Isaac Newton

I just finished reading a biography on Isaac Newton. A lot has already been written about Newton, and I don’t have a lot of original insight to contribute, but I’ll briefly summarize my thoughts. The book (“Isaac Newton” by James Gleick) was excellent, and my only complaint is that it was too short. It chronicles Newton’s life from birth – in an obscure village farmhouse, to obscure parents – to his death at age 84, at which point he had grown relatively wealthy, powerful, and famous. Even at his death, though, his legendary status and place in history was just beginning.

portrait of isaac newton looking at a glass prism emitting rainbow of colors, with planets orbiting sun in background sky
isaac newton. courtesy of national geographic

Newton was brilliant, but also a loner. He never married and had few friends, and he spent much of his time alone, reading and performing experiments and writing. Much of what he wrote was entirely private and he did not publish, yet it was groundbreaking in scope. In a nutshell, Newton single-handedly invented calculus, creating concepts like derivatives (measuring the rate of change over time) and integrals (measuring the area under a curve) and connecting the two; he was the first to set forth an accurate theory of light by using a prism to show that white light is composed of the spectrum of all colors of the rainbow; and he effectively “discovered” gravity. Without going into a lot of detail, it’s hard to even comprehend these achievements without full historical context.

Before Copernicus, Galileo, Kepler, and Newton, and a few other remarkable scientists who lived in the 1500s and 1600s, it was generally taken for granted that the earth is stationary, that other planets, the moon, and the sun (and the stars) all move around the earth in regular cycles, and that there is a fundamental distinction between the imperfect earth and the perfect celestial sphere, or series of spheres, in the heavens (perfect in part because of their religious association with God). In Newton’s time, it had only recently been discovered that the planets, including Earth, move around the sun (Copernicus), and that these orbits are not even perfect circles but are elliptical (Kepler). The use of the telescope also revealed lunar craters and other imperfections, as well as moons orbiting other planets like Jupiter (Galileo). This was all an affront to Christianity and its view of the world. But there were still enormous questions about nature: why did the planets orbit at all? What was keeping them from flying apart at great speed? The concept of a “force” of attraction hadn’t been invented yet – and there was argument about whether space was even a vacuum or was filled with the mysterious “ether.” Newton showed decisively that such a force existed (gravity), even if he couldn’t explain its cause, and that space is a vacuum – there is no ether. Furthermore, matter is the same everywhere in the universe, whether on earth or other planets or stars: it is all composed of the same types of matter and obeys the same natural laws.

Setting forth well-articulated theories of gravity and optics, and creating a new, more powerful mathematics are not even Newton’s biggest achievements. It was his insistence on using data and math – to measure things that were previously unmeasured – that was truly a colossal shift in the way that societies approached nature. Newton, more than any other person, is responsible for taking what was previously called “philosophy” and hammering out concrete rules for how to measure things and how to approach questions scientifically, so that theories could be tested and disproven using evidence and data.

There have been many things written about Newton, but a famous poem by Alexander Pope probably summarizes his life and his contributions as well as anything else:

“Nature and nature’s laws lay hid in night;

God said, Let Newton be! and all was light.”

What exactly is a spaceport?

The starting point for any discussion about spaceports is a definition, so that we know what we’re talking about. In its most general sense, a spaceport is just a site for launching spacecraft. In addition to launches, the site would typically test, store, and perform maintenance on spacecraft, and may also have related facilities and operations for storing and/or processing liquid rocket fuel. A spaceport may even have on-site tenants that rent space as part of their ongoing launch operations.

kennedy space center, including large white and grey buliding on the left, and launch tower with vertical rocket on the right
NASA’s Kennedy Space Center in Florida, with the Space Launch System (SLS) rocket and Orion spacecraft.

Spaceports are a relatively recent concept, but the idea – and the word itself – is just an extension of other types of transportation hubs that have existed for hundreds or even thousands of years. Airports are similarly sites for airplanes taking off and landing; seaports are places where ships launch and return (and where ships may be built, repaired, stored, maintained, and so on). The analogy for space travel is clear.

So what kind of spacecraft qualify? There are a few different types or categories for spaceports based on the method of launch, as well as what is being launched. The majority of spaceports support a vertical rocket launch, but there are a few – which appear to be exclusively in the United States – that allow for a horizontal launch, e.g., a vehicle that takes off on a runway like an airplane but that is capable of reaching space.

Along similar lines, spacecraft can have a human crew (manned) or no crew (unmanned). They are also designed for different purposes and can reach different heights: sub-orbital or orbital, or beyond.

As of 2022, the total number of spaceports worldwide is just 35. Of these, 15 are in the US, from locations as far-flung as Cape Canaveral Air Force Station or the Kennedy Space Center in Florida to the Pacific Spaceport Complex on Kodiak Island in Alaska. It’s worth noting the other countries that have at least one spaceport, given that it’s somewhat rare: Russia, Kazakhstan, China, Mongolia, Japan, India, Brazil, New Zealand, French Guiana, Kenya, Norway, and South Korea.

So can anyone just build their own spaceport?


I’ve been thinking about spaceports a lot recently.

futuristic spaceport
futuristic spaceport

Not sure why, exactly – I think that they’ve coincidentally been brought to my attention from several independent sources around the same time. I just finished re-reading Isaac Asimov’s Foundation novels (for the hundredth time) in which there are frequent references to spaceports, a necessity in a Galactic Empire spanning around 25 million inhabited worlds. I also recently read an article in The Atlantic about a (very real) spaceport being planned in Melness, at the very northern border of Scotland, and its economic impacts on the local population. And of course I try to keep up with rocketry news in general, including SpaceX and its spaceport at Boca Chica, as well as various launches out of Spaceport America in New Mexico.

All of this makes me a bit curious about the history and origin of spaceports, as well as the rules governing them. When I first got into rocketry, I knew absolutely nothing. Some might say I still know nothing, and this would not be an inaccurate characterization. But in the beginning, no question was too stupid. How do you go about building a rocket? Can anyone just launch a rocket, from anywhere? Is it legal? Are there any rules?

Having never given more than a cursory thought to spaceports before, I’m in a similarly ignorant position. What exactly is a spaceport? What are the criteria to qualify as one? Can anyone – with sufficient time and resources – just build one? Can it only be in certain locations, or could it be anywhere? What does the government have to say about spaceports, if anything?

Time to find out!

Stegosaurus plates

Last year, I took a geology course focused entirely on dinosaurs. It was about as fascinating as you’d expect for someone who loved dinosaurs as a kid (and who didn’t?) and who now gets to to revisit the subject in detail as an adult. I’ve written a few posts as a result. One of the topics from the class that I found rather surprising was stegosaurus plates: why did they evolve, and what function did they serve?

stegosaurus walking in foreground with trees and other dinosaurs in background
stegosaurus with characteristic plates along its back

I initially assumed that the plates were used primarily for defense in some way. They look kind of.. spikey. Maybe it’s like a hedgehog and the spikes ward off predators? But the plates weren’t actually armor or defensive in any way – and upon closer inspection, this makes sense. They didn’t cover very much of the stegosaurus’ body and left most of it vulnerable on the sides and bottom, whether the plates laid flat or stood vertically. What defensive purpose could this serve?

Even more interesting, the plates were not made of solid bone connected to the rest of the spine and skeleton, but rather were lined with grooves that likely meant they contained rich blood vessels. This makes it even less likely the plates were for defense: why expose vulnerable blood vessels to an attacker?

The real function of the plates has been debated, and some paleontologists suggested that the plates were a visual display to recognize other members of the same species, or to attract mates. This is definitely one possibility, although not one I find particularly interesting. But the evidence for blood vessels has also led some to suggest that the plates helped regulate body temperature. In other words, they would have acted as radiators to help the dinosaur cool off when too hot, and as “solar panels” to absorb more sunlight over a greater surface area to help warm the dinosaur when it was too cold.

However, some additional research has demonstrated that while this temperature regulation theory was possible, it probably isn’t why the stegosaurus evolved the plates in the first place and it also likely didn’t have much of a significant effect. If the plates did play a role in helping cool or warm the animal, one obvious question would be why other dinosaurs didn’t evolve something similar. Furthermore, if the plates served this purpose and were really more about function, then they would not have varied so much across different species of stegosaurids. Instead, this makes it more likely that they were simply used for display.

I’d prefer for the functional (temperature regulation) hypothesis to be true, but it seems more likely that the plates evolved more for display. In the end, it’s a debate that remains unsettled. The two different suggestions are not mutually exclusive – both could be true, to some extent. Or perhaps there’s some totally separate explanation that hasn’t yet been proposed by anyone just yet.

Stegosaurus, American Museum of Natural History

Stegosaurus ungulates, National Park Service

Stegosaurus Plate Debate, Smithsonian Magazine

The Stegosaurus Plate Controversy