We start, once again with Orion…but we move east (left) and south (down) a bit…at least as seen from the Northern Hemisphere, around midnight. Shortly after sunset, just look straight down. Follow the line of the belt stars towards the eastern horizon.

See that very bright star there? That’s Sirius. It’s the brightest star in the night sky, and I mentioned it in passing last time.

It’s almost on the Milky Way (you can see a faint suggestion of it in the picture). In the picture, up and to the left, is Procyon, and moving right from Procyon there’s a yellowish star, and that’s Betelgeuse. Those three stars form a nice equilateral triangle, and it’s known as the Winter Triangle. (I personally find Rigel to be bright enough to ruin the pattern, so it only works for me after Rigel has set, or if it’s covered by a cloud.)

Our OTHER star? It’s also right there.

Binary Stars

Most stars are actually parts of a star system, a group of stars that orbit each other. It could be two, three…even up to six stars. In fact, a triple-star system is the most common. From Earth, with its oddball one-star system, we cannot tell any star is a multiple star, without the aid of a telescope, but once we had telescopes (thank you Galileo), the truth became apparent, quickly.

Shades of Tattoine! That was a double star, and as you’ll remember, in Star Wars, they looked very similar; they basically just took a double image of our Sun.

In the real universe the stars rarely match that well.

The nearest star to us (other than the sun, of course) is Alpha Centauri; it is a triple. It has one star a bit more massive than the Sun, another one a bit less massive, orbiting their common center of gravity in very elliptical orbits (the closest distance is 11 AUs–about the distance between Saturn and the Sun, and the furthest is 36 AUs, more distant than Neptune is from the sun) every eighty years. There is a third star, very small and faint–too dim to be seen by the unaided or “naked” eye. It’s called Proxima Centauri. It’s estimated to be 12% of the mass of the Sun, and 1/20,000th as bright. (Remember, a more massive star is disproportionately bright, so a less massive star will be disproportionately dim.)

It’s about an eighth of a light year from the two big stars in the Alpha Centauri system. And right now it’s closer to us, in fact it is the closest star to the Sun. (And yet, we can’t see it.) If we could see it it would appear about four moon diameters away from Alpha Centauri.

(Digression. Step outside some clear night, and look up. Red dwarfs are the most common stars there are, roughly three quarters of all stars are red dwarfs. But not a single star that you can see is a red dwarf. They’re just too dim to be seen from far away without a telescope, or at the very least, binoculars. OK, end digression.)

That’s a not atypical situation for a multiple star system. Very different stars, elliptical orbits, and really not much chance that a planet could have a stable orbit in that mess (sorry, Star Wars fans). In fact the only known planet orbits Proxima Centauri–the other two stars are far enough away not to mess up that planet’s orbit.

So what does this have to do with Sirius?

Sirius, it turns out, is a binary star. The two stars in this tale are Sirius A and Sirius B. If you look towards one, you look towards both.

Sirius And History

Sirius, being the brightest star in the night sky, has been important to many ancient cultures, particularly the Egyptians. They would align their calendar to start on the day that Sirius becomes visible in the eastern sky just before sunrise (then, of course, gets blotted out again by the daytime). This is called the heliacal rising of Sirius. This was about July 19th on our current calendar. They’d then count off a year of 365 days, precisely. Never a leap day, never a leap year. So in a few years, the heliacal rising of Sirius would happen a day late. A few more years, another day. After 1,461 of these no-leap Egyptian years, they’d be lined up again, and the heliacal rising of Sirius would fall at the beginning of the year once again. This was the sothic cycle. And yes, Ancient Egypt was around long enough to experience at least two of these cycles, the first starting in 2781 BC. (There’s a tiny possibility that in fact the prior cycle was the first one, but that would push things back to 4241 BC, and most Egyptologists think that was 1100 years before the First Dynasty.) Now that is a long-lived country!

Sirius is the brightest star in the constellation Canis Major (the larger of Orion’s two hunting dogs–no word on whether they were Labs), so it’s sometimes called the “Dog Star.” And the “Dog Days Of Summer” get that name because…Sirius and the Sun are up at the same time during the summer, and some people actually thought Sirius contributed to the summer heat. Many simply associated Sirius with heat and drought.

The Polynesians, in the Southern Hemisphere, associated Sirius with winter and used it as a reference for navigating (and they were, and are, incredibly good navigators).

Sirius A

Sirius A is by far the brighter of the two stars.

In fact the first telescopes couldn’t see Sirius B at all; we thought it was a single-star system.

Sirius A is twice as massive as the Sun. Which, if you’ve been following along, means it is going to be more than twice as bright as the Sun. In fact, it’s twenty five times as bright. And its temperature is 9,940 degrees Kelvin, compared to our sun’s 5,572 K So basically, it ought to have 1/12th the lifetime of our sun since it’s burning a stock of fuel two times as big, but doing it 25 times faster.

Sirius’ age appears to be between 237-247 million years. That’s young for a star, by comparison our Sun comes in at about 4,600 million years.

Sirius is only 8.6 light years away, by contrast with Betelgeuse and Rigel from last time. This close distance and being the brightest star in the immediate neighborhood combine to make it the brightest star in the night sky, bar none.

Sirius is, in fact close enough that we can measure its distance directly. We do that by noting its position against the more distant stars at one end of our orbit, then doing the same six months later. Since Earth has moved about 300 million kilometers in that time, a nearer star should have shifted position against the background of more distant stars.

At a distance of 3.26 light years, that shift is two arc seconds, which is to say 2/60ths of 1/60th of a degree. The moon is 1800 times wider than this in the sky. That distance, where the earth’s orbit’s radius gives one arc second of parallax, is called a parsec, and it’s what astronomers use (they use light years when talking to non-astronomers; parsecs amongst themselves).

Sirius appeared to be a pretty typical large star, not hugely large, but any star larger than the sun is notable; small stars are much more common than large ones.

Sirius B

But one other thing they noticed as they studied Sirius–it wobbles. Over the span of about 50 years, it traces a small ellipse in the sky, one about the size of Uranus’ orbit. This was first noticed in 1844.

OK, so Sirius has some tiny little red dwarf companion, right? That would make sense, it’s so bright it would probably drown out a red dwarf.

Well, no.

One can tell how massive an object is, by watching things orbit it. And it became clear that whatever Sirius (A) was orbiting, was something the mass of the sun. And that’s too big to be a red dwarf. In fact, if there’s a star there, the mass of the sun, it should be as bright as the sun, and visible in a telescope. But there could be no doubt; Sirius and something half as heavy that should be visible, but wasn’t were orbiting each other around their common center of gravity.

This was a bit of a mystery.

But in 1862, Alvan Graham Clark had just made a telescope, an 18.5 inch refractor. It was the largest in the US, and one of the largest in the world. He had taken exacting care in grinding the lenses, and now he needed to test it. He’d do so by looking at stars, to see how sharp they were as points of light. Any flaw in his work would be apparent.

He pointed it at Sirius, and noticed a tiny fleck of light very close to Sirius. One can imagine the litany of four letter words that ran through his mind, but then he pointed it at other stars (plenty of other bright stars nearby…you can name just two of them, if you’ve read my prior post.) And there was no flaw visible with those stars.

It dawned on him that his optics weren’t bad. No. They were fantastic. He was been the first person to lay eyes on Sirius B!

It turned out that now people knew what to look for, smaller telescopes could see it, and less than two months later, his discovery was confirmed by other instruments.

Sirius B, it turned out, is very, very tiny. It got nicknamed “The Pup” to go with the “Dog Star.” And it is very, very hot! 25,000 Kelvins, hotter than Rigel. Something that hot glows with X rays, and you can see in the picture above that Sirius B is much more conspicuous in X rays.

If you know the temperature (from looking at the spectrum, which someone managed to do in 1915 after blotting out Sirius A) and the brightness, you can figure out the size.

Sirius B is the size of the Earth. In fact it’s actually a tiny bit smaller than Earth.

Say what!?

OK, so far, when talking about stars, I’ve compared their mass to the Sun’s mass. So it might not be apparent how ridiculous this seemed.

How about we compare it to the Earth? Sirius B and the Sun are roughly the same mass, and the Sun is…330,000 times as massive as the Earth.

So Sirius B packs 330,000 times the Earth’s mass…in a sphere the size of the Earth.

Think about that. On average, a cubic centimeter of the earth weighs about 5.5 grams. (Your typical surface rock is about 3 grams per cubic centimeter; the iron core raises the average to 5.5 grams.)

A cubic centimeter of Sirius B would have to average about 1.8 million grams. Or about two tons.

Set that cubic centimeter on dirt, and it’d probably just sink into the ground.

Okay, this is one weird star. It is a “white dwarf,” a small star (one solar mass) with the surface temperature you’d expect from a much bigger star, and very, very dense. As it turns out it’s one of the most massive white dwarfs…there’s a strict upper limit on their size.

It breaks the rules for “Main Sequence” stars, like the Sun, and Sirius A, and Rigel (and all three stars of the Alpha Centaur system). Betelgeuse is not on the “Main Sequence,” but it seems to be different in opposite ways, bloated instead of compact, cool instead of very, very hot.

But the thing about the Main Sequence is, it’s where the stars that are “burning” hydrogen for fuel are.

A star that is not on the Main Sequence is not burning hydrogen, and Sirius B isn’t on the main sequence. No white dwarf is.

So what’s the story?

Sirius B is a dead star.

It’s not fusing hydrogen. It ran out. It didn’t go supernova either–it wasn’t massive enough.

It started out about 5 times the mass of the sun. It and Sirius A were “born” at the same time about 240 million years ago, but, being more massive than Sirius A, Sirius B ran out of hydrogen about 120 million years ago, and became a red giant, burning helium.

It produced plenty of carbon, and some oxygen, and most of the outer layers of the star basically boiled off, too hot to be retained. (Some of that matter probably ended up becoming part of Sirius A.) This sort of thing happens a lot to these sort of mid-size stars, and results in something called a planetary nebula. They have nothing to do with planets, but in early telescopes they often looked round, a bit like a planet. Here’s a well known example (in the constellation of Vega). I’ve seen it through a six inch telescope (that’s the diameter, not the length).

Once all that outer stuff blew off, the bare core of a star was now less massive and under less pressure, and could not go on fusing heavier and heavier elements. So it began to contract, and the temperature climbed as it did so, but no internal source of energy would come along to stave off the final collapse. So the star kept shrinking, and shrinking.

That much matter is heavy, and, when it’s packed into such a small volume, the force of gravity becomes gigantic. That simply compresses it further.

Eventually the only thing holding the star “up” is something called electron degeneracy pressure; basically, it’s an upper limit on how much you can squash the electrons in an atom. The atoms are still distinct…just very, very crowded.

With all that gravity, any hydrogen that happens to be left over ends up on the surface; the heavier carbon and oxygen go to the center. When astronomers examine the spectrum of a white dwarf, therefore, they see pure hydrogen.

The star is hot due to the heat generated by compression, and it radiates all that heat off–it cools. But there is so much matter here, compelled to radiate through such a small surface area, that it will take billions of years for the star to cool down enough that it isn’t glowing any more. In fact, it takes longer than the universe has been around, so no such star has cooled that much…yet. The oldest known white dwarfs are still at a few thousand Kelvins.

Another Kind of Supernova

But, as I mentioned, there is an upper limit to a white dwarf.

When they reach about 1.44 solar masses, the white dwarf is now too heavy for the electron degeneracy pressure to hold it up. This number is so critical that it has been named after the astronomer who first figured out its value, it is Chandrasekhar’s Limit.

Suddenly the carbon is forced together, all at once (not gradually like in a regular red giant that is burning it for fuel), and there is a titanic KABOOM…and we have a supernova, of a different type from the core collapse supernova expected for Betelgeuse. These are called type 1a supernovas.

You might think that this can never happen. After all, it’s a white dwarf sitting out there. How is it going to gain mass?

White dwarfs that orbit close to other stars often slowly pick up mass from their companions, it looks something like this:

That poached matter will accumulate until Chandrasekhar’s limit has been exceeded, and, like I said…KABOOM!

Type 1a supernovas are very useful to astronomers. Since they all result from basically the exact same kind of explosion on stars of the exact same mass, they are all of the same brightness. And like core collapse supernovas, they often outshine the entire rest of the galaxy they are in. Even if not, if we can see the galaxy…we can see the supernova.

And they have a distinctive signature, so you can tell a Type 1a from other types of supernovas.

So astronomers look, over and over again, at thousands of galaxies, hoping to spot a Type 1a supernova when it happens. They spot a few every year. They can measure how bright it looks. And since they know exactly how bright it actually is, because all Type Ias are identical, they now know how far away that supernova, and the galaxy it is in, actually is.

There are other, older methods of measuring the distance to galaxies; they all involve measuring how fast it’s moving away from us, and that was, until recently, assumed to be a simple function of how far away it was; the speed was a constant times the distance. But now, by knowing the actual distance, and (from the galaxy’s spectrum) knowing how fast it’s moving, we know that’s not really true (it was close, but not quite), and we were able to make the determination that the universe is expanding faster and faster, NOT slower and slower as one would expect.

So white dwarfs, and Type Ia supernovas, have helped us learn some really surprising things about the universe, as if white dwarfs themselves aren’t bizarre enough on their own!

Meanwhile, we’re in no danger of having Sirius B go supernova on us. It’s far too light to be a hazard today, and it’s certainly not gaining much mass from Sirius A, because it’s 20 AUs from that star. (That’s about the distance from the Sun to Uranus.) I haven’t been able to locate a professional’s estimate for how long Sirius A will last before it uses up its hydrogen, but it’s certainly hundreds of millions of years away. If it ends up lasting 12 times as long as Sirius B did, it’s good for a bit over a billion years. But when that time comes, it will become a red giant, and maybe, despite the huge distance, almost two billion miles, between the two stars, that will push enough matter out there for Sirius B to pick up some of it. And maybe…maybe…there will be a supernova.

We’re unlikely to be anywhere near it at the time. Sirius is moving closer and closer to us now, as both stars orbit the center of the Milky Way at different speeds, but in well under a million years it will be pulling away from us and should be nowhere nearby a billion years, or four orbits, from now.

Sorry, you still have to do your taxes next year!

NOTE:  I had a beautiful version of this.  Then I tried to move a picture, and lost it all.  This is but a shadow of its former self.
Today marks the 50^th anniversary of one of the greatest achievements of humanity, the landing of men on the moon for the first time, July 20^th, 1969.

It was a long, long time coming. Technologically, we can trace it back to the first use of fire to smelt copper, or even further back to fire itself (see the back end of the Saturn V rocket), and stone tools.
Scientifically, it goes back to about 500 BCE, when people in a certain area of southeastern Europe we now call “Greece” began to think in a naturalistic way about the skies. Eclipses, both solar and lunar, were terrifying because they were unusual, they were thought to be bad omens; signals from the gods. But it had been noticed that solar eclipses could only happen at new moons, and lunar eclipses only at full moons. The Greeks, however, figured out why: A solar eclipse was due to the moon passing directly between the observer and the sun, while a lunar eclipse was the moon passing through the Earth’s shadow. Furthermore, the Sun’s path against the stars—the Zodiac—was figured out with ease; the moon’s path was harder to predict but did follow regular patterns. All you had to do was look forward to a situation where the sun and moon to be in the same place in the sky at the same time, and you knew there would be a solar eclipse; if the moon would be perfectly opposite from the sun, lunar eclipse. (Note: these descriptions of geometry are as seen from Earth) That took the mystery out of eclipses; they were totally predictable, and simply the result of regular movements of celestial bodies. It didn’t make sense to most people for eclipses to be omens if they could be predicted a hundred years in advance.
That began an over-two-thousand-year-long process of figuring out how things worked up there, and how big things were and how far apart they were. It was, for various reasons, far easier to figure out the sizes of the Earth and the moon, and the distance to the moon, than it was for the other planets and the Sun (we got our first good measurements of these things in the 1700s).
We knew, very roughly, sizes, distances, and shapes, but not the “how it works,” quite early in this timespan. But much of the real progress happened in the 1500s and 1600s. Copernicus put forward a new vision of a sun-centered universe, with the planets, including the earth, which had not before been considered a planet, in orbit around the sun, rather than everything going around the earth in circular orbits. He, however, insisted that the orbits were still circular, so the past two thousand years of observational data simply couldn’t be reconciled with his theory, any better than they could be with a simple geocentric model (but in the fullness of time, it would turn out he got the Big Idea right). Galileo saw things through the telescope that overthrew some of the dogmatism imposed on science by the Church (though the story is more complicated than that); but he still insisted on the circular orbits. The Jesuits knew (correctly) that that couldn’t be true. Galileo also did enough work in mechanics to lay the groundwork for Newton.

But before Newton, we have to talk about Tycho Brahe and Johannes Kepler. Brahe made observations of the planets’ positions (as seen from Earth) of unprecedented accuracy; Kepler was able to use these to discover that we were observing planetary motion along elliptical orbits…from an planet following an orbit that was also elliptical! The ellipses all had the sun at one focus, but they were of different sizes, shapes, had different orientations of their long axes, and were even tipped so they weren’t in the same plane. To top it off the motion wasn’t at a constant speed, either; it’d be slower at one end of the ellipse—the one furthest from the sun—and faster at the other end. Kepler was able to figure out that if you drew a line from the Sun to a planet (or the earth to its moon), that line would sweep out equal areas in equal times…a thinner, longer slice farther away, a wider, shorter slice when the planet was nearer to the sun.

He did this using nothing but the direction the planets appeared from earth—no distances (he had to figure them out!)—and he did it without calculus, without a calculator, and without knowing the law of gravitation.  And I would love to know how he did it.
Many, many years later he figured out a relationship between the size of the orbit, and the period—the time it took to complete an orbit. For Earth that’s almost (but not quite) one tropical year.
So now, between Copernicus, Galileo and Kepler we had an accurate model of how the planets behaved. But we didn’t know why they did so, nor did we know how our own (prospective) spacecraft would behave “up there.”
Isaac Newton was the greatest scientist who ever lived. He put mechanics, the most basic branch of physics, on a firm footing, founded optics as a science, and he figured out that the force that caused the planets to orbit the sun, and the moon to orbit the earth, was the same force that makes things fall to the ground when you drop them. [That was a revelation.  Up to then, things “up there” were believed to be fundamentally different from things “down here.”]  And a spacecraft would be subject to the same forces. He could figure this out because he knew the distance to the moon, and realized that if some force followed the inverse square law, it matched the behavior of the moon in its orbit and the falling hammer. He also eventually proved that a force that followed such a law would cause things to move in elliptical orbits. He needed calculus to do this; unfortunately he didn’t have calculus.  No one did, it didn’t exist. So he invented it. (Another person in Germany, Leibniz, were also inventing calculus at the time, but they didn’t know about each other’s work, so it’s effectively as if each of them invented it in full.)
At first, Newton didn’t publish this work; but someone else, trying to figure out what could make the planets moved in ellipses, asked him, and he told them. “Can you show me the proof?” was basically the response. Newton had to go look for the papers. While the greatest minds in Europe was wondering what could make planets move in elliptical orbits…Newton had found the answer and lost it!
(If you get the idea that I admire Galileo, Kepler, and Newton, you’re damned right I do!)
Of course we now call that force “gravity.”  Here is the law that governs it (except near extremely massive objects, as Einstein discovered).

At this point, we knew that to get to the moon, we’d have to fight earth’s gravity all the way, a quarter million miles or so, but that (at least) you could coast large parts of the way, much as the planets basically coast in their orbits around the Sun. We had some conception, finally, of what we’d have to do to make it happen. We ultimately learned we’d have to bring our own air with us, because our atmosphere didn’t extend to the moon; and we’d have to solve a huge number of other problems as well, problems people in the 1600s couldn’t dream of. But from this point forward, we basically knew the size of the problem and in principle what we had to do; now it was “just” engineering; creating craft that could do those things, and keeping people alive on them in a very adverse environment.
It should be noted that Apollo 11 could not have succeeded if our basic understanding of the Earth-Moon system, and the force of gravity, were wrong. Claiming that our theory of gravity is wrong, or that the earth and moon aren’t spheres of the sizes they are, or that the distance is wrong, is logically equivalent to the claim that we’ve never gone into space, much less to the moon, either manned or unmanned. If our theory is wrong, the things we’ve done based on it could not have been done.
So how was it done?
Our astronauts first had to be put in orbit around the Earth. This requires a rocket, a big one, because we have to go from moving about a thousand miles an hour relative to the earth (we get that from the fact that the earth is rotating on its axis) to moving at fifteen or sixteen <i>thousand</i> miles per hour, or roughly 7000 meters per second. The rocket has to get our astronauts, and their spacecraft, and their food and air, up above the atmosphere <i>and</i> moving at that speed, roughly horizontally. There are a couple of ways to convey how this works without getting technical. But it’s important to know they aren’t “beyond the reach of gravity” or anything like that. The Earth still pulls on them, they are still falling down, towards the earth, but they are moving so far sideways in the same amount of time that the earth, being spherical, has dropped away the same amount. Or you can look at it another way: the centrifugal force of moving around the earth in such a big circle counterbalances gravity.

The Saturn V—the billion horsepower wonder, the most powerful machine ever designed by man that wasn’t a big bomb—had three stages, all below the service module (cylindrical) and command module (conical). The astronauts lived in the command module; the service module supplied oxygen and included its own rocket motor for propulsion. The bottom two stages were jettisoned during the ascent, the third stage remained attached to the service module and command module in orbit.

I’ll point out here that the reason the Saturn V rocket was so big was because it had to be able to put the service module, command module and its own third stage, all into orbit at once. A heavy load like this required a heavy rocket.
So now that the Apollo astronauts were in orbit, the next step of the process was to wait until the right point in the spacecraft’s orbit around the earth, and fire the rocket in the third stage. This added more speed to the spacecraft…which has the effect of raising the other end of the orbit, lengthening the eclipse.  Eventually, the ellipse was long (or tall, depending on your point of view) enough to reach the moon’s orbit.

It had to be aimed in the right direction when this happened, or it wouldn’t be headed toward the moon.
This started about three days of coasting, with the earth pulling back at Apollo 11 the whole time, gradually slowing it down as it climbed in it’s orbit.  Remember what Kepler said about orbital speed?
One very important thing had to be done during this coast. The astronauts had to separate the command module and service module (together known as Columbia) from the Saturn V third stage, swivel around to face the third stage, and dock with the lunar module, the lander known as Eagle, which was stored in the third stage. They then had to pull the lander out of the third stage, and then continue on to the moon without the stage.

The Eagle had to be stored in the third stage, below/behind Columbia, because if it had been put on top of the command module during launch, it would have been shredded by the earth’s atmosphere. This was a complicated maneuver, and part of the Gemini program of the mid 1960s was learning how to dock spacecraft. It had a complicated name, too: it was called the transposition, docking, and extraction, and it was executed flawlessly by Michael Collins.)
By the time Apollo 11 got near the moon, it was traveling at a mere 1 mile per second. But, this was too fast! You see, Apollo 11 may have been near the moon, but it was traveling faster than the moon’s escape velocity.  Without slowing down, it would just coast on by.
In fact, the third stage had also continued coasting after the extraction, and it was nearby.  It would sail on past the moon, getting a slingshot and escaping earth entirely, going into its own orbit around the sun.  It’s still out there, somewhere.
So it was time for another “burn”, this time pointed in the direction of travel, to slow Apollo 11 down. This was done by firing the rocket motor in the Service module. Once that was done, the astronauts were in orbit around the Moon! They waited about 30 orbits, then Armstrong and Aldrin moved into the lander, and detached from the Command Module.
All of this had been done before. Apollo 8 had orbited the moon and returned, and Apollo 10 had actually almost landed on the moon with its own “lander.” (Is it a lander if it never lands?)
But this time it was for real. A landing site had been picked, but there was much we did not know. One possibility was that the dust on the surface there would be so deep it would swallow the spacecraft.  (Though we had sent unmanned craft to the moon earlier, and they had not got lost in deep dust, who knew if this part of the moon was the same way?) Also, we had never seen the landing site up close—it could be filled with boulders instead of being flat.
As it turned out, the landing site was treacherous, and Neil Armstrong had to burn more and more fuel, looking for a good place to land. He barely found one before he would have had to abort, and return to the Command Module,. That was why the mission controllers were almost blue in the face.  Armstrong had just played “chicken” with the moon, and won.
“Tranquility Base. The Eagle has Landed.” Men were on the moon.
Men were on the moon!
Think about that. We have existed as a species for something on the order of 200,000 years. And for 199,950 of those years, we had never been on the Moon.
(I was five when this happened.  I don’t remember it, though I do remember Apollo 12.  This is the one thing…the one thing…that sometimes makes me wish I were just a little bit older.)
Six and a half hours after landing, Neil Armstrong set foot on the moon, soon to be joined by “Buzz” Aldrin.

President Nixon called them while they were setting up the flag (which was troublesome; far from being deep dust, just below surface it was so hard they couldn’t plant the pole). Nixon said:

Hello, Neil and Buzz. I’m talking to you by telephone from the Oval Room at the White House. And this certainly has to be the most historic telephone call ever made. I just can’t tell you how proud we all are of what you’ve done. For every American, this has to be the proudest day of our lives. And for people all over the world, I am sure they too join with Americans in recognizing what an immense feat this is. Because of what you have done, the heavens have become a part of man’s world. And as you talk to us from the Sea of Tranquility, it inspires us to redouble our efforts to bring peace and tranquility to Earth. For one priceless moment in the whole history of man, all the people on this Earth are truly one: one in their pride in what you have done, and one in our prayers that you will return safely to Earth.

One line bears repeating.
Because of what you have done, the heavens have become a part of man’s world.

Soon enough, it was time to return. The top half of the lander, known as the ascent stage, blasted off, using the lower part of the lander as a launch pad. It had to rendezvous in orbit with Columbia, requiring exact timing on the launch (or it would reach orbit and Columbia would be somewhere else), and another docking maneuver. Then, with Armstrong and Aldrin back in Columbia the ascent stage was jettisoned. Columbia then did a burn to escape from lunar orbit, heading back to Earth.
The trickiest part was yet to come. On return to earth, there was simply no fuel left in the Service module. The two big burns near the moon, plus minor corrections, had used up everything. The craft couldn’t do another burn to go into orbit and then another to gracefully descend. Instead, the Service module, too, was abandoned, once it put the Command Module on a precise trajectory. It had to be aimed at the earth’s atmosphere at a very precise angle, one with would allow it to aerobrake. Too shallow and it’d basically bounce off the atmosphere, too steep, and it becomes a meteor.
Of course we know that they hit it right, and returned safely.

The entire gigantic pile of explosives known as a Saturn V had been needed to send the Command Module to the moon and bring it back to Earth, to do an aerobrake because there was no fuel left. It was only made possible by using a light tin can of a lander and abandoning everything once it was no longer needed. Each abandoned piece was responsible for carrying the weight of the remaining part of the mission; if you think about that, that necessitates big pieces at the beginning, small ones at the end.
So what did I mean by subtitling this, “A Triumph of Man Living In Freedom”?
This whole thing was made possible by man’s mind, his rational thought processes, his reason.
None of this could have happened, without minds free to think, free to reason. We’d never have understood what needed to be done.
None of this could have happened, without people free to build prosperous lives, to learn practical skills, or we’d never have had the resources nor the technical skills to do it.
Only FREE people could do these things. The Soviets came close…but they were piggybacking on the free world; they couldn’t have done it without free people, past and present.
And only FREE people can make any sort of progress, produce wealth which enhances our lives, allows us to thrive rather than just existing.
Don’t let them take it away from us. If they do, we lose not just what took us to the moon, we lose what we could do in the future.  Worse, we also lose what makes it possible to thrive here on earth.
Don’t let them take it away from us.
Don’t let them.
Don’t.

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Of course, I didn’t do a coin picture on July 4.  Luckily, I have another one to show you to make up for it.

 
 
 
 
 
 

This special Super Blood Red Wolf Moon Open Topic post is dedicated to your thoughts on this day, perhaps the day that will be remembered as the beginning of the eclipse of the Opposition.
I’ll talk a lot about the Super Blood Red Wolf Moon later, in lieu of an editorial, but first, the usual administrivia:

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As always, you can say what you want, comment on what other people said, and so on. BUT: Keep it civil. Rules much like the Old Treehouse, except of course Q discussion is not only allowed but encouraged. A couple of other important things to consider:
https://wqth.wordpress.com/2019/01/01/dear-maga-open-topic-20190101/ contains some general guidelines for things that are really, really not kosher to post here.
And Wheatie’s Rules (as amended by me):

1. No food fights.
2. No running with scissors.
3. If you bring snacks, bring enough for everyone.
4. No shooting at the nuclear warheads.

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Super Blood Red Wolf Moon?

It’s “Super” because the Moon is an elliptical orbit, sometimes it’s closer to Earth, sometimes farther.  When it’s close during a full moon, it gets called a Super Moon.  (Frankly, I think those are a bit overhyped, but there it is.)
“Blood Red” because what we will have is a lunar eclipse.  During lunar eclipses the Moon is not lit directly (like a full moon is) but gets all of its illumination from sunlight refracted through the Earth’s atmosphere around the sunrise/sunset line (known as the “terminator” but Ahnuld has nothing to do with it).  Red light, of lower energy and frequency but longer wavelength, gets refracted more than blue light, so the Moon gets a lot of red light.
And finally, the full moon in January is traditionally known as the “Wolf Moon” and let’s face it, WolfMoons are pretty cool, and here at the Q Tree House we eagerly await the return of a certain WolfMoon.

How A Lunar Eclipse Works

The following diagram is not even remotely to scale, but it gets the critical things right.  The Sun is bigger than the Earth, and the Earth is bigger than the Moon.

Earth orbits the sun in an ellipse in a flat plane.  The moon orbits the earth in another, much smaller ellipse, in a flat plane.  But those two planes are tilted with respect to each other.  So usually, when the moon passes “behind” the earth, as seen from the sun, it looks like it passes above or below the earth.  We, on Earth, get to see a fully illuminated “front side” of the Moon, and we call it a “full moon.”  Or to put it another way, the Moon misses Earth’s shadow completely.  But sometimes it does pass through Earth’s shadow, either grazing it or plowing more deeply through it.  Those are lunar eclipses, and they can be partial or full.
The umbra, in the diagram above, is the full shadow of Earth.  If you’re in the umbra, you can’t see any part of the Sun.  That’s true for anyone standing on Earth at night time–yes, at night you’re in Earth’s shadow, it’s often true for the International Space Station, and sometimes it’s true of the Moon, too–when the Moon is entirely in the umbra, that’s a total lunar eclipse.
The penumbra is the part of space where, if you look towards the Sun, the Earth partially covers it.  If you’re far enough out in space Earth appears smaller than the sun, if your closer, it’s larger but the Sun is partially behind it.  (If you think about it, the Sun, as it rises and sets, is in this situation; your head is in the penumbra at those times.)
OK, so let’s abandon our “God’s eye” view of the situation, and put ourselves back on Earth’s surface, and look down the cone of Earth’s shadow.  It’s normally invisible, unless something crosses through it, and then we’ll see the shadow cast.

The moon tracks from right to left, through the shadow.
[That might surprise you, but the earth rotates, west to east, faster than the moon moves, and so the earth’s shadow (and the stars, planets, sun and moon) appears to move the opposite way from the rotation.  So we see everything move left to right, east to west, even though the real motion of everything up there is west to east.]
So when there is a total lunar eclipse, the moon first makes contact with the penumbra, at P1.  Then it moves entirely into the penumbra, looking a bit dimmer but not red (it’s still getting some direct sunlight) and eventually touches the umbra at U1.  As it moves into the umbra, it loses direct sunlight and picks up indirect sunlight.  Finally at U2, the entire moon is inside the umbra, and it will look red, brighter closer to the edge of the shadow.  It then reaches the middle of the eclipse, and at U3, the first bit of the moon exits the umbra.  At U4 the moon is entirely out of the umbra, and at P4, it’s completely out of Earth’s shadow.
From the point of view of someone on the moon:  P1:  One person at just the right spot on the moon would see Earth just touching the sun.  U1:  Every place on the moon sees the Earth partially covering the sun; one spot just had the sun completely disappear behind the earth.  U2-U3:  At no place on the moon is the sun even partially visible.  After U3, the sun starts to come out from behind the earth.  U4, parts of the moon start to see the entire sun.  P2:  The entire sunward side of the moon sees the entire sun, Earth is no longer even partially blocking the Sun.

The Particulars for This Eclipse

OK, I’m going to give these times in Mountain Time.  Why?  Because I think just for once people in the Eastern Time Zone should feel our pain.  (Add two hours if you’re ET, e.g., 7:37 becomes 9:37 ET.)
7:37 PM MT:  P1.  The Moon moves partially into the Earth’s Shadow
8:34 PM MT:  U1.  The first parts of the moon move completely into Earth’s shadow, no direct sunlight.  What you’ll see is a definite outline of the Earth’s umbra as the moon moves further in, but part of the Moon will still be brightly lit by the sun, so the weak red refracted light will be completely overwhelmed, the shadow will look black.
9:41 PM MT:  U2.  Now the Moon is entirely in the umbra, the full shadow of Earth.  By now it should look quite red, with the part closest to the edge of the umbra looking brighter.
10:12 PM MT:  Mid Eclipse.  The Moon is farthest away from the edges of the shadow.  For this eclipse (most lunar eclipses, actually), the Moon doesn’t actually cross through the center of Earth’s shadow.  The picture at the top of this post shows the geometry of this eclipse.
Note: Sometimes not a lot of light gets refracted, and the Moon is unusually dark, but blood red is what’s usually seen.  Again, the upper/north side of the Moon should look brighter than the southern/lower side, because it’s nearer to the edge of the shadow and more light refracts onto it.
10:43 PM MT:  U3.  Part of the Moon now exits the umbra, and starts receiving some direct sunlight again, and the red will rapidly disappear.
11:51 PM MT:  U4.  Part of the Moon exits the penumbra and is now getting full sunlight, while the right hand side will still look a bit darker because it’s only getting a partial dose of direct sunlight.
12:48 AM (21st of January) MT:  P2:  The Moon has completely left Earth’s shadow, anyone on the day side of the Moon sees the entire Sun’s disk.
Tying this all together, now:  Here’s a GIF of today’s eclipse.  You’ll see Earth’s shadow and the moon tracking west to east across the night sky, complete with special effects.

That’s it!  Pretty much anyone in the lower 48 should be able to see this; it’s not like a solar eclipse where you have to be standing along a specific line on the ground to see totality (that’s because the Moon’s umbra is almost down to a point at Earth’s surface during a solar eclipse).

And remember, it’s a WolfMoon!!!

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May we look back on this day, years from now in a restored American Republic, and find it symbolic that a lunar eclipse marked the Eclipse of the Demoncratic (rule by demons is demoncracy) Party.

MAGA ON!!!

And (I gotta do this, I just can’t help myself):

MOAR SHUTDOWN!!!

MOAR!!! MOAR!!! I’m Still Not SATISFIED!!!