1. Are we alone in the universe?
We’ve now found over a thousand planets outside our solar system, and are starting to work out what those planets are like. We’ve also sent out messages to the cosmos by radio waves and on spacecraft. But scientists have not yet found a planet that would be habitable by creatures like us. Or picked up any alien transmissions. Some think it’s only a matter of time, but others are doubtful – the vast scale of the universe might mean we’re destined to think we’re alone forever, even if we’re not.
2. How did Tyrannosaurus rex evolve from its tiny ancestors?
T. rex lived during the Cretaceous period, between 145 million and 66 million years ago. Before that, in the Jurassic period, was a smaller, fluffier dinosaur that would go on to become the mighty T. rex. “They were more lapdogs than top predators,” Stephen Brusatte of the University of Edinburgh, UK, told Nature. More fossils from the beginning of the reign of the the Cretaceous era T. rex are needed to solve the mystery.
3. What is dark matter?
We’ve never seen dark matter, but its existence seems necessary to explain many observations of the universe. Recent experimental results have told physicists a lot about what dark matter isn’t. But they’re really struggling to get a handle on what the elusive substance is. The latest result, from an experiment called LUX, didn’t find any dark matter, and actually contradict hints of the stuff seen by other experiments.
4. Why are the bees disappearing?
More than a third of the food we eat is dependent on pollination by bees. But colonies of honey bees began dying in their droves a few years ago, and scientists don’t know why. Beekeepers and scientists are calling the phenomenon of apparently healthy colonies disappearing from their hives ‘colony collapse disorder’. Although it seems to be caused by a combination of parasites, agricultural chemicals and poor nutrition, no direct links have yet been established – but scientists are working on it.
5. Why does hot water freeze faster than cold water?
This apparent paradox has been a mystery to scientists for thousands of years. Last week a study was published with a possible explanation – hot water has stronger bonds between molecules, so it can release energy faster when put in a freezer – but that’s unlikely to be the full story. It may seem like a small question in the grand scheme of things, but it does have some real world applications, such as how you should defrost your car’s windscreen.
6. What would happen if you fell into a black hole?
It used to go like this: you’d barely notice at first, but then you’d begin to feel gravity pulling at your feet a bit harder than your head, until eventually you were ripped apart and crushed in the infinitely dense centre of the black hole. But new calculations in 2012 suggest the black hole’s victim would hit a wall of fire and be burnt to a crisp. If the firewall theory is true, general relativity breaks down. But if the previous theory is right, quantum mechanics is in trouble. At the moment physicists don’t know which way to turn.
7. Why do humans have so few genes?
Before the human genome project was completed, scientists expected us to have between 50,000 and 140,000 genes. But it turns out we only have between 20,000 and 30,000. That might sound like a lot, but it’s fewer than a tomato and a grape. This revelation has led scientists to realise that there is more to our genome than just its genes. Non-coding DNA, aka “junk DNA”, seems to play an important role too. Exactly how all the aspects of our genome work together is a question many scientists are trying to address.
8. Why is there more matter than antimatter?
Matter and antimatter are almost exactly alike, except one crucial difference: they have the opposite charge. When a particle meets its antiparticle, they annihilate each other. At the beginning of the universe, scientists think there were almost exactly equal quantities of matter and antimatter. If they’d been exactly equal, the whole universe would have been annihilated before it had really begun. But we don’t know where the initial imbalance came from.
9. Where does consciousness come from?
This is a tough one, and scientists might never be able to explain what consciousness is. But they should be able to at least help define the questions we ask about it. Descartes thought mind and body were completely separate, but scientists studying that brain are challenging that notion. Are the billions of neurons in your brain really you?