"To know, is to know that you know nothing," said Socrates, the famed ancient Greek philosopher.
By Lauren Cahn
And while we know a LOT thanks to science, there’s still so much that we don’t know.
These mysteries have stumped scientists throughout the ages—and will leave you scratching your head.
1. How did the universe form?
A few things we know about the universe: it’s infinite, it’s littered with black holes, and thinking about it can make your brain hurt.
And one of those things we don’t know: how it began. Even otherwise all-knowing Stephen William Hawking, PhD, theoretical physicist, cosmologist, and director of research at the Centre for Theoretical Cosmology in Cambridge, England, isn’t sure.
Some brilliant minds wonder if it even had a beginning at all, or if it was always there.
2. What happens inside a black hole
Black holes are places in space where gravity is so strong that even light can’t escape, so no one has ever been able to say what happens inside a black hole.
That said, Dr. Hawking has theorized that rather than being stored within the deep clutches of a black hole, information from “within” a black hole actually remains outside of it (in the “event horizon”) and is therefore theoretically accessible. (Still with us?)
Of course, since the event horizon is outside the black hole, the theory itself is a paradox.
3. The fate of the universe
Just as scientists haven’t figured out how the universe started, they haven’t figured out how it will end.
They do know that life on earth can’t continue forever, because life on earth is supported by the sun, which, like all stars, will eventually die.
And they do know the universe will end, but how that will happen depends on many unknowns (including the shape of the universe, its density, and the amount of dark matter within it).
4. Speaking of dark matter...
Scientists believe that most of the universe is made up of “dark matter,” which does not emit light or energy.
While scientists can tell you what dark matter is not, they can’t tell you what it actually is, or what it is composed of.
“We have a complete inventory of the universe,” Sean Carroll, a California Institute of Technology cosmologist, told Smithsonian Magazine, “and it makes no sense.”
And until scientists can make sense of it, the fate of the universe shall remain forever unknown.
5. How did life start?
We’re talking about life, not just human life, here.
There’s no shortage of scientific speculation, and new findings turn up all the time about how life’s basic building blocks could have been generated in primordial conditions or delivered to Earth from outer space.
And it’s not like scientists can even agree on which area of science will provide the answer, or if science is even where we should look.
6. Egypt's great pyramids
Constructed between 2589 and 2504 B.C., the Egyptian pyramids would be a wonder of engineering and physics even if they had been built today.
So how did those ancient people living in the ancient desert manage it?
There are legitimate scientists who believe aliens from another planet must have been involved.
Other scientists believe the answer lies in ramps, wet sand, and pulleys.
What we do know is that we don’t know.
7. Is there intelligent life outside of earth?
The Great Pyramids. Stonehenge. Crop circles. How’d any of this happen without help from intelligent life from somewhere beyond our own planet?
While we haven’t found signs of extraterrestrial intelligent life, wouldn’t basic probability lead to the conclusion that somewhere out there are beings who have at least as much intelligence as earthlings?
But let’s say there was such a thing as extraterrestrial intelligent life – would we even be able to recognize it with our earthling senses?
For now, the whole thing remains a mystery.
8. What are those strange radio bursts from space?
Somewhere “out there,” something’s making quite a racket.
Scientists have observed huge blasts of radio waves coming from three billion light-years away (based on incredibly complicated calculations).
“People love to believe they’re from an advanced extraterrestrial civilisation, and this hypothesis hasn’t been ruled out entirely by researchers at Breakthrough Listen, a scientific research program dedicated to finding evidence of intelligent life in the universe,” according to CNN.
But no one knows, and there are many other hypotheses, including those involving black holes and dying stars.
9. What on earth are tardigrades?
You may have heard of tardigrades, aka eight-legged microorganisms that are often found around mossy trees.
They can live without water, withstand temperatures from -328 to 304 degrees Fahrenheit, and even survive in outer space.
Their incredible survival skills have led some to speculate they actually came from outer space, but scientists believe they did originate on earth.
That said, even with the most elaborate of gene sequencing, scientists have not been able to figure out exactly what tardigrades are or even the phylum to which they belong.
Could they be insects? Worms? Crustaceans?
10. Why do we sleep?
We know the human body is regulated by a sleep-wake cycle.
We know we spend nearly a third of our lives snoozing. We know our bodies repair themselves during sleep. We know that we dream during sleep. We know the many ways that sleep affects our bodies.
But not all living organisms require sleep. So then why do we?
One promising theory is that sleep plays a major role in the brain’s plasticity.
Scientists are following that trail as we speak (by studying “glia” cells), so stay tuned.