gif

and text

http://eesc.columbia.edu/courses/v1003/lectures/ozone/

to see that the temperature over there is indeed just a little bit cooler than on surface. It's because the temperature grows up with the height in the stratosphere below this 50 km height - the higher you go, the more you are irradiated from the Sun, and the circulation doesn't spoil that because it is not there.

Those who say it is -100 etc. are probably incorrectly extrapolating the decrease that only holds in the stratosphere.

reader Ariel Panelli said...

Thanks lubos for the info, now I understand the changes on the earth atmosphere. But you misunderstood my question.

My question was about Venus. Why there is so much discrepancies at 1 bar 50km height, if you look up for different charts about venus temperature over altitude you would fine differences of 70 degrees for the same altitude.

My question is relate to the Geoffrey Landis proposition about floating cities at that height. If temperatures there are equal to earth, is fine, but if there are like other charts show, there are not.

Besides, it also point a big difference in your calculations that you do to measure the greenhouse effect.

reader Luboš Motl said...

Dear Ariel, I don't know the answer on Venus on top of my head, apologies. There's no reason to think that the layers are exactly equally thick as on Earth etc. There are still qualitative similarities.

reader Gene Day said...

Wonderful! I think this should make it easier to get funding for future colliders.

When is it coming to Chattanooga? I see Boise, Idaho but no Jacksonville, Florida. I guess they think us white folk in the deep south are just too dumb to enjoy it. :)

reader w h demisch said...

Wonderful movie. Highly recommended!
The producers should get a substantial placement fee from Apple, given that Macs seem to be ubiquitous in the particle physics community.
Noted that your friend Matt Strassler had a cameo at the end, participating in the Higgs briefing. Hoped to see you as well, but missed you.

reader Andrew Kidd said...

Also check out a documentary called SCIENCE AT WORK on Fermilab, available on its YouTube channel.

reader Barry Sheridan said...

While the LHC is a hugely impressive feat I do feel it is a monumental waste of human intellect and resource. The world is in need of some fundamental technical answers to its need for clean power and the like. The resource devoted to this project could have delivered some of those answers. Lubos, does that make me enemy #1. Sorry!

reader Luboš Motl said...

Dear Barry, the (currently) clean power was already found well over 100 years ago - it's called "coal". Today, when it burns, it only produces H2O and CO2 both of which are beneficial and harmless.

You probably meant an abundant source of energy like fusion.

At any rate, the main ultimate purpose of lots of energy and baking breads and driving trains etc. is to allow fundamental physicists to study the fundamental laws of the Universe. I don't know whether you are doing anything useful with your life, but the ultimate purpose and only meaning of your life is to contribute your modest contribution to make fundamental physics possible.

If I am the first one who has informed you about this key fact about "where you are coming from" and "where you are going", then I apologize for those who failed to inform you earlier.

reader Barry Sheridan said...

Thanks Lubos, I had to chuckle at your rapier like thrust. I'll leave it be, keep at it, I enjoy your blog.

reader Andrew Kidd said...

I think we have there the beginnings of a new talking point in the Green anti-science agenda: "Down With Basic Science! Fund Ecological and Clean Energy Research Only!"

reader Pavel Bažant said...

An old thread, me knows, but anyway. All you write is pretty basic physics, so of course I agree with what you have written. The problem is one of terminology. The definition of GH effect on Wikipedia is that it is just the suppression of radiative surface cooling due to the opaqueness of the atmosphere in IR. This effect is obviously very important on Venus, as you have actually mentioned. The problem is that in 90 % (or 99 %?) of cases, the GH effect is discussed in the context of atmospheres that are transparent in the visible range, implying surface irradiation as the heating mechanism. This is not the case on Venus, as only a few percent of solar radiation makes it to the surface.

So, in the most general definition of the GH effect, GH effect prevents Venus' surface to cool, but in the narrower sense implied by just about any discussion of the topic (atmosphere transparent in visible, opaque in IR), this is certainly not the case on Venus.

It would be interesting to estimate the conditions if all dust, H2SO4 etc. were replaced by the GHG CO2. My guess is that Venus would actually start to cool, as the atmosphere would become more transparent.

reader Luboš Motl said...

Good questions - well, I think that in your scenario with the transparent atmosphere, you would have to say what is the albedo (color) of the surface in order to calculate the new temperature, right?

reader Pavel Bažant said...

My intuition is that CO2 does not block all IR, only a certain band, so there is a limit to its ability to prevent the surface from cooling. I would expect H2SO4 aerosols to block radiation in a much wider band. If you remove the aerosols and other dirt, the surface should actually start to cool, as pure CO2 does not block all bands.

Anyway comparing the role of CO2 on Earth with its role on Venus seems rather absurd, the systems are different in so many ways. Doing so in order to scare people is even worse: Venus-like temperatures are impossible on earth, as Earth has 100x less atmosphere, therefore a much thinner troposphere. CO2 does not play a central role.

reader Pavel Bažant said...

No, if the surface were reflecting, it should be actually hotter, as it would not radiate the heat away. I am still assuming that the air compression is the main cause of the high temperature, not solar surface heating. This holds provided there is still some mechanism for the vertical winds.

reader Luboš Motl said...

Dear Pavle, the infrared spectra of CO2 and H2SO4 are analogous, see

http://webbook.nist.gov/cgi/cbook.cgi?Spec=C77781&Index=1&Type=IR

http://blogs.ch.cam.ac.uk/pmr/files/2010/06/061510-1821-openclimate3.png

The transmittance is above 0.9 for most infrared frequencies, and for some special intervals/frequencies, the transmittance is much lower. That's for the pure chemicals.

Aerosols are very different, of course. Most aerosols *reflect* the sunlight (like a mirror) and there's some limited absorption in some of them, too.

I agree that the comparison with Venus is demagogic fearmongering. After all, the absolute concentration of CO2 on Venus is about 100,000 times larger than on Earth. Because the greenhouse effect is logarithmic, it translates to a less extreme ratio – like 100-1,000 – but it still qualitatively changes the game.

reader Luboš Motl said...

Now, you're wrong, Pavle. A higher albedo (reflectivity) means that less solar radioation is absorbed in the first place, so this affects the "in" side of the energy budget. The "out" side is affected less than that by the albedo, and it's often assumed that the thermal radiation remains at sigma*T^4, see

reader Pavel Bažant said...

Dear Luboši, my point is that there is this H2SO4 aerosol covering the whole planet, which is opaque at almost all wavelengths, preventing the surface to lose heat by radiation. CO2 contributes only little, as it's opaque at only a few bands, whereas the aerosols at all bands.

I used to believe CO2 is the main factor before reading your article.

reader Pavel Bažant said...

Emissivity at lambda = 1-albedo at lambda (Kirchhoff's law). If by albedo you mean the reflectivity specifically in the visible range, then of course you are right.

If the albedo is high in IR, the emissivity in IR wil be also low. So, with _other_ heating sources present, low IR absorption would actually help keep the surface hot :-)

reader Pavel Bažant said...

Sorry, I accidentally did't read the whole post! Of course I agree.

reader Luboš Motl said...

Dear Pavle, it is not true that the H2SO4 aerosol is opaque at almost all frequencies.

reader Pavel Bažant said...

I thought reflective \subset opaque = does not let rays through. The main point was that it prevents long-range radiative heat transfer. The other main point about relatively low importance of CO2 still holds, I think.

reader Luboš Motl said...

Dear Pavle, a reflective material is indeed a special case of "opaque material".

But the Venus atmosphere is not a reflective *material*. It contains aerosols which is a union of very small dust particles. Light gets through in between them, and reflects - and still gets through - when it hits the dust particle.

So the Venus' atmosphere as a whole is rather opaque but light still gets through and this light that gets through is very important.

reader Pavel Bažant said...

Okay, I see.

reader Pavel Bažant said...

After some googling, I retract my claim regarding CO2 not being important. Its absorption bands are much wider than I thought
http://homeclimateanalysis.blogspot.cz/2010/02/co2-spectrum.html .

There are little or no aerosols in the lower 30 km, so CO2 has to be the main mechanism preventing radiative heat loss from the surface.

The dependence on CO2 concentration is also interesting. There should be two regimes: low concentration regime, where the surface loses heat directly to space, and high concentration regime where most heat is radiated by the gas itself at some characteristic height h_CO2.

The problem is that the clouds also absorb and radiate and have their own characteristic height h_clouds.

Depending on whether h_CO2 is <, >, or apx. = to h_clouds, there could be three possible regimes.

It would be interesting to investigate these three regimes -- their properties and stability.

Anyway, my previous posts were not adequate. Things are more complicated.

After reading a few other articles, I actually think the greenhouse effect is indeed keeping Venus hot and CO2 seems to be a contributor on par with the clouds, if not more important.

I still maintain that Earth cannot be extrapolated to Venus, though. The conditions are qualitatively different.