Physics Is A "Troubled Field"? Not As Much as Biomedical Research And Psychology

Image of  artificial CME successfully produced in laboratory experiment in 2016. Is physics a "troubled field"?  Only in the opinions of those who know little or nothing about it.

I confess I was rather mystified on reading the recent reviews of two books by physics superstars: Stephen Hawking ('Brief Answers to the Big Questions') and Martin Rees ('On the Future').    These appeared under the banner 'Serious Doubt On Serious Earth' in the WSJ Review section (p. C12, Oct. 20-21) by John Horgan.  

Horgan, after giving reasonable reviews of each book, then writes:

"Hawking and Mr. Rees recognize science's declining status. They call for better science education to lure more young people into science." 

 Then quoting Hawking:

"The low esteem in which science and scientists are held is having serious consequences."

True, but only in some fields - not all. Case in point, Horgan goes on to note:

 "Both authors fail to mention science's wounds are at least partially self-inflicted. In 2005, statistician John Ioannidis presented evidence that 'most published research findings are wrong'"


Now that is flat out false, and leads the unwary reader to believe all the sciences are publishing error- prone research. In fact,  Joannidis - a meta -researcher- was focused almost exclusively on the credibility of medical research.   

 In effect, his investigations found that much of what biomedical researchers concluded in  their published studies was often misleading, exaggerated or flat wrong. These included studies related to the prescription of antibiotics or blood pressure meds, treatments for back pain, surgery recommended for heart conditions, and advice concerning consumption of fiber and more or less meat.   See e.g.

Dr. John Ioannidis Exposes the Bad Science of Colleagues - The Atlantic

https://www.theatlantic.com/magazine/archive/2010/11/lies-damned-lies.../308269/

The "crisis in replication" as he refers to it is also rampant in psychology. Thus, three years ago in a NY Times report ('Psychology's Fears Confirmed: Rechecked Studies Don't Add Up')   we learned of multiple failures in that discipline including (according to author Benedict Carey):

- A top social psychologist was caught fabricating data, leading to more than 50 retracted papers

- A top journal published a study supporting the existence of ESP that was widely criticized

- The journal Science pulled a paper on the effect of gay canvassers on voters' behavior because of faked data concerns. 

Added to that one also learned (in the same piece)  of a painstaking yearlong effort to reproduce 100 studies published in three leading psychology journals, finding more than half couldn't be validated. According to author Carey (ibid.):

"The vetted studies were considered part of the core knowledge by which psychologist understand the dynamics of personality, relationships, learning and memory"

Note at no point does physics or  its subdisciplines enter into any of this. The beauty of physics is, in fact, its robust quantitative basis which often provides a rigorous cross check on the experiments or observations. (Nearly all of them tied to quantitative models.) Because it isn't merely the outcome of one or more experiments that must be considered, but also the governing quantitative and theoretical dynamic. How can a model be expressed in consistent, quantitative form that gives body to the interpretation of the experimental data? If that quantitative model is defective, then more than likely the whole experimental set up is as well.   So given nearly every physics publication is quantitatively based then there are inherent checks on the model and the capacity for replication.

Take as an example, the astounding replication in the laboratory of an artificial  coronal mass ejection (see top image).  This marked the first time ever solar researchers successfully generated an artificial coronal mass ejection in the laboratory as part of a plasma experiment. The researchers, Ha and Bellan, used a plasma gun in concert with an artificial strapping field to create their own flux ropes in their lab and from these CME-eruptions inside a vacuum chamber.  The strapping field itself  (that field which secures or holds back any emerging flux ropes) had to be carefully computed so that it decayed as a precise function of height. The reason is that the pair needed to generate the most likely instability - called the "torus instability". One self-consistent geometry is shown below as proposed by proposed by DeMoulin and Titov.

Assume then the detailed toroidal structure is initially in equilibrium, what happens to trigger the torus instability? Well, according to one variation proposed by Yuhong Fan, the configuration becomes unstable to an expansion  D R, when the toroidal radius R attains a critical dimension relative to the separation of the charges +q and -q.

Specifically, one will be looking at the decline of the potential field   B _q  with R and when it becomes critically deep.   This is evaluated using a decay index with torus instability occurring when the condition holds:

n = - d ln B _q   / d ln R > 1.5

In respect of their CME -generating experiment, Ha and Bellan would likely have taken these considerations into account to a suitable scale to create their strapping magnetic field that decays with increasing altitude.

The point here is that the replication basis of the model as well as the demonstration could easily be checked for self-consistency and adherence to the physical principles. 

Incredibly, despite this, we are informed by Horgan :

"But physics, which should serve as the bedrock of science, is in some respects the most troubled field of all. ...Over the last few decades it has become increasingly disconnected from empiircal evidence."

He then makes the mistake of citing the "proponents of string and multiverse"  conjectures - which of course grab most of the highlights in the corporate press.   But what about the Parker Solar Probe launched Aug. 12 which will provide us new and hitherto imagery and insights into the dynamic nature of our nearest star?  He doesn't mention that space mission at all. Nor the fantastic discoveries of hundreds of exoplanets by the Kepler telescope.

Nor the recent huge success of the Cassini -Huygens mission to Saturn.

Cassini-Huygens changed the game when it found complex hydrocarbons on Saturn’s ocean moons, hinted at hydrothermal vents on Enceladus, and revealed a cycle of liquid methane on Titan. The bottom line is, ocean worlds encapsulated by ice are now more propitious targets in the broader search for life beyond Earth.

If Horgan would have also taken the time and trouble to peruse recent issues of Physics Today he'd have born witness to dozens of new,  empirically validated discoveries, which seldom make the news like string theory or multiverse conjectures.  These have included:

'Isotope Measurements Help Pin Down The Ancient Rise Of Oxygen' (June, p. 16)

'First direct views of attosecond electron-nuclear coupling' (p. 17)

QED experiment detects two distinct photons simultaneously resonant with an optical cavity  (and with one of two electronic transitions of the same atom)  (August, p. 14)

'Use of Xenon isotopes to track volatile recycling in Earth's mantle' (October, p. 14)

'Acoustic metasurface creates quiet locations in a room' (August, p. 18)

Granted, none of these are especially 'sexy'  or exotic but all give the lie to Horgan's claim that physics has somehow become unmoored from empirical evidence.  The error made by Horgan? Focusing too much on the attention -headline grabbing stuff as opposed to the more prosaic but equally important findings.

Because of this selective attention he also commits the logical error of fallacy of composition:  attributing to the whole a characteristic or property that only applies to a part. Hence, concluding erroneously all of physics is somehow "troubled" because he perceives certain deficiencies in two exotic areas.  (Which he also egregiously describes as "modern physics" when string theory and multiverse concepts are only a part, and a very speculative part at that.)

Never mind, Horgan's 'Debby Downer' take, there is plenty in modern science- and certainly in physics-  to enlist and attract the best minds, and fuel their continued curiosity. 

Kepler Finds 715 New Planets - Does It Mean A Greater Probability Of Life On Them? No

Two representations of 603 exoplanets around Sun-like stars found up to the end of 2013. The data are plotted with planet radius (R) vs. orbital period in days - P (a), and against stellar irradiation flux (b) (From Physics Today, January)

The news that the Kepler telescope has found 715 new planets is now making the general media rounds, but many outlets seemed to have jumped the gun and extrapolated from these a "higher possibility of life being found". This isn't true at all. As I noted in a previous blog post, one of the most critical first objectives  - to assess for an "Earth-like planet",  is to obtain the periodicity or the time it takes the planet to circle its Sun. This is based on the fact that with the period, one can determine a planet's distance, i.e. from Kepler's 3rd law, see e.g.
http://brane-space.blogspot.com/2011/08/solution-to-simple-astronomy-problems-6.html

If then the period is too short,  a planet will be too close to its host star, never mind it may have the mass or radius of Earth. Then it can't really be called "Earth like" in the strict technical sense of actually being a place one could survive.  With those limitations in mind, Geoffrey Marcy of the University of California, Berkeley and Andrew Howard of University of Hawaii, last year reported an analysis of 603 planets (found via Kepler)  orbiting Sun-like stars, including with a few having periods longer than 300 days.

Bear in mind the Earth's orbital period is 365 days so any exoplanets with P > 300 days are of major interest since they could mark a genuine Earth-like planet, i.e. which could actually be colonized one day. This makes the Marcy-Howard research especially significant given they also corrected for observational biases and limitations, and restricted their searches to stars less than 3,000 light years away - with low photometric noise and Sun-like surface temperatures, or around 11,000 F.

But at the end of the analysis, a core of only one single planet of the 603 was adjudged to be in any way "livable". (Which still doesn't mean anything actually inhabits it)  This was identified within the small green inset box (from 10 plausible initial candidates) seen in the graph (b) at the right. (Plotting the radius vs. stellar irradiation flux.)  The candidate planet met the key criteria for in occurring in the vicinity of stellar flux  F_o = 1 and planetary radius R =1 (determining the acceleration of gravity g) .

 NASA on Wednesday announced the discovery of 715 new planets, but of these only four were designated as existing in any habitable zone.  The 715 planets were found to orbit 305 different stars, and were discovered by the Kepler space telescope using a new technique called "verification by multiplicity".  It relies in part on the logic of probability. Instead of searching blindly, the team focused on stars that the technique suggests are likely to have more than one planet in their orbit.

Let's examine briefly an assay of the planets thus far discovered. According to NASA, 95% of the planets discovered by Kepler are smaller than Neptune, which is four times as big as Earth. With such large radii, and likely accompanying density, none of them are plausible habitable worlds.

Meanwhile, one of the new planets is about twice the size of Earth and orbits a star half the size of Earth's sun in a 30-day cycle. This again eliminates it as being habitable based on the Kepler harmonic law. It would be too close to its parent star, hence too hot.  The other three planets in habitable zones also are all roughly twice the size of Earth, again likely making their gravity too great for any life to evolve.

Of course, more observations are needed, and planetary astronomers expect to find a higher percentage of new planets that could potentially have a life-supporting climate like Earth's.

But still, the best approach is not to get ahead of ourselves. While the more than 1,700 new planets discovered is exciting to be sure it doesn't mean that any of them harbor any life forms.  We have a plethora of planets, thanks to Kepler, but so far zero evidence for life on any of them.

Finding a "Second" Earth? We Better Make the Best of THIS One!

Two representations of 603 exoplanets around Sun-like stars. The data are plotted with planet radius (R) vs. orbital period in days - P (a), and against stellar irradiation flux (b) (From Physics Today, January)

In  recent TIME article ('Finding A Second Earth') we learn that Harvard lecturer Lisa Kaltenegger is busy modeling previously discovered exoplanets. Of coure, many astronomers are also doing this. What's different with Kaltenegger is her incorporation of data about our own Earth: its meteorology, geology and volcanology......plus its history. The point is, our own planet - seen by any alien civilizations, would look very differently depending on the time point it was being observed. For example, the Earth observed 3.9 billion years ago, would have appeared very differently - as a brownish globe with an atmosphere mostly of hydrogen sulfide (the rotten egg smelling gas), CO2 and nitrogen.

Data collected by hypothetical advanced aliens-  using many of the same methods we're using today - i.e. parsing exoplanets' atmospheres during transits of their parent stars,  likely would have concluded an inhabitable world - never mind its placement in a "habitable" zone.  (Assuming the observing aliens have roughly the same biology)

Now, in terms of recent advances, we're actually able to discern the approximate number of livable, Earth-like worlds - from a photometric record of some 43,000 stars observed using the Kepler telescope. Launched in March, 2009, Kepler's primary mission was to continuously monitor  large numbers of stars over long periods to in search of the very slight dimming that indicates the repeated transit of an exoplanet across the face of its host star.

One of the most critical parameters to obtain - to assess for an Earth-like planet, is the periodicity or the time it takes the planet to circle its Sun. This is based on the fact that with the period, one can determine a planet's distance, i.e. from Kepler's 3rd law, see e.g.
http://brane-space.blogspot.com/2011/08/solution-to-simple-astronomy-problems-6.html

If then a planet is too close to its host star, never mind it may have the mass or radius of Earth, then it can't really be called "Earth like" in the strict technical sense of actually being a place one could survive.  With those limitations in mind, Geoffrey Marcy of the University of California, Berkeley and Andrew Howard of University of Hawaii, recently reported an analysis of 603 planets orbiting Sun-like stars, including with a few having periods longer than 300 days.

Bear in mind the Earth's orbital period is 365 days so any exoplanets with P > 300 days are of major interest since they could mark a genuine Earth-like planet, i.e. which could actually be colonized one day. This makes the Marcy-Howard research especially significant given they also corrected for observational biases and limitations, and restricted their searches to stars less than 3,000 light years away - with low photometric noise and Sun-like surface temperatures, or around 11,000 F.

To perform their automated searches they used a software package called TERRA - developed by Marcy's grad student Erik Petigura. The program cleansed the photometric records of suspected outliers, intrinsic stellar variations, and a variety of other systematic errors.  Incredibly, Petigura next vetted by eye thousands of records for which the program found transit evidence - to weed out any anomalies due to instrumental or cosmic ray effects.

The team also eliminated any candidates with binary companions with radii (measured by the depth of the dimming during transit  trough) that exceeded 20 times the Earth's radius. (The fractional dimming of a star of radius R* during transit of a planet with radius R(p) is (R(p)/R*)²

The graphic shown gives the Marcy-Howard final sample of 603 planets, plotted in two distinct graphs, with (a) showing planet radius vs. orbital period in days (P) and graph (b) plotting the radius vs. stellar irradiation flux. (Note: uncertainties in stellar size, diameter contribute to uncertainties in both R* and the stellar flux F_p.)

Figure (b) is perhaps the more crucial graphic, with the stellar flux F_p  calculated from the orbital separation and the star's intrinsic luminosity (which is determined from its surface temperature and area (deduced from radius), see e.g. http://brane-space.blogspot.com/2011/09/tackling-intermediate-astronomy_22.html

The solar flux ( F_o ) at Earth's mean distance from the Sun (1 A.U. = 1.5 x 10 ¹¹ m )  is 1.36 kW/ m²  for reference.  The green patch in (b) contains those few candidates occurring in Earth-like habitable zones, with fluxes limited to 0.25 - 4F_o   and with planet sizes 1-2 R.  

So  how many of those 603 planets might actually be livable habitats for Earthlings? As it turns out not very many! Inside the green box one counts 10 in all. But....in the vicinity of stellar flux  F_o = 1 and planetary radius R =1 (determining the acceleration of gravity g) we find exactly one candidate planet. Given the photometric uncertainty (vertical-horizontal crosses on right side of (b) even this candidate could conceivably be knocked out.

The takeaway? We had better be good stewards of this planet and not look afar for colonizing opportunities (assuming we reach the level of starship builders and don't blow ourselves up, squander all our resources on stupid wars, or perish in a greenhouse holocaust). At the rate we are going, consuming the equivalent of 1.5 Earths every year, the future isn't promising.

The Planetary Parade Continues

News of NASA's Kepler's telescope and its planetary findings continues to fascinate many, as more and more Earth-like planets are reported. Most recently, astronomers have reported for the first time the discovery of two Earth-sized planets, one of which (Kepler 20f) is almost the exact same size as Earth, and the other (Kepler 20e) is about 4/5 its radius. The pair were discovered between three much brighter planets orbiting a star designated as Kepler 20 in a solar system 1,000 light year distant. That means its light has taken 1,000 years to reach us and also when Kepler observes these planets now, or their sun, it is seeing them as they were in our year of 1011, when the Inquisition was barely being planned and no printed books yet existed.

On the downside, both planets appear much too hot to expect the emergence of any Earth-type carbon based life, and they may lack water or a normal atmosphere as well. Kepler 20f 's orbit is so near its star that its year lasts only 19.5 days or 0.053 Earth years. Using Kepler's 3rd law this leads to a distance of only about 0.14 AU or 13 million miles. By comparison with our system, the planet Mercury is about 36 million miles from the Sun and parts of its surface are hot enough to melt lead! Meanwhile, Kepler 20e is so close that its period is only 6.1 days or 0.017 yrs. so its distance works out to slightly over 6 mllion miles. Roast much?

Despite the unearthly conditions, Kepler astronomers are still confident that they will eventually detect one or more worlds that have very nearly Earth-like conditions as well as physical properties. After all, the odds are with them. Kepler is designed (see graphic attached) with ultra-sensitive photometers - to detect and analyze the slightest light variations- to look for any planets around 156,000 stars orbiting within 3,000 light years.

As the graphic shows, the craft can determine a number of key parameters, including:

- Planet size (from how much the light of the star dims when the planet passes in front)

we call this the "light curve" during partial eclipse and use it also for binary stars along with radial velocity curves, see e.g.

http://brane-space.blogspot.com/2011/09/solutions-to-intermediate-astronmoy-7.html

- - The size of the planet's orbit - calculated by the interval between dips of light during the "eclipse"

- The planet's temperature, computed from the orbital size (e.g. using semi-major axis a) and the temperature of its star (found from its spectrum)

Say the given planet is found to reflect a certain fraction A of light from its star, and hence must absorb (1- A) and that the "solar constant" of the star (amount of radiation arriving at the planet) is k, then the energy absorbed would be:

E(A) = (1 - A) πR^2 x k/ a^2

where R is the radius and a the mean distance from its star

Setting this equal to the stellar luminosity:

(1 - A) πR^2 x k/ a^2 = 4 π R^2 oT^4

enables one to work out the effective temperature T, where o = 5.67 x 10^-8 Wm^-2 K^-4, the Stefan-Boltzmann constant). Then:

T = {(1 - A) x k/ 4π a^2x o}^¼

- The star's surface temperature, meanwhile, was discussed in a previous blog in conjunction with its luminosity, e.g.

http://brane-space.blogspot.com/2011/09/solutions-to-intermediate-astronomy-9.html


The good news is more than 2,000 so-called exoplanets have been found. The bad news is we are still looking for that specific Earth-type planet that not only possesses similar gravity and size, mass, but also the distance from its star to put it in the 'Goldilocks zone" for life as we know it.