Predictions of physics theories

Over at Cosmic Variance, Sean Carroll posted yesterday about a straw poll taken at a small gathering of physicists who focus on the cosmological theory of inflation, asking them what they thought the likelihood of the general principle of the theory being true was. He noted that his estimate of of 75% chance was on the low side compared to the majority of the people attending the conference who put the likelihood of inflation being a fact at around 90%. After the conference, he asked several of his colleagues at Caltech, and found that many of them, none of whom were directly working on inflation, put the likelihood at only 25%.

He then asked his readers to present their own estimate for the probability that inflation was true. And he added a few other major theoretical concepts in physics: supersymmetry, string theory, the Higgs boson, large extra dimensions, WIMP dark matter, and “any non-cosmological-constant explanation for cosmic acceleration.” He left the categories quite vague (for example, does “large” mean, “micro/macroscopic” or just “larger than Planck length”) because there are often multiple theories within each category, but for the most part there is a single unifying concept for each theory.

60+ people with a wide range of backgrounds have responded with their estimates now. And the results are interesting in a couple of ways. The two charts below show the how many people proposed specific percentages of the likelihood of each theoretical concept. The interactive versions are available on GoogleDocs.

Compiled likelihoods of several physics theories, based on predictions given by commenters at Cosmic Variance



Compiled likelihoods of several physics theories, based on predictions given by commenters who indicated an educational/professional background in physics at Cosmic Variance

The first things that jump out at me are that pretty much no one believes that large extra dimensions have any chance of existing (average likelihood being 9.08% with a standard deviation of 15.47), while the Higgs particle is considered quite likely to exist (average = 79.52%, std dev = 26.77), with inflation also having a better than 2/3 chance (average = 67.02%, std dev = 28.81). Amongst those who claimed an educational and/or professional background in physics (and astronomy), large extra dimensions are considered similarly unlikely, but the Higgs boson, inflation, and WIMPs are both considered ~10% more likely than by the commenters as a whole.

On the other hand, the chances given to supersymmetry, string theory, and non-cosmological-constant cosmic expansion are all stable in being considered relatively unlikely by both laymen and scientists alike.

It’s an interesting little bit of meta-analysis, really, which raises some questions about why certain major theories are accepted both in and outside of those educated in physics, why some of those are more accepted within the subset, and why other theories are considered equally less likely, regardless of education. It is likely that “insiders”, as it were, have a firmer basis in the fundamentals of physics and so they are better able to evaluate the theories themselves, which would explain the variation between the insiders and outsiders on certain topics. But I don’t think there is anything about the Higgs boson, or inflation, or WIMPs which differentiates them from the other theories that makes them less comprehensible to those with a physics background.

And since this is a non-rigorous, loosely defined survey, I wouldn’t really want to try to draw any significant conclusions from it. But it is interesting to get a general picture of how various theories are viewed and accepted within the physics community as a whole, and amongst the larger population of laypeople who are interested in modern advancements in the science.

Update 2/11/2011: Over 100 people have commented now.

Inflation SuSy Strings Higgs
Avg Std Dev Avg Std Dev Avg Std Dev Avg Std Dev
Everyone 66.79 28.63 44.07 30.24 30.52 30.47 76.96 27.41
Physics Background 71.43 22.13 45.56 27.99 25.37 26.83 85.32 20.61
Difference 4.64 -6.5 1.49 -2.25 -5.15 -3.64 8.36 -6.8
large xtra D WIMPs non-CC exp
Avg Std Dev Avg Std Dev Avg Std Dev
Everyone 11.76 20.01 58.41 29.36 27.74 28.38
Physics Background 8.54 14.67 60.84 25.48 25.07 25.01
Difference -3.22 -5.34 2.43 -3.88 -2.67 -3.37

Compiled likelihoods of several physics theories, based on predictions given by commenters at Cosmic Variance



Compiled likelihoods of several physics theories, based on predictions given by commenters who indicated an educational/professional background in physics at Cosmic Variance

The ebb and flow of battle

For as long as humans have been describing warfare and battles we have described the ebb and flow as first one side and then the other gains the upper hand, pushing their opponent back across the battlefield (or, in the larger picture, across the map.) However, I don’t think any accounts of such events have ever really lent themselves to a true understanding of just how battle lines can shift within the duration of a fight.

Prior to the development of the modern firearm and the introduction of armored vehicles, a battle line was very much a line. A mass of men armed with melee weapons and short range projectiles, occasionally aided by archers and/or cavalry. The two sides faced up against each other and bashed each other in the face. Depending on the situation, it might have been tightly formed lines such as the Roman legions or Greek phalanx, where only the first few lines were actively fighting at any one moment, or it might have been more loosely formed, where the two masses became wholly interspersed amongst one another (as seen in Braveheart).

Early modern firearms still relied on massed lines of men, but that was because of the inaccuracy of the weapons and because battles usually still resorted to hand-to-hand combat.

Both of these periods saw tactics in which reserve units were sent to reinforce ones’ own weak lines, or to overload weak spots in the opponents. The attacks and counters in this manner are what led to the forward and backwards movement of the fighting across unprepared (lacking significant constructed defenses) battlefields.

Even into the 1900s, hand-to-hand combat was quite common, despite the increase in accuracy of firearms. Bayonet charges were quite common in both WW1 and WW2. However, in WW1, battles were often dependent upon the ability of one side to gain control of prepared defensive positions, making it a much more static environment in terms of what could be gained and lost. Attacks were often made with multiple waves of infantry charges. If an attack failed, the defender had not lost any ground and the attacker had not gained any.

By WW2, the days of inaccurate, low rate of fire weapons were gone. And as a result, so too was the day in which two groups massed on a field and fought face to face (if they could help it). The nature of the war had one side utilizing infantry distributed amongst prepared, static, defensive positions and artillery with mechanized reinforcements, while the other used a combination smaller individual units of infantry supported by armored vehicles, aircraft, and much more accurate artillery and naval fire to help overcome heavily prepared defensive positions. Because of the less solid nature of the lines of combat, the ebb and flow of the battles were much less obvious (to anyone who wasn’t actually in the middle of it all).

The modern development of video has given us the ability to record and see just how lines of combat ebb and flow. But because of the shift away from massed front lines, there isn’t much chance for us to actually view the ebb and flow of a battle. And most cameras brought to the front lines of a combat zone are usually in the thick of things, not getting a bird’s eye view of the larger situation. But the last few days have presented us with something we’ve never had before. A top-down look at fighting between two large crowds primarily armed with melee weapons and simple projectiles — rocks and molotov cocktails. The clashes between the anti-government protesters and what seem to be government controlled thugs have been recorded and broadcast by several news agencies who have set up their cameras on balconies, high up in nearby hotels.

In the clip below, the government thugs have maneuvered some trucks across the road to provide themselves with some cover, and to force the protesters back into Tahrir Square. However, the protesters attack and push the thugs back. There are numerous similar videos available if you can find them, where you can see first one crowd flowing forward and the other backward, and then the process reverses. At one point the group attacking the protesters sends people up into a nearby building to throw rocks and brickwork down on the protesters. At various points, the attackers pushed the protesters all the way back into the square, but by nightfall the protesters had pushed out to the end of the road and set up makeshift barricades (which I have been calling Mubarricades in my head), to defend themselves from the rocks and molotov cocktails which were being hurled at them. I asked a couple of folks on Twitter who are in the military and/or study military history and didn’t get any affirmative responses that there is any video from earlier conflicts which show this back and forth. It’s definitely something that might be of interest to the military, riot police and security forces. And anyone who might be contemplating any popular insurrections as well.

Odd what can stand out

I was reading through the NY Times liveblog of the protests in Egypt, and in the 9:19am update, there was a series of videos and pictures. One of those pictures was of one of the oft-mentioned US-made tear gas canisters.

What jumped out at me, more than the fact that it was made in the US, is that the canister expired 5 years ago. Just at the top of the shell, two lines of text are visible:

3. SHELF LIFE 5 YEARS AFTER DATE OF MANUFACTURE
4. DO NOT USE AFTER EXPIRATION DATE

And then of course, there is the big sticker which reads “MFG 2001”. And since “MFG” is a fairly standard abbreviation for “manufacturing”, it would seem as though the canister expired some time in 2006.

Tunisia & Facebook: private global entities acting on a national scale

At this point you’re probably at least somewhat aware of the revolution of sorts which has been going on in Tunisia. You’ve probably heard that it was instigated by the self-immolation of a fruit vendor who the government had put out of business. You may even have heard that a prominent Tunisian Twitterer has joined the newly formed government and that Twitter itself has been key for Tunisians to spread the word of their protests and the government’s abuses.

There is no doubt that social media has played a role in widespread protests in several nations. But in Tunisia, Facebook has taken it to a new level. Prior to, and during the widespread protests, the Tunisian government, which controlled internet access in Tunisia had instituted a script which was harvesting login information for the people who were accessing Facebook and using that information to delete the profiles of people who were posting anti-government and pro-protest statements and information. It does not appear that they took the next step and rounded up any of those people, but the story isn’t completely clear.

What’s interesting to me is that Facebook took it upon itself to counter the government’s actions by adding some extra security to the login process for Tunisian IP addresses. I don’t know Tunisian law or international law (or any law, for that matter), but I’m curious about the larger issue. If a government says that it has the legal right to access any information transmitted through the internet service which it provides, what legal right does a private entity, based outside of that government’s nation, such as Facebook, have to circumvent the government’s access to that information? Especially after the fact? Facebook was not using https to encrypt the login information preventing the keylogging style harvesting script the Tunisian government put into place until after they became aware of the keylogging.

Even in the US there is a disconnect between an individuals privacy regarding electronic information on stored on computers and networks and their privacy regarding physical information on paper and objects in their homes. And if the US government obtained a warrant to access a US citizen’s Facebook account, I believe that Facebook would be obligated to give that information to the government. Maybe Tunisia doesn’t require a warrant. So, again, would not Facebook be obligated to allow Tunisia’s government to access that information?

On the whole, I’m rather happy that Facebook took the steps it did. (Amused also, considering how much Facebook tries to default to sharing an individual’s personal information with other people and companies.) But with the global growth of the internet and entirely online entities such as Facebook and Twitter and Google and others, I’m curious about how they are able to interact with different nations and their informational policies. Last year we saw Google close up shop in China because of that government’s informational practices which the company did not want to support. And it briefly (I think it’s no longer functioning) provided full Google access to Chinese citizens by directing their access through a different domain.

Over the past 100 years we’ve seen massive growth of international businesses. Calling companies like Coca-Cola “American” simply because that is where their headquarters is located is almost farcical when they are publicly traded and have ownership distributed globally and do most of their business and base most of their employees outside of the US. And internet based ventures blur those lines even further. How are such companies to be governed and policed? While they are headquartered in a country like the US, they are nominally subject to certain laws and restrictions and obligations. But what if they don’t want to be?

Perhaps I’ve read too much dystopian science fiction, but imagine a world in which various internet corporations have banded together to purchase a small area of land, say, an island in the Caribbean or South Pacific and declared that island’s independence from it’s prior government, or just buy off that government. They then draft up a constitution that is completely beneficial to their own needs and desires, completely freeing them from the obligations of the laws of their original host nations. How then would they be restricted, or held responsible? Some might say that the powers of the free market would compel them. But that isn’t really likely when they already control so much of the activity within their business domains. And at that point, they’d essentially be a nation (or nations) themselves. Forget granting companies the rights of the individual which people got up in arms about after the Citizens United case a couple years ago. Now they’d have the ability to declare war. Imagine a group of the most significant international businesses and internet entities placing an embargo on a nation. They would possibly be able to almost completely isolate that nation electronically.

This idea is pretty far ranging from the original issue. Morally, Facebook very much had an obligation to protect the identities and privacy of its users from a hostile government. And it came through on that obligation. But considering the criticism Facebook has faced regarding its policy toward user privacy, it might be somewhat surprising. And at the same time (or possibly before) we concern ourselves with corporate nations, we need to concern ourselves with the ability of any government accessing our private information which we maintain online. In Tunisia it was just Facebook accounts getting shut down. But what if next time it is people getting arrested or killed? How do people protect themselves from that? What ability and legal right do companies have to take action to prevent that?