Marcelo Gleiser

In his recent book, The Meaning of Human Existence, the celebrated evolutionary biologist, entomologist and essayist Edward Wilson sets off to chart a possible path toward the unification of the sciences and the humanities — taking off from his 1998 book Consilience: The Unity of Knowledge. If we are successful, claims Wilson, we should arrive at a deeply transformative understanding of the meaning of our existence.

Even with all the drama — and now the prolonged silence, possibly permanent — the European Space Agency's (ESA) mission to land a fridge-sized probe on a comet zipping at about 80,000 miles per hour, some 300 million miles from Earth, was a resounding success. This first ever comet landing has captivated the world as very few events in the history — certainly the recent history — of space exploration have.

Every child must leave home one day — but rarely because he has destroyed his home.

The crash of Virgin Galactic SpaceShipTwo over the Mojave Desert last Friday, killing co-pilot Michael Alsbury and seriously injuring pilot Peter Siebold, has renewed discussions on the value of commercial space exploration. Should we continue to do this at the unavoidable cost of human life? Is this simply a moneymaking enterprise so that a few people that can afford the $250,000 price tag can float for a few minutes at the edge of Earth's atmosphere?

Last week, our own Tania Lombrozo ignited an intense discussion of the differences between factual and religious belief. I want to take off from there and examine a no less controversial issue, one that has been in the limelight of cutting-edge physics for the past few years: Do some scientists hold on to a belief longer than they should? Or, more provocatively phrased, when does a scientific belief become an article of faith?

At least when it comes to physical reality, which I define here as that which exists in the cosmos, there is no such thing as complete emptiness.

Quite the opposite, it seems that the more we learn about nature, the busier space becomes. We can, of course, contemplate the idea of a metaphysical emptiness, a complete void where there is nothing, what some people like to call absolute nothingness. But these are concepts we make up, not necessarily things that exist. In fact, calling nothingness a "thing" automatically makes it into a something, a curious paradox.

The other day, I was giving a public lecture when someone asked me a question that I wish people would ask me more often: "Professor: Why are you a scientist?"

I answered that I couldn't do anything else, that I considered it a privilege to dedicate my life to teaching and research. But what's really special in this profession, to me at least, is that it allows us the space to create something new, something that will make us matter. It gives us an opportunity to engage with the "mystery," as Albert Einstein called our attraction to the unknown:

I recently started reading Superintelligence, a new book by Oxford University philosopher Nick Bostrom, who is also director of the Future of Humanity Institute. (Now, that's a really cool job title.)

A recent article in The New York Times explores the explosive wave of smartphone recordings of events, from the most meaningful to the most trivial.

Some of you may have seen "Our Story in 2 Minutes," a 2012 video edited by Joe Bush and with music from Zack Hemsey. As of this writing, it had more than 17.2 million views on YouTube from people all over the world. If you haven't seen it, here is your chance:

Perhaps I shouldn't have used a conditional in the title. After all, we are already creating life.

Recently, Craig Venter, from the J. Craig Venter Institute, announced the creation of a living, self-reproducing bacterial cell with a DNA sequence produced in the laboratory. According to Laurie Garrett's article in Foreign Affairs late last year, the creature "moved, ate, breathed, and replicated itself."

It was the Roman poet Lucretius, writing around 50 B.C., who famously proclaimed reason as a tool to achieve individual freedom, as a means of breaking free from superstitions that enslave the human mind:

"This dread and darkness of the mind cannot be dispelled by the sunbeams, the shining shafts of the day, but only by an understanding of the outward form and inner workings of nature."

Given that science is believed to be about certainty, betting on a scientific idea sounds like an oxymoron.

Yet scientists bet on ideas all the time, even if mostly for jest. Of course, this only makes sense before we have any data pointing toward the correctness of the disputed hypothesis.

Well into the 21st century, it is indisputable that we know more about the universe than ever before.

So that we don't get lulled into a false sense of confidence, today I provide a short list of open questions about the cosmos, focusing only on its composition. These are some of the mysteries that keep many fundamental physicists and astronomers busy and hopeful.

Mortality is humanity's blessing and its curse.

Because we are aware of the passage of time, because we know that one day we won't be here — and neither will everyone we love (and everybody else) — we have always searched for an answer to this most painful of mysteries: Why do we die?

However painful death is, to many people immortality is not any better. Why would someone immortal want to live? Where would his or her drive come from?

The origin of life remains one of the most challenging open questions in science.

We don't know (yet) how lifeless molecules self-organized to become a living entity. We do know it happened at least here on Earth some 3.5 billion years ago, possibly earlier. Perhaps "self-organized" is the wrong word, as it gives the impression that there was some kind of intention, that life is a cosmic goal and not an accident.

Last week, I came across George Johnson's piece for The New York Times, "Beyond Energy, Matter, Time and Space," where he writes, in his usually engaging style, about two recent books with opposite viewpoints concerning what we can and cannot know of the world.

Pages