Sagittarius Time Machine

The bright stars that outline our constellations beckon to us from a remarkably wide range of distances. Many of these stars are super-luminous giant stars and hot blue dwarf stars. More typical stars like our Sun—and the even more abundant red dwarf stars—are much too faint to see with our unaided eyes, unless they are only a few light years away. Thus many of the stars we see when we look up at the night sky are the intrinsically brightest ones, the “whales among the fishes.”

Trigonometric parallax directly provides us with the best estimate of the distance to each of these stars (provided they are not more than a few hundred light years away), and once you know the distance, it is easy to calculate when the light you are seeing tonight left each one of them. It is enjoyable to contemplate what was going on in Earth history when each star’s light began its long journey across interstellar space, the tiniest fraction of which is reaching your eyes as you look up on a clear night.

This article is the next in a series featuring the major stars of a prominent constellation. We turn now towards Sagittarius, which is currently crossing the celestial meridian at the end of evening twilight.

Below you will find a chart showing the constellation Sagittarius and the bright stars that define its outline. The official IAU-approved star names are listed, where available, or the Bayer designation. There’s a printer-friendly PDF version of this chart at the bottom of this article. There’s room for you to write in the year when the light we are currently receiving left the photosphere of each star, using the provided table (which is updated automatically to today’s date).

The “Teapot” asterism of Sagittarius

The table below contains all the relevant information. There are three tabs: Parallax, Distance, and Time. The first three columns of each tab show the star name, the Bayer designation, and the spectral type and luminosity class listed in SIMBAD.

On the Parallax tab, the parallax in millarcseconds (mas) is listed in column D, along with the uncertainty in the parallax in column E, and the year the parallax was published in column F. All are from SIMBAD. I will update these values as new results become available, but please post a comment here if you find anything that is not current, or is incorrect.

On the Distance tab, the parallax and parallax uncertainty for each star is used to calculate the range of possible distances to the star (in light years) in columns D through F. The nominal value given in column E is our current “best guess” for the distance to the star.

On the Time tab, the range of distances from the Distance tab are used to determine the range of years when the light we are seeing at this point in time would have left the star. The earliest year (given the uncertainty in parallax) is shown in column D, the most likely year in column E, and the latest year (given the uncertainty in parallax) in column F.

Here’s a printer-friendly PDF version of the Sagittarius chart where after printing you can enter the nominal year from column E of the Time tab next to the name for each star. The year values on the Time tab will update automatically to reference the current date.

Interest Connect

Make a list of your interests, either mentally or on paper. Are you curious about who else living in your area shares an interest with you? Wouldn’t it be nice if there were a safe online platform that would provide you with email addresses of others in your area who have a mutual interest so that you could exchange private emails? This might lead to a productive email exchange, meeting in person, forming an advocacy group, or working on a special project together. Two people or several. Your choice. And no advertising or marketing! I don’t think anything like this exists yet. Here’s my vision.

The name of the online platform will be Interest Connect.

A management organization (an independent non-profit entity or benefit corporation) will create and manage Interest Connect.

Each member will have a profile on the service that contains only the following basic information, viewable in its entirety only by the member and the management organization.

  • Your name (real name, no aliases)
  • Your email address
  • Your geographic region
  • Your interests

The list of geographic regions will be created and maintained by the management organization. The list will include the names of metro areas, subregions of metro areas, cities, towns, counties, and so on. Members can always ask for a new geographic region to be added. A member can only belong to one geographic region and will have no visibility into the other regions. There could, however, be visibility into levels of the same geographic region. For example: NW Tucson, Tucson, Pima County. Each member must provide proof of residency in their chosen geographic region by sharing their residential address with the management organization. That address will be independently verified, kept confidential, and will never be made public.

The management organization approves interest types and adds them to the list that members can select to add to their profile. There will be a large number of interests to choose from, and members can always ask for new ones to be added.

Some interests will be general, and others highly specialized.

Interest Connect is not a public discussion group, but a group to foster person-to-person private communication.  More than two members with the same interest could certainly arrange to communicate collectively amongst themselves via email.

As a member of Interest Connect, what would you see? You would see the names and email addresses of others in your geographic region that share the same interest as you.

Safety from predators is crucial, and the management organization will have complete authority to remove anyone from membership in Interest Connect that violates their terms and code of conduct.

Here’s a simplistic example showing four hypothetical individuals in the same geographic region. Interests A, B, C, D, E, F, and G are simply placeholders in our example for the actual interests that would be listed in Interest Connect.

Each member has a private profile that looks like this…

Marija Kelemen
mkeleme@gmail.com
Tucson, AZ
Interests: Interest A, Interest B, Interest C

Nikolaos Hubbard
nikhubb2@icloud.com
Tucson, AZ
Interests: Interest D, Interest E, Interest F

Slavica Brankovič
slavica2933@aol.com
Tucson, AZ
Interests: Interest B, Interest D

Aidan Storstrand
aidan.storstrand@outlook.com
Tucson, AZ
Interests: Interest B, Interest D, Interest G

Each member would have visibility into other members like this…

Marija would see the following:

Interest B
Slavica Brankovič: slavica2933@aol.com
Aidan Storstrand: aidan.storstrand@outlook.com


Nikolaos would see the following:

Interest D
Slavica Brankovič: slavica2933@aol.com
Aidan Storstrand: aidan.storstrand@outlook.com


Slavica would see the following:

Interest B
Marija Kelemen: mkeleme@gmail.com
Aidan Storstrand aidan.storstrand@outlook.com

Interest D
Nikolaos Hubbard: nikhubb2@icloud.com
Aidan Storstrand: aidan.storstrand@outlook.com


Aidan would see the following:

Interest B
Marija Kelemen: mkeleme@gmail.com
Slavica Brankovič: slavica2933@aol.com

Interest D
Nikolaos Hubbard: nikhubb2@icloud.com
Slavica Brankovič: slavica2933@aol.com


Each member’s interest lists will be dynamic, so that interests can be added or removed at any time. Perhaps notifications could be set up (optionally) so that if someone new adds one of your interests, you will automatically be notified.

How to fund this noble endeavor without resorting to hosting irritating advertising? Each member would pay a modest annual membership fee. No mandatory automatic renewals, please!

What do you think? Has something like Interest Connect already been done somewhere? Do you have suggestions or concerns? I would be interested in hearing your thoughts. Feel free to post a comment here.

Peculiar Neutron Stars

There’s a lot we don’t know about neutron stars. Neutron stars are the densest objects we can directly observe, and we have little understanding of how matter behaves under such extreme conditions. Though there are a lot of neutrons in neutron stars, they are not entirely made of neutrons. Whether the interiors of neutron stars contain something other than the known elementary particles is an open question.

The nearest neutron star we know of is RX J1856.5-3754 in Corona Australis, just below Sagittarius. It regales us at a distance between 352 and 437 light years, with the most likely distance being 401 ly. Though most neutron stars we know of are pulsars (a good example of observational selection—we tend to discover what is easiest for us to discover), this one is not.

In addition to its intrinsic properties, how a neutron star looks to us also depends upon its orientation and the environs with which it interacts. These three factors have led to a variety of nomenclature that requires some explanation.

Pulsar – a highly-magnetized, fast-rotating neutron star whose magnetic poles emit beams of electromagnetic radiation. If either of the beams sweeps past the Earth, we observe periodic pulses of electromagnetic radiation coming from the neutron star.

Magnetar – an extremely-highly-magnetized, more-slowly-rotating neutron star that produces bursts of X-rays and gamma rays. Only some magnetars are pulsars. Anomalous X-ray pulsars (AXPs) are now thought to be magnetars.

Rotating Radio Transients (RRATs) – a neutron star that is a pulsar, but with the peculiar property that it emits a single short-lived and extremely bright radio burst quasi-periodically with long lulls in between. The radio bursts last only 2 to 30 milliseconds, with intervals ranging from 4 minutes to 3 hours between pulses.

Soft gamma repeaters (SGRs) – a neutron star—possibly a type of magnetar—that emits large bursts of gamma-rays and X-rays at irregular intervals. If not a magnetar, it may be a neutron star with a disk of material in orbit around it.

Compact Central Objects in Supernova remnants (CCOs in SNRs) – a radio-quiet X-ray-producing neutron star surrounded by a supernova remnant. These have thermal emission spectra, and a weaker magnetic field than most neutron stars.

X-ray Dim Isolated Neutron Stars (XDINS) – an isolated, nearby (otherwise, it would be too faint to see) young neutron star. Only seven of these have been discovered to date (see The Magnificent Seven).

And that’s not all. Clearly, we have a lot more to learn about neutron stars.

There are currently about 3,200 known neutron stars, almost all of them pulsars, and all of them in our Milky Way galaxy and the Magellanic Clouds. About 5% are members of a binary system.

I know of no comprehensive catalog of neutron stars, but here is a catalog of pulsars:

ATNF Pulsar Catalogue
https://www.atnf.csiro.au/research/pulsar/psrcat/

A new and exciting frontier for exploring neutron stars is gravitational wave astronomy. All gravitational-wave observations to date have come from merging binaries consisting of black holes and neutron stars. Events include black hole – black hole mergers, neutron star – neutron star mergers, and neutron star – black hole mergers.


Three Pulsars of Note

The Fastest – PSR J1748-2446ad in the constellation Sagittarius is the fastest-spinning pulsar known, rotating once every 1.40 milliseconds, or 716 times per second (716 Hz). An educated guess at the neutron star’s radius (16 km) tells us that the equatorial surface is spinning at about 24% of the speed of light! PSR J1748-2446ad is located at a distance of about 18,000 ly in the globular cluster Terzan 5. Fortuitously, PSR J1748-2446ad is an eclipsing binary system with a bloated and distorted low-mass main-sequence-star companion.

The Slowest – PSR J0901-4046 in the southern constellation Vela is the slowest-spinning pulsar known*, rotating once every 75.886 seconds. It is located at a distance of approximately 1,300 ly.

The Most Massive – PSR J0952–0607 in the constellation Sextans is the most massive neutron star (2.35±0.17 M) known, and the second-fastest-spinning pulsar known (1.41 ms, 707 Hz). PSR J0952–0607 is located in a binary system with a (now) substellar-mass companion that has been largely consumed by the neutron star. The distance to this system is highly uncertain.

* The white dwarf in the red-dwarf – white-dwarf binary system AR Scorpii rotates once every 117 seconds, and is thought to be the only known example of a white-dwarf pulsar.

References

Liz Kruesi (2022, July 2). Slowpoke pulsar stuns scientists. Science News, 202(1), 8.
https://www.sciencenews.org/article/pulsar-radio-waves-neutron-star-astronomy

Govert Schilling (2022, July 28). Black widow pulsar sets mass record.
https://skyandtelescope.org/astronomy-news/black-widow-pulsar-sets-mass-record/

Dvořák – Symphony No. 8

Antonín Dvořák in 1890

Antonín Dvořák (1841-1904) was a remarkably talented composer, and though he is best known for his Symphony No. 9, “From the New World”, there is so much more to explore. Here is one writer, at least, who believes that his renown has not yet reached its peak.

One Dvořák compact disc that soars high above the crowd is the October 26, 1984 recording by the Cleveland Orchestra under Christoph von Dohnányi of Dvořák’s Symphony No. 8 and Scherzo capriccioso, released by Decca London in 1986. These are superlative performances.

This recording is still available through Presto Music, along with Dvořák’s other best symphonies, Nos. 7 & 9, and you might be able to find a copy of the original recording through Amazon, or elsewhere.

Dvořák composed and orchestrated his Symphony No. 8 in just two and a half months (August 26 to November 9) in 1889 at his summer resort in Vysoká u Příbramě, Bohemia (Czech Republic, today). The 8th is a high-energy work, cheerful and optimistic, with minor key excursions adding depth and emotional weight. Each of the four movements exhibit a tremendous variety of thematic material, much of it inspired by Bohemian folk music.

The first performance of the Symphony No. 8 in G major, op. 88 was on February 2, 1890 in Prague. During Dvořák’s extended stay in the United States, 1892-1895, he conducted the Exposition Orchestra (the Chicago Orchestra—later the Chicago Symphony Orchestra—expanded to 114 players) in a rousing performance of the 8th symphony and two other of his works at the 1893 Chicago World’s Fair. The August 12, 1893 performance was enthusiastically received by an audience estimated to number at least 8,000.

At that time, Dvořák’s symphonies were numbered in order of publication, and the first four were published after the last five, hence Symphony No. 4 = Symphony No. 8 today

Here are samples from each of the four movements, as performed by Christoph von Dohnányi conducting the Cleveland Orchestra in the fabulous recording recommended here.

Symphony No. 8 – Antonín Dvořák: I. Allegro con brio [excerpt]
Symphony No. 8 – Antonín Dvořák: II. Adagio [excerpt]
Symphony No. 8 – Antonín Dvořák: III. Allegretto grazioso [excerpt]
Symphony No. 8 – Antonín Dvořák: IV. Allegro, ma non troppo [excerpt]

This disc finishes out with another superb work by Antonín Dvořák, the Scherzo capriccioso in D♭ major, op. 66, written six years earlier in 1883. It also received its first performance in Prague, on May 16, 1883.

“Scherzo capriccioso” translates to “lively, playful character, with animated rhythm” (scherzo) and “capricious” (capriccioso). In other words, a capricious scherzo. And indeed it is—Enjoy!

Scherzo capriccioso – Antonín Dvořák [excerpt]

Scorpius Time Machine

The bright stars that outline our constellations beckon to us from a remarkably wide range of distances. Many of these stars are super-luminous giant stars and hot blue dwarf stars. More typical stars like our Sun—and the even more abundant red dwarf stars—are much too faint to see with our unaided eyes, unless they are only a few light years away. Thus many of the stars we see when we look up at the night sky are the intrinsically brightest ones, the “whales among the fishes.”

Trigonometric parallax directly provides us with the best estimate of the distance to each of these stars (provided they are not more than a few hundred light years away), and once you know the distance, it is easy to calculate when the light you are seeing tonight left each one of them. It is enjoyable to contemplate what was going on in Earth history when each star’s light began its long journey across interstellar space, the tiniest fraction of which is reaching your eyes as you look up on a clear night.

This article is the first in a series featuring the major stars of a prominent constellation. We turn now towards Scorpius, which is currently crossing the celestial meridian at the end of evening twilight.

Below you will find a chart showing the constellation Scorpius and the bright stars that define its outline. The official IAU-approved star names are listed, where available, or the Bayer designation. There’s a printer-friendly PDF version of this chart at the bottom of this article. There’s room for you to write in the year when the light we are currently receiving left the photosphere of each star, using the provided table (which is updated automatically to today’s date).

Scorpius

The table below contains all the relevant information. There are three tabs: Parallax, Distance, and Time. The first three columns of each tab show the star name, the Bayer designation, and the spectral type and luminosity class listed in SIMBAD.

On the Parallax tab, the parallax in millarcseconds (mas) is listed in column D, along with the uncertainty in the parallax in column E, and the year the parallax was published in column F. All are from SIMBAD. I will update these values as new results become available, but please post a comment here if you find anything that is not current, or is incorrect.

On the Distance tab, the parallax and parallax uncertainty for each star is used to calculate the range of possible distances to the star (in light years) in columns D through F. The nominal value given in column E is our current “best guess” for the distance to the star.

On the Time tab, the range of distances from the Distance tab are used to determine the range of years when the light we are seeing at this point in time would have left the star. The earliest year (given the uncertainty in parallax) is shown in column D, the most likely year in column E, and the latest year (given the uncertainty in parallax) in column F.

Here’s a printer-friendly PDF version of the Scorpius chart where after printing you can enter the nominal year from column E of the Time tab next to the name for each star. The year values on the Time tab will update automatically to reference the current date.

Children One or Zero

I have written about the overpopulation crisis before, but a Population Connection webinar on July 13 by Nandita Bajaj, Executive Director of Population Balance, motivated me to write more. Her presentation, Pronatalism and Rapid Population Growth: Challenging the Social Pressures to Have Children, was excellent and informative. I will post a link to her presentation in a comment as soon as it is available. Even though this article draws upon some of the material Nandita presented, what follows reflects my point of view alone.

The United Nations issued a report this week that announces that the world’s human population will surpass 8 billion people in mid-November 2022. Think about it. Later this year, 8 billion people will be living on this planet. The age of the Earth is 4.54 ± 0.05 billion years, so we have nearly two people currently living and consuming resources for every year this planet has existed. That’s a sobering thought.

Powerful forces of ignorance and misinformation are at work today that prevent us from adequately addressing a number of critical issues that—if we don’t act quickly—will result in a serious decline in the quality of life for most of the human race within the next few years. Chief among these is overpopulation, which is the primary driver of most of the other problems we are facing (climate change, environmental degradation, the decline in biological diversity, conflict over resources, and so on). Rather than feel powerless, or resign ourselves to a dystopian future, or take false solace in an afterlife that doesn’t exist, we must act. That is the only moral choice, and it gives our life meaning. What kind of a world do we want for ourselves and future generations? We must work towards building that world, no matter how difficult or protracted the effort.

As it is, we have commodified every possible part of the natural world to meet our insatiable needs. What could possibly go wrong?

The rapid increase in human population during the past couple of centuries is not normal. The Earth’s resources can sustain a world population of around 3 billion indefinitely, but we exceeded that limit in 1960. Since then, we have been living on borrowed time, all of us. And the debt is coming due. Techno-optimism isn’t going to save us.

The only humane way to get us back to 3 billion people is to reduce the birth rate. Having one child or none at all has to become the new normal. But the many facets of pronatalism are getting in the way of that.

Pronatalism is the idea that having children is both expected and a purely personal act.

Having children should never be incentivized . Many of us are ill-suited to be parents, and certainly living a deeply fulfilling life of great value to society does not depend upon bringing children into the world or child-rearing. And for those of us who do want children and are likely to be good parents, why not have one child, and no more?

Every child should be wanted, and born into a nurturing environment. Did you know we spend more money on imprisonment than we do on education in the U.S.? The right to contraception (including permanent contraception) and, yes, abortion are deeply personal human rights that must not be taken away by anyone. The idea that an embryo or fetus is somehow equivalent to a fully-formed human being is the opposite of rational: it is irrational. Many who oppose abortion do so for religious reasons. And such irrational considerations have no place in law or governance. Unfortunately, for many, religion is a “gateway drug” that predisposes one to holding other beliefs and opinions that are not supported by a shred of evidence. This is dangerous in the extreme.

The idea that having children is a purely personal act is also wrong. If you have more than two children, then you are directly contributing to unsustainable population growth and a certain increase in human suffering due to that growth. We talk the big talk about “personal freedoms” in this country, but almost never about “societal responsibilities” that must put limits on those freedoms. Freedom without responsibility is selfishness, plain and simple.

There are a number of pronatalism pressures that must be effectively countered. These include cultural pressures (e.g. “when are you going to get married and have children?”), religious pressures (e.g. more followers, “believers” vs. “non-believers”), economy-driven pressures (e.g. more consumers and workers), and political pressures (e.g. more taxpayers, more soldiers to fight in our endless wars).

“Baby-bust alarmism” is often in the news, and must be countered wherever it occurs.

And then there’s “great replacement theory”, which is the idea that “our” people are soon going to be outnumbered by other, less desirable, people. There’s an inherent racism in this idea. Often, people who sound the “underpopulation alarm” are really talking about underpopulation of white people.

We certainly have our work cut out for us, but we don’t have to change the minds and hearts of everyone to save humanity and our natural world. We only need to reach a critical mass of enlightened individuals to effect real and lasting change. And that may be a lot fewer than you think.

The greatest legacy we can leave our children is fewer children.

Constellations Old and New

The celestial sphere is a jigsaw puzzle with 88 pieces. The oldest piece is arguably the constellation Ursa Major, The Great Bear. Based on historical writings, prehistoric art, and the knowledge that this group of stars represented a bear in many cultures scattered throughout the world leads scholars to believe that this constellation was first described around 11,000 B.C., perhaps earlier.

The newest constellations are the 17 listed in the table below. Thirteen of these were invented by French astronomer Nicolas-Louis de Lacaille (1713-1762) during his stay at the Cape of Good Hope in 1751 and 1752, and the other four (Puppis, Pyxis, Vela, and Carina) are portions of the ancient enormous constellation Argo Navis, described by Ptolemy (c. 100 – c. 170). Though all of these constellations reside completely in the southern hemisphere of the sky (and thus can be best observed in the southern hemisphere), all but two of them (Mensa and Octans) have a portion that rises above the southern horizon as seen from Tucson, however scant and brief.

Newest Constellations

Constellation Description Declination
Puppis The Stern (of Argo Navis) -51˚ to -11˚
Pyxis The Compass (of Argo Navis) -37˚ to -17˚
Fornax The Laboratory Furnace -40˚ to -24˚
Antlia The Air Pump -40˚ to -25˚
Sculptor The Sculptor's Workshop -39˚ to -25˚
Caelum The Sculptor's Chisel -49˚ to -27˚
Microscopium The Microscope -45˚ to -27˚
Vela The Sail (of Argo Navis) -57˚ to -37˚
Horologium The Pendulum Clock -67˚ to -40˚
Norma The Carpenter's Square -60˚ to -42˚
Pictor The Painter's Easel -64˚ to -43˚
Telescopium The Telescope -57˚ to -45˚
Carina The Keel (of Argo Navis) -76˚ to -51˚
Reticulum The Net -67˚ to -53˚
Circinus The Compasses -71˚ to -55˚
Mensa The Table Mountain -85˚ to -70˚
Octans The Octant -90˚ to -74˚

Which (mostly) northern constellations were added last? Around 70 years prior to Lacaille, Johannes Hevelius (1611-1687) described the seven constellations in the table below. These constellations were first published posthumously in 1690.

Newest More Northerly Constellations

Constellation Description Declination
Lynx The Lynx +33˚ to +62˚
Lacerta The Lizard +35˚ to +57˚
Canes Venatici The Hunting Dogs +28˚ to +52˚
Leo Minor The Lion Cub +23˚ to +41˚
Vulpecula The Fox +19˚ to +29˚
Sextans The Sextant -12˚ to +6˚
Scutum The Shield -16˚ to -4˚

Let us now return to the oldest constellation, Ursa Major. The earliest extant literary work describing the constellations, including Ursa Major, is Phainómena by the Greek didactic poet Aratus (c. 315 BC – 240 BC). Phainómena is based on an earlier work by the Greek astronomer and mathematician Eudoxus of Cnidus (c. 408 BC – c. 355 BC), now lost. Earlier, the Greek poets Homer and Hesiod (~700 BC) mentioned the constellations, and we know that the Babylonians had a well-developed system of constellations (~2000 BC), as did the Sumerians even earlier (~4000 BC), later assimilated by the Greeks.

Here is what Aratus says in Phainómena about Ursa Major, in context.

The numerous stars, scattered in different directions, sweep all alike across the sky every day continuously for ever. The axis, however, does not move even slightly from its place, but just stays for ever fixed, holds the earth in the centre evenly balanced, and rotates the sky itself. Two poles terminate it at the two ends; but one is not visible, while the opposite one in the north is high above the horizon. On either side of it two Bears wheel in unison, and so they are called the Wagons. They keep their heads for ever pointing to each other's loins, and for ever they move with shoulders leading, aligned towards the shoulders, but in opposite directions. If the tale is true, these Bears ascended to the sky from Crete by the will of great Zeus, because when he was a child then in fragrant Lyctus near Mount Ida, they deposited him in a cave and tended him for the year, while the Curetes of Dicte kept Cronus deceived. Now one of the Bears men call Cynosura by name, the other Helice. Helice is the one by which Greek men at sea judge the course to steer their ships, while Phoenicians cross the sea relying on the other. Now the one is clear and easy to identify, Helice, being visible in all its grandeur as soon as night begins; the other is slight, yet a better guide to sailors, for it revolves entirely in a smaller circle: so by it the Sidonians sail the straightest course.

Between the two Bears, in the likeness of a river, winds a great wonder, the Dragon, writhing around and about at enormous length; on either side of its coil the Bears move, keeping clear of the dark-blue ocean. It reaches over one of them with the tip of its tail, and intercepts the other with its coil. The tip of its tail ends level with the head of the Bear Helice, and Cynosura keeps her head within its coil. The coil winds past her very head, goes as far as her foot, then turns back again and runs upward. In the Dragon's head there is not just a single star shining by itself, but two on the temples and two on the eyes, while one below them occupies the jaw-point of the awesome monster. Its head is slanted and looks altogether as if it is inclined towards the tip of Helice's tail: the mouth and the right temple are in a very straight line with the tip of the tail. The head of the Dragon passes through the point where the end of settings and the start of risings blend with each other.

A Planetary Crisis

On my recent Amtrak trip between Tucson, AZ and Alpine, TX, I caught up on some reading. The highlight of that reading was an article by Alexandra Witze entitled “A Planetary Crisis” in the March 12, 2022 issue of Science News (pp. 16-24). This is absolutely the best article I have ever read about the history of our scientific knowledge on the topic of human-induced climate change.

You can read the print edition of this article, or the version online.

One important point to call out. The Mauna Loa Observatory in Hawaii has been continuously monitoring atmospheric CO2 levels since March 1958, and the annual mean CO2 level has increased 31.8% between 1959 and 2021.

1959315.98 ± 0.12 ppm
2021416.45 ± 0.12 ppm
Annual Mean CO2 at Mauna Loa expressed as a mole fraction of dry air
(micromol/mol = parts per million = ppm)

And, most recently,

May 2021419.13 ppm
May 2022420.99 ppm

Alarmingly, the rate of increase is not linear.

We know that carbon dioxide is a potent greenhouse gas. And, as Witze’s article explains, that fact has been known since 1856.

One thing is crystal clear. Human activity (mostly the burning of fossil fuels) is causing the increase in the atmospheric concentration of carbon dioxide, and that is causing our planet to warm. We need to quickly and substantially reduce the amount of CO2 we are dumping into the atmosphere—or risk catastrophic consequences. I’m trying to do my part. We just installed rooftop solar panels that should generate most or all of the electricity we consume, including that required to power an electric car. As soon as I can get one (this fall?), I will be trading in my gasoline-powered car for an electric one.


By the way, I’ve been a subscriber to Science News for the past 50 years, and in my opinion there is no better newsmagazine covering all areas of science. If you aren’t already a subscriber, please consider becoming one.

Classical Music Exploration Club

You’ve heard of a book club, where people get together to discuss an assigned book that everyone in the group has read. Well, how about a music club? A music club would be a group of people who get together to listen to and discuss music. Unlike a book club, however, it wouldn’t be necessary for the participants to listen to the music prior to meeting.

I’d like to help start a Classical Music Exploration Club here in Tucson. We would need a place to meet that has decent audio equipment. We’d get together, say, once a month, and each month a member of the group would bring a favorite piece of music to share with the group. We’d all listen to the music, perhaps take some notes, and then discuss afterwards. The presenter-of-the-month would certainly have the opportunity to present information about the composer and the work both before and after the work is played.

I’m sure I’m not the only one in Tucson who is bursting at the seams with great music we’d love to share with others. Much of that music will be new and exciting for other members of the group, and that’s the idea. The pieces we’ve heard in live performance and even on the radio is but a small subset of all the great music that is out there, waiting to be heard and to be performed.

If you’d like to help me start a Classical Music Exploration Club here in Tucson (or elsewhere, for that matter), please post a comment here, or email me at doesper@icloud.com.


A little over a year ago, I created an online discussion group to showcase great classical music that is not currently available on CD. It is called Classical Music Little-Known Favorites and is on groups.io.

I realize that there probably aren’t a lot of people who are actively researching little-known works and composers, but it profoundly saddens me that after 15 months, our group only has three members, and I am the only one who has posted anything. Perhaps serious classical music enthusiasts are not familiar with groups.io, or the folks most likely to participate do not reside in the U.S., or they are not fluent in English, or…

Nothing would make me happier right now than to have at least one other person actively participating. Please join, or let others know about it.


A friend of mine recently told me (emphatically) that “Classical music is boring”. I told him that I agree that a lot of it is boring, but that there is so much that isn’t! He probably just hasn’t heard any of the “good stuff”. I grew up in the heady days for popular music in the 1960s and 1970s, and I still love a lot of rock and roll and “pop” music – especially from that era. But for me, popular music took a nosedive starting with the disco craze of the late 1970s, and since then I’ve turned increasingly towards classical music.

As much as I love rock and roll (especially The Beatles), the emotional response that that sort of music evokes in me is different than it is with classical music. When I listen to a great piece of rock music such as the medley at the end of Abbey Road, or Maybe I’m Amazed, it makes me feel happy, motivated, and alive. But only classical music can profoundly move me and bring tears to my eyes.


I’m at the age now where a lot of people I knew and admired in my youth are dying. Often, I’ll read an obituary of someone I worked with or casually knew outside of work, only to discover something fascinating about their background or an interest that we shared, and feeling sad that I never talked with them about x, y, or z.


It is so hard to get to know your neighbors these days. COVID-19 and its numerous variants, partisanship, and (for some of us) working remotely have acted to isolate us even further. Much of our interaction with other humans is of a superficial nature. This seems especially true for older adults. I now live in a large but beautiful gated community. It is obvious that a lot of thought and good planning went into designing it 20 years ago. And yet, we have a community swimming pool but alas no meeting room or common house.


Much to my delight, I now live in a neighborhood where the streets are well-maintained. Riding a bicycle is no longer a bone-jarring experience across “rubblized” pavement, as it was in Dodgeville (Wisconsin) and Alpine (Texas). Our HOA dues here are $43 per month, and much of that money goes towards resurfacing the streets every four years. As far as I’m concerned, it is money well spent. I wonder how many people living in Dodgeville or Alpine would be willing to pay a monthly fee of $43 per month (and probably less) to keep all their city streets in good condition?

Total Lunar Eclipse 2022 #1

The first of two total lunar eclipses this year visible from Tucson will occur conveniently this Sunday evening, May 15 (16 May 2022 UT).

Here are the local circumstances for Tucson, Arizona.

Time (MST)EventAltitude
7:06 p.m.Moonrise
7:28 p.m.Partial Eclipse Begins
8:29 p.m.Total Eclipse Begins14°
9:12 p.m.Greatest Eclipse21°
9:54 p.m.Total Eclipse Ends26°
10:56 p.m.Partial Eclipse Ends33°
11:30 p.m.Penumbra last visible?35°
11:51 p.m.Penumbral Eclipse Ends36°

There are few astronomical events as impressive as a total lunar eclipse, and we’ll have a front-row seat Sunday evening.

Every month, the full moon passes close to the Earth’s shadow, but because of the Moon’s tilted orbit it usually passes above or below the shadow cone of the Earth. This month is different!

Sunday evening, the Moon orbits right through the Earth’s shadow. At 6:32 p.m., the Moon dips his proverbial toe into the Earth’s shadow, when the Moon is still 7˚ below Tucson’s ESE horizon. This is the undetectable beginning of the eclipse, when the leading edge of the eastward orbiting-Moon “sees” a partial solar eclipse. When no part of the Moon sees anything more than the Earth blocking some but not all of the Sun, we call that a penumbral eclipse. The very subtle penumbral shading may just begin to be detectable around 7:00 p.m., but here in Tucson the Moon won’t even rise until six minutes after that.

When the partial eclipse begins at 7:28 p.m., the lower left edge becomes the first part of the Moon to “see” a total solar eclipse. In other words, from part of the Moon now, the Earth totally eclipses the Sun.

Totality begins at 8:29 p.m. when all of the Moon sees the Earth completely blocking the Sun. Mid-totality occurs at 9:12 p.m., when the center of the Moon is closest to the center of the Earth’s shadow. At that moment, the Moon’s color should be darkest.

That color is caused by sunlight refracting (bending) through the Earth’s atmosphere and shining on the Moon even though from the Moon the Earth is completely blocking the disk of the Sun. The reddish or orangish color imparted to the Moon during totality is the combined light of all the world’s sunrises and sunsets. What a beautiful thought! Had the Earth no atmosphere, the Moon would utterly disappear from view during totality—the time it is completely within the Earth’s umbral shadow.

Totality ends at 9:54 p.m., and the partial eclipse ends at 10:56 p.m. As the last vestiges of partial solar eclipse leave the Moon, the (penumbral) eclipse ends at 11:51 p.m.

This leisurely event can be enjoyed with the unaided eye, binoculars, a telescope, or all three. Don’t let anyone in the family miss seeing it!