Kate Comisso

If history is written by the victors, the story of life on Earth belongs to blue-green cyanobacteria. Since they first appeared in the oceans perhaps 3 billion years ago, they are thought to have caused mass extinction, triggered climate change so catastrophic that even the equator was covered in glaciers, and taken dominion over the land by embedding themselves into every plant in the world. Spirulina /by Will Power / CC BY-ND 2.0 That's quite a profile for simple little blue-green bacteria that we usually come across as toxic “scum” on ponds, or as health-promising spirulina. When cyanobacteria first evolved, there was very little oxygen in the Earth’s atmosphere, and hence no ozone layer to block out the Sun's deadly UV radiation. Primitive life therefore confined itself to the oceans, using chemicals such as sulfur to make food. Cyanobacteria did things differently. It absorbed the sun’s energy to make food by photosynthesis, creating oxygen as a by-product, ju

In a few weeks’ time, the oyamel fir forests high in Mexico’s mountains will start to twitch. Millions of orange and black wings will lift from the trees, as overwintering monarch butterflies leave their winter shelter to start their last journey. The flight ahead is short compared with the one they made late last year, but their fat reserves from autumn feasting are down to just a few milligrams. The priorities now are to mate and to find milkweed on which to lay their eggs, providing food for the next generation. Monarchs in Motion/Image: Tarnya Hall / CC BY-NC-ND 2.0 These butterflies were themselves born under a milkweed leaf perhaps 2500 miles away, as summer neared its end last year. How did they find the energy for such an arduous journey, and how did they all find their way from across the northeastern USA and Canada to just a dozen overwintering sites in Mexico? The flapping of wings would not take the monarch butterfly very far. The small body can scarcely carry enough

In 1905, long before Albert Einstein was a household name, the young man spent his days assessing inventions as a patent clerk. I suppose that made physics his hobby. Yet that year he reasoned his way to a whopping four papers, plus a doctoral thesis. These weren’t minor papers making incremental advancements in an esoteric area of knowledge. These were game changers. Among them, Einstein changed the way scientists perceive light, and unified time and space. Einstein’s iconic equation didn’t appear until the last of his papers that year. It was a short paper, almost an addendum to his earlier work on special relativity, a short paper in which Einstein reached "a very interesting conclusion”: that mass and energy are two forms of the same thing. E=mc 2 . Energy is equal to mass multiplied by the speed of light squared. Since the speed of light multiplied by itself is a very large number, a little bit of mass is equivalent to a huge amount of energy. Energy and mass ar

Show a young child a feather and they will proudly say, “bird”. Show an older child the feather and they might gleefully say, “dinosaur”. It’s a source of smugness my generation missed out on because, back then, dinosaurs were supposed to be covered in scales, not to mention extinct. What changed, and if birds really are dinosaurs, why did it take so long to make the connection? Archaeopteryx  / by  Peter Montgomery / CC BY-NC 2.0 The first “missing link” between reptiles and birds was found way back in the 1860’s. Archaeopteryx had a long tail with many vertebrae, as well as strong curved claws - like a dinosaur - but its feathered wings were enough to define it as a primitive bird by simply stretching the definition of birds. When teeth were found on some specimens (the first discovery was headless), the solution was to stretch the definition of birds a little further. Enter Thomas Henry Huxley, the outspoken champion of Darwin’s freshly minted theory of evolution. In a

It’s not the prettiest of telescope images. It doesn’t have the majesty of spiral galaxies, nor the sharp chic of Saturn’s rings. The color scheme is not exactly appealing, and there’s nowhere obvious to focus. Yet it's one of my favorites, a snapshot of the universe as it was in its infancy. Planck CMB / Image: ESA and the Planck Collaboration Some 13.7 billion years ago, a mere 380,000 years after the Big Bang, photons of electromagnetic radiation were set loose to journey across the universe. Up until that time, photons couldn’t travel far without being scattered by free electrons, in the same way that photons of light on Earth get scattered by fog. As a result, the universe itself was opaque, one giant fog. That changed when the universe cooled enough that electrons could no longer roam free, but were bound to protons as hydrogen atoms. With the electrons tied up, the photons were on their way. Those photons are travelling still, some of them are passing us now, but the