One of our Elders, Elder MJ, has a fascinating family tree. We’re going to focus on Elder MJ‘s mother, Lupita, born in the Mexican state of Chihuahua in 1913. Today we’ll start with the big picture and drill down a bit.
1913 – The Drill-Down
The Universe
On January 1, 1913, the universe was approximately 13.8 billion years old. The universe had settled in for the long haul – atoms formed around BB+ 380,000 years, followed by stars and galaxies, followed by many generations of stars, each building on the materials of the earlier stars, finally creating all the wonderful elements we enjoy today.
But over the last 113 years, since Lupita’s birth, not a lot has changed, big-picture-universe-wise. But a lot was going on in the universe’s middle-aged day-to-day. As Elder G says: “During the single year 1913, countless stars would have formed across the observable cosmos and enormous numbers would have died. Galaxies would have merged. Black holes would have fed. Photons that had already traveled for billions of years continued silently across space.”
Interestingly, at the time of Lupita’s birth, humanity didn’t know that galaxies existed! Astronomers thought the entire universe was contained in the Milky Way.
Elder G:
September 17, 1912 Only 106 days before our chosen date, astronomer Vesto Melvin Slipher, working at Lowell Observatory in Arizona, had exposed the photographic plate from which he would determine the radial velocity of the Andromeda “nebula.”
He was beginning a program of measuring Doppler shifts of spiral nebulae. Over subsequent years, Slipher discovered that most of them showed enormous recession velocities. Those observations would eventually become crucial evidence in the discovery of cosmic expansion.
Astronomers could see beautiful spiral objects such as Andromeda, but there was fierce disagreement over what they were. Were these comparatively nearby structures within our own stellar system, or enormously distant “island universes” comparable to the Milky Way?
Early 20th century astronomers discussing the red-shift phenomena and the implications for the possibility of galaxies outside the Milky Way: this was a big moment for humanity!
One of the greatest discoveries in the 20th century was made by one of today’s lesser-known scientists, a man called Vesto Slipher. When we hear the term red shift or the expanding universe many people automatically associate those concepts with Edwin Hubble, the famous pioneer who in the 1920s found a straight-line correlation between galactic distance and velocity of recession, since known as the Hubble Law.
I’ve been writing about astronomy and science since I was three feet tall. Literally. Well, I started by copying. During my elementary school years in Brentwood, California, I used to write long passages from our Book of Knowledge encyclopedia and the Almanac about astronomy and fascinating people like Edward Pickering and the ladies of the Harvard College Observatory and what they had discovered about stellar spectra.
I especially like to probe the past’s nagging issues that kept natural philosophers awake at night, to better understand history. I use mathematics to try to ‘get into their heads’ and follow their logic. After all, mathematics – particularly geometry – is a shared language with the past.
In October 1923, Edwin Hubble used the newly constructed 100-inch Hooker Telescope at Mount Wilson, California—then the largest telescope in the world—to photograph the outer spiral arms of the Andromeda Nebula (M31). Hubble spotted what he initially thought were novae on glass photographic plates. Comparing plates taken over consecutive nights, he realized one star repeatedly faded and brightened every 31.4 days. He crossed out the letter “N” (for nova) on his plate and wrote “VAR!” in red ink.
Applying Leavitt’s period-luminosity relation, Hubble calculated that this star—and therefore Andromeda—lay roughly 900,000 light-years away (later recalibrated to about 2.5 million light-years).
Elder G
Astronomy Picture of the Day: 2011 July 1 In the 1920s, examining photographic plates from the Mt. Wilson Observatory’s 100 inch telescope, Edwin Hubble determined the distance to the Andromeda Nebula, decisively demonstrating the existence of other galaxies far beyond the Milky Way. His notations are evident on the historic plate image inset at the lower right, shown in context with ground based and Hubble Space Telescope images of the region made nearly 90 years later. By intercomparing different plates, Hubble searched for novae, stars which underwent a sudden increase in brightness. He found several on this plate and marked them with an “N”. Later, discovering that the one near the upper right corner (marked by lines) was actually a type of variable star known as a cepheid, he crossed out the “N” and wrote “VAR!”. Thanks to the work of Harvard astronomer Henrietta Leavitt, cepheids, regularly varying pulsating stars, could be used as standard candle distance indicators. Identifying such a star allowed Hubble to show that Andromeda was not a small cluster of stars and gas within our own galaxy, but a large galaxy in its own right at a substantial distance from the Milky Way. Hubble’s discovery is responsible for establishing our modern concept of a Universe filled with galaxies.
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
Henrietta Leavitt (by Elder G)
What are the Odds?
Let’s say you were a time traveler, and you could randomly go to any date in the past. What are the odds that you would land in the time between Lupita’s birth and now?
How does that compare with winning the Powerball? You are more almost 2 1/2 times likely to end up in this 113 year timeframe than win the Powerball!
The Milky Way
The Milky Way, big and beautiful in the clear night sky of 1913 Chihuahua, had been around for a long time. As Elder G summarizes:
On January 1, 1913, the Milky Way was already a mature barred spiral galaxy about 13 billion years old, containing on the order of 100–400 billion stars. Its stellar disk was roughly 100,000 light-years across, embedded in a much larger halo of dark matter. At its center sat Sagittarius A*, the roughly four-million-solar-mass supermassive black hole we know today.
Elder G
But our solar system is never at rest, and has been traveling around the galactic center at roughly 230 km/s. Since 1913, we’ve traveled about 820 billion kilometers, or about 5,500 AU, or 0.087 light-years around the Milky Way.
Bev, our HR manager, declined to fill out the mileage reimbursement form.
Where were all eight planets when Lupita was born?
Elder G explains: Yes. If we freeze the Solar System at 00:00 UTC on January 1, 1913, we get a wonderfully lopsided little family portrait.
For consistency, I’m describing each planet by its heliocentric ecliptic longitude, meaning its direction as seen from the Sun, measured around the plane of Earth’s orbit from the direction of the March equinox. Modern ephemerides can reconstruct planetary positions this far back with excellent precision; JPL Horizons is the standard public system for this sort of calculation.
Planet
Position around Sun
Distance from Sun
Mercury
193.4°
0.409 AU
Venus
29.95°
0.724 AU
Earth
99.99°
0.983 AU
Mars
251.8°
1.493 AU
Jupiter
267.7°
5.257 AU
Saturn
62.0°
9.074 AU
Uranus
303.3°
19.799 AU
Neptune
114.5°
29.980 AU
Those numbers become more intuitive if we translate them into the old zodiac divisions of the ecliptic:
Mercury: 13.4° Libra
Venus: 29.95° Aries
Earth: 10.0° Cancer
Mars: 11.8° Sagittarius
Jupiter: 27.7° Sagittarius
Saturn: 2.0° Gemini
Uranus: 3.3° Aquarius
Neptune: 24.5° Cancer
That does not mean those planets necessarily appeared in those zodiac constellations from Earth. This is the view looking down upon the Solar System from above its north pole, with the Sun at the center.
A few things jump out.
Earth was near perihelion
Earth was only about 0.983 AU from the Sun, almost its minimum orbital distance. That’s exactly what we’d expect in early January, since Earth reaches perihelion around January 3.
So when 1913 opened in Chihuahua, Earth was traveling at nearly its maximum orbital speed, close to 30.3 km/s. Lupita entered the world aboard a planet that was flooring it.
Mars and Jupiter were almost lined up
This is particularly nice. Mars was at: 251.8°while Jupiter was at: 267.7°, only about 16° apart as viewed from the Sun. They weren’t physically close, of course. Mars was about 1.5 AU from the Sun and Jupiter more than 5 AU. But in our overhead portrait they occupy roughly the same sector of the Solar System.
Earth and Neptune were pointing roughly the same way
Earth: 100.0° Neptune: 114.5° Only about 14.5° apart in heliocentric longitude.
Again, Neptune was nearly 30 times Earth’s distance from the Sun, so this resembles two people standing along approximately the same compass bearing, one across the room and the other somewhere beyond Amarillo.
Saturn was off by itself
Saturn sat at about 62°, while Jupiter was around 268°. So the two gas giants were widely separated around the Sun. They were nowhere near one of their roughly 20-year Jupiter-Saturn conjunctions.
Uranus and Neptune were nowhere near each other
Uranus was around 303°. Neptune was around 115°. That’s almost opposite sides of the Solar System, separated by roughly 171°.
And because those planets move so slowly, this is one area where our 1913 snapshot really differs from today’s Solar System. Neptune requires about 165 years to make one circuit of the Sun, Uranus about 84 years, Saturn about 29½, and Jupiter about 11.86.
Mercury, meanwhile, would regard our painstaking January 1 photograph as hopelessly obsolete by lunchtime.
And Pluto?
Here’s a lovely historical footnote. On January 1, 1913, humanity knew about eight planets: Mercury through Neptune. Pluto existed, of course, minding its own frozen business, but nobody had discovered it yet. Clyde Tombaugh wouldn’t identify Pluto until 1930.
So our modern phrase “all eight planets” happens, amusingly, to produce the same planet count an astronomer in 1913 would have given, although for completely different reasons. They had eight because Pluto hadn’t been discovered. We have eight because Pluto has been reclassified as a dwarf planet.
The Earth
(text by Elder G)
Geological time: the Holocene
In 1913 Earth was about 4.54 billion years old, in the Cenozoic Era, Quaternary Period, Holocene Epoch. More specifically, under today’s formal geological timescale, it was in the Meghalayan Age, which began about 4,200 years ago.
The last great glacial period had ended roughly 11,700 years earlier. Agriculture, cities, writing, Rome, medieval Europe, and industrial civilization had therefore all appeared during one extraordinarily brief warm interglacial.
Plate tectonics was doing its patient work. In 113 years, typical plates moving a few centimeters annually have shifted only a few meters.
So Chihuahua in 1913 and Chihuahua today are, geologically speaking, sitting in virtually the same chair.
The continents were already where we recognize them
But run Earth’s tectonic clock backward far enough and Chihuahua becomes a traveler.
Two hundred million years ago, the continents were assembled into Pangaea. The Atlantic did not yet exist as the ocean we know. North America subsequently separated from Africa and Europe as the Atlantic opened. Much later, tectonic extension helped produce the Basin and Range landscape of northern Mexico and the southwestern United States.
By 1913, though, the familiar world map was essentially complete. Africa and South America were continuing to separate. India was pressing into Asia and helping raise the Himalayas. The Pacific basin was being consumed around many of its margins. California was sliding northwest along the San Andreas system.
The Earth beneath the newborn child in Santa Bárbara looked permanent. It wasn’t. It was simply moving too slowly for humans to notice.
Astronomically, Earth was between ice ages
Now we encounter one of the grand clocks: the Milankovitch cycles. Earth’s climate is influenced over tens to hundreds of thousands of years by changes in its orbit and orientation:
Cycle
Approximate timescale
What changes
Eccentricity
~100,000 years
Shape of Earth’s orbit
Obliquity
~41,000 years
Tilt of Earth’s axis
Precession
~19,000–23,000 years
Direction Earth’s axis points
These cycles redistribute sunlight geographically and seasonally and help pace glacial and interglacial periods.
In 1913 Earth’s axial tilt was about 23.45°, slowly decreasing. We’re presently heading toward a smaller tilt, which by itself tends toward milder seasonal contrasts.
And precession was slowly turning Earth’s rotational axis. Polaris was the North Star in 1913, just as it is today, but it hasn’t always been and won’t always be.
Thirteen thousand years from now, the northern celestial pole will point toward an entirely different part of the sky.
Climate: an interglacial within an ice age
Here’s an important terminology distinction. Technically, Earth in 1913 was, and still is, in an ice age.That’s because permanent ice sheets exist at the poles. The Quaternary ice age began roughly 2.6 million years ago.
Within that ice age, however, Earth alternates between colder glacial periods and warmer interglacials. We are living in the Holocene interglacial. The great Laurentide Ice Sheet that once covered much of Canada and reached into today’s United States was long gone. But Antarctica and Greenland retained enormous ice sheets, and mountain glaciers were considerably more extensive than they are today.
And 1913 came just after the Little Ice Age
On a much shorter climate clock, the world was emerging from the generally cooler centuries commonly called the Little Ice Age, roughly the 14th through 19th centuries, although its timing and magnitude varied substantially by region.
By 1913 global temperatures had begun the transition toward the modern warming period, but the dramatic warming of the later 20th and early 21st centuries was still ahead.
Homo sapiens had existed for roughly 300,000 years. Our species had already spread across most habitable parts of Earth. The other surviving human species were gone. Neanderthals had disappeared roughly 40,000 years earlier.
Agriculture was only about 10,000–12,000 years old.
If we compare those numbers:
Earth: ~4,540,000,000 years Complex animals: ~600,000,000 years Dinosaurs: appeared ~230,000,000 years ago Non-avian dinosaurs disappear: 66,000,000 years ago Genus Homo: ~2,500,000+ years Homo sapiens: ~300,000 years Agriculture: ~12,000 years 1913 → today: 113 years
Earth’s rotation is gradually slowing, primarily because of tidal interactions with the Moon. The Moon, in turn, is slowly receding from Earth at roughly 3.8 centimeters per year today.
Over 113 years, that’s only about: 4.3 meters.
So when Elder MJ‘s mother was born, the Moon was approximately four meters closer to Earth than it is today.
The Timeline
13.8 billion years: Universe. ~13 billion years: Milky Way. 4.54 billion years: Earth. ~2.6 million years: Quaternary ice age. ~300,000 years: Homo sapiens. 11,700 years: Holocene. 1913: one human child is born.
Here is Lupita’s cosmic address:
January 1913 Santa Bárbara, Chihuahua, Mexico Planet Earth Solar System Orion Spur Milky Way Galaxy Local Group Universe, age approximately 13.8 billion years
Semi-Sequitor: 1913 CO2 Estimates (Elder G)
For 1913, a good estimate is about 300 ppm CO₂, give or take roughly 1–2 ppm. That estimate comes from Antarctic ice-core records, particularly the high-resolution Law Dome record. Those cores preserve ancient air bubbles and extend well into the 20th century; the published uncertainty is about ±1.2 ppm.
So when Elder MJ’s mother was born, humanity had already nudged atmospheric CO₂ upward by perhaps 20 ppm, or roughly 7%, above the preindustrial level. But most of the climb hadn’t happened yet:
~280 ppm → preindustrial ~300 ppm → 1913 ~316 ppm → 1958, around the beginning of continuous Mauna Loa measurements ~428 ppm → 2026
That gives us a rather vivid planetary marker for our 1913 portrait. Roughly three-quarters of the total CO₂ increase from preindustrial times to today occurred after she was born.
