Observation, Theory, and Reality

We continue our series of excerpts (and discussion) from the outstanding survey paper by George F. R. Ellis, Issues in the Philosophy of Cosmology.

8.3 Limits of Representation and Knowledge of Reality
It follows…that there are limits to what the scientific method can achieve in explanatory terms.  We need to respect these limits and acknowledge clearly when arguments and conclusions are based on some philosophical stance rather than purely on testable scientific argument.  If we acknowledge this and make that stance explicit, then the bases for different viewpoints are clear and alternatives can be argued about rationally.

We human beings want so badly to be able to explain our existence and existence itself that we tend to “fill in the blanks” and treat speculation (no matter how well reasoned) as if it were something akin to fact.  This is true for both science and religion.  A more reasonable approach, it seems to me, is to reject absolute certainty—especially where physical evidence is sparse or nonexistent—while always striving to deepen our understanding.  That is the scientist’s stock-in-trade—or should be.  Each of us needs to become more aware of the limitations of our understanding!

Thesis F6: Reality is not fully reflected in either observations or theoretical models.
Problems arise from confusion of epistemology (the theory of knowledge) with ontology (the nature of existence): existence is not always manifest clearly in the available evidence.  The theories and models of reality we use as our basis for understanding are necessarily partial and incomplete reflections of the true nature of reality, helpful in many ways but also inevitably misleading in others.  They should not be confused with reality itself!

We humans create our own “realities”, but under the very best of circumstances (science, for example), our “reality” is only an imperfect model of what actually exists.

The confusion of epistemology with ontology occurs all the time, underlying for example the errors of both logical positivism and extreme relativism.  In particular, it is erroneous to assume that lack of evidence for the existence of some entity is proof of its non-existence.  In cosmology it is clear for example that regions may exist from which we can obtain no evidence (because of the existence of horizons); so we can sometimes reasonably deduce the existence of unseen matter or regions from a sound extrapolation of available evidence (no one believes matter ends at or just beyond the visual horizon).  However one must be cautious about the other extreme, assuming existence can always be assumed because some theory says so, regardless of whether there is any evidence of existence or not.  This happens in present day cosmology, for example in presentations of the case for multiverses, even though the underlying physics has not been experimentally confirmed.  It may be suggested that arguments ignoring the need for experimental/observational verification of theories ultimately arise because these theories are being confused with reality, or at least are being taken as completely reliable total representations of reality.

Absence of evidence is not evidence of absence.  But, without evidence, all we have is conjecture, no matter how well informed.  As Carl Sagan once said, “Extraordinary claims require extraordinary evidence.”

No model (literary, intuitive, or scientific) can give a perfect reflection of reality.  Such models are always selective in what they represent and partial in the completeness with which they do so.  The only model that would reflect reality fully is a perfect fully detailed replica of reality itself! This understanding of the limits of models and theories does not diminish the utility of these models; rather it helps us use them in the proper way.  This is particularly relevant when we consider how laws of nature may relate to the origins of the universe itself, and to the existence and nature of life in the expanding universe.  The tendency to rely completely on our theories, even when untested, seems sometimes to arise because we believe they are the same as reality—when at most they are descriptions of reality.

Ellis makes a pretty good case here against dogma.  Though he does not specifically mention religion (and why should he, as the subject at hand is cosmology), I do think these ideas apply to religion as well.

Always a journey, never a destination.

References
Ellis, G. F. R. 2006, Issues in the Philosophy of Cosmology, Philosophy of Physics (Handbook of the Philosophy of Science), Ed. J. Butterfield and J. Earman (Elsevier, 2006), 1183-1285.
[http://arxiv.org/abs/astro-ph/0602280]

Bike Ride to Ridgeway (and back)

Ridgeway, Wisconsin is a special place.  A point right on the central meridian of the Central Time zone and the 43rd parallel (90° W longitude and 43° N latitude) is within the city limits of Ridgeway, and you can almost get there from here.

The point 43° N, 90° W

You can easily bicycle to this location by taking the Military Ridge State Trail into the west side of Ridgeway and turning north onto Ternes Ct.  I wonder if there’s a marker along Ternes Ct. at its closest point to 43° N, 90° W. If not, we need to put one there.

Getting to the point 43° N, 90° W

But wait!  Right where Ternes Ct. intersects Bier St. and becomes a gravel road, there’s a sign that says “Game Farm, No Trespassing”.  Foiled!

You know, we should have regular bike rides from Dodgeville to Ridgeway and back along the Military Ridge State Trail.  Anyone interested?  The distance from the Wisconsin DNR parking lot in Dodgeville to Badger Mart right next to the trail in Ridgeway is 9.2 miles, so it would be an 18.4 mile round trip along pretty flat terrain.  Badger Mart in Ridgeway is a convenient place to stop for a snack and a beverage before heading back to Dodgeville, and they are open from 5:00 a.m. until 9:00 p.m. every day of the week.

Would love to see this trail receive an asphalt surface someday, but the existing screened limestone surface isn’t bad.

Please post a comment here or email me if you’re interested in making this ride with me from Dodgeville to Ridgeway and back!

Meteor Shower “Clumpiness”

Have you ever noticed while watching a major meteor shower like the Geminids, Perseids, or the Leonids (esp. 1997-2002) that meteors come in clumps?  Often, you’ll see a bunch of meteors over a period of one to five minutes, followed by several (sometimes many) minutes with nothing.  In other words, if a rate of 60 meteors per hour is predicted, that does not mean you will see a meteor each minute!  Not even close.  This indicates that the particles in a meteor stream are somewhat bunched together rather than evenly distributed in space.

I can’t tell you how often someone has told me that they went out to watch meteor shower x, y, or z and didn’t see a thing.  Invariably, when I ask “how long did you watch?” they say something like 5, 10, or 15 minutes.  That’s not long enough!  If you’re serious about seeing some impressive meteor activity you really need to be out for two hours minimum, at a time when the meteor shower radiant is above the horizon.  Look generally toward the radiant direction—unless the Moon is in your field of view, in which case you will want to look in a direction opposite the Moon.  You also need to be reasonably well dark-adapted, and that means—ideally—no terrestrial lights should be in your field of view that are brighter than the brightest stars.

Turn Down the Lights, Turn Up the Stars

We are presently witnessing a rapid transformation of our outdoor nighttime environment as many older lighting sources such as high pressure sodium, metal halide, and fluorescent are being replaced with solid state lighting, specifically light emitting diodes (LEDs).  Many of the lighting decisions being made today with little or no citizen input will have consequences that impact our nighttime environment for decades.

Rather than continuing to subscribe to the “more is better, dusk-to-dawn” approach to outdoor lighting, we need to utilize this new technology in creative and innovative ways (many already available) to improve our nighttime built environment while minimizing lighting’s deleterious effects on the natural world.  Three paradigm shifts are needed.

Paradigm Shift #1
Less light will usually work just fine (a little light goes a long way)

Paradigm Shift #2
Dusk-to-dawn lighting → Lighting on Demand

Paradigm Shift #3
Full intensity lighting → Multi-Intensity Lighting (dimmable)

When choosing the amount of light you need, one should always consider the task or tasks needing to be performed.  For example, the amount of light needed to identify a rural intersection is much less than is needed to play a baseball game at night.  In both cases, though, the light needs to be restricted to only the area needing to be illuminated: the intersection or the playing field.

Another example.  When my wife and I bought a house in Dodgeville, Wisconsin back in 2005, our front porch had a 100-watt frosted incandescent light bulb to light the porch that we could turn on whenever we had company in the evening.  Thinking it too bright, we replaced the 100-watt bulb with a 60-watt bulb, then tried a 40-watt bulb, and finally a 25-watt bulb.  The 25-watt bulb adequately illuminated the porch and the stairs leading up to the porch, so in it stayed.

Then there is the issue of dusk-to-dawn lighting.  Many years ago, we switched outdoor lighting on or off as needed, but technological advancements later allowed us to have a light come on at dusk and stay on all night until dawn.  Now, think of all those lights burning when no one is there to use them.  If security is a concern, there is even newer technology that will do a far more effective job of detecting intruders than simply leaving a light on all night long.  In fact, a dusk-to-dawn light is not needed at all as part of an effective security system.  So, why not use 21st-century technology to have outdoor lights automatically turn on when needed and turn off when not needed?  Some LED light bulbs even come now with integrated occupancy sensors.  Lighting on demand could and should be replacing most dusk-to-dawn lighting within the next few years.

What about some roadway and parking lot lighting that must remain on all night long?  Those lights could be at full brightness during times of high traffic such as during the evening hours, but dimmed to 50% when traffic is lower, such as after midnight.  Once again, 21st-century technology makes this easy to do.

LED lighting lends itself very well to frequent on-off switching and dimming, but much of what is currently being installed is too blue.  As you can see in the table below, typical LED light sources have a substantial “spike” at the blue end of the visible light spectrum as compared with other white light sources.

Not only does blue light scatter more in the atmosphere and within our eyes, but many people perceive bluish-white light as colder, more clinical, than the warmer white light where this blue spike is absent, as shown below.  The blue spike in LED lighting can be removed either by using filtering, or by using a different phosphor that gives a warmer white spectrum.  Strongly preferred for both indoor and outdoor lighting are LED light sources with a correlated color temperature (CCT) of 2700K or 3000K.  2700K is the standard for indoor lighting, and yet 4000K is most often used for outdoor lighting.  Why?  Let’s move the standard for outdoor lighting to 2700K or 3000K.

By properly shielding lights so they only shine downwards, by using lights that are no brighter (or bluer) than they need to be, and by turning lights off when they are not needed—or dimming them during times of lower activity—we all will be helping to improve both our natural and celestial environment.

Turn Down the Lights, Turn Up the Stars *

* Suzy Munday, May 11, 2018

Additional Thoughts

In thinking about 21st-century lighting, one’s thoughts naturally towards 21st-century power generation.  We do not think often enough about the many advantages of a more decentralized power grid, where nearly everyone is generating some power with solar panels and small-scale wind turbines, as well as other local sources of energy such as geothermal.   As we once again consider building nuclear power plants (which will still be quite vulnerable to terrorism) and continue to build expensive fossil fuelish power plants and ugly high-voltage transmission lines, why not a paradigm shift towards decentralized energy production instead?

Lovely Coma Berenices

One of the special joys of getting out under a dark rural sky this time of year is seeing the gossamer beauty of the surprisingly expansive star cluster called Melotte 111, also known as the Coma star clusterMel 111 makes up a large part of the constellation Coma Berenices, “Berenice’s Hair”.  This constellation, which entertains the North Galactic Pole as well as a gaggle of galaxies, can be found about midway between Denebola (some call the Coma star cluster the end of the “tail” of Leo the Lion) and Arcturus, as well as midway between Spica and the Big Dipper.  Coma Berenices is transiting the meridian this week as evening twilight ends.  At a distance of just 284 light years, the Coma star cluster is the third nearest star cluster to us, surpassed only by the open cluster remnant Collinder 285—the Ursa Major association (80 ly)—and the Hyades (153 ly).

One Good Shirt Deserves Another

Who hasn’t tried to replace an article of clothing when it finally wears out, only to find that it is no longer available?  When I find something I like, I like to stick with it—or at least something quite similar.  Increasingly, I am having a harder and harder time finding clothing I like.  Is it my age?

Take, for example, long sleeve shirts.  I like button-down dress casual shirts, but if you’re looking for a pattern shirt that doesn’t include blue, good luck.  Look at the shirt below.  It goes well with tan or brown pants, but I can’t find anything like it anywhere!  For such a basic style, this really surprises me.

Here’s a close-up showing the pattern:

So, the moral of the story is if you find an article of clothing you like, purchase another two of them right away, because there’s no guarantee it will be available (or of the same quality) in a couple of years when you’ll be wanting to replace it with something comparable.

Unless, of course, it is blue.

Interstellar Object 1I/2017U1 ‘Oumuamua

After years of searching and hypothesizing, we have finally discovered a macroscopic object passing through our solar system that came from interstellar space!  An elongated rocky object with approximate dimensions 755 × 115 × 115 ft. entered the solar system from the direction of the constellation Lyra at a velocity (v) of 26 km/s (16 mi/s or 58,000 mph), and will exit the solar system at essentially the same speed in the direction of the constellation Pegasus, within the Great Square.

This interstellar object (ISO) is called 1I/2017U1 ‘Oumuamua.  What’s in a name?  A lot!  Let’s separate the three different parts of this designation, discussing each in turn.

1I – “I” stands for “interstellar” and “1” indicates that it is the first interstellar solar system visitor discovered.

2017U1 – indicates that it was the first object discovered during the half-month October 16-31 in the year 2017.

‘Oumuamua [pronunciation] is a Hawaiian word for “scout”, reflecting how this object is like a scout or messenger reaching out to us from the distant past.

‘Oumuamua Enters the Solar System

Here’s a brief timeline of the encounter.

September 9, 2017 – Closest approach to the Sun (0.26 AU)

October 14, 2017 – Closest approach to the Earth (0.16 AU)

October 19, 2017 – Discovered by Robert Weryk with Pan-STARRS

It is very difficult for us to discover objects coming towards us from the inner solar system and the glare of the Sun, so it is not surprising that ‘Oumuamua was discovered after it had passed by the Earth on its way out of the solar system.

‘Oumuamua in the Inner Solar System
NASA Animation Showing ‘Oumuamua’s Journey Through the Inner Solar System
‘Oumuamua Exits the Solar System

Rob Weryk, a post-doc at the University of Hawaii Institute for Astronomy, discovered ‘Oumuamua in images taken by the Pan-STARRS1 1.8-meter Ritchey–Chrétien telescope at the summit of the dormant volcano Haleakalā on the island of Maui.  Pan-STARRS is an acronym for “Panoramic Survey Telescope and Rapid Response System” and is primarily used to search for Near Earth Objects (NEOs).  It has been estimated that Pan-STARRS should be able to detect an interstellar object like ‘Oumuamua passing through our solar system about once every 5 years.

But the 8.4-meter Large Synoptic Survey Telescope (LSST) in Chile, which will see first light in 2019, is expected to be able to detect at least one interstellar object passing through our solar system each year.

While we don’t know ‘Oumuamua’s place of origin, we do know that it originated outside our solar system, and that is exciting.  Was it ejected from a binary system?  Or through a chance encounter with a giant planet in its outer solar system?  Is it an “extinct” interstellar comet?  Perhaps it is a former asteroid of a dying star.  Even our own Sun, which is expected to reach a peak luminosity of 5200 L as a red giant star in a few billion years, will lose mass and transition to a white dwarf, causing a dynamical reshuffling that will eject a large number of asteroids, trans-Neptunian objects, and comets from our solar system (Seligman & Laughlin 2018).  Perhaps ‘Oumuamua long ago suffered a similar fate.

A detailed astrometric study (ground-based and HST) of ‘Oumuamua’s trajectory through the inner solar system has revealed a small non-gravitational acceleration component directed radially away from the Sun (Micheli et al. 2018).  After ruling out other known gravitational and non-gravitational accelerators, the authors conclude that the most probable explanation is cometlike outgassing, though ‘Oumuamua displayed no detectable coma during its all-too-brief apparition.  Astronomers expect that only a small fraction of interstellar objects should be asteroidal, and this study bolsters—but does not prove—the notion that ‘Oumuamua is an interstellar comet.

However, no change in the rotational state of ‘Oumuamua occurred during the month-long interval over which it was observed.  If the anomalous acceleration away from the Sun was caused by cometary activity, a measurable effect on ‘Oumuamua’s rotation should have been seen (Rafikov 2018).  This argues against the idea that ‘Oumuamua is an interstellar comet.

What, then, is the cause of the anomalous acceleration?  It is worth considering that ‘Oumuamua might be of artificial origin (Bialy & Loeb 2018) .  It could be a lightsail that long ago was ejected from its solar system of origin, and this interstellar debris just happened to encounter our solar system.  Or, perhaps, it is (or was) an operational space probe purposefully directed towards Earth’s vicinity by an alien civilization.  Incidentally, no radio emissions were detected from ‘Oumuamua (yes, we looked).

There may yet be some other explanation for the acceleration ‘Oumuamua experienced during its journey through our solar system.  Our experience with the Pioneer anomaly (now explained), or the still unexplained flyby anomaly, might lead us towards new insights.  The likelihood that ‘Oumuamua is a highly elongated and/or flattened object only adds to the mystery.

References
Bialy, S., Loeb, A. 2018, ApJL, in press (arXiv: 1810.11490)
McNeill, A., Trilling, D. E., Mommert, M. 2018, ApJL, 857, L1 (arXiv:1803.09864)
Micheli, M., Farnocchia, D., Meech, K.J., et al. 2018, Nature,
https://www.nature.com/articles/s41586-018-0254-4
Rafikov, R. R. 2018, arXiv preprint 1809.06389
Seligman, D. & Laughlin, G. 2018, AJ, in press (arXiv:1803.07022)

Howard Goodall

I first became familiar with British composer, musician, and music presenter extraordinaire Howard Goodall on August 7, 2017, when his documentary Sgt. Pepper’s Musical Revolution aired on Wisconsin Public Television.  As a lifelong Beatlephile who knows a thing or two about the Beatles and their music, I was immensely impressed with the quality and content of this documentary.  I especially liked his detailed analysis (vis-à-vis Alan W. Pollack) of what makes the music of the Beatles so extraordinary, and his obvious enthusiasm for the subject.  After watching this wonderful hour-long (yes, no commercials!) programme, I vowed to do two things:

  1. Purchase an official DVD copy of Sgt. Pepper’s Musical Revolution
  2. Find out more about Howard Goodall and his work

#1  Sad to say, periodic searches have only turned up bootleg copies from questionable sources.  When will the DVD finally be released?

#2  Somehow I missed it when it was originally broadcast on PBS, but I was delighted to find Howard Goodall’s Big Bangs available through Netflix, so I recently ordered it.

First broadcast in the UK in the autumn of 2000, Howard Goodall’s Big Bangs is a series of 50-minute documentaries on five transformative developments in the history of Western music.  They are

  1. Notation
  2. Equal Temperament
  3. Opera
  4. The Piano(forte)
  5. Recorded Sound

I just finished watching this series, and would highly recommend it for anyone interested in music history.

I enthusiastically look forward to other music documentaries by Howard Goodall.  After watching Sgt. Pepper’s Musical Revolution, I believe that he may well be the best person in the world to develop an entire documentary series on the music of The Beatles.  Here’s hoping!

There are those who say that if music has mass appeal it can’t also be music of great significance or depth. What The Beatles proved once and for all is that this idea is hopelessly and absurdly wrong. – Howard Goodall

There are very, very few composers in history whose work changed all the music that followed it: Beethoven was one, Wagner was another. I believe that posterity will add to their select ranks The Beatles. – Howard Goodall