Astronomy – Page 11 – Cosmic Reflections

Desiderata

The word desideratum has been a part of the English language since at least 1651, according to the Oxford English Dictionary, which provides this definition:

Something for which a desire or longing is felt; something wanting and required or desired.

This word comes from the Latin dēsīderātum “thing desired”, and its plural is desiderata.

The French astronomer Auguste Charlois (1864-1910) discovered the asteroid 344 Desiderata on 15 Nov 1892 at the Nice Observatory, in southeastern France near the border with Italy. Like most of his 99 asteroid discoveries between 1887 and 1904, it is named to honor a woman. In this case, that would be Désirée Clary (1777-1860), French woman who became Queen Desideria of Sweden.

On 25 Feb 2019, I recorded 14.1-magnitude 344 Desiderata passing in front of the 14.6-magnitude star UCAC4 639-020401 in the constellation Auriga. Right before the event, star and asteroid formed a 13.6-magnitude blended image, and when the asteroid covered up the star, the brightness dipped 0.5 magnitude to the brightness of the asteroid alone. This great cover-up event lasted 16.8 seconds. Here’s a light curve of the event as a function of time.

Light curve of asteroid 344 Desiderata passing in front of UCAC4 639-020401 in Auriga

That dip to the right (after) the asteroid covered up the star suggests that a smaller satellite of the asteroid might have also passed in front of the star. Alas, it is only noise. We can tell this by looking at the light curve of a nearby comparison star at the same time.

Wind gust caused a dip in brightness of both stars at the same time after the main occultation event

A view of just the comparison star clearly showing the dip in brightness from a wind gust

Here is the smoothed and fitted light curve of the asteroid occultation event.

Asteroid occultation of the star UCAC4 639-020401 by the asteroid 344 Desiderata on 25 Feb 2019

Max Ehrmann (1872-1945) wrote a prose poem Desiderata (Latin: “things desired”) in 1927 that has since become well known, and for good reason.

Desiderata

Go placidly amid the noise and the haste, and remember what peace there may be in silence. As far as possible, without surrender, be on good terms with all persons.

Speak your truth quietly and clearly; and listen to others, even to the dull and the ignorant; they too have their story.

Avoid loud and aggressive persons; they are vexatious to the spirit. If you compare yourself with others, you may become vain or bitter, for always there will be greater and lesser persons than yourself.

Enjoy your achievements as well as your plans. Keep interested in your own career, however humble; it is a real possession in the changing fortunes of time.

Exercise caution in your business affairs, for the world is full of trickery. But let this not blind you to what virtue there is; many persons strive for high ideals, and everywhere life is full of heroism.

Be yourself. Especially do not feign affection. Neither be cynical about love; for in the face of all aridity and disenchantment, it is as perennial as the grass.

Take kindly the counsel of the years, gracefully surrendering the things of youth.

Nurture strength of spirit to shield you in sudden misfortune. But do not distress yourself with dark imaginings. Many fears are born of fatigue and loneliness.

Beyond a wholesome discipline, be gentle with yourself. You are a child of the universe no less than the trees and the stars; you have a right to be here.

And whether or not it is clear to you, no doubt the universe is unfolding as it should. Therefore be at peace with God, whatever you conceive Him to be. And whatever your labors and aspirations, in the noisy confusion of life, keep peace in your soul. With all its sham, drudgery and broken dreams, it is still a beautiful world. Be cheerful. Strive to be happy.

Lyman-Alpha Forest

The Lyman-alpha transition occurs when an electron in a hydrogen atom transitions from the first excited state (n=2) to the stable ground state (n=1), emitting an ultraviolet photon at 1215.67 Å. This and the other Lyman transitions to the ground state are named after American physicist and spectroscopist Theodore Lyman (1874-1954) who discovered and studied these spectral lines.

About 75% of the mass of our universe is hydrogen, so when we look at a very distant object, such as a quasar, the light from that distant object passes through a large number of tenuous hydrogen clouds between us and the distant object. The cooler hydrogen clouds absorb ultraviolet light at a wavelength of 1215.67 Å, so this wavelength is “removed” from the light from a distant object, as evinced by an absorption line in the spectrum of the distant object. But because the intervening neutral hydrogen clouds are moving at different speeds and cosmological redshifts, a number of different wavelengths have light removed (as seen from Earth), resulting in what is known as a Lyman-alpha forest. Analysis of the Lyman-alpha forest can tell us much about the neutral hydrogen clouds between us and any distant extragalactic source.

When a hydrogen cloud atom absorbs a 1215.67 Å ultraviolet photon, its electron jumps from the n=1 ground state up to the n=2 first excited state. However, excited electrons can’t stay in the n=2 state for long, and quickly return to the ground state again, emitting a photon of light at 1215.67 Å. So, why do we even see an absorption line? Yes, ultraviolet photons from the distant extragalactic source are removed from our line of sight by an intervening hydrogen cloud, but when ultraviolet photons are re-emitted, the photons radiate in all directions, and only a few travel towards us along our line of sight. The net result is an absorption line.

Further reading:
Lyman-alpha forest
Gunn-Peterson trough

Cold Matters

Our current best estimate for the age of the universe (as we know it) is 13.799 Gyr ± 21 Myr. The Great Flaring Forth (GFF) occurred 13.8 billion years ago, and the universe has been expanding and cooling ever since.

The background temperature of the universe is today 2.72548 ± 0.00057 K. “K” stands for Kelvin, a unit of temperature named after William Thomson, 1st Baron Kelvin (1824-1907) – Lord Kelvin – who championed the idea of an “absolute thermometric scale”. A temperature in Kelvin is equivalent to the number of Celsius degrees above absolute zero. Put into terms we may be more familiar with, the cosmic background temperature is -270.42452° C, or -454.764136° F. While in the absence of nearby stars or other energy sources, the universe is certainly cold, scientists have artificially produced temperatures as low as 100 pK (1 picoKelvin = 10^-12 K).

Using Wien’s displacement law, we can calculate the wavelength of electromagnetic radiation where the background universe is brightest.

$\lambda _{max}=\frac{2.8977729\ \pm \ 0.0000017\ mm\cdot K}{T_{K}}=\frac{2.8977729\ \pm \ 0.0000017\ mm\cdot K}{2.72548\ \pm\ 0.00057 K}=\\1.0632\pm0.0002\ mm$

So, we see here that the background universe is “brightest” in the microwave part of the radio spectrum, at a peak wavelength around 1 mm. Using the relationship between frequency and wavelength, c = νλ, we can determine the microwave frequency where the background universe is brightest.

$\nu =\frac{c}{\lambda }=\frac{299,792,458\ m/s}{1.0632\times 10^{-3}\ m}=281.97\pm 0.05\ GHz$

Microwaves at this frequency are in the extremely high frequency (EHF) radio band, above all our allocated communications bands (275-3000 GHz is unallocated).

Of course, a significant amount of emission occurs either side of the peak, particularly at longer wavelengths and lower frequencies. (The background universe radiates with an almost perfect blackbody spectrum.)

There are several ways to define the wavelength/frequency of maximum brightness. The above is one. Depending on the method we choose, the peak wavelength lies between 1.0623 and 3.313 mm, and the peak frequency between 90.5 and 282.0 GHz.

Thank the Sumerians

Over five thousand years ago, the Sumerians in the area now known as southern Iraq appear to have been the first to develop a penchant for the numbers 12, 24, 60 and 360.

It is easy to see why. 12 is the first number that is evenly divisible by six smaller numbers:

12 = 1×12, 2×6, 3×4 .

24 is the first number that is evenly divisible by eight smaller numbers:

24 = 1×24, 2×12, 3×8, 4×6 .

60 is the first number than is evenly divisible by twelve smaller numbers:

60 = 1×60, 2×30, 3×20, 4×15, 5×12, 6×10 .

And 360 is the first number that is evenly divisible by twenty-four smaller numbers:

360 = 1×360, 2×180, 3×120, 4×90, 5×72, 6×60, 8×45, 9×40, 10×36, 12×30, 15×24, 18×20 .

And 360 in a happy coincidence is just 1.4% short of the number of days in a year.

We have 12 hours in the morning, 12 hours in the evening.

We have 24 hours in a day.

We have 60 seconds in a minute, and 60 minutes in an hour.

We have 60 arcseconds in an arcminute, 60 arcminutes in a degree, and 360 degrees in a circle.

The current equatorial coordinates for the star Vega are

α_2019.1 = 18^h 37^m 33^s
δ_2019.1 = +38° 47′ 58″

Due to precession, the right ascension (α) of Vega is currently increasing by 1^s (one second of time) every 37 days, and its declination (δ) is currently decreasing by 1″ (one arcsecond) every 5 days.

With right ascension, the 360° in a circle is divided into 24 hours, therefore 1^h is equal to (360°/24^h) = 15°. Since there are 60 minutes in an hour and 60 seconds in a minute, and 60 arcminutes in a degree and 60 arcseconds in an arcminute, it follows that 1^m = 15′ and 1^s = 15″.

Increasingly, you will see right ascension and declination given in decimal, rather than sexagesimal, units. For Vega, currently, this would be

α_2019.1 = 18.62583^h
δ_2019.1 = +38.7994°

Or, both in degrees

α_2019.1 = 279.3875°
δ_2019.1 = +38.7994°

Or even radians

α_2019.1 = 4.876232 rad
δ_2019.1 = 0.677178 rad

Even though the latter three forms lend themselves well to computation, I still prefer the old sexagesimal form for “display” purposes, and when entering coordinates for “go to” at the telescope.

There is something aesthetically appealing about three sets of two-digit numbers, and, I think, this form is more easily remembered from one moment to the next.

For the same reason, we still use the sexagesimal form for timekeeping. For example, as I write this the current time is 12:25:14 a.m. which is a more attractive (and memorable) way to write the time than saying it is 12.4206 a.m. (unless you are doing computations).

That’s quite an achievement, developing something that is still in common use 5,000 years later.

Thank the Sumerians!

ZZ Ceti Stars

About 80% of all known white dwarf stars have hydrogen atmospheres, showing only hydrogen absorption lines in their spectra. These have been assigned the white dwarf spectral type of DA (presumably D for dwarf and A for the first, or most common, type of white dwarf). Arlo Landolt (1935-) was the first to discover variability in a white dwarf by observing the m_v=15.0 DA white dwarf star named HL Tau 76 (not to be confused with HL Tau!), in front of a dark nebula in Taurus (LDN 1521C = MLB 3-13), in December 1964. This star now has the standard variable star designation V411 Tauri.

A second DA white dwarf, m_v=14.2 Ross 548 in Cetus, was discovered to be variable by Barry Lasker (1939-1999) and Jim Hesser in 1970, and in 1972 it was assigned the variable star designation ZZ Ceti.

By 1976, seven luminosity-variable DA white dwarfs had been discovered, and John T. McGraw and Edward L. Robinson stated in an ApJ paper

We suggest that the recently proposed ZZ Ceti class of variable stars be reserved for the DA variables in Table 1 and specifically exclude the DB variables since the mechanism of variation is almost certainly different.

McGraw & Robinson, Astrophysical Journal, Vol. 205, p. L155-L158 (1976)

So, why wasn’t this new class of luminosity-variable DA white dwarfs named after V411 Tau, the first of its class discovered? Why are they called ZZ Ceti stars, after the second such star discovered, instead? In each constellation, variable stars are given one- or two-letter designations in order of discovery, and when the letter designations run out, the letter “V” is used followed by a number. The first “V” star is V335, the 335th variable star to be discovered in a constellation. Well, V411 Tau was the 411th variable star discovered in Taurus, and as a matter of tradition, no class of variable stars is ever named after a “V” designation. So, the honor fell to the runner-up, ZZ Ceti. Besides, ZZ Cet is a little brighter than V411 Tau, so not a bad choice.

ZZ Ceti stars, also known as DAV stars (as in DA Variable), are multimodal pulsating white dwarfs having periods ranging from 70 seconds to 25 minutes. But the amplitude of the brightness variations is tiny to small, ranging from less than 0.001 magnitude up to 0.3 magnitudes.

V411 Tau has a dozen detected pulsation modes. In order of amplitude (in millimagnitudes), they are (without error bars):

Period (seconds)	Amplitude (mmag)
540.95	30.89
382.47	17.88
664.21	16.22
596.79	15.63
1064.97	12.27
781.0	9.88
492.12	7.73
449.8	7.27
976.38	7.01
799.10	5.63
1390.84	4.26
933.64	2.61

ZZ Cet has eleven detected pulsation modes. In order of amplitude, they are (without error bars):

Period (seconds)	Amplitude (mmag)
213.1326	7.119
274.2508	4.658
212.7684	4.448
274.7745	3.368
212.9463	1.477
274.5209	1.253
186.8740	0.9518
318.0763	0.7836
333.6447	0.6740
217.8336	0.3506
318.7657	0.3289

ZZ Ceti stars are not radial pulsators, that is they do not undergo radial oscillations (changes in size). White dwarf stars typically have diameters of only 0.9 to 2.2 that of the Earth, so they are much smaller than “normal” stars. As short as the pulsation periods are, they are not short enough if the cause were radial pulsations. Instead, the pulsations are due to shock waves traversing the atmosphere of the ultradense star. The slow rotation of these stars often causes closely spaced “double periods” such as we see in ZZ Cet.

The brightest (and closest) ZZ Ceti star yet discovered is DN Draconis, shining at visual magnitude 12.2. DN Dra pulsates with an amplitude of just 0.006 magnitude (6 millimagnitudes), and its pulsation period is 109 seconds.

What ZZ Ceti star has the largest amplitude? As they say, “it’s complicated”. Even though references to a maximum amplitude as high as 0.3^m can be found in the literature, I was unable to find any ZZ Ceti stars with amplitudes greater than 0.12^m. Moreover, pulsation modes of ZZ Ceti stars can come and go, so one observer may observe a higher amplitude but the next may not. Though pulsation modes can and do appear and disappear over time, there is also the changing additive nature of many pulsation modes to consider from one observing run to the next.

Patterson et. al (1991) report m_v=13.0 ZZ Psc having a pulsation amplitude of 0.116^m and period 614.9^s in blue light. Mukadam et al. (2004) report m_v=15.2 UCAC4 448-059643 (in the constellation Serpens) having a pulsation amplitude of 0.121^m and period 873.2^s in blue light.

One challenge in the literature is that pulsation amplitudes are variously given in units of milli-modulation amplitude (mma), milli-magnitudes (mmag), percent, or parts per thousand. Here are the unit conversions:

$1\:mma = \frac{1}{2.5\log_{10}e}\:mmag = 0.1\% = 1\:ppt$

The study of the pulsation modes of white dwarfs and other stars is called asteroseismology. I hope this article has piqued your interest in learning more about this rapidly developing and fascinating field!

References
Bognár, Z., Sódor, Á. 2016, Information Bulletin on Variable Stars,6184
Castanheira, B. G. & Kepler, S. O. 2008, MNRAS, 385, 430
De Gerónimo, F. C., Althaus, L. G., Córsico, et al. 2017, A&A, 599, A21
Dolez, N., Vauclair, G., Kleinman, S. J., et al. 2006, A&A, 446,237
Giammichele, N., Fontaine, G., Bergeron, P., et al. 2015, ApJ, 815, 56
Haro, G., and Luyten, W. J. 1961, Bol. Obs. Tonantzintlay Tacubaya, 3, 35
Kepler, S. O., Robinson, E. L., Koester, D., et al. 2000, ApJ, 539, 379
Kukarkin, B. V., Kholopov, P. N., Kukarkina, N. P., et al. 1972, IBVS, 717, 1
Landolt, A. U. 1968, ApJ, 153, 151
Lasker, B. M. & Hesser, J. E., 1971, ApJ, 163, L89
Lynds, B. T. 1962, ApJS, 7, 1
McGraw J. T. & Robinson E. L., 1976, ApJ, 205, L155
Mukadam, A. S., Mullally, F., Nather, R. E., et al. 2004, ApJ,607, 982
Myers, P. C., Linke, R. A., & Benson, P. J. 1983, ApJ, 264,517
Patterson, J., Zuckerman, B., Becklin E. E., et al. 1991, ApJ, 374, 330

A Warm Day on Pluto

The coldest weather I’ve ever experienced occurred January 30-31, 2019. Here in Dodgeville, Wisconsin, I measured a low temperature the morning of Wednesday, January 30, 2019 of -31.0° F and a high that day of -14.4° F. It was even colder the following night. On Thursday, January 31, 2019 the low temperature was -31.9° F.

Thanks to the National Weather Service, we had advance notice of the arrival of the Arctic polar vortex that was to bring the coldest weather to Wisconsin in a generation. Concerned about the effect this would have on my observatory electronics, I started running my warming room electric heater continuously from 8:30 p.m. CST Monday, January 28 until 9:45 a.m. CST Friday, February 1. Of course, I left the warming room door open to the telescope room to ensure that some of the heat would reach the telescope and its associated electronics.

During this time, I made a number of temperature measurements from an Oregon Scientific weather station inside the house, connected by 433 MHz radio frequency signals to temperature sensors inside the observatory and on the north side of my house.

Here are those observations:

Polar Vortex 2019 Download

And here is graph plotting both temperatures at each time:

Air (north side of house) and Observatory (inside the observatory) temperatures January 28-February 1, 2019.

And here is a plot of the temperature difference vs. the outside Air temperature:

Temperature difference vs. Air temperature with a linear regression line

There seems to be a general trend that the colder it was outside the observatory, the bigger was the temperature difference between inside the observatory and outside the observatory. Why is that? The electric heater is presumably putting out a constant amount of heat, so you might think that the temperature difference would remain more or less constant as the temperature goes up and down outside. It doesn’t.

There are a number of factors influencing the temperature inside the observatory. First, there is the thermal mass of the observatory itself, and some heating of the inside of the observatory should occur when the sun is shining on it. There is the wind speed and direction to consider. There may be some heating through the concrete slab from the ground below. It seems to me that thermodynamics should be able to explain the general downward trend in ΔT as the outside air temperature increases. Can you help by posting a comment here?

You’ll notice three outliers in the graph above where ΔT is quite a bit lower than the regression line. The points (-22.0,16.6) and (-10.5,10.1) were consecutive measurements just 76 minutes apart (8:32 a.m. and 9:48 a.m.), the first readings I made after the lowest overnight temperature of -31.9° F on 1/31. The point (8.2,7.6) was my first reading on 1/28 at 8:42 p.m., soon after turning the space heater in the observatory on. The points (-16.4,25.2), (-17.9,26.0), (-19.5,26.3), (-25.1,27.2), and (-26.9,27.4) all are above the regression line and are consecutive readings between 8:29 p.m. on 1/29 and 3:20 a.m. on 1/30 before the -31.0° F low on the first really cold night.

My weather station keeps track of the daily high and low temperatures, but not the time at which those temperatures occur. On 1/30 when the outside low temperature of -31.0° F was recorded, the low inside the observatory was -4.0° F (though not necessarily at the same time). ΔT = 27.0°. The high temperature that day was -14.4° F and 6.4° F inside the observatory (ΔT = 20.8°). The next night, 1/31, the low temperature was -31.9° F and -6.2° F inside the observatory (ΔT = 25.7°).

So, despite the many factors which influence the temperature differential between outside and inside the observatory, the clear trend of smaller ΔT at warmer outside temperature begs for an explanation. Can you help?

Turnkey System for Occultations

Finally, a turnkey system is available for recording stellar occultations by asteroids and trans-Neptunian objects (TNOs)! All you need besides the kit is a telescope and a PC. A big thank you to Ted Blank and IOTA for putting this together!

Occultation Recording Kit

Highly sensitive RunCam Night Eagle Astro Edition video camera
0.5x focal reducer & adapters to attach camera to 1¼-inch eyepiece holder
IOTA VTI (Video Time Inserter) V3
StarTech SVID2USB23 USB video capture device
Instruction manual
Cost: $518

https://occultations.org/observing/recommended-equipment/iota-vti/

We need more observers in the Midwest (everywhere, really) to give us more chords across the asteroids and TNOs, thus increasing the scientific value of the observations. Right now, we are desperately in need of observers in Iowa (where I lived for many years and will always be home to me), and we have precious few active observers in Wisconsin (yours truly), Minnesota (Steve Messner), and Illinois (Bob Dunford, Aart Olsen, Randy Trank).

If you have an interest in pursuing this interesting and rewarding speciality that gives you the opportunity to make a valuable scientific contribution, feel free to post a comment here and I’ll be happy to help!

Lost in Math: A Book Review

I recently finished reading a thought-provoking book by theoretical physicist Sabine Hossenfelder, Lost in Math: How Beauty Leads Physics Astray. Hossenfelder writes in an engaging and accessible style, and I hope you will enjoy reading this book as much as I did. Do we have a crisis in physics and cosmology? You be the judge. She presents convincing arguments.

The basic premise of Hossenfelder’s book is that when theoretical physicists and cosmologists lack empirical data to validate their theories, they have to rely on other approaches—”beauty”, “symmetry”, “simplicity”, “naturalness“, “elegance”—mathematics. Just because these approaches have been remarkably successful in the past is no guarantee they will lead to further progress.

One structural element that contributes to the book’s appeal is Hossenfelder’s interviews with prominent theoretical physicists and cosmologists: Gian Francesco Giudice, Michael Krämer, Gordon Kane, Keith Olive, Nima Arkani-Hamed, Steven Weinberg, Chad Orzel, Frank Wilczek, Garrett Lisi, Joseph Polchinski, Xiao-Gang Wen, Katie Mack, George Ellis, and Doyne Farmer. And, throughout the book, she quotes many other physicists, past and present, as well. This is a well-researched book by an expert in the field.

I also like her “In Brief” summaries of key points at the end of each chapter. And her occasional self-deprecating, brief, soliloquies, which I find reassuring. This book is never about the care and feeding of the author’s ego, but rather giving voice to largely unspoken fears that theoretical physics is stagnating. And an academic environment hell-bent on preserving the status quo isn’t helping matters, either.

Anthropic Principle

Do we live in a universe fine-tuned for life? If so, is it the only possible universe that would support life? Recent work indicates that there may be more than one set of parameters that could lead to a life-supporting universe.

Beauty is in the Eye of the Beholder

Is our sense of what is “beautiful” a reliable guide to gaining a deeper understanding of nature? Or does it sometimes lead us astray? We know from history that it does.

In the past, symmetries have been very useful. Past and present, they are considered beautiful

When we don’t have data to guide our theory development, aesthetic criteria are used. Caveat emptor.

Experiment and Theory

Traditionally, experiment and observation have driven theory. Now, increasingly, theory drives experiment, and the experiments are getting more difficult, more expensive, and more time consuming to do—if they can be done at all.

Inflation

The rapid expansion of the universe at the time of the Big Bang is known as cosmic inflation, or, simply, inflation. Though there is some evidence to support inflation, that evidence is not yet compelling.

Mathematics

Mathematics creates a logically consistent universe all its own. Some of it can actually be used to describe our physical universe. What math is the right math?

Math is very useful for describing nature, but is math itself “real”, or is it just a useful tool? This is an ancient question.

Memorable Quotations

“I went into physics because I don’t understand human behavior.” (p. 2)

“If a thousand people read a book, they read a thousand different books. But if a thousand people read an equation, they read the same equation.” (p. 9)

“In our search for new ideas, beauty plays many roles. It’s a guide, a reward, a motivation. It is also a systematic bias.” (p. 10)

On artificial intelligence: “Being unintuitive shouldn’t be held against a theory. Like lack of aesthetic appeal, it is a hurdle to progress. Maybe this one isn’t a hurdle we can overcome. Maybe we’re stuck in the foundations of physics because we’ve reached the limits of what humans can comprehend. Maybe it’s time to pass the torch.” (p. 132)

“The current organization of academia encourages scientists to join already dominant research programs and discourages any critique of one’s own research area.” (p. 170)

Multiverse

The idea that our universe of just one of a great many universes is presently the most controversial idea in physics.

Particles and Interactions

What is truly interesting is not the particles themselves, but the interactions between particles.

Philosophy

Physicists and astrophysicists are sloppy philosophers and could stand to benefit from a better understanding of the philosophical assumptions and implications of their work.

Physics isn’t Math

Sure, physics contains a lot of math, but that math has traditionally been well-grounded in observational science. Is math driving physics more than experiment and observation today?

Quantum Mechanics

Nobody really understands quantum mechanics. Everybody’s amazed but no one is happy. It works splendidly well. The quantum world is weird. Waves and particles don’t really exist, but everything (perhaps even the universe itself) is describable by a probabilistic “wave function” that has properties of both and yet is neither. Then there’s the many-worlds interpretation of quantum mechanics, and quantum entanglement…

Science and the Scientific Method

In areas of physics where experiments are too difficult, expensive, or impossible to do, some physicists seem to be abandoning the scientific method as the central pillar of scientific inquiry. Faith in beauty, faith in mathematics, faith in naturalness, faith in symmetry. How is this any different than religion?

If scientists can evaluate a theory using other criteria than that theory’s ability to describe observation, how is that science?

Stagnation

Some areas of physics haven’t seen any new data for decades. In such an environment, theories can and do run amok.

Standard Model (of particle physics)

Ugly, contrived, ad hoc, baroque, overly flexible, unfinished, too many unexplained parameters. These are some of the words used to describe the standard model of particle physics. And, yet, the standard model describes the elementary particles we see in nature and their interactions with extraordinary exactitude.

String Theory

String theory dates back at least to the 1970s, and its origins go back to the 1940s. To date, there is still no experimental evidence to support it. String theory is not able to predict basic features of the standard model. That’s a problem.

Triple Threat: Crises in Physics, Astrophysics, and Cosmology?

Physics: Sure, the Large Hadron Collider (LHC) at CERN gave us the Higgs boson, but little else. No new physics. No supersymmetry particles. Embarrassments like the diphoton anomaly. Do we need a bigger collider? Perhaps. Do we need new ideas? Likely.

Astrophysics: We’ve spent decades trying to understand what dark matter is, to no avail. No dark matter particles have been found.

Cosmology: We have no testable idea as to what dark energy is. Plenty of theories, though.

See Hossenfelder’s recent comments on the LHC and dark matter in her op-ed, “The Uncertain Future of Particle Physics” in the January 23, 2019 issue of The New York Times.

The book concludes with three appendices:

Appendix A: The Standard Model Particles
Appendix B: The Trouble with Naturalness
Appendix C: What You Can Do To Help

Hossenfelder gives some excellent practical advice in Appendix C. This appendix is divided into three sections of action items:

As a scientist
As a higher ed administrator, science policy maker, journal editor, or representative of a funding body
As a science writer or member of the public

I’m really glad she wrote this book. As an insider, it takes courage to criticize the status quo.

References
Hossenfelder, S., Lost in Math: How Beauty Leads Physics Astray, Basic Books, New York (2018).
Hossenfelder, Sabine. “The Uncertain Future of Particle Physics.” The New York Times 23 Jan 2019. https://www.nytimes.com/2019/01/23/opinion/particle-physics-large-hadron-collider.html.

Zodiacal Light 2019

In this year of 2019, the best dates and times for observing the zodiacal light are listed below. The sky must be very clear with little or no light pollution. The specific times listed are for Dodgeville, Wisconsin.

2019	Begin	End	Direction
Tue. Jan. 22	6:39 p.m.	7:03 p.m.	West
Wed. Jan. 23	6:40 p.m.	7:40 p.m.	West
Thu. Jan. 24	6:41 p.m.	7:41 p.m.	West
Fri. Jan. 25	6:42 p.m.	7:42 p.m.	West
Sat. Jan. 26	6:43 p.m.	7:43 p.m.	West
Sun. Jan. 27	6:44 p.m.	7:44 p.m.	West
Mon. Jan. 28	6:45 p.m.	7:45 p.m.	West
Tue. Jan. 29	6:46 p.m.	7:46 p.m.	West
Wed. Jan. 30	6:48 p.m.	7:48 p.m.	West
Thu. Jan. 31	6:49 p.m.	7:49 p.m.	West
Fri. Feb. 1	6:50 p.m.	7:50 p.m.	West
Sat. Feb. 2	6:51 p.m.	7:51 p.m.	West
Sun. Feb. 3	6:52 p.m.	7:52 p.m.	West
Mon. Feb. 4	6:53 p.m.	7:53 p.m.	West
Tue. Feb. 5	6:55 p.m.	7:55 p.m.	West
Wed. Feb. 6	7:09 p.m.	7:56 p.m.	West

Thu. Feb. 21	7:14 p.m.	8:14 p.m.	West
Fri. Feb. 22	7:15 p.m.	8:15 p.m.	West
Sat. Feb. 23	7:16 p.m.	8:16 p.m.	West
Sun. Feb. 24	7:17 p.m.	8:17 p.m.	West
Mon. Feb. 25	7:19 p.m.	8:19 p.m.	West
Tue. Feb. 26	7:20 p.m.	8:20 p.m.	West
Wed. Feb. 27	7:21 p.m.	8:21 p.m.	West
Thu. Feb. 28	7:22 p.m.	8:22 p.m.	West
Fri. Mar. 1	7:23 p.m.	8:23 p.m.	West
Sat. Mar. 2	7:25 p.m.	8:25 p.m.	West
Sun. Mar. 3	7:26 p.m.	8:26 p.m.	West
Mon. Mar. 4	7:27 p.m.	8:27 p.m.	West
Tue. Mar. 5	7:28 p.m.	8:28 p.m.	West
Wed. Mar. 6	7:30 p.m.	8:30 p.m.	West
Thu. Mar. 7	7:31 p.m.	8:31 p.m.	West
Fri. Mar. 8	8:01 p.m.	8:32 p.m.	West

Fri. Mar. 22	8:50 p.m.	9:24 p.m.	West
Sat. Mar. 23	8:52 p.m.	9:52 p.m.	West
Sun. Mar. 24	8:53 p.m.	9:53 p.m.	West
Mon. Mar. 25	8:54 p.m.	9:54 p.m.	West
Tue. Mar. 26	8:56 p.m.	9:56 p.m.	West
Wed. Mar. 27	8:57 p.m.	9:57 p.m.	West
Thu. Mar. 28	8:59 p.m.	9:59 p.m.	West
Fri. Mar. 29	9:00 p.m.	10:00 p.m.	West
Sat. Mar. 30	9:01 p.m.	10:01 p.m.	West
Sun. Mar. 31	9:03 p.m.	10:03 p.m.	West
Mon. Apr. 1	9:04 p.m.	10:04 p.m.	West
Tue. Apr. 2	9:06 p.m.	10:06 p.m.	West
Wed. Apr. 3	9:07 p.m.	10:07 p.m.	West
Thu. Apr. 4	9:09 p.m.	10:09 p.m.	West
Fri. Apr. 5	9:10 p.m.	10:10 p.m.	West
Sat. Apr. 6	9:12 p.m.	10:12 p.m.	West
Sun. Apr. 7	10:03 p.m.	10:13 p.m.	West

Thu. Aug. 29	3:39 a.m.	4:39 a.m.	East
Fri. Aug. 30	3:40 a.m.	4:40 a.m.	East
Sat. Aug. 31	3:42 a.m.	4:42 a.m.	East
Sun. Sep. 1	3:43 a.m.	4:43 a.m.	East
Mon. Sep. 2	3:45 a.m.	4:45 a.m.	East
Tue. Sep. 3	3:46 a.m.	4:46 a.m.	East
Wed. Sep. 4	3:48 a.m.	4:48 a.m.	East
Thu. Sep. 5	3:49 a.m.	4:49 a.m.	East
Fri. Sep. 6	3:50 a.m.	4:50 a.m.	East
Sat. Sep. 7	3:52 a.m.	4:52 a.m.	East
Sun. Sep. 8	3:53 a.m.	4:53 a.m.	East
Mon. Sep. 9	3:55 a.m.	4:55 a.m.	East
Tue. Sep. 10	3:56 a.m.	4:56 a.m.	East
Wed. Sep. 11	3:57 a.m.	4:57 a.m.	East
Thu. Sep. 12	4:52 a.m.	4:59 a.m.	East

Fri. Sep. 27	5:11 a.m.	5:18 a.m.	East
Sat. Sep. 28	4:19 a.m.	5:19 a.m.	East
Sun. Sep. 29	4:20 a.m.	5:20 a.m.	East
Mon. Sep. 30	4:21 a.m.	5:21 a.m.	East
Tue. Oct. 1	4:23 a.m.	5:23 a.m.	East
Wed. Oct. 2	4:24 a.m.	5:24 a.m.	East
Thu. Oct. 3	4:25 a.m.	5:25 a.m.	East
Fri. Oct. 4	4:26 a.m.	5:26 a.m.	East
Sat. Oct. 5	4:27 a.m.	5:27 a.m.	East
Sun. Oct. 6	4:29 a.m.	5:29 a.m.	East
Mon. Oct. 7	4:30 a.m.	5:30 a.m.	East
Tue. Oct. 8	4:31 a.m.	5:31 a.m.	East
Wed. Oct. 9	4:32 a.m.	5:32 a.m.	East
Thu. Oct. 10	4:33 a.m.	5:33 a.m.	East
Fri. Oct. 11	4:43 a.m.	5:34 a.m.	East

Sat. Oct. 26	4:51 a.m.	5:19 a.m.	East
Sun. Oct. 27	4:53 a.m.	5:53 a.m.	East
Mon. Oct. 28	4:54 a.m.	5:54 a.m.	East
Tue. Oct. 29	4:55 a.m.	5:55 a.m.	East
Wed. Oct. 30	4:56 a.m.	5:56 a.m.	East
Thu. Oct. 31	4:57 a.m.	5:57 a.m.	East
Fri. Nov. 1	4:58 a.m.	5:58 a.m.	East
Sat. Nov. 2	4:59 a.m.	5:59 a.m.	East
Sun. Nov. 3	4:01 a.m.	5:01 a.m.	East
Mon. Nov. 4	4:02 a.m.	5:02 a.m.	East
Tue. Nov. 5	4:03 a.m.	5:03 a.m.	East
Wed. Nov. 6	4:04 a.m.	5:04 a.m.	East
Thu. Nov. 7	4:05 a.m.	5:05 a.m.	East
Fri. Nov. 8	4:06 a.m.	5:06 a.m.	East
Sat. Nov. 9	4:07 a.m.	5:07 a.m.	East
Sun. Nov. 10	4:34 a.m.	5:08 a.m.	East

Sun. Nov. 24	4:23 a.m.	4:27 a.m.	East
Mon. Nov. 25	4:24 a.m.	5:24 a.m.	East
Tue. Nov. 26	4:25 a.m.	5:25 a.m.	East
Wed. Nov. 27	4:26 a.m.	5:26 a.m.	East
Thu. Nov. 28	4:27 a.m.	5:27 a.m.	East
Fri. Nov. 29	4:28 a.m.	5:28 a.m.	East
Sat. Nov. 30	4:29 a.m.	5:29 a.m.	East
Sun. Dec. 1	4:30 a.m.	5:30 a.m.	East
Mon. Dec. 2	4:31 a.m.	5:31 a.m.	East
Tue. Dec. 3	4:32 a.m.	5:32 a.m.	East
Wed. Dec. 4	4:33 a.m.	5:33 a.m.	East
Thu. Dec. 5	4:34 a.m.	5:34 a.m.	East
Fri. Dec. 6	4:35 a.m.	5:35 a.m.	East
Sat. Dec. 7	4:35 a.m.	5:35 a.m.	East
Sun. Dec. 8	4:36 a.m.	5:36 a.m.	East
Mon. Dec. 9	4:37 a.m.	5:37 a.m.	East
Tue. Dec. 10	5:29 a.m.	5:38 a.m.	East

The best nights to observe the zodiacal light at mid-northern latitudes occur when the ecliptic plane intersects the horizon at an angle of 60° or steeper. The dates above were chosen on that basis, with the Sun at least 18° below the horizon and the Moon below the horizon being used to calculate the times. An interval of time of one hour either before morning twilight or after evening twilight was chosen arbitrarily because it is the “best one hour” for observing the zodiacal light. The zodiacal light cone will be brightest and will reach highest above the horizon when the Sun is 18° below the horizon (astronomical twilight), but no less.

If you are interested in calculating the angle the ecliptic makes with your horizon for any date and time, you can use the following formula:

$\cos I = \cos \varepsilon \sin \phi-\sin \varepsilon \cos \phi \sin \theta$

where I is the angle between the ecliptic and the horizon, ε is  the obliquity of the ecliptic, φ is the latitude of the observer, and θ is the local sidereal time (the right ascension of objects on the observer's meridian at the time of observation).

Here’s a SAS program I wrote to do these calculations:

Zodiacal Light.sas Download

References
Meeus, J. Astronomical Algorithms. 2nd ed., Willmann-Bell, 1998, p. 99.

Total Lunar Eclipse 2019

We’ll be treated to a front-row seat for the total lunar eclipse this coming Sunday night and Monday morning, January 20/21, 2019! Here are the local circumstances for Dodgeville, Wisconsin.

Time (CST)	Event	Altitude
8:36:29 p.m.	Penumbral Eclipse Begins	40°
9:10 p.m.	Penumbra first visible?	46°
9:33:55 p.m.	Partial Eclipse Begins	50°
10:41:19 p.m.	Total Eclipse Begins	60°
11:12:18 p.m.	Greatest Eclipse	64°
11:43:18 p.m.	Total Eclipse Ends	66°
12:14:31 a.m.	Moon crosses the celestial meridian	67°
12:50:42 a.m.	Partial Eclipse Ends	66°
1:15 a.m.	Penumbra last visible?	64°
1:48:06 a.m.	Penumbral Eclipse Ends	60°

This is the first total lunar eclipse visible in its entirety from SW Wisconsin since September 28, 2015; the next such event won’t occur again until May 16, 2022. You’ll note in the table above, the Moon will be 64° above the horizon at mid-totality. The Moon has not been this high in our sky at mid-totality since November, 29, 1993 (66°), and it will not be this high again at mid-totality until January 21, 2048 (67°).

The first hint of shading will occur on the left (eastward-facing) edge of the Moon around 9:10 p.m. The first sliver of the full Moon enters the umbral shadow of the Earth at 9:33 p.m., so you’ll want to be watching by then. The entire Moon will be immersed in the umbral shadow of the Earth 67 minutes later at 10:41 p.m. This means that if you were anywhere on the nearside of the Moon you would see the dark Earth (except for city lights) completely covering the Sun, with a spectacular “ring of fire” all the way round the limb of the Earth refracting orangish-red light through our atmosphere—the combined light of all the world’s sunrises and sunsets at that moment.

This, of course, will continue as the Moon penetrates deeper into the umbral shadow of the Earth, reaching its closest to the center of the Earth’s shadow at mid-eclipse at 11:12 p.m.

The best place in the world to view this total lunar eclipse (assuming it is clear) will be Guantánamo Province in Cuba. Just 8 miles north of the municipality of El Salvador, Cuba, the Moon will be directly overhead at mid-eclipse.

There has been an unfortunate tendency of the mainstream media in recent years to use the term “Blood Moon” to describe a total lunar eclipse. Why must we use imagery so often associated with violence, death, and destruction in our discourse? The color of a total lunar eclipse depends upon the condition and transparency of the Earth’s atmosphere during the eclipse, and it can range from orange to coppery to red, and rarely even gray or brownish, so why not say orangish-red and leave it at that?