How can the Sun keep shining with its furnace switched off? Two nineteenth-century aristocrats, Helmholtz and Lord Kelvin, worked out the answer mostly by accident. It comes down to stored heat, gravitational shrinking, and the strange self-regulating thermostat of hydrostatic equilibrium.

When someone asks me what originally got me interested in space exploration, my answer is always the same - the Hubble Deep Field. That image, taken in 1995, came out when I was in middle school, and had an everlasting impact on my sense of place in the universe. It’s since been improved upon by various other images, and even last week the Hubble team released yet another jaw-dropping image of the galaxy cluster MACS0329-0211 which recaptures some of the magic of that original image, and still provides the same sense of scale that never seems to truly fade once you come to terms with it. While the original Hubble Deep Field was a blind experiment to see what lay in a seemingly empty patch of sky, this new image comes from the targeted Cluster Lensing and Supernova survey with Hubble (CLASH) program, focusing on the dynamics of a specific massive galaxy cluster.

We think of atomic clocks as the definitive timekeepers. They are famous for being accurate down to the picosecond. Unfortunately, they are still subject to general relativity, so if you put them on a different planet, they will track time slightly faster or slower than on Earth, depending on the planet’s gravity. In Mars’ case, an atomic clock on its surface is sitting in a slightly shallower gravity well, meaning that time moves slightly faster there. Therefore, as we begin to expand our technological footprint on the Red Planet, we will need a way to standardize how time is measured there. Dr. Slava Turyshev, a researcher at NASA’s Jet Propulsion Laboratory, proposes just such a framework in a new paper available in pre-print on arXiv.

Even at this early stage in our space faring age, humanity has already begun sending probes that will eventually reach other solar systems, even if that was not their original intention. Five robotic explorers - Pioneer 10 and 11, Voyager 1 and 2, and New Horizons - are all on escape velocities out of the solar system, and might someday enter another one. They will no longer be operational at that point, but they serve as a proof of concept that spacefaring civilizations do indeed build interstellar probes. Which raises the obvious question - has anyone else sent their own robotic explorers to ours? In a recent paper, published in the Proceedings of the IAU Centenary Symposium, astronomer T. Joseph W. Lazio, points out a painful truth - we still have no idea, and our technology will need to get much better if we plan to find out.

Our search for technosignatures - clear signs of advanced civilizations beyond Earth - takes many forms. Many are driven by the famous Drake equation, which attempts to estimate how many technological civilizations there are in the Milky Way. However, there’s a big fat question mark at the end of that equation in the form of a variable intended to account for the “longevity” of a civilization. And to be clear, that doesn’t mean how long the civilization itself survives. It simply means how long it actively creates a signature that is detectable by our current technology. A new paper, available in pre-print on arXiv from Oxford astrophysicist Brian C. Lacki, argues that, since the chances of us overlapping in time with any such civilization are miniscule, we’re much more likely to find the ruins of a “dead” civilization - and, surprisingly, the best place to do so might be in our own solar system.

If the Sun's fusion shut off right now, you would not notice for a very long time. The first stop is understanding the Sun itself: a vast pile of gravitating matter where fusion is so absurdly inefficient that, pound for pound, a compost heap beats it.

One of the hardest things to calculate for an asteroid is its mass - but it is such a critical feature. It determines how much of an impact it would have if it hits something, or how many resources are potentially available on it. But to accurately measure it we typically use optical sensing and a guesstimate of its density based on its spectral profile. A new paper suggests a completely novel way to use the Laser Interferometer Space Antenna (LISA) flagship mission to potentially provide highly accurate mass calculations for nearby asteroids without any change in hardware.

We have spent centuries being knocked off our pedestal. Earth isn't the centre of the Solar System, the Sun isn't the centre of the Galaxy, and we are not the point around which everything else turns. Now two philosophers want to take the demotion one step further and apply it to the thing we hold most precious of all, our own conscious minds. If they're right, awareness may be far more widespread, and far stranger, than we ever dared imagine.

For three years they've been one of the strangest puzzles in astronomy. Tiny, mysterious red dots scattered across the early universe, so abundant and so bright that some researchers wondered if they had "broken" cosmology itself. Now the James Webb Space Telescope has captured the most detailed look yet at one of them, and the answer it reveals is as exotic as the name suggests: a star sized object that is, in fact, a black hole wearing a disguise.

We are used to thinking of gravitational waves as messengers from catastrophes in space, the ringing of spacetime after black holes collide for example. But our own Galaxy hums with a fainter, steadier signal, a chorus of millions of unseen binary stars. A new study has found that this hum carries a hidden fingerprint of the Milky Way's spin, and that if a future space mission ignores it, our picture of the Galaxy itself could come out subtly wrong.

Somewhere in the plane of the Milky Way, a dead star is spinning 220 times a second, and it's circling its companion in almost the most perfect orbit astronomers have ever measured. China's giant FAST radio telescope has just found it, and the shape of that orbit is a near flawless record of a billion year relationship between two stars.

In a recent NASA-supported study, researchers assessed Titan's resource base and how it could be leveraged for ISRU. Compared with other locations under study (the Moon, Mars, etc.), they concluded that there is unrivaled potential for human exploration and settlement.

Venus’ extraordinarily slow retrograde rotation was likely caused by a chance encounter with a moon-sized impactor. One that some 4.5 billion years ago likely slammed into our sister planet at a high angle and high velocity.

It’s 2134, and humanity has finally embraced green technologies while ridding the Earth of harmful fossil-burning technologies, most notably gasoline, wood, coal, and oil. As a result, soot has been rendered obsolete, and all commercial products from soot, including shoes, wires, computer products, and eye products, are now produced from eco-friendly technologies. However, the uber-rich who still fancy non-eco-friendly products are willing to pay soot’s weight in gold for it. Therefore, the Exoplanet Research Corporation outfits its best ship to search for soot-enriched exoplanet atmospheres.

NASA-supported scientists have provided new information about how the early Earth may have acquired some elements necessary for the planet to become habitable. They also suggest a new role for Jupiter in the distribution of these elements throughout the young solar system. The study, published in Science Advances, examines this history by looking at the ratio of phosphorus to nitrogen in iron meteorites and in younger objects known as chondrites.

Last year, a study sent a quiet tremor through the field of cosmology. A team of researchers claimed that the universe's expansion might be slowing down, not speeding up, suggesting that dark energy, the mysterious force thought to be driving the cosmos apart, could be weakening. If true, it would have shaken the foundations of our understanding of the universe. Now, a new study including two Nobel laureates has looked carefully at the evidence and reached a clear verdict - crisis averted.

Every so often, the Sun hurls billions of tonnes of charged particles toward Earth in what are called coronal mass ejections and if a big one hits at the wrong moment, the consequences for satellites, power grids, and communications systems could be catastrophic. Our best defence is to predict them before they happen, and that means watching the Sun's magnetic fields constantly and precisely. Now, a component smaller than a shirt button could transform how we do exactly that.

Every galaxy you've ever seen in a photograph is hiding something. Beyond the glowing disc of stars and gas that the camera captures lies a vast, ghostly outer region called a halo, too faint to see easily but packed with clues about how that galaxy came to be. ESA has just formally committed to a mission designed to reveal those hidden haloes in unprecedented detail, and in doing so, finally answer one of the most fundamental questions in astronomy: how did galaxies like our own Milky Way form?

Black holes are already strange enough, regions of space where gravity is so extreme that not even light can escape. But physicists have long known there's another layer of weirdness, that black holes also behave like thermodynamic objects, with temperature, entropy, and phase transitions just like a gas or a liquid. Now, a new approach borrowed from pure mathematics is revealing hidden patterns in that behaviour and hinting at something fundamental about the nature of black holes themselves.

A small rock found in the African desert has just handed scientists an extraordinary window into one of the most violent and consequential periods in the history of the Solar System. Inside this lunar meteorite, a chunk of the Moon knocked to Earth by an ancient collision, researchers have found evidence of a massive impact event 3.5 billion years ago, one that matches the timing of known impacts on Earth and in the asteroid belt. Three worlds but one shared bombardment and a story that may have everything to do with the origins of life.