Physics Discussion Thread

[rsingh]

Amber G wrote:
4. If a water molecule leaves (it evaporates).. normally it means it has higher energy (moving faster than average) so when it leaves, the average energy of surface is now less than what it was before.
(Some thing akin to - if a few richer people leave a group - the group (on average) is now poorer)

(The critical part: in water, there are some faster (than average) molecules.. if they come close to surface, the attractive force of other molecules is not able to prevent them from "leaving" the water body..- they are now water vapor escaped in the atmosphere..water (on average) becomes cooler.. the air above becomes warmer..)
Hope this helps.

It explains very well. Thanks Saar ; My sahabjada asked this over dinner and I was left like

[Amber G.]

It explains very well. Thanks

I am glad it was helpful ..
All - few comments..

A follow-up question.....if there is a layer of water over a flat surface, e.g. say someone pours a cup of water on stone surface; Assume air, water and the stone surface are all at the same temperature (30 C, say). Would we expect the water to evaporate?...
<snip>

Yes, as you said, the stone surface will become cooler.

Also, on a stone, after the water is gone (stone is dry) the process will stop.

On a Matka (clay pot), since it is porous, more water will come to the outer surface, which will keep out side wet for the water to evaporate and the water will get cooler for a longer time. In fact, since the out side surface of a matka is more than, say the top part of an open container, it is better water cooler.

---
Yes the water will get cooler than its surroundings.

.. If the answer is yes, it seems to suggest that heat flowed from a cooler surface to warmer surface...

Well unlike the first law of thermodynamics, which says energy is conserved, the second law of thermodynamics only says that it is **less likely ** for heat to flow from "cooler" to "warmer".. NOT IMPOSSIBLE.

In other words, some times, (or on molecular level ), a high energy molecule can move from "colder" (where other molecules are slower and thus on "average" - temp is lower, to a "warmer" place...

So on "local level (or open systems) you may see such things.. but not at larger level.

In a strict sense, if you are holding a glass of water, and you wait LONG enough (say trillion times the age of universe ) ..it may happen that top part of water may boil while bottom left corner forms ice

Except that it is NOT likely to happen. (Probability is pretty close to zero).

If you are not familiar with term like "Maxwell Demon" (See wiki entry or Gamow's excellent "Mr Tomkins book") The ebook link ;http://ebooks.cambridge.org/chapter.jsf ... 644143A018

BTW, if you have not seen/read it, as I have done many times before, I HIGHLY recommend George Gamow's book(s) - "Mr Tomkins in Paperback"
(It explains, Relativity, Space/Time, Thermodynamics, nuclear Physics etc in simple terms)

some quotes from previous posts, relevant to this.

Following are some relevant observations: (i) if one sprinkles water on a surface and it evaporates, the area feels cooler after some time. (ii) Water stored in a desi matka (earthen pot) is definitely cooler than water in a glass/cup, and this, as I understand, is due to the evaporation of water from the matka surface....(so some capillary effect is also at work here).

.... and how can heat flow from a "cooler object" to a hotter object (2nd law of thermodynamics)?

***

Humidity is related to how much water vapor is already in the air - more humid the air-- less evaporation. At 100% (R) humidity there is no evaporation - that is the number of water molecules leaving the surface of water is (on average) equal to number of water molecules from air entering the water and getting stuck inside.


..

[SriKumar]

Well unlike the first law of thermodynamics, which says energy is conserved, the second law of thermodynamics only says that it is **less likely ** for heat to flow from "cooler" to "warmer".. NOT IMPOSSIBLE.......In other words, some times, (or on molecular level ), a high energy molecule can move from "colder" (where other molecules are slower and thus on "average" - temp is lower, to a "warmer" place.......

Thanks for the response....the 2LT being 'less likely' was a bit of a surprise but explained from a molecular level it makes sense (reminds of kinetic theory of gases in high school).

So, between the (i) air, (ii) water on solid surface and the (iii) solid surface all at the same temperature, the water will cool first (and the air presumably warms up by receiving the high energy atoms from water). As the process continues, the water cools further and this has a cooling effect on the solid surface below due to heat flow from solid surface to water puddle/patch. Thanks.

[Amber G.]

On the other end of Matka... we have...
Super Hydrophobic Metals

Which is hard to get wet...

(From University of Rochester News)

Scientists at the University of Rochester have used lasers to transform metals into extremely water repellent, or super-hydrophobic, materials without the need for temporary coatings.

Super-hydrophobic materials are desirable for a number of applications such as rust prevention, anti-icing, or even in sanitation uses. However, as Rochester’s Chunlei Guo explains, most current hydrophobic materials rely on chemical coatings.

<snip>

[ramana]

AmberG, Have you read the phys.org article on big bang vs continuum model of the universe. It came on my phone so don't have a link. Its written by Saurya Das and Ahmed Farag Ali using the Amal Raychaudhri theory.
Paper published in Physics Letters B. (?)

Title is Cosmology from Quantum Potential. Only abstract shows.

Can you interpret this for lay people? Or Aam Aadmi as the flavor is now!

[Amber G.]

^^^ Thanks for the pointer.
For interested people:
The article (Physics.org)
No Big Bang? Quantum equation predicts universe has no beginning
The link is below.
http://phys.org/news/2015-02-big-quantu ... verse.html

The pdf of the paper, mentioned in the above article

Can be found here:
pdf copy of physics letter article "Cosmology from quantum potential by Farag Ali and Saurya Das

I do not feel qualified to interpret this to aam aadmi .. If there are specific questions, and I know the answer, or if I note something interesting for audience here, I will certainly try to post it here.

Meanwhile , for those who want to understand very basic geometry/physics of "big bang" or "steady state" some of the old popular books are still quite good. I will recommend George Gamow - It is very old - but basic concepts for aam aadmi are quite nicely presented. (Read the chapters about non-Euclidean geometry, cosmology - big bang etc- in One Two Three Infinity, or Mr. Tomkins book)

The old Original Mr. Tomkins book is very old (I have some vintage edition), but get a 1993 "Canto Edition with additional stuff by Roger Penrose.

There is another addition in 1999 "The New World of Mr. Tompkins" (coauthor Stannard) which has updates to the original Mr. Tompkins in Paperback.

***

For those who are unfamiliar with "Mr. Tomkins", Gamow invented this guy (back in 1940).. A aam aadmi who is bored one afternoon and wants to go to a movie and finds no good movie running. He sees a notice that there is a public lecture by a physicist in local university about Einstein's Relativity. So he goes there. He falls asleep while listening to the lecture and in the dream and goes to a "wonderland" where he can "observe" the strange phenomena predicted by Relativity....

He learns a lot of things.. (he gets hooked, and then attends many such lectures).. some in classroom, but mostly in his dream where author skillfully explains main points)..

Whole book is consist of such chapters, and the book goes through Relativity, (Both special and general), cosmology, atomic science, nuclear science, thermodynamics, elementary particles etc...

(Meanwhile Mr. Tomkins falls in love with professor's daughter and marries her and has more interaction with the professor

In all a very good book...requires some freshman level math but no higher math. Of course it has become one of the most popular book in popular physics.

[ramana]

AmberG, Now in aam admi speak. What does it mean and is it pucca?

[nandakumar]

Talking of quantum physics, here is a link to an article spoofing all those fancy theories of how the Universe evolved.

http://waterfordwhispersnews.com/2015/0 ... physicist/
The humour is so subtle that if you didn't know that the website is devoted to article satirising popular developments (they have one on Irish cricket after they beat West Indies) you would say, "Oh My God these physicists were taking us for a ride all these years!"
For some reason I am unable to copy-paste the link. But if you type waterfordwhispersnews and physicist amit goswami in a google search you would land the article
http://waterfordwhispersnews.com/2015/0 ... physicist/

[Amber G.]

[The humour is so subtle that if you didn't know ]... you would say, "Oh My God these physicists were taking us for a ride all these years!"
******

OTOH They may have been in fact taking all for a ride, and only now one is giving an honest answer to

" is it pucca?

Any way the cut and paste: (Excerpts only)

THEORETICAL Quantum Physicist Dr. Amit Goswami admitted today that he, and his peers, have absolutely no idea what they’re doing, and claims they were no nearer than prehistoric man to figuring out the Universe.

“We have been just winging it to tell you the truth,” explained the 78-year-old in an exclusive interview with WWN. “Seriously, I haven’t a clue what’s going on. Either does anyone else in my field. We keep proving stuff that never actually happened”.

“Our cover is blown, what can I say? He added.

Dr. Goswami’s comments came after yet another alleged breakthrough in quantum mechanics which claims the universe has existed forever, { see Ramana's post )as opposed to being created by a ‘big bang’.

“Over the years there have been just a handful of us pretending to know something about the universe that no one else does,” he went on. “But this is all lies to feed the charade. I’ve had some great times during the years; travelling the world, and giving talks on our pretend finds”.

When asked how he got away with it for so long, he replied: “I found out a long time ago that everything can be proven with a mathematical equation..

(To tell the truth, I was seriously thinking of putting something like this but was waiting for the usual April 1)

[nandakumar]

Amber G
Not being an expert, i would have hesitated to say it myself. I am referring to your claim in the post as above, "OTOH They may have been in fact taking all for a ride, and only now one is giving an honest answer to..". But I will say this. When I read the line in the article, "Firing particles at each other at the speed of light can’t end well.” , I did for a fleeting moment think, "Humour apart, how do we know that there isn't going to be some horrible backlash which makes Fukushima seem like celebrations on Diwali"?

[Amber G.]

^^^ I was saying( the "OTOH" part) with "tongue in cheek" .

As to Fukushima, as I have pointed out the fact *many* times in brf - the number of deaths due to radiation - zero, number of cancers attributed to radiation - zero , number of cancers likely to be added due to Fukushima radiation in next 50 years - can not be scientifically detected - IOW negligible) . (This is after *every* detail study after 2011)

Of course, the panic and violent protests due to Fukushima caused some deaths and injury in India..
So the fear of particles moving at the speed of light could be much more dangerous...

(A slow moving train, or a bullet (about .000002 speed of light) can be more dangerous than a photon )

[Suraj]

For some reason I am unable to copy-paste the link. But if you type waterfordwhispersnews and physicist amit goswami in a google search you would land the article

It doesn't parse because the URL has a cussword in it, and forum software eats it for dinner. Your search suggestion is the only way that'll work cleanly.

[Rahul M]

Amber ma'm, asking as someone who has lost touch with current research, now that the standard model is more or less confirmed by experiments, what next ? where does theoretical physics go from here ?
any promising theories ?

[Bade]

Symposium presentations

The presentations from The Particle Physics at the Crossroads symposium 2013 are available to download as PDF.

http://www.ed.ac.uk/about/edinburgh-glo ... sentations

[Vayutuvan]

Please allow me to rain on the SM and BSM parade a little ("tongue in cheek" as AmberG put it )

A few questions.

0. Why is it called Edinburgh India Symposium?

1. So how much does a dual phase xenon detector cost?

2. Can dark energy be a source of endless energy?

3. What is with all the color images and all? They look "popular science"y in the mold of Kaku and Sagan. Where is the beef, i.e. the real papers or are they in pay-walled journal? Links to arxiv would be great. I haven't found a single link hat has put a link to an arxiv article. May be there is one. I would like to know.

4. Please tell me I am wrong but IMHO the slides I have looked at are almost like poster presentations in every seminar/symposium/conference I have yet seen (I confess I have not seen many but enough to get a general idea). They are just a regurgitation of what is known and hence are very close to being useless. The only purpose of the slides and the whole conference seems to be to ask for funding to construct costly - may be moderate, but still costly - facilities to investigate the Rabbit Hole of Dark Energy! Looking at all those nice images who in their right mind would object to throwing a few millions if not billions at the some of the research, eh?

[Bade]

Tongue in cheek onlee....I assume you are smart enough to find the arxiv url where you will find boatloads of papers getting published daily.

Rahul_M, best is to refer to the HEPAP panel report to see which direction is high energy physics headed with community consensus as funding is critical.

http://www.usparticlephysics.org/p5/
http://science.energy.gov/~/media/hep/h ... 060214.pdf

[nandakumar]

Thanks Suraj for clarifying that point. I confess, I was a little taken aback at the use of that four letter word in the headline of the story. But then I thought it isn't used in what is being posted as message in the forum so it doesn't violate any of the forum guidelines.

[SaiK]

http://mars.nasa.gov/msl/multimedia/ima ... ageID=6538

what the..

[Vayutuvan]

I forget the paper/Wiki link. There was a series of 26 photos of animals each of which have one of the 26 English alphabet (not same font or any thing like not on the same animal - but there is no question of not being able to recognize the shape of the letter). I was reading on of the original papers of Alan Turing on Morphogenesis which was a ground breaking paper at that time on that subject. The idea was that the patterns found in nature are so large that a few apparent organizational aspects appear spontaneously. Any similarity to any thing man made is simply a coincidence.

There is a theory that submerged city of dwAraka and rAma sEtu are nothing but such random features which developed during Pleistocene

Pleistocene marine deposits are found primarily in shallow marine basins mostly (but with important exceptions) in areas within a few tens of kilometers of the modern shoreline. In a few geologically active areas such as the Southern California coast, Pleistocene marine deposits may be found at elevations of several hundred meters.

[Rahul M]

thanks Bade saar. reading those now.

[Vayutuvan]

Pantheon: A Dataset for the Study of Global Cultural Production

Amy Zhao Yu, Shahar Ronen, Kevin Hu, Tiffany Lu, César A. Hidalgo
Subjects: Physics and Society (physics.soc-ph); Social and Information Networks (cs.SI)

May be they are using spare cycles at MIT. Sorry to be critical but euro-centrism and western universalism arising out of Greeks is being pushed a hard science paper. It is not even "physics and society" paper. All write-only papers go to arxiv to die, I suppose.

[RamaY]

Request our resident science minds to take few minutes and watch this speech by Rajiv Malhotra. Do any of you have access to the 9volumes of Indian sciences published so far? If so can you please post some of the interesting things?

This reminds me of the math poetry I see on Social Media and elsewhere. Some of these equations are proven, some aren't. But almost all of them I cant fathom/prove. Yet I enjoy the elegance and beauty of Mathematics. Now the question is - Does the mathematician who wrote them first have to know the proof to propose them or not?

some thing like this:

If no proof is required/given by the original writer of such equations, is it still called math or poetry or worse math-mythology?

Some examples are: http://en.wikipedia.org/wiki/List_of_un ... athematics

[Bade]

Vaiko Welcomes HC Stay on India-Based Neutrino Observatory Project

Knives are out against anything with a nuclear tag in India.

Madras High Court Stops Rs. 1500 Crore Underground Science Project

[johneeG]

Amber G saar,
we had much discussion about Bhaskara wheel. At that time, you had said that I was just making theories and not testing them out. You had said that it would be quite easy to test. You are right. But, I don't think I am upto it. If I have to do it, I would perhaps need lots of money and perhaps it would never materialize. You said you could do it with much more easily.

So, I have a serious suggestion: Would like to collaborate with me? I'll provide the theory part and you can test it out to see if the theory is correct or not. If we make some interesting discovery/invention, then we can share the rewards.(I am not talking about just the Bhaskara wheel, but other works as well. Of course, Bhaskara wheel can be the starting point).

Since, you know Sanskruth and maths, we can work together on the ancient works. I'd be much obliged if you agree.

[Rahul M]

you need a lot of money to create a wheel ? I don't think so. a few thousand rupees would suffice.

in any case this has been tried for the last 2000 years in one form or other and has failed every single time. for perpetual motion engine to work basic energy conservation laws have to be violated which AFA we know is not done. otherwise much of modern S&T, including the internet will vanish.

other PME's.


a long list : http://www.strangehorizons.com/2002/200 ... ense.shtml

[Bade]

There was a nice article recently on Emmy Noether and her contributions to physics at the turn of the last century. She basically mathematically formalized the reason for existence of conservation laws like momentum conservation, energy conservation, Angular momentum conservation etc. Even today the same principle is invoked to understand symmetries in particle physics.

In the end if energy conservation needs to be violated then one of the associated symmetry principles would not be true. Energy and time are connected, as energy is expressed as a time derivative...loosely speaking. Anyways, if time translation is lost, ie physical laws do not depend on the time but if it were to violated, only then would energy conservation break down. So it does not take much to demonstrate that a perpetual motion machine will not work. Just do simple experiments to see if time translation breaks or not.

[Neshant]

For all you physics high rollers out there, what do you make of this.

Is it science or more like science fiction.

He's a professor of Physics at a big name university. One of the few African American folks to reach such standing. His theories on time travel are downright bizarre. Apparently something to do with Einstein's Theory of Special Relativity.

[RamaY]

Can any resident Phjjiks guru explain what these guys are saying in pinglish? TIA.

http://home.web.cern.ch/about/updates/2 ... ence-force

RahulM ji: I remember reading a book on perpetual motion machines in my childhood. None of them work.

[Bade]

Forget that spoof, here is some news from India.

TIFR: star sound discovered?

An experimental work by a team of researchers at the Mumbai-based Tata Institute of Fundamental Research (TIFR) may have led to the discovery of the sound of stars.

The results were published recently in the journal Physical Review Letters.

In a table-top experiment, scientists at TIFR were able to produce a very hot (millions of Kelvin), solid density plasma, much like that found in stars. A femtosecond laser of very high intensity was used to produce the star-like object.

“We were able to produce the star-like object for hundreds of picoseconds (10) to nanoseconds (10) using the laser,” said Amitava Adak, Research Scholar at the Ultrashort Pulse High Intensity Laser Lab, TIFR. He is the first author of the paper.

[Bade]

Maybe India can pitch in early and even provide a site to locate it, as it is well into 2025+ that it will get built.

Particle Physicists Gather to Plan Next Accelerator

Participants in the meeting, which was organized by IEEE in conjunction with the U.S. Department of Energy and CERN, hope to complete the FCC’s technical report by about 2018 in time for the next update to the European Strategy for Particle Physics in 2019 or 2020.

“The LHC is the main machine and now we have people looking at what else can be [built],” said Frederick Bordry, the director for accelerators and technology at CERN.

The final design for the FCC is up against a parallel effort to design the Compact Linear Collider, or CLIC. The potentially 42-kilometer long, 3 TeV lepton linear collider would also be located under the French and Swiss countryside.

Once both designs are completed, CERN administrators will recommend one of the two options when it is time to update its particle physics strategy. The event in Washington, D.C. was the second annual design conference for the FCC, and the first held in the United States.

Though researchers at the meeting said that there seemed to be no obvious scientific showstoppers, there would be a number of engineering challenges to overcome. The biggest will be designing strong enough magnets for the giant particle accelerator’s storage ring.

The dipole and quadrupole magnets that would direct and focus the 100 TeV particle beams will need to be significantly more powerful than any built so far. Researchers estimate that the magnets will have to produce 20-tesla magnetic fields to contain and control the beam. Currently, LHC magnets produce about 8 tesla, while Fermilab has built 11 tesla prototypes. Designs for the HL-LHC call for 16 tesla magnets.

Another significant technological challenge is containing the synchrotron radiation emitted by the particle beam as it circles the outer storage ring. The LHC currently produces a relatively negligible seven kilowatts of radiation, while the FCC would generate about five megawatts of radiation, enough to potentially wreak havoc on its sensitive cryogenics, electronics and other equipment.

Because they make up the majority of the machine, the magnets and their raw materials, would also be the project’s biggest cost driver. Based on the size of the accelerator, it’s estimated that at least 6,000 metric tons of superconducting niobium-tin would be needed to build the requisite magnets.

“The present cost of niobium-tin is a showstopper, ” said Ezio Todesco, a researcher at CERN. He added that the cost would have to drop to about $800 a kilogram, down from the current $1600 a kilogram price tag. Though he said manufacturers he spoke to are willing to take on the challenge, “we are still very far from this.”

Surprisingly, computing power to track the vast numbers of particles produced in collisions was also highlighted as a potential concern. Microprocessors have continuously gotten smaller and cheaper over the years, but it is unknown whether that trend will continue. “Extrapolating computer technology 20 years into the future is non-obvious,” said Ian Bird, the computing grid project leader at CERN. “We’re close to the physical limits for feature size.”

On the flip side, as long as computer power progresses, detector technology is generally expected to keep up with the needs of the particle physics community. “Much detector technology is driven by silicon technology and computing power, so we can count on significant improvements,” said Werner Riegler, chair of the technical board of the LHC’s ALICE detector.

Making the science case for building the machine is also a top priority, but complicated by the discovery of the Higgs boson in 2012. There are no more obvious holes left in the standard model to fill in, though mysteries persist about the nature of dark matter and supersymmetry.

“The first goal is the complete exploration of the Higgs boson and its dynamics,” said Michelangelo Mangano, a theoretical physicist at CERN. “Dark matter remains a crucial element in the search.”

But without a clear next step, articulating the need to funders for the next generation machine could be difficult. “I’m not convinced we can actually make it make sense to the people who actually pay the bills… unless we have some really compelling arguments,” said James Siegrist the associate director of the office of high energy physics at the Department of Energy.

The role of the United States in the project is uncertain in part because the timing of the study is awkward for the high-energy physics community. Two years ago, before the FCC project geared up, the U.S. physics community came together for a field-wide meeting to help develop a broad, ten-year roadmap for future high energy physics projects. The meeting, known as Snowmass on the Mississippi, played a major role in informing the final report of the Department of Energy’s subsequent Particle Physics Project Prioritization Panel, which laid out the agency’s official ten-year strategic plan.

“I don’t think at Snowmass [the FCC] was thoroughly assessed,” Siegrist said. “From an agency perspective, we don’t really know what the U.S. community thinks about this.”

He added that the consensus that emerged out of the 2013 meeting was to put the heft of U.S. research behind developing technologies for the proposed International Linear Collider, and the high luminosity upgrade planned for the LHC in the mid 2020s. “The HL-LHC is the highest priority in the near term,” Siegrist said. “We can’t have everybody run off to work on the FCC while we’re still not finished with the high luminosity LHC.”

The LHC Accelerator Research Program, or LARP, is the U.S.’s main collaboration with CERN to advance accelerator technologies. Right now, the program is geared entirely towards developing magnets for the high luminosity LHC upgrade.

“In terms of direct studies, [FCC] is not something I can directly invest in,” said Giorgio Apollinari, the LARP director at Fermilab. “I would love to be able to help but the mandate is what it is.”

American scientists have a lot of experience to draw on. The United States was almost always pushing the cutting edge of accelerator technology until the cancelation of the Superconducting Supercollider in 1993. Even after accelerator dominance was ceded to Europe, U.S. researchers put together a major theoretical study in 2003 for a 240-kilometer “Very Large Hadron Collider” at Fermilab.

“The U.S. has a lot to contribute,” said Michael Syphers of Michigan State University. “The U.S. has 25 years [experience] in running a 2 TeV collider, and 10 years designing and partially constructing a 40 TeV collider.”

Throughout the conference, the ghost of the SSC seemed to loom over much of the proceedings. Presenters made frequent references to a variety of lessons learned from the aborted project.

“Had we gone down that route, we could have had the Higgs a decade ago,” said Rep. Bill Foster (D-Ill.) who opened the conference. He was an accelerator physicist at Fermilab before running for Congress, and worked on some components of the SSC. “[Europe] got the project and we didn’t, so doing the politics right is important.”

One of the biggest lessons he said he drew from the failure was the need to bring in a broad coalition of regions into the project, either across U.S. states or countries around the world. “You need a balance of effort going from region to region and you need a balance of money going from region to region,” Foster said.

Though the LHC experiments and detectors are international projects, with collaborations with dozens of nations around the world, the accelerator itself was a European funded and built machine. “Everyone is convinced that the next machine is a world-wide machine,” Bordry said.

[SriniY]

Can any resident Phjjiks guru explain what these guys are saying in pinglish? TIA.

http://home.web.cern.ch/about/updates/2 ... ence-force

RahulM ji: I remember reading a book on perpetual motion machines in my childhood. None of them work.

I am no guru but this article is humor. The Force is the force mentioned in star wars movies, me thinks.

[Bade]

Newly discovered link between Calaveras, Hayward faults means potentially larger quakes

InSAR revolutionizes mapping

Chaussard said that the many years of InSAR data, in particular from the European Space Agency's ERS and Envisat satellites from 1992 to 2011, were critical to connecting the two faults.

Creep, or the surface movement along a fault, is evidenced by offset curbs, streets and home foundations. It is normally determined by measuring points on opposite sides of a fault every few years, but that is hard to do along an entire fault or in difficult terrain. InSAR provides data over large areas even in vegetated terrains and outside of urban areas, and with the repeated measurements over many years InSAR can detect deformation with a precision of 2 millimeters per year.

"With InSAR, we have access to much larger spatial coverage," said Chaussard, who has been expanding the use of InSAR to measure water resources and now ground deformation that occurs between earthquakes. "Instead of having a few points, we have over 200,000 points in the Bay Area. And we have access to areas we couldn't go to on the ground."

She noted that while creep relieves stress on a fault gradually, eventually the surface movement must catch up with the long-term underground fault movement. The Hayward Fault moves at about 10 millimeters per year underground, but it creeps at only 3 to 8 millimeters per year. Earthquakes occur when the surface suddenly catches up with a fault's underground long-term movement.

"Creep is delaying the accumulation of stress needed to get to an earthquake, but it does not cancel the earthquake," Chaussard said.

This is where the new inSAR mission of ISRO's with NASA/JPL will yield dividends, in mapping out all the fault lines and improving our understanding of quakology. Meantime, bay area residents need to ponder to buy or not to buy and where.

[johneeG]

Rahul M saar,

it seems to me that the wheel should work. Here is my theory part for that:

Okay looking at Bhaskara's wheel, assuming that this problem was given as a problem to his students-
Can you use simple logic to predict how the wheel will behave? (I would like to see the solution without using calculus.. simpler the better)

The original Bhaskara's wheel looks like this: (Black part mercury)


But let me simplify and assume this is like (see below - assume each curved part is semicircle):


(red part is mercury liquid - how will the wheel behave?- Can you show simple math to support your conclusion)

PS - (Added later - One can use old fashioned Newton's Method, or Lagrangian to solve the above problem )

hmm... I never quite understood calculus. (I didn't even try because I disliked it so much)

Anyway, it seems to me that the Bhaskara's wheel is very different from the simplified version that you posted. The difference seems to me that the Bhaskara's wheel is designed to put greater torque on one side of the wheel all the time.

I'll try to convey my understanding in simple manner:
I have put numbers on the spokes of the wheel to better convey my point:


There are 8 spokes on the wheel numbered from 1 to 8. There is a rim on which the torque(i.e angular force acts). There is an axle at the centre of the wheel which is the centre of gravity. The force on the axle will not produce any movement in the wheel. The force at the rim will produce movement.

The whole thing seems to be based on torque.

Torque is the angular force.

WHAT IS TORQUE?
Torque is a measure of how much a force acting on an object causes that object to rotate. The object rotates about an axis, which we will call the pivot point, and will label 'O'. We will call the force 'F'. The distance from the pivot point to the point where the force acts is called the moment arm, and is denoted by 'r'. Note that this distance, 'r', is also a vector, and points from the axis of rotation to the point where the force acts. (Refer to Figure 1 for a pictoral representation of these definitions.)



Torque is defined as

= r x F = r F sin().

In other words, torque is the cross product between the distance vector (the distance from the pivot point to the point where force is applied) and the force vector, 'a' being the angle between r and F.

Using the right hand rule, we can find the direction of the torque vector. If we put our fingers in the direction of r, and curl them to the direction of F, then the thumb points in the direction of the torque vector.

Imagine pushing a door to open it. The force of your push (F) causes the door to rotate about its hinges (the pivot point, O). How hard you need to push depends on the distance you are from the hinges (r) (and several other things, but let's ignore them now). The closer you are to the hinges (i.e. the smaller r is), the harder it is to push. This is what happens when you try to push open a door on the wrong side. The torque you created on the door is smaller than it would have been had you pushed the correct side (away from its hinges).

Note that the force applied, F, and the moment arm, r, are independent of the object. Furthermore, a force applied at the pivot point will cause no torque since the moment arm would be zero (r = 0).

Link

So, the spokes 8, 1, and 2 will not experience much torque. The mercury(or any liquid) in these spokes is near the axle. Because there will be less torque. Because the distance between the liquid and the centre of gravity(axle) would be less and therefore the torque would be less.

The spokes 4,5, and 6 will not experience much torque because the force(Gravity) has approx 0 degrees to the radius.
The formula for Torque is Torque = r*F*Sin(theta).
Theta is the angle between r and F.
Here, r is the radius of the wheel. And F is the force of gravity which is acting downwards.

In spokes 4, 5, and 6 the torque will be less because Sin 0 is 0. So, Torque = r*F*0 = 0.
So, in spoke 5, Torque will be 0.

In spokes 7 and 3, the gravity force makes an angle of 90 degrees with the radius of the wheel. Sin 90 is 1.(1 is the maximum value that a sine angle can get). So, the maximum torque will be in either spoke 7 or 3. These are the spokes that will decide whether there will be motion in the wheel or not.

In Spoke 7, the liquid is spread out. Considerable amount of the liquid is near the axle(and hence less torque because of less radius). Very little liquid is near the rim.

In Spoke 3, most of the liquid is near the rim. And therefore this spoke will experience maximum torque. So, the wheel will move because of the torque in spoke 3.

The torque experienced by other spokes is less or negligent.

Your simplified version seems to be completely different.

Link to post

Is building a wheel difficult?

hmm...I think building a simple wheel may not be difficult or costly, but building a wheel with curved and empty spokes where liquid can be filled in is a bit more difficult. And they have to be at precise angles, I presume to make it work properly.

As for the wheel with balls:

I just happened to stumble on this.The solution to this "perpetual motion" thing has been elegantly explained in "Physics for entertainment" by Ya Perleman- an old classic from Mir Publishers- one of the best and entertaining set of books I have ever read and then I went into medicine

Saar,
I just glossed over it. I found two points about perpetual motion wheels:
a) he generally deals with wheels having balls inside them. He does not mention wheels having liquids inside them. If he had atleast dealt with wheels having several small balls in each spoke, it would be more interesting.
b) For perpetual motion to happen in a wheel, the torque on the one side(say right side) has to be consistently more than the other side(say left side). His only objection to perpetual motion wheels seems to be that at some point the wheel will be in such a position where torque on one side(right side) will not be consistently more than the other side(say left side). This seems like a silly objection. Anyway, the Bhaskara wheel which is being discussed in this thread seems to be able to consistently maintain more torque on one side(right side) than the other side(left side). If this is the only objection being raised, then I think perpetual motion wheels are certainly possible.

Also the shrill tone of that book against perpetual motion wheels sounds like reading koran or bible. They also have the same shrill tone when they are advocating something which is based on faith.

Link to post

----
A PHD in molecular biology says the following about Darwinian theory:

SURVIVAL OF THE FAKEST
SCIENCE NOW KNOWS THAT MANY OF THE PILLARS OF DARWINIAN THEORY ARE EITHER FALSE OR MISLEADING. YET BIOLOGY TEXTS CONTINUE TO PRESENT THEM AS FACTUAL EVIDENCE OF EVOLUTION. WHAT DOES THIS IMPLY ABOUT THEIR SCIENTIFIC STANDARDS?
--
JONATHAN WELLS

Survival of the fakest by Jonathan Wells

[Vayutuvan]

Machinery of an Energy Dream

and No it is not a perpetual motion machine. There are some interesting tidbits in the article regarding the cost to build. Just this past Friday, there was a a half hour segment on NPR (I think the program is called Science Friday, IIRC) in which three different cheap energy technologies were discussed with the lead investigators of each project talking about the technology and progress. LIF head was also featured who essentially said that they were supposed to have reached break even last year. Instead they are off by factor of 2. IOW, they got only half the energy than they put in. Costs of he LLNL NIF facility is about $5.2 Billion and going. There seems to be lot of cost overruns and unexpected problems. One of them he mentioned is the instability of the frozen layered Deuterium/Tritium pellet.

The above NYT article says the machine should have worked perfectly (i.e. achieve ignition after a complete implosion of the pellet) from the word go if one went by the computer simulations that were run. $5.2 billion and 35 years later all we have is "half" working (literally) expensive facility.

Usually the last part is going to be the hardest as the low hanging fruit of getting the efficiency up from 2% (which was the figure when they started) to 50% is already plucked.

Lt us wait and se what is going to happen in 2020 when Iter is supposed to come on-line.

[Rahul M]

@johneeG, here is what will happen. create such a wheel, fill it up and all it would do is oscillate a bit and then come to rest.

please, by all means, show us otherwise and I personally guarantee you a reward of 1 Cr.

till then though, please give it a rest.

p.s. dear god, we are now reduced to quoting '(un)intelligent design' websites in this thread !
henceforth any such OT posts would attract immediate warnings.

[Vayutuvan]

johneeG: There are several ways you can proceed though in all honesty I think that you are doomed to fail.

1. Simulate using a computer. But then you need to read up on and understand the Mathematics requires quite a bit of advanced calculus and as Bade already pointed work of Emmy Noether. Of course, you need to understand the physics quite well too to be able to construct a mathematical model. If you do due diligence, you yourself would discover that this is a fool's errand.

2. Construct several wheel designs:
a. Self-fund the project: Then it is your time/money you are risking.
b. Go to NASA/NSF/UGC or other foundations. For the latter, you need to give solid proof that it is worthwhile endeavor for people to sink their money into. In that case you need to show, at the minimum, a computer simulation. So you are back to square one - you still need to understand the math and physics involved.

No more on this particular topic from me.

[Amber G.]

JohneeG ji -
Since you explicitly asked me, let me respond. As you said when I challenged you to find any solution to a high-school level math problem using all your resources..

I am very bad at maths in general. Please go ahead and educate me. Thanks in advance.

Yes, I do agree with you about your judgement about your ability in math. Since you asked me to educate you, my simple advice is to learn math, at least basic elementary. This will avoid arguing and looking for things which are absolutely absurd. Basic math is required in any "theory" if one is going to talk about any science.

For example,

You made posts after posts about Hanuman Chalisa's description (Hanuman jumping 150,000,000 Km "up" and biting sun like a fruit)..

Simple math: Use simple geometry about Sun's apparent angular diameter. (about "1/108"- the 'holy' number I am sure you would know - this is about 1/2 a degree) (hint: divide the distance "12 million yojans as you said by 108 and you will get the diameter of the sun -- about 1,400,000 Km -- (l see that it is little larger than a piece of fruit)

Or take the temperature of sun (Hint: 600 watt/meter at 12,000,000 yojans - rest is simple Stephen-Boltzman eq to find surface temperature of Sun about 6000 C )...
Again you will find it is too "hot" for any fruit to put in the mouth...

May be Tulsidasji was simply using his beautiful poetry skills to convey his thoughts about strength and virtues of Hanuman rather than 'measuring distance of the sun"..

***

The Bhaskara's wheel - Again - you can not only do your own experiment or use a SIMPLE geometry to see the obvious absurdity which Bhaskara or his students, I am sure knew right away..
(You made a good start about calculating torques.. but just complete the math part accurately)

***

So, I have a serious suggestion [for amberG]: Would like to collaborate with me? I'll provide the theory part and you can test it out to see if the theory is correct or not. If we make some interesting discovery/invention, then we can share the rewards.(I am not talking about just the Bhaskara wheel, but other works as well. Of course, Bhaskara wheel can be the starting point).

Since, you know Sanskruth and maths, we can work together on the ancient works. I'd be much obliged if you agree.

Thanks for asking but I don't have time or interest. For me "theory" with absolute ignorance of math and logic having faith only in absurd non-demostrable experiments is not helpful.

[Amber G.]

Coming back to "physics"...
Here is one simple, yet beautiful way to think about bhaskara's wheel .. This is what most likely Bahskara argued (or any good physics student will argue)..

(For detail, see the figure of the wheel posted here again for convenience)


Hint1: What if each spoke (1-8) was fully filled with mercury. Where the center of Gravity of the whole system will be. (Hint: symmetry - it will be at the center)

Hint2: Now think of each spoke, half/partially filled. The center of gravity in each sub-section has to be LOWER than when it was fully filled with Hg. (Don't worry about horizontal direction, just worry about the component in z-axis)

Hint3: Now since, in each case (for each sub-section), the CG went LOWER than before, the TOTAL effect will be -- yes- Center of Gravity Lower than the center.... ALL THE TIME... (it can be left or right of the center but NEVER above the center)

If CG remains lower than the center, (ALL THE TIME) does it tell you something??

[Amber G.]

...
This reminds me of the math poetry .... Yet I enjoy the elegance and beauty of Mathematics. Now the question is - Does the mathematician who wrote them first have to know the proof to propose them or not?

some thing like this:

If no proof is required/given by the original writer of such equations, is it still called math or poetry or worse math-mythology?

RamaY - I am sure, you may know this, but, at least for the above equation.. the problem came later after the proof was already known..so to speak..

The "proof" is fairly simple, if you hit the right thought. Requires the most basic trig (just use two formulas - sin(x) = 2 sin(x/2) cos (x/2) and cos (x/2) = sqrt(1+cos(x))/2)... The method is basically what ancient Indian (or Chinese or Greek etc) astronomers used to produce trig tables..

A moments thought will tell you that this is nothing but the perimeter of limiting case of drawing polygons inside a circle. (Only math one needs is Pythagorus theorem)

for example .. draw a square inside the circle of radius 1.. the perimeter is (4 sqrt(2)).
Now draw an octagon..The perimeter will be .. related to first two terms..
Now draw a polygon with 16 sides... you use first three terms...
And so on.,,
In limiting case, the perimeter would be 2*pi..

(BTW, Many ancient mathematicians, used this method to calculate pi)

Added later: See for example wiki article : Viete's formula
The picture (taken from wiki) is quite nice:

(A sequence of regular polygons with numbers of sides equal to powers of two, inscribed in a circle. The ratios between perimeters of consecutive polygons in the sequence give the terms of Viète's (above) formula.

[Amber G.]

1. Simulate using a computer..

Or for Bhaskara's wheel ... (assume red dots are drops of Hg)




(Simulation can be fun though... ..)