by James Morris
On the first anniversary of this blog, I thought it would be interesting to look at what we know, what we think we know, and what we don’t know. Enjoy!
We walk around with all kinds of knowledge. Most of us can name the first president – George Washington. Around New England, and certainly elsewhere, we all know that Boston is the capital of Massachusetts. Most of us realize that Shakespeare wrote Hamlet and Romeo and Juliet.
And then there are shared, common sayings: “An apple a day keeps the doctor away.” Everyone knows that. Or, “People in glass houses shouldn’t throw stones.” Whatever that means.
Most of us probably know that DNA is the “blueprint of life.” Its structure is iconic – a double helix, like a spiral staircase. Those of us who recall high school biology might even be able to remember DNA’s four bases – A, C, T, and G.
That’s all common knowledge.
Then there are simple facts that are known, but most of us don’t know. What’s the capital of Montana? Or how about Nigeria? What year was the Battle of Gettysburg? What does LASER stand for? (and did you know it’s an acronym?) The answers, for those of you who just have to know, are: Helena, Abuja, 1863, Light Amplification by the Stimulated Emission of Radiation, and it is.
And there are things we think we know, but actually don’t. For example, we often say that the sun is only up during the day and the moon is only up at night. This is true of the sun, but not of the moon. The moon is up during the day as much as it up at night; only the full moon is up all night. And scholars argue whether Shakespeare really wrote Shakespeare.
There are also complex ideas that only a few of us know, like quantum mechanics or relativity or string theory.
But I am struck with another category – aspects of the natural world that are well known and established, that you might think would be shared knowledge, but that most of us really don’t know, or can’t recall, or maybe never knew in the first place.
Like the age of the Earth. That’s something that you might think we all would know, but in fact, if you ask students in a classroom or people on the street (or yourself), you may be surprised. Most people do not walk around with this kind of information in their back pocket.
The answer is 4.6 billion years old. Or, more accurately, 4.567 billion years old, which seems like it holds some sort of cosmic significance to me, in that we only came to the answer when, improbably, it is a string of consecutive numbers.
It’s also kind of surprising to me to learn that most of us don’t realize that the universe is older than the Earth. In other words, the two didn’t form at the same time. If we stand at a point of time that represents the formation of the Earth, with the history of life extending to the right like the words on this page, what’s to the left? It’s the vast stretch of time between the formation of the Earth and the Big Bang, about 14 billion years ago.
Why do we know some things and not others? Why do some facts stick and others don’t? Why do we remember that DNA is a double helix but not that the Earth is 4.6 billion years old?
Perhaps the reason is trivial – numbers come and go easily, but the double helix shows up not just in textbooks, but all over the place – on billboards, magazines, even t-shirts. Or perhaps it reflects what we learn in school, and the emphasis placed on some facts over others. Or maybe we never learned it in the first place, though it is part of our common heritage as a resident of this planet.
Not long after the formation of the Earth, life originated and later diversified spectacularly. How diverse is it? How many species share our planet with us? This again is one of those questions that you would think we would all know – like our first president – but in fact most of us don’t – like the age of the Earth.
But this one is different, in that no one really knows. And the funny thing is that most people probably think we do know it.
We of course can count the number of species that have been given a scientific name – that number is around 2 million. But beyond that, we have just estimates based on what we do know. These numbers range from roughly 10 million to as many as 100 million species alive today, sharing our planet with us.
As a teenager, I read a book called Life on a Little-Known Planet by Harvard University entomologist Howard Evans. I still remember this book for its insightful and witty look into the largely unknown world of insects (at least to me at age 15). The book is at once whimsical – with chapter titles like “The Intellectual and Emotional Life of the Cockroach” and “In Defense of Magic: The Story of Fireflies” – and also informative.
Evans taught me how much I didn’t know about creatures that are right under my nose. He also reminded me how uncommon some forms of knowledge really are, that it’s worth taking a closer look not just at what we don’t know, but also at what we think we know. It is in these areas where we can ask questions, where science begins, and where surprises might be in store for us.
© James Morris and Science Whys, 2015.