X-ray astronomers in the US have begun a campaign to save the Chandra X-ray Observatory from budget cuts that would effectively end the mission. They assert that the craft, which was launched in 1999, has plenty of life left in it. Cancelling support could, they say, damage scientific efforts to understand the Universe and the careers of an emerging generation of X-ray astronomers. Like other government agencies, NASA is facing financial restrictions. Although US President Joe Biden’s budget request for financial year (FY) 2025, which starts on 1 October, aims to increase funding for most scie ..read more

Surprising similarity: the magnet field surrounding Sagittarius A* (left) is very similar to that of the field surrounding the supermassive black hole at the heart of M87 (right). Both images were created by using the Event Horizon Telescope to observe the polarization of radio waves from the objects. (Courtesy: EHT Collaboration) The magnetic field surrounding the supermassive black hole at the centre of the Milky Way has been observed for the first time. Astronomers using the Event Horizon Telescope (EHT) have been surprised by the orderly nature of the field, which exists in the extremely v ..read more

A novel experimental platform known as a giant quantum vortex mimics certain behaviours of black holes, giving scientists an opportunity to observe the physics of these astrophysical structures up close. The vortex appears in superfluid helium cooled to near-absolute zero temperatures, and according to the team that made it, studies of its dynamics could offer hints as to how cosmological black holes produce their characteristic rotating curved spacetimes. Black holes exert huge gravitational forces on their surroundings, curving the fabric of spacetime to an extent that is unprecedented among ..read more

The first technique capable of measuring the pull of gravity on a particle just microns in diameter could aid the quest for a quantum theory of gravity – a longstanding goal in physics. The new experiment uses a superconducting quantum interference device (SQUID) to detect the force on the particle at ultralow temperatures and suppresses vibrations that might interfere with motion due to gravity. Gravity differs from the other fundamental forces because it describes a curvature in space-time rather than straightforward interactions between objects. This difference explains, in part, why t ..read more

Scientists and engineers have announced the completion of the Legacy Survey of Space and Time (LSST) – the largest camera ever built. Taking almost two decades to build, the 3200 megapixel instrument will form the heart of the 8.4 m Simonyi Survey Telescope based at the Vera C. Rubin Observatory in Cerro Pachón in the Andes. First proposed some three decades ago to help study the nature of dark matter, the LSST has been built at the SLAC National Accelerator Laboratory. It is 3 × 1.65 m – roughly the size of a small car – and with a mass of 3000 kg. The LSST includes three lenses, which have b ..read more

Space weather events known as whistler mode chorus emissions have been observed in the laboratory for the first time. These emissions occur naturally within regions of space dominated by planetary magnetic fields – magnetospheres – and they are related to the aurorae that light up our northern and southern skies every winter. However, their exact origins are poorly understood, and until now, studying them has involved either spacecraft observations or numerical simulations. By recreating the conditions that produce these emissions, researchers at Japan’s National Institute for Fusion Science a ..read more

On 12 April 1961 Yuri Gagarin became the first human to orbit the Earth, launching into space in his Vostok-1 craft with an enthusiastic shout of “Poekhali!” (“Let’s go!”). A quarter of a century later, and more than a decade after Gagarin’s death, his “Poekhali!” was considered so iconic that Soviet media included it in the opening sequence for the country’s nightly TV news programme. By the early 2000s, though, the fall of the Soviet Union had taken some of the shine off Gagarin’s legacy. When a survey (one of several carried out in Russia by local newspapers on anniversaries of Gagarin’s fl ..read more

An astrophysical process that creates elements heavier than iron may be even more challenging to reproduce in the laboratory than was previously believed – but not impossible. This is the conclusion of researchers at the Laboratoire pour l’Utilisation des Lasers Intenses (LULI) in France, who report that reproducing conditions typically seen during neutron-star mergers will require major improvements to both proton and neutron sources. This insight is crucial, they say, because it provides a more realistic framework for future efforts to replicate stellar processes. Many heavier-than-iron elem ..read more

Alternative to black holes: physicists at Goethe University Frankfurt have calculated that a nested gravastar (nestar) could look like a matryoshka doll. (Courtesy: Daniel Jampolski and Luciano Rezzolla/Goethe University Frankfurt) Gravastars, hypothetical alternatives to black holes, could end up nested inside one another like a Russian Matryoshka doll  – according to new calculations that combine quantum mechanics with Einstein’s general theory of relativity. If such exotic objects exist, they could reveal their presence in gravitational-wave signals. Black holes form by the gravitation ..read more

The motion of freely-falling bodies is independent of their composition. This is one of the foundations of Einstein’s Equivalence Principle (EEP), which underpins our modern understanding of gravity. This principle, however, is under constant scrutiny. Any violations of it would give us hints in our search for dark energy and dark matter, while also guiding our understanding of black holes and other systems where gravity and quantum mechanics meet. Scientists from the US, France and Germany have now created a new system for testing the EEP: a mixture of two ultracold quantum gases that orbits ..read more