Marcelo Gleiser

As the fox told the prince in Antoine de Saint-Exupéry's wonderful fable The Little Prince: "What is essential is invisible to the eye."

If the fox had not been talking about love, she could have been referring to the elementary particles of matter, the building blocks of everything that exists. The poetry here is in knowing that the world is made of tiny, invisible bits of stuff that carry, in them, the story of creation itself.

On Tuesday, Elon Musk's SpaceX successfully launched its most ambitious rocket to date, the Falcon Heavy.

This is a transformative spacecraft, a behemoth that essentially straps three Falcon 9 rocket cores together. At 224-feet tall, it's smaller than NASA's giant Saturn V (363 feet) — but it is the largest privately built spacecraft to date. The Falcon Heavy is capable of lifting 70 tons of payload to low-Earth orbit and almost 30 tons to a geostationary transfer orbit.

If Victorians were offended by Charles Darwin's claim that we descended from monkeys, imagine their surprise if they heard that our first ancestor was much more primitive than that, a mere single-celled creature, our microbial Eve.

I'm old enough to have grown up in a household with a single rotary telephone.

I imagine that most children would not know what to do with one today. Conversely, my grandparents, if I could bring them back to life, would have had no idea of what to do with a smartphone.

Technology changes the way we live — and it also changes us.

In the 19th century, Ralph Waldo Emerson wrote in his essay Nature: "A man is a god in ruins."

Ever since people contemplated the existence of a divine dimension — and this belief must go back to the very early stages of Homo Sapiens or even earlier — with Neanderthals, a split occurred between the human condition and the eternal.

As humans, it is our curse and our blessing to be aware of our own mortality — and to suffer with the loss of our close ones — and, in a broader sense, with the predicament of others.