Planet Nine might not exist, many astronomers now think

Planet Nine is a theoretical, undiscovered giant planet in the mysterious far reaches of our solar system. The presence of Planet Nine has been hypothesized to explain everything from the tilt of the sun’s spin axis to the apparent clustering in the orbits of small, icy asteroids beyond Neptune. But does Planet Nine actually exist? …

We need faster spaceships. Nuclear-powered rockets may be the answer

With dreams of Mars on the minds of both NASA and Elon Musk, long-distance crewed missions through space are coming. But you might be surprised to learn that modern rockets don’t go all that much faster than the rockets of the past. Iain Boyd, University of Colorado Boulder

Will humans go extinct? For all the existential threats, we’ll likely be here for a very long time

Will our species go extinct? The short answer is yes. The fossil record shows everything goes extinct, eventually. Almost all species that ever lived, over 99.9%, are extinct. Some left descendants. Most – plesiosaurs, trilobites, Brontosaurus – didn’t. That’s also true of other human species. Neanderthals, Denisovans, H. erectus all vanished, leaving just H. sapiens. …

The Sun is less active than sibling stars, study shows – here’s what that could mean

All stars emit varying amounts of light over time – and the Sun is no exception. Such changes in starlight can help us understand how habitable any planets around other stars are – a very active star may bombard its planets with harmful radiation. Now a new study, published in Science, shows that the Sun …

Moon rocks could help reveal how life evolved on Earth

…and may enable us to resurrect extinct species Life is the last thing you would associate with the eternally dark craters of the lunar poles. But these craters could hold the key to explaining how complex, multi-cellular organisms evolved on Earth hundreds of millions of years ago, affording unimaginable insights into our planet’s biological past. …

Evolution: that famous “march of progress” image is just wrong

Evolution explains how all living beings, including us, came to be. It would be easy to assume evolution works by continuously adding features to organisms, constantly increasing their complexity. Some fish evolved legs and walked onto the land. Some dinosaurs evolved wings and began to fly. Others evolved wombs and began to give birth to …

Proxima Centauri c: how we spotted a potential new planet around the Sun’s neighbouring star

Most exoplanets, bodies orbiting stars other than the sun, are too far away for us to be able to send probes to. So it’s no wonder that the discovery of a possibly habitable planet around the sun’s nearest neighbour star, Proxima Centauri, a few years ago generated a lot of excitement. Now we have spotted …

Betelgeuse: star’s weird dimming sparks rumours that its death is imminent

Every season has its characteristic star constellations in the night sky. Orion – one of the most recognisable – is distinctly visible on crisp, clear winter nights in the northern hemisphere. The constellation is easy to spot even in light-polluted cities, with its bright stars representing the shape of a person. Betelgeuse, marking Orion’s top …