- The app included on every iOS device and a great way to enjoy a variety of subjects with your morning coffee! ↩︎
What is Earth Made of
One aspect of astronomy that I have grown to love and appreciate is the tie in to the other areas of science. For example, planetary geology which, in turn, ties into our study of our own Earth’s geology. Of course this also ties into chemistry. And biology. And on on and.
This morning as I browsed Apple News1 I came across this very nice introduction to the geology of our planet. A quick read that might lead you to a much deeper exploration.
So, for example, this little bit about the Earth’s crust:
Earth's crust is made up of several elements: oxygen, 46.6 percent by weight; silicon, 27.7 percent; aluminum, 8.1 percent; iron, 5 percent; calcium, 3.6 percent; sodium, 2.8 percent, potassium, 2.6 percent, and magnesium, 2.1 percent.
I always enjoy sharing with folks that particular tidbit about the crust being almost half oxygen. I think we generally think of oxygen as an important part of the air we breath and forget that it’s not just a gas. It’s fun to remind people that it also exists as a primary element in the oxide compounds of the ground we walk on!
Story of a sunset
As the sun begins to set the world around me begins to dance.
As my feet crunch along the rock road below, dragonflies spin through the air just above my head. There are so many of them feeding in the fading light of the day that they form a small swarm. Higher in the air the night hawks perform their own acrobatic maneuvers above the fields, also in search of an evening meal.
Nearby, whitetail deer run across the road just as a light breeze finds this smiling human on a quiet rock road. The movement of air brings a mix of sensations to my skin and a sweet scent to my nose.
In the background of it all a sunlit cloud arrangement, complex in its movement, an ongoing description of the forces creating it.
The earth’s rotation pulls the sun further down.
Earth — Shot on iPhone with Carl Sagan narration
Carl Sagan’s Pale Blue Dot is fantastic and this is a good use of it.
Precarious
As is my usual routine I took my dog Cosmo out for our walk to the mailbox yesterday. Along the way I had a thought about the precariousness of our existence on Earth. We live in this sort of illusion as our daily life is wrapped in an assumption of stability. For the most part our human brains encounter the same environment everyday. Most of us wake up in the morning and are active during the day. The light from our sun scatters in our atmosphere, heating and lighting and otherwise presenting a world around us that seems stable. Somedays are cloudy, others sunny, often a mix of the two. As we go about our days we see a mix of human and non-human species, natural and human environments. We eat and breath, work, play, and talk.
But our life on this planet exists on the thinnest of onion skins. The biosphere of our planet, the zone in which all life happens is remarkably thin. While the actual thickness of the biosphere is not easily measured it generally falls within a range of 6.5 miles. At the highest we have birds flying as high as 1.1 mile and at the depth we have fish 5.2 miles below the water. There are examples of higher flying birds and deeper dwelling organisms but they are exceptions to the general. The diameter of the earth is 7,918 miles. The radius is 3,959 miles. Almost all life on our planet lives on the outer 6.5 miles of that.
As an amateur astronomer I’ve spent a good bit of time viewing and contemplating space and distance. For all of the beauty of the stars in the night sky, space is mostly empty. The space between stars is vast. The space between galaxies even more so. If we just turn our attention to our own solar system and what exists here well, again, it’s mostly empty space. Our Sun makes up 99.86% of the matter in our solar system. Our Earth, though it is the densest planet in the solar system, is only the tiniest proportion of the mass of our solar system. It barely registers. On the scale of our solar system our Earth is merely a tiny point separated from the sun and other planets by vast distances. To get a sense of it watch this amazing video by Wylie Overstreet in which three guys drove out to the desert of Nevada with a to-scale model to demonstrate the spacing of our solar system.
Our lived experience, our world, is just a precarious, thin layer on what amounts to a very tiny planet. On a clear, dark night I can lookup and see several thousand stars with my naked eyes. In remote locations such as mine there is little light pollution and the atmosphere disappears. It is in this star-lit darkness that I can begin to experience the Earth as a space ship of sorts. It really is a living space ship. In our orbit around the sun we move through space at 67,000 miles per hour. But remember, our solar system is also moving around the center of the Milky Way galaxy at 490,000 miles per hour. Of course we don’t see it or feel it directly but it is happening nonetheless.
Life on Earth is precarious. It’s stability is not permanent. Our sense of day-to-day continuity is something we’re used to and something we assume will continue. I’d suggest that if more people had a better sense of how it all works, had a better sense of just how thin the envelope of safety is, perhaps they might be more inclined to take seriously the warning of science regarding climate change, habitat loss and other aspects of biosphere stability. It’s too late to stop much of what we’ve set in motion but if we don’t make real change very soon we will experience the worst case scenarios.
Cosmic Dance
A few weeks back I wrote about viewing the supernova in M82. It was first observed around the same time that an article was circulating about the continuing and drastic decline of Monarch butterfly populations. I had both the supernova and the threat to the Monarch on my mind when I sat down to write about my observation of M82 but I couldn't quite make the connection I wanted to make. A few days ago the Bad Astronomer, Phil Plait, in describing the earlier generations of star birth and death, comes close to articulating what it was I was pondering:
This happened in the Milky Way billions of years ago, and those elements from some long-dead star made their way into you. Your bones, your teeth, your blood, your very DNA have elements in them forged in the heart of a mighty star that violently tore itself to bits so that eventually you may live. It is a transformation on a literally cosmic scale.
I should hope the metaphorical metamorphosis is obvious enough. The only constant in the Universe is change, and much of it is a cycle. Birth, life, death, restructuring, and rebirth. That is also the theme of much of human art, from paintings and movies to myths and great novels.
Some say science is cold, dealing unemotionally with hard data. But that’s far from the reality. Humanity and life are reflected in the stars, and the Universe itself is poetry.
The thoughts I'd had were specific to the harsh reality of extinction on Earth. The Monarch is not there yet but it's numbers have declined drastically. Other species are also in decline and extinctions happen every day. In fact, according to the Center for Biological Diversity we are now experiencing the 6th mass exctinction event of the planet, loosing dozens of species a day:
It’s frightening but true: Our planet is now in the midst of its sixth mass extinction of plants and animals — the sixth wave of extinctions in the past half-billion years. We’re currently experiencing the worst spate of species die-offs since the loss of the dinosaurs 65 million years ago. Although extinction is a natural phenomenon, it occurs at a natural “background” rate of about one to five species per year. Scientists estimate we’re now losing species at 1,000 to 10,000 times the background rate, with literally dozens going extinct every day. It could be a scary future indeed, with as many as 30 to 50 percent of all species possibly heading toward extinction by mid-century .
Unlike past mass extinctions, caused by events like asteroid strikes, volcanic eruptions, and natural climate shifts, the current crisis is almost entirely caused by us — humans. In fact, 99 percent of currently threatened species are at risk from human activities, primarily those driving habitat loss, introduction of exotic species, and global warming. Because the rate of change in our biosphere is increasing, and because every species’ extinction potentially leads to the extinction of others bound to that species in a complex ecological web, numbers of extinctions are likely to snowball in the coming decades as ecosystems unravel.
For most of my adult life I've gone through a cycle of depression connected to or caused by my awareness of what we are doing to the planet and our fellow species. I will never accept what our species has done, is doing, to our planet but I have found a certain peace in the understanding that the Universe will go on regardless. Our fragile planet and the life on it has an end date. In 600 million years our sun will have have increased in luminosity significantly and the carbon cycle plants depend on will shift causing mass die-off of plant life and animal life. By the time the sun transitions from a main sequence star (4.5 bililon years from now) life on the planet will have long since disappeared. Such is the case for all life supporting planetary systems in the Universe. All stars have a limited lifespan.
The Monarchs will end. Humanity will end. Our planet, our solar system and our Sun will all have an end. So it goes. The cosmic dance will continue... for awhile anyway. What can we do but live our lives in the best possible way? I for one will try to live with a respect for the fragility of life on this Pale Blue Dot and with an understanding that the star stuff that makes up my body and this planet will one day be pushed forth into the Cosmos.
Of Monarchs and Birthdays
It’s Royal’s birthday so I’ll put on a happy face. But this. This. I’m having a real hard time imagining a summertime without Monarchs. What else will we kill off because we don’t know how to live within limits, don’t know how to live as species that recognizes the needs of other species. Every grass lawn, every golf course is a problem.
Prime example, I’ve just had a bit of a family kerfluffle because now that I’m not living at the lake they are making changes. Gone are the native wildflowers, including the butterfly milkweed I planted (the exact food source mentioned in this article), the coneflowers, etc…. replaced by? Grass. Every area we humans occupy (at least those of us I have come to know in my life) we insist upon wiping nature clean with a green lawn or concrete.
Of course I often hear “Oh what does this one little patch matter”? There’s more growing over there (wave hands in some direction). It is as though we each live in a bubble and unwilling to acknowledge that what we do matters because millions (in this nation) of others are doing it as well. The denial of collective behavior and collective effect is very intentional.
So, today Monarchs. Tomorrow?