Of Space and Time
"Vast" doesn't begin to cover it
Well it has been a good break. Thank you to all my readers for giving me the time away from The Chalkboard Life. I hope you also took the time this summer to recharge and rest from your labors during the school year. We will need those batteries full to charge into the classroom brimming with commitment and excited about the possibilities new students bring. Renewal in the best sense awaits.
As promised, it is August 6, and I am back. Covid recovered, and somewhat exhausted from the garden projects, and pointing toward meeting two new groups of students in just over a week from today. Busy with Syllabi and wrangling our Canvas home for the year. It will come together, I’m sure. Or, I’m pretty sure. Maybe.
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Something happened this summer that I want to reflect on with you for today, and to see where it might lead us in our teaching. Not just for the Physics teachers, but all of us who teach something else.
I am referring, of course, to the Webb Telescope’s first images, released on July 12th. I know this seems like old news, but that is part of my point. Can we ever really make it old news? The astonishment factor seems to have passed, and I think there is something off about that. I will review a few facts here to bring it back to mind, and to consider the numbers perhaps more deeply than we did on first hearing.
The telescope was a $10 Billion project, and it suffered innumerable delays and cost overruns, taking over more than 30 years to design, build, and send into space. Launched on Christmas Day, in South America. A Christmas present to the world - to all of us.
Sent into space, to a place called “L2” - which stands for the Second Lagrange Point, a perfect combination of gravity and orbital mechanics for a telescope, which is located a million miles from earth. The earth itself is 25,000 miles around. So that’s forty times around the earth away from us. Out there, it is minus 447 degrees Fahrenheit (- 266 Celsius). The coldest temperature ever recorded on earth is minus 128 degrees Fahrenheit, and humans can not survive much lower than minus 100 degrees Fahrenheit, and at that, not for long. So where the Webb telescope set up shop in space is four times colder than we humans could survive.
Imagine working on the Webb project for 20 or 30 years of your life. A fragile set of mirrors and mechanics and computers, folded up into a rocket, and shot into space to this magical, intensely cold place. If it did not unfold correctly - a process with over 300 points of failure - your work is done, billions wasted. But it did. If the mirrors could not be properly aligned - with signals sent over a million miles from earth - your work and the money spent is a loss. But it unfolded perfectly, and the mirrors aligned perfectly. The scientists and engineers who did this are themselves astonished at how well the telescope is working.
On July 12, five images were released. You have seen them. I will just focus on two. Before doing so, it is helpful to be reminded of two facts known before Webb: Earth is part of the Milky Way galaxy - we all learned that in school, yes. But I do not remember being taught that earth is 25,000 light-years from the center of the galaxy and 25,000 light-years away from the edge of it. To give you a sense of how far that is, if a person were in the space shuttle - which travels roughly five miles per second (or 18,000 miles per hour) - it would take 37,000 human years to travel one light year. The second fact it is helpful to be reminded of is that each light-year is the equivalent of 5.8 Trillion miles.
SMACS 0723: “Deep Field”
This image is said to cover the portion of the universe you could see if you held a grain of sand at arm’s length standing on the earth. In that tiny amount of sky, the Webb discovered dozens and dozens of galaxies, many of them the size of our own. The light from the most distant of those galaxies and collected by Webb in this photo originated more than 13 Billion years ago. For reference, the oldest human artifacts on earth ever found were 2.5 million years old, and human language was first developed 35,000 years ago. So the light the Webb recorded in this image predates human existence on earth by roughly 12 billion nine hundred ninety seven million years.
The Carina Nebula
This image looks like something we can understand, sort of. It looks like a sand dune, or a Mountain range. It is part of the Carina Nebula, a swirling cloud of dust that begets stars, and contains some of the most luminous stars in our Milky Way. Being part of our own galaxy, it seems at first more understandable and reachable than the Deep Field image above. And yet, it is 7,600 light years away from us, or 44 thousand trillion miles. The image seems understandable at first, and yet it is 7 light years across, or 40 trillion miles across. It would take 260,000 human years to traverse it at speeds we currently have achieved in space. These are times and distances that - despite the numbers - are impossible for the human mind to truly comprehend.
What is the impact of this knowledge, and how should it inform what we teach?
Perhaps the most important thing - which we knew before Webb, but not quite this vividly - is that each of us are but specks. We go about our daily business, making breakfast, driving to work, etc. and it often seems like that is all. But it is not. There is a vast universe around us, which is essentially impossible for humans to fully fathom. So we choose not to try, most days. But I think we lose touch with our insignificance at our peril. We must continually teach, and remind, our students of this reality - in one way or another. And remind ourselves too. Humility is an important human skill, and we must cultivate it in ourselves, and in our students.
Second, I think there are many people today who believe that technology will solve everything. Looking at the Webb Telescope, one can see why many have a strong faith in technology - it is breathtaking as an instrument, not just in the photos it is producing (and will produce). But I think we also do that at our peril.
I thought it was interesting that the Webb scientists partly justified the $10 Billion cost on the basis that it will help us look for life elsewhere in the universe. A notion of nearly endless human fascination, the subject of many books and films. But if these images do anything - at least for me - they indicate yet again that earth is all we have. We only had to go as far as Mars (with a rover) to learn that, and we have. But looking this far, this deeply into space… there’s nothing there but dust and stars and galaxies of stars. It is colder than a human can function by a factor of four. If anything, this should remind us that earth is it, and we must take better care of our home. We are in danger of destroying it - one way or another - and then what will we have? The idea that we are going to build a rocket ship to travel trillions of miles over multiple generations of human lives is quite obviously preposterous. Putting our hope in such a solution is the opposite of humility, and I fear it just hastens the demise of our planet.
Please post your comments with ideas for how we teach the vast and limitless notion of the Universe in ways that matter to our students on earth, and for its future.
Letters of Recommendation
In 1990, as the Voyager space craft was about to leave our solar system, Carl Sagan asked NASA to turn it around and take a picture of earth. This is what it sent back:
He wrote a book about it, which I recommend this week: Pale Blue Dot, a Vision of the Human Future in Space. His view was that human were doomed on earth - at some point an asteroid would hit us - and so to save the species, we had to explore space. But in the meantime, we had to take care of that pale blue dot.
Q of the Week
The Q of the Week this week is a Quote from Carl Sagan in the “Pale Blue Dot” book recommended above:
From this distant vantage point, the Earth might not seem of any particular interest. But for us, it’s different. Consider again that dot. That’s here. That’s home. That’s us.
On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.
The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every ‘superstar,’ every ‘supreme leader,’ every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.
The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that in glory and triumph they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner.
How frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.
The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.
It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.