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Watching Rome Burn & Hell Freeze
The fun physics of global cataclysmPosted in For Your Consideration
What do record fire seasons in the West, record hurricane seasons in the Atlantic, record winter storms in the South and the hottest years in history have to do with each other? Everything.
This article originally appeared in the December 2019 issue of my Astronomy Magazine column, For Your Consideration.
Schools in the Time of COVID
The Decision Will Ultimately Make ItselfPosted in Thoughts
You don’t tug on Superman’s cape. You don’t spit into the wind. Yes, schools are desperately important to kids. No, COVID-19 doesn’t care, and COVID is making the rules right now. Attempts to open schools this fall will fail of their own accord. The relevant question is how to meet the needs of children, families and the community in the face of that reality.
COVID-19 Arrives
The Humanitarian Disaster is HerePosted in Thoughts
Currently new cases of COVID-19 in Arizona are doubling every 7 days. ICU beds in the state are already full. The rest of the country isn’t that far behind us. You do the math.
Correctly Predicting Failure
It’s time for scientists to get loudPosted in Thoughts
Now is not the time for scientists to be circumspect and silent. We are on the short end of a battle over whether truth even matters. If scientists do not stand up for what is real, who will?
Typhoid Mary on Two Wheels
Spreading COVID one lap at a timePosted in Thoughts
The morning cyclist in my neighborhood may not be standing in the Michigan Statehouse carrying a gun and demanding her right to spread contagion far and wide, but she may as well be.
Pine Boxes
Invest now, the numbers are going upPosted in Success & FailureThoughts
You know those nice charts and graphs that make it look like we are over the hump of COVID-19 and that things are about to get better? Those predictions are dead wrong, with an unfortunate emphasis on “dead.”
Scientists Stuck Inside
Curiosity in the Time of COVIDPosted in For Your ConsiderationThoughts
Imagine three gregarious scientists, each with the gift of the gab, all coping with stay-at-home orders. Of course we started a livestream/podcast talk show! What else would we do? Welcome to the kickoff episode of Scientists Stuck Inside.
After COVID’s First Wave
No getting back to normalPosted in Success & FailureThoughts
Even after COVID-19 kills hundreds of thousands in the U.S. over the coming weeks, we will still be almost as vulnerable to the pandemic as we are today. We’d all love to “get back to normal” after that, but the price could be a second wave, worse than the first. Some see us facing either economic Depression or allowing vast numbers of preventable deaths, but that is a fool’s choice. There are better options if we have the will to find them.
COVID-19
Cutting through the confusionPosted in Success & FailureThoughts
There is a lot of information about COVID-19 out there, much of it misleading. When looking at the future, start with what the science really says.
Great Deceiverism 101
Explanation or Theory? Therein lies the rub.Posted in For Your ConsiderationUnreasonable Faith
If someone can’t tell you how they would know that they are wrong, they don’t have a clue whether they are right.
This article originally appeared in my Astronomy Magazine column, For Your Consideration.
One Step at a Time
The not-so-mysterious origin of lifePosted in For Your ConsiderationUnreasonable Faith
Once seemingly incomprehensible, the origin of life no longer seems such a mystery. Most of what once appeared as roadblocks are turning out to be superhighways.
This article originally appeared in my Astronomy Magazine column, For Your Consideration.
The Mind’s Siren Call
Being certain is a primrose pathPosted in For Your ConsiderationUnreasonable Faith
Being certain lights up our brains like a junkie’s next hit. Literally. Unfortunately, being certain and being right are two very, very different things.
This article originally appeared in my Astronomy Magazine column, For Your Consideration.
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Watching Rome Burn & Hell Freeze
The fun physics of global cataclysmPosted in For Your Consideration
-
Schools in the Time of COVID
The Decision Will Ultimately Make ItselfPosted in Thoughts
-
COVID-19 Arrives
The Humanitarian Disaster is HerePosted in Thoughts
-
Correctly Predicting Failure
It’s time for scientists to get loudPosted in Thoughts
-
Typhoid Mary on Two Wheels
Spreading COVID one lap at a timePosted in Thoughts
-
Pine Boxes
Invest now, the numbers are going upPosted in Success & FailureThoughts
-
Scientists Stuck Inside
Curiosity in the Time of COVIDPosted in For Your ConsiderationThoughts
-
After COVID’s First Wave
No getting back to normalPosted in Success & FailureThoughts
-
COVID-19
Cutting through the confusionPosted in Success & FailureThoughts
-
Great Deceiverism 101
Explanation or Theory? Therein lies the rub.Posted in For Your ConsiderationUnreasonable Faith
-
One Step at a Time
The not-so-mysterious origin of lifePosted in For Your ConsiderationUnreasonable Faith
-
The Mind’s Siren Call
Being certain is a primrose pathPosted in For Your ConsiderationUnreasonable Faith
-
What do record fire seasons in the West, record hurricane seasons in the Atlantic, record winter storms in the South and the hottest years in history have to do with each other? Everything.
This article originally appeared in the December 2019 issue of my Astronomy Magazine column, For Your Consideration.
You don’t tug on Superman’s cape. You don’t spit into the wind. Yes, schools are desperately important to kids. No, COVID-19 doesn’t care, and COVID is making the rules right now. Attempts to open schools this fall will fail of their own accord. The relevant question is how to meet the needs of children, families and the community in the face of that reality.
Currently new cases of COVID-19 in Arizona are doubling every 7 days. ICU beds in the state are already full. The rest of the country isn’t that far behind us. You do the math.
Now is not the time for scientists to be circumspect and silent. We are on the short end of a battle over whether truth even matters. If scientists do not stand up for what is real, who will?
The morning cyclist in my neighborhood may not be standing in the Michigan Statehouse carrying a gun and demanding her right to spread contagion far and wide, but she may as well be.
You know those nice charts and graphs that make it look like we are over the hump of COVID-19 and that things are about to get better? Those predictions are dead wrong, with an unfortunate emphasis on “dead.”
Imagine three gregarious scientists, each with the gift of the gab, all coping with stay-at-home orders. Of course we started a livestream/podcast talk show! What else would we do? Welcome to the kickoff episode of Scientists Stuck Inside.
Even after COVID-19 kills hundreds of thousands in the U.S. over the coming weeks, we will still be almost as vulnerable to the pandemic as we are today. We’d all love to “get back to normal” after that, but the price could be a second wave, worse than the first. Some see us facing either economic Depression or allowing vast numbers of preventable deaths, but that is a fool’s choice. There are better options if we have the will to find them.
There is a lot of information about COVID-19 out there, much of it misleading. When looking at the future, start with what the science really says.
If someone can’t tell you how they would know that they are wrong, they don’t have a clue whether they are right.
This article originally appeared in my Astronomy Magazine column, For Your Consideration.
Once seemingly incomprehensible, the origin of life no longer seems such a mystery. Most of what once appeared as roadblocks are turning out to be superhighways.
This article originally appeared in my Astronomy Magazine column, For Your Consideration.
Being certain lights up our brains like a junkie’s next hit. Literally. Unfortunately, being certain and being right are two very, very different things.
This article originally appeared in my Astronomy Magazine column, For Your Consideration.
Over his 30 year career as an internationally known astrophysicist, Dr. Jeff Hester was a key member of the team that repaired the Hubble Space Telescope. With one foot always on the frontiers of knowledge, he has been mentor, coach, team leader, award-winning teacher, administrator and speaker, to name a few of the hats he has worn. His Hubble image, the Pillars of Creation, was chosen by Time Magazine as among the 100 most influential photographs in history.

A Saguaro’s universe
Building a cactus starts with the Big Bang
The iconic saguaro cactus gives the desert an otherwordly beauty. That beauty does not exist in isolation. It embodies the fascinating and awe-inspiring processes that have shaped the universe, going all the way back to the Big Bang itself.
This article originally appeared in my Astronomy Magazine column, For Your Consideration.
I live in the desert near the Superstition Mountains, east of Phoenix, Arizona. Not far from my house is a gorgeous Saguaro cactus that I drive by daily. I’ll be honest: I had no clue how big those things were until I stood beside one and looked up! This particular monster has eight arms growing from its 60-foot-tall body.

The desert home of the Saguaro owes its existence to many factors, including solar-driven convection, the heat of vaporization of water, the Coriolis effects due to Earth’s rotation, the thermal properties of land and water, ocean currents, and mountain ranges and other terrain that control global wind and weather patterns. The top image shows surface winds on a day in late April. The effects of surface features on wind patterns are clear. The lower frame shows high-altitude winds for the same day that more closely track the large-scale convection patterns that carry heat from the equator toward the poles. (Data from Cameron Beccario. Interactive maps available at https://earth.nullschool.net)
A Saguaro doesn’t even get its first arm until it’s at least 75 years old, and it can live for 200 years or longer. Judging by its splendor, this guy has been around long enough to see European settlement in the Valley of the Sun grow from a few buildings along the Salt River into a sprawling metropolis of 4.6 million people spanning 9,000 square miles.
Which came first, the desert or the cactus?
The Sonoran Desert is the only place on Earth where Saguaros grow. That’s because the cactus and the desert grew up together. As the climate around here became what it is today, plants that fared better survived, reproduced, and passed along their genes. Less successful plants didn’t. Generation after generation, as the climate changed, the Saguaro evolved to keep up.
But wait a minute! Why is this a desert at all? That has a lot to do with the physics of water and convection. Sunlight heats the tropics, driving planetwide convection that carries much of that thermal energy toward the poles. As warm, moist tropical air rises, it also cools, dumping much of its moisture as rain. As water vapor condenses, it releases heat. By the time that once-moist tropical air completes its upward path, it is both dry and a lot warmer than it might have been.
What goes up must come down. As convection carries that air back to lower altitudes, it compresses, turning already relatively warm, dry air into a veritable blast furnace. Welcome to the horse latitudes, latitudes around 30° along which many of the planet’s deserts are located.
A home for the saguaro, spinning in space.
Now we have to worry about Earth’s rotation. As convection carries air north and south, the Coriolis effect diverts that air into strong bands of easterly and westerly winds and the powerful jet streams that carry weather systems west to east around the planet.
And then there’s the star that formed at the center of that rotating, collapsing interstellar cloud. Nuclear reactions in the Sun’s core power the whole show of climate and life.
Anyway, there is a nice jet stream drawing moist air from the Pacific eastward toward the Sonoran Desert. So why is it still dry? The culprits this time are the mountains that surround it. When moist air flows into the side of a mountain, it moves upward. And just like what happens in the tropics, rising air loses its moisture as precipitation and is heated by condensation. When that now dry and relatively warm air comes flowing down the backside of the mountain, well, there’s that blast furnace again!

The Crab Nebula is the expanding remnant of a supernova explosion witnessed by Chinese astrologers in 1054 AD. Like you and I, the saguaro is made of atoms that were formed in starts that lived and died long before the Sun and Earth formed.
A living planet is a legacy of stars long dead.
If you want to know about that cactus I smile at when I drive by, you have to know about mountains. That gets us into the forces that shape Earth’s surface. Convection of hot, viscous rock in our planet’s interior carries heat outward from the center toward the surface. The scum floating on top, otherwise known as the crust, gets shoved around by those convection currents. Tectonic plates crash together, forcing mountains skyward. Friction near plate boundaries heats rock that ultimately reaches the surface, building towering volcanoes.
By the way, the energy powering that convection comes from the radioactive decay of atomic nuclei that were synthesized in the hearts of stars that lived and died long before the Sun and Earth formed. The same can be said for the carbon, nitrogen, and every other chemical element apart from hydrogen that makes up my friend the Saguaro.
To know the saguaro is to know the universe.
And so the story goes. If you really want to know about that cactus, ask biologists studying evolution. Ask oceanographers or climate scientists. Ask geologists or planetary scientists. Ask astrophysicists studying the life cycles of stars. Ask cosmologists studying the origin and evolution of the universe. Ask particle physicists who are grappling with the nature of the dark matter, without which our galaxy would have never formed.
There is a gorgeous Saguaro cactus near my house. If you really want to know about it, you kind of have to talk to everybody. To really understand that cactus is to understand the universe.
A Saguaro’s universe ^ Building a cactus starts with the Big Bang ©
Dr. Jeff Hester
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