Scorpius Time Machine

One remarkable aspect of looking up at the bright stars that outline our constellations is that those stars are often at vastly different distances. The super-luminous giant stars and the hottest blue dwarf stars can be seen much further away than the much more common cooler dwarf stars like our Sun. Because of this, when we look up at the night sky with the unaided eye, many of the stars we are seeing are of the super-luminous variety, the “whales among the fishes”.

Once you know the distances to these stars, 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 represents the first in a series that will feature the distances to the major stars of a prominent constellation. We begin with 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, where the white text boxes have room for you to write in the nominal year when the light we are currently receiving left the photosphere of each star. The base chart was generated using SkySafari 6 Pro.

Scorpius

Next you’ll find a table that 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 value in millarcseconds (mas) is listed in column D, along with the mean error of 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 error for each star is used to calculate the range of distance to the star (in light years) in columns D through F, with the nominal value given in column E being our current “best guess” for the distance to the star.

On the Time tab, the range of distance from the Distance tab are used to calculate 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 you can enter the nominal year from column E of the Time tab for each star. The year values on the Time tab will update automatically to reference the current date. I’ve used the “Replace Color” adjustment feature in Adobe Photoshop to lighten the background color so your printer will save on ink when printing out the full-page chart.

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.