At last the complex map was complete. "I remember this moment," says Viren Jain, a neuroscientistNeuroscience is the study of the brain and nervous system. There is a lot of overlap between neuroscience and psychology, but neuroscientists tend to focus more on the way that nerves function. who works for Google:¹ "going into the map and looking at one individual synapseThe point at which signals move from one nerve cell to another. from this woman's brain - and then zooming out into these other millions of pixelsThe smallest unit of an image on a screen. ." It felt, he adds, "sort of spiritual."

The fragment of brain he was looking at was 1 cubic millimetre in size - equivalent to a sharpened pencil point. But scientists managed to cut it into 5,000 slices, each 34 nanometres thick. That is about as much as a fingernail grows in 30 seconds.

The slices were photographed using electron microscopesA device which uses a beam of electrons to make a big image of a small object. . Then Viren Jain put all the photographs together and used them to create a 3D map.

The map covered roughly one millionth of the brain. It showed around 57,000 cells and 150 million of the connections between neuronsNeurons, also known as nerve cells, are cells in the nervous system that use chemical or electrical signals to transmit information throughout the body.  known as synapses.²

The map also revealed some amazing things about neurons. There were pairs that were almost mirror images of each other. And some had tendrils that formed knots around themselves.

The map is a triumph of science. But at the same time, writes David Von Drehle in The Washington Post, it is an "awe-inspiring" example of our ignorance. The map shows that we are nowhere near a basic understanding of how the brain works.

Humans tend to think that "our understanding of ourselves and our universe and our place in it is nearly complete... In truth, the more we learn, the less we know for certain".

He gives the findings of the James Webb Space TelescopeA high resolution space telescope that overtook the capabilities of the Hubble telescope. It was launched in December 2021. as another example. But rather than be discouraged, we should be excited:

"The age of discovery is only beginning, and its duration is limited only by our willingness to learn and grow. To see the miraculous tangle of connections... is to find nearly infinite possibility and to feel a surge of hope."

Is this the dawn of a new age of discovery?

Yes: The making of the map is a really astonishing achievement, as is the James Webb Space Telescope. Now we have AI there is no limit to the expansion of our knowledge about ourselves and the universe. 

No: You cannot draw a line between one age and the next, because every scientific advance depends on what others have done before: even Isaac Newton spoke of "standing on the shoulders of giants".

Or... It may be, but it is important to look backwards as well as forwards. We can learn as much from history as we can from science, and the most traditional ways of doing things are often among the best.

Neuroscientist - Neuroscience is the study of the brain and nervous system. There is a lot of overlap between neuroscience and psychology, but neuroscientists tend to focus more on the way that nerves function.

Synapse - The point at which signals move from one nerve cell to another.

Pixels - The smallest unit of an image on a screen.

Electron microscopes - A device which uses a beam of electrons to make a big image of a small object.

Neurons - Neurons, also known as nerve cells, are cells in the nervous system that use chemical or electrical signals to transmit information throughout the body. 

James Webb Space Telescope - A high resolution space telescope that overtook the capabilities of the Hubble telescope. It was launched in December 2021.