Unanswered Questions for Humans.

Are We Alone In the Universe?

The mathematical odds say no: There are hundreds of billions of stars in our own galaxy, the Milky Way, and hundreds of billions of galaxies in the universe. Close to home, scientists have already discovered 150 planets orbiting nearby stars. In short, scientists say the universe is likely full of places where the conditions are ripe for intelligent life to evolve. "The really big question is when, if ever, we'll have the technological wherewithal to reach out and touch such intelligence," writes Richard A. Kerr. We haven't been able to discover any other signs of life but the quest is ongoing.


How did life begin? 

Life appeared on Earth some 3.5 billion years ago, perhaps earlier. Four billion years ago, something started stirring in the primordial soup. A few simple chemicals got together and made biology – the first molecules capable of replicating themselves appeared. We humans are linked by evolution to those early biological molecules. But how did the basic chemicals present on early Earth spontaneously arrange themselves into something resembling life? How did we get DNA? What did the first cells look like? More than half a century after the chemist Stanley Miller proposed his "primordial soup" theory, we still can't agree about what happened.

What makes us human?

Just looking at your DNA won't tell you – the human genome is 99% identical to a chimpanzee's and, for that matter, 50% to a banana's. We do, however, have bigger brains than most animals – not the biggest, but packed with three times as many neurons as a gorilla (86bn to be exact). A lot of the things we once thought distinguishing about us – language, tool-use, recognising yourself in the mirror – are seen in other animals. Perhaps it's our culture – and its subsequent effect on our genes (and vice versa) – that makes the difference.

Why do we dream? 

We spend around a third of our lives sleeping. Considering how much time we spend doing it, you might think we'd know everything about it. But scientists are still searching for a complete explanation of why we sleep and dream. Subscribers to Sigmund Freud's views believed dreams were expressions of unfulfilled wishes – often sexual – while others wonder whether dreams are anything but the random firings of a sleeping brain.

Why does matter exist? 

According to the laws of physics, matter shouldn't exist on its own; each particle of matter, each electron, proton, neutron, should have a companion of antimatter, like twins. So, there should be positrons, antiprotons and antineutrons in abundance. But there aren't. The problem is that when matter and antimatter meet, they disintegrate in a puff of high-energy radiation. If you shook hands with your antimatter other, a good chunk of the United States would blow up in smoke. So, the mystery is what happened to this antimatter. Clearly, if the universe had equal amounts of both earlier on, something happened to favor matter over antimatter.

What's at the bottom of the ocean?

Ninety-five per cent of the ocean is unexplored. What's down there? In 1960, Don Walsh and Jacques Piccard travelled seven miles down, to the deepest part of the ocean, in search of answers. Their voyage pushed the boundaries of human endeavour but gave them only a glimpse of life on the seafloor. It's so difficult getting to the bottom of the ocean that for the most part we have to resort to sending unmanned vehicles as scouts. The discoveries we've made so far – from bizarre fish such as the barreleye, with its transparent head, to a potential treatment for Alzheimer's made by crustaceans – are a tiny fraction of the strange world hidden below the waves.

Why is there stuff?

You really shouldn't be here. The "stuff" you're made of is matter, which has a counterpart called antimatter differing only in electrical charge. When they meet, both disappear in a flash of energy. Our best theories suggest that the big bang created equal amounts of the two, meaning all matter should have since encountered its antimatter counterpart, scuppering them both and leaving the universe awash with only energy. Clearly nature has a subtle bias for matter otherwise you wouldn't exist. Humans themselves are very complicated and so is the universe, the mysteries that it holds perhaps will always stay a mystery.

What is the universe made of?

Astronomers face an embarrassing conundrum: they don't know what 95% of the universe is made of. Atoms, which form everything we see around us, only account for a measly 5%. Over the past 80 years it has become clear that the substantial remainder is comprised of two shadowy entities – dark matter and dark energy. The former, first discovered in 1933, acts as an invisible glue, binding galaxies and galaxy clusters together.Unveiled in 1998, the latter is pushing the universe's expansion to ever greater speeds. Astronomers are closing in on the true identities of these unseen interlopers.

How did languages begin?

The origin of human language—the ability of men and women to communicate with one another in intelligent, symbolic, often abstract speech and writing is a complete mystery to evolutionists. Evolutionary paleoanthropologists claim that they have certain tenuous evidences of human physical evolution in the various fragments of hominid skeletal parts that have been excavated in Africa and elsewhere. But they have no evidence whatever for the origin of language—and language is the main entity that separates man from the apes and other animals.

What is the mystery of Prime numbers?

The fact you can shop safely on the internet is thanks to prime numbers – those digits that can only be divided by themselves and one. Public key encryption – the heartbeat of internet commerce – uses prime numbers to fashion keys capable of locking away your sensitive information from prying eyes. And yet, despite their fundamental importance to our everyday lives, the primes remain an enigma. An apparent pattern within them – the Riemann hypothesis – has tantalised some of the brightest minds in mathematics for centuries. However, as yet, no one has been able to tame their weirdness. Doing so might just break the internet.