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

Hello 2023

I haven’t had a chance to update this blog in a while, which seems to be a common fate for most blogs. I’ve just been uncommonly busy. 

My last update was a few months back in August 2022, shortly after I attempted another L3 certification. As noted there, it was a failed attempt, but as always I learned some important lessons. 

The last post before that was from June 2022 when I attended the 40th annual launch of Large Dangerous Rocket Ships (LDRS) in southern California, way out in the high desert. This was the first time I’d attended a big national launch like this. 

On a personal note, the last six months or so have been nonstop. Shortly after LDRS, we moved from Los Angeles back to the midwest to be closer to family (all in the Chicago area) and the cross-country move, with an 18 month old toddler, was eventful to say the least. We spent fall getting settled into our new home in a new community, figuring out childcare for our daughter, and exploring the area while the weather was still relatively warm. Later in the fall I took another math class, differential equations, which was incredibly demanding and time-consuming, but I successfully completed it – another math class under my belt, after taking calculus I, II, and III, as well as linear algebra last year. 

I still have a lot more classes to take if I want to knock out all of the math and science pre-requisites (one more math, a three-part physics sequence, and four or five engineering classes), but working my way through them slowly is better than not doing it at all. And to be honest, slowly – one class at a time – is all I can possibly muster right now, given my schedule.

Now that this most recent class is over and we’re much more settled into our new place, though, I really want to get back into rocketry. I still have that L3 certification to finish, and I have half a dozen other rocketry projects I want to dive into as well. I’ll be sure to post more updates accordingly!

Large Dangerous Rocket Ships (LDRS) 40th annual launch in California

A rocket launch in the high desert!

san bernardino national forest official brown sign with desert in background
on the way to the launch

Earlier this month, I was able to make it to my first rocket launch in over a year. At first glance, this seems inexcusable for someone whose blog and other social media accounts are primarily dedicated to rockets and rocket launches. In my defense, the past year has been a whirlwind. We moved from Seattle to Los Angeles (with a 5 month old baby) and are getting ready to move out of Los Angeles (with a 17 month old baby). I completed two classes – linear algebra and environmental science – and we tried to see and do as much as possible, knowing that we had just one year to explore southern California. We made it to San Diego (twice!), Santa Barbara, Ojai, Big Bear, Palm Springs and Joshua Tree National Park, and lots of beaches, from Malibu and Santa Monica down through Crystal Cove and Laguna Beach, not to mention the countless things we did and places we ate within LA itself. (Griffith Observatory and California Science Center to name just two.)

desert landscape with sand and dirt in foreground, mountain range in background
lucerne dry lake bed in southern california

That said, LDRS 40 – a national rocket launch – was being held just a few hours’ drive outside of LA. How could I not attend?

people standing or sitting with folding tables and chair, under a tent in the desert
LDRS volunteers

I left my rockets, motors, tools and equipment up in Seattle temporarily before we moved, so I didn’t bring anything to launch myself. But I wanted to take the opportunity to see other rocketeers and some spectacular launches, and to just meet up with old friends and chat.

variety of large rockets lying horizontally
an assortment of large rockets

Large Dangerous Rocket Ships (“LDRS”) is an annual rocket launch hosted by Tripoli Rocketry Association, a national organization, and the Rocketry Organization of California (“ROC”), a local club. LDRS held its 40th annual event in Lucerne Valley, California, on Lucerne Dry Lake Bed, which is very much a desert. The daily high temperatures were about 105 degrees F. Conditions were what you’d expect: very hot and very dry. There were also some strong winds which carried a lot of the dry dust and sand everywhere.

dust storms from strong winds in the desert, with people and tents partially visible
dust storms

It was an awesome experience – my first LDRS annual event, and first large national rocket launch event that I’ve ever attended, and my first launch of any kind in over a year. All you needed were sunglasses and an oversized hat, plenty of sunscreen, a limitless supply of water bottles, plus an N95 if you wanted to breathe. Ideally, in retrospect, I should have just worn an astronaut suit for maximum protection but there’s always next year.

Besides, the intense sun and winds were no match for the enthusiasm of this group of people!

Did dinosaurs have high blood pressure?

I recently took a class all about dinosaurs, and one topic was whether dinosaurs were cold-blooded, which has traditionally been the conventional view, or in fact warm-blooded. The evidence, it turns out, is mixed, and just learning about the different types of evidence is really interesting. One of the pieces of evidence listed stood out to me in particular: dinosaur blood pressure. I thought I would do a little research on this topic to find out more.

sauropods chatting it up

Basically, a warm-blooded (endothermic) metabolism requires high blood pressure to rapidly circulate the blood throughout the body. Endotherms have higher blood pressure than cold-blooded animals (ectotherms). So did dinosaurs have high or low blood pressure? 

At first glance, this doesn’t seem particularly helpful. If we don’t know whether dinosaurs were cold or warm blooded, how would we know their blood pressure levels either? Fascinatingly, it is (somewhat) possible to answer this question!

Since one of the most critical functions of the heart is to pump blood to the brain, we can estimate dinosaur blood pressure based on the vertical distance between the dinosaur’s heart and brain. And we do have lots of fossils where we can measure this distance directly. Considering the extremely long necks of certain gigantic sauropods, this distance could be enormous. If we extrapolate blood pressures in dinosaurs from current animals, the pressures in sauropods would be so high that it is questionable how this was even possible without something rupturing or exploding.

However, the picture is further complicated by a separate but related debate about dinosaur posture. What did sauropods do with their enormously long necks? Did they keep them relatively low to the ground and horizontal when walking and feeding, or did they hold them much higher (closer to vertical) in order, for example, to reach higher vegetation on trees? The answer to this makes a huge difference when estimating blood pressure because it takes a much higher pressure to move blood up a vertical neck, against gravity, than sideways when the neck is kept low. The answer to this is we don’t know for sure, but there seems to be a lot of evidence in favor of the more vertical neck/ posture (from the structure of the bones in the neck), which leaves open the question of how exactly their bodies could pump blood with such high pressure to the brain.

One possibility is a gigantic heart to pump with more power, literally weighing several tons. This would probably be very inefficient, and the problem of such explosive high blood pressure would remain. Another alternative some have proposed are multiple smaller hearts in the neck to assist the primary heart. This isn’t physically impossible, but there doesn’t seem to be any evidence for this either. One other possibility would be using some sort of valves or muscle contractions in the neck, like living giraffes, to transport blood to the brain (although a sauropod neck is much, much longer than a giraffe’s neck).

Paleontologists like Robert Bakker in the 1970s and more recently Michael Habib argue something along these lines. Bakker suggested sauropods use neck muscle contractions to pump blood up the neck. Habib agrees and points to large neck bones called cervical ribs that are actually a very flexible form of bone, and can act as springs. This could have allowed a sauropod with a very long neck to move the blood without an impossibly high blood pressure.

This idea makes sense to me. These sauropod necks that were 30 or 40 feet long must have had extremely powerful muscles. From an evolutionary standpoint, why not co-opt these muscles into more than one function, and use them to assist the heart with pumping blood? Of course like many hypotheses and arguments with dinosaurs, this idea is also not without criticism.

There are other interesting related questions involving blood pressure that would never have occurred to me. For example, no matter what the mechanism to pump blood with such high force to the brain (whether a gigantic heart or assistance from neck muscles), when a sauropod did lower its head to the ground (e.g. to drink water), how did it prevent a huge rush of blood to its head? Modern day giraffes have evolved a web of little arteries that solves this problem, but it’s not clear whether dinosaurs had something similar.

There is a lot of speculation and unanswered questions about dinosaurs’ circulatory system. Unlike the skeleton, it didn’t fossilize and there’s no direct evidence of things like the size of the heart or the structure of arteries. But it’s an interesting area with vigorous debate because these were real problems that had to be addressed, and sauropods managed to address them one way or another!

Further reading:

How Long-Necked Dinosaurs Pumped Blood to Their Brains

The Evidence for Endothermy in Dinosaurs

Of Barosaurus and Blood Pressure

Bakker, Dinosaur feeding behaviour and the origin of flowering plants, Nature

itch slapped

Introducing itch slap!

smiling man holding small box labeled itch slap
slapping *itches

Last summer, Katie and I were getting bit by mosquitoes, and we typically put this strong medical tape over the bite to relieve the itching. At the time, Katie said: why not sell this? WHY NOT INDEED?

Fast forward a few months and I had designed and manufactured a custom adhesive patch for bug bites, and filed a bunch of paperwork to create an LLC, get a unique product UPC/ bar code, and more fun stuff. The patch is an elastic fabric with a medical strength glue, and it effectively eliminates itching.

You can also give it as a gift to any of your friends and family who love hiking, nature, and the outdoors. Let them know they just got *itch slapped!

Also, the company has a serious philanthropic mission and donates 10 percent of all revenue to an organization that fights malaria: Nothing But Nets. So please help us by doing anything from the list below:

  1. Buy it, and leave a review!
    available on amazon:
  2. Follow itch slap on social media!
    Instagram: @itchslap
    Twitter: @itchslapped
  3. Share the post and help us spread the word!

Air & Space Exhibit at the California Science Center

Los Angeles has plenty of sunny weather, and rain is pretty unusual. But recently, it was pouring rain, and we had taken a day off work. What to do? We took the opportunity to check out the local California Science Center! We had never been before, and it had a lot of great exhibits. I was primarily interested in the Air & Space exhibit, and the museum is also the permanent home of the Space Shuttle Endeavor.

replica of the viking lander on mars
replica of the viking lander on mars

The space exhibit is broken out into a few sections: air and aircraft; humans in space; the solar system and planets; and telescopes and stars. The “humans in space” part of the exhibit has some really impressive things on display, including an actual Apollo command module, a Gemini capsule, and a Mercury-Redstone capsule.

apollo command module on display
apollo command module

For those who are less familiar with the details, the US space program back in the 1950s and 60s involved the creation of NASA and several successively ambitious projects designed to accomplish specific goals or milestones:

gemini capsule on display
gemini capsule

Project Mercury. Beginning immediately after the Soviet Union launched the first satellite into orbit (Sputnik in 1957), Project Mercury was the first human spaceflight program in the US and ran from 1958 to 1963. The goal was to put a man into orbit and, of course, return him safely. The program involved 20 spacecraft launches with no crew (some with an animal), and eventually it successfully launched humans into orbit.

Project Gemini. The purpose of Gemini (1961 to 1966) was to develop space travel techniques to support the ability to eventually land astronauts on the moon (which was ultimately done with Apollo). These techniques included things like extra-vehicular activity, rendezvous of spacecraft, and docking. The name Gemini comes from the fact that the spacecraft carried a two-person crew, named after the Gemini twins in Greek mythology.

Project Apollo. Running from 1968 to 1972, the goal of Apollo was to land the first astronauts on the moon. It involved a three person spacecraft and was originally conceived during the Eisenhower administration in the 1950s, but later dedicated to JFK’s goal of landing a man on the moon, and of course eventually achieved its goal with Apollo 11 in 1969.

space shuttle endeavor on display
space shuttle endeavor on display, front view

The highlight of the museum (for me, at least) was the Endeavor exhibit. The US only produced a total of six space shuttles, which were in operation from the first flight in 1981 through the last flight in 2011: Enterprise, Columbia, Challenger, Discovery, Atlantis, and Endeavor. The first shuttle, Enterprise, was only used for testing purposes. Two of the six shuttles, Challenger and Columbia, were lost in two disasters when they disintegrated during their missions, in 1986 and 2003, respectively. That means only four of the six shuttles are still in existence, and the California Science Center houses one of them. The Endeavor was gifted to the museum and, through seemingly herculean efforts, transported to southern California back in 2012.

It was pretty amazing to learn about the difficult journey to physically move the shuttle through the streets of Los Angeles, and to see one of the few remaining shuttles up close.

space shuttle endeavor on display, rear view
space shuttle endeavor on display, rear view

The space shuttle is currently on display in this building, but the museum is in the process of building another even larger building where the shuttle will sit vertically, attached to the booster tanks as if it were ready for launch. This will be the only place in the world where the shuttle will be displayed in this manner. I’m not sure when the exhibit will be completed, but it should be pretty impressive.

I didn’t grow up during the space race in the 1950s and 60s, but rather during the 1980s and 90s when the space shuttle program seemed like the future. Now, of course, it’s been retired and NASA is developing the Space Launch System, and private companies like SpaceX, Blue Origin, and others are building massive rockets to put humans into space (which SpaceX has already successfully done). But this exhibit really hit home for me; I was in awe at the experience of seeing one of the only space shuttles in existence. If you live in LA or are planning to visit, I’d definitely recommend a trip to the California Science Center.