Tag

Gravity

All articles tagged with #gravity

science22 hours ago•7 min saved

Disco-ball satellite nails Einstein’s relativity test to 0.2%

A dense, thruster-free satellite named LARES-2, paired with the older LAGEOS, was laser-tracked from Earth to isolate the frame-dragging effect predicted by general relativity. By canceling Earth’s oblateness and tidal perturbations over a 1,050-day cycle, the team measured the Lense-Thirring precession to about 0.2% accuracy, confirming Einstein and narrowing alternatives like Chern-Simons theory, while also delivering a more precise Earth-tide benchmark.

via Ars Technica|

#frame-dragging #gravity #lares-2

science3 days ago•15 min saved

Space Rewires the Brain: Neuroplasticity in Microgravity

A BBC report synthesizes 15 brain-imaging studies (about 377 participants) showing that microgravity triggers structural and functional changes in brain regions involved in movement, balance and multisensory processing, revealing the brain rewires itself to life without gravity. While astronauts can counter bone and muscle loss with exercise, brain adaptation takes time and could complicate long-duration missions to the Moon or Mars, prompting exploration of countermeasures such as centrifugation or non-invasive brain stimulation to help pilots and crews adapt and stay safe.

via BBC|

#astronauts #brain #gravity

science11 days ago•66 min saved

Time's Flow Reimagined: Gravity, Quantum Arrows, and the Shape of Reality

New theoretical ideas suggest time may emerge from gravity via Shape Dynamics, while open quantum systems could host two arrows of time; other approaches explore time as potentially emergent or even illusory, with concepts like tachyons and quantum entanglement hinting at multi-dimensional or timeless frameworks.

via Yahoo|

#arrow-of-time #entropy #gravity

physics-and-chemistry17 days ago•16 min saved

Lugworm Poop Maps Gravity-Driven Elastic Coiling, Science Confirms Emoji Shape

Physicists show lugworms defy gravity with upward-defecating poop whose shape follows elastic rope-coiling physics, explaining why the poop emoji’s cone form emerges from gravity and suggesting biology leverages basic physical laws rather than requiring special biological design.

via Gizmodo|

#elastic-coiling #gravity #lugworm

space19 days ago•1 min saved

ESO fires lasers to create artificial guide stars for sharper cosmic observations

The European Southern Observatory uses lasers on the Very Large Telescope Interferometer to create artificial guide stars ~90 km up, enabling adaptive optics that correct atmospheric blur and deliver sharper observations of the Tarantula Nebula as part of the GRAVITY+ upgrade.

via BBC Sky at Night Magazine|

#adaptive-optics #astronomy #gravity

science26 days ago•96 min saved

Quantum gravity narrows the hunt for a possible fifth fundamental force

A new quantum gravity framework based on asymptotic safety narrows the parameter space for a hypothetical fifth fundamental force, ruling out part of the possible strength and range and suggesting that high-precision gravity experiments—like atomic interferometry and lunar laser ranging—could test these ideas and potentially reveal observable effects of quantum gravity at macroscopic scales.

via Space|

#asymptotic-safety #atomic-interferometry #fifth-fundamental-force

science28 days ago•9 min saved

Elevator-Test Claims Gravity Changes Light Speed, Rekindling Einstein’s 1911 Idea

Physicist Enbang Li at the University of Wollongong has built a gravity-based test in an elevator shaft to detect variations in the speed of light, arguing that gravity can speed up light on local scales and reviving Einstein’s 1911 notion that c might vary with gravity. General relativity holds that the speed of light is constant locally, so Li’s claims, if validated, would challenge a foundational assumption and could have implications for Earth science applications; the result remains a subject of scrutiny and replication.

via ZME Science|

#einstein #experiment #generalrelativity

science1 month ago•11 min saved

Canada’s gravity puzzle: mantle dynamics take the lead over ice rebound

GRACE satellite data show that the Hudson Bay gravity low cannot be explained by glacial rebound alone; older ice-sheet models account for only about 25–45% of the anomaly, leaving a substantial portion attributed to deep mantle structure and slow convection beneath Laurentia. The mantle’s buoyancy and deep-root dynamics, not surface ice history, appear to shape the regional gravity field, though quantifying the split depends on rebound modeling and longer observation records from GRACE Follow-On.

via Space Daily|

#grace #gravity #hudson-bay

science1 month ago•5 min saved

Envelope Trick Highlights Subtle Biases in Measuring Gravity’s Constant

An NIST redo of the 2007 BIPM measurement of the gravitational constant G, using a blinded-envelope approach to avoid bias, yields a result close to the French value but with a 0.0235% discrepancy after adjustments; Schlamminger also identifies a newly observed spurious torque driven by temperature gradients and residual gas in the vacuum, suggesting unaccounted biases in the uncertainty budget and underscoring the ongoing challenge of precisely measuring G and the importance of reproducibility.

via The Debrief|

#gravitational-constant #gravity #metrology

science1 month ago•75 min saved

Gravity’s oldest constant remains unsolved after 340 years

Space.com reports that the gravitational constant Big G—the oldest fundamental constant in physics—remains the least precisely known after 340 years. A decade-long effort led by NIST’s Stephan Schlamminger used a refined torsion‑balance experiment with an envelope bias to avoid “intellectual phase locking,” producing a Big G value slightly lower than CODATA’s standard. The result, among 17 measurements, suggests a possible revision to Earth's mass if correct, but the persistent discrepancies between experiments mean the fundamental mystery of gravity’s strength is not solved.

via Space|

#big-g #codata #gravity

science1 month ago•3 min saved

Deep mantle heat flow explains Indian Ocean gravity dip

Scientists modeling Earth’s interior propose a long-lived, hot, low-density mantle upwelling originating beneath Africa drifts east beneath the Indian Ocean, reducing local mass and producing the observed geoid low. The idea, supported by 100-million-year simulations and the Indian plate’s motion, explains why satellite data show a persistent dip in the sea surface, though the interpretation is still debated.

via The Times of India|

#geoid #gravity #indian-ocean

science1 month ago•4 min saved

Great Pyramid as Interstellar Beacon: Iranian Scientist Proposes Cosmic Signal

An Iranian physicist proposes the Great Pyramid of Giza served as a gravitational transmitter and interstellar beacon to communicate Earth's position to extraterrestrials; he cites its coordinates and alignments as encoded data, but the idea is speculative, not peer-reviewed, and physicists say there was no ancient technology to broadcast such signals.

via New York Post|

#astronomy #extraterrestrials #geospatial

science2 months ago•6 min saved

Cosmic gravity passes its biggest test yet, keeping dark matter in the spotlight

Using the kinematic Sunyaev-Zeldovich effect on about 686,000 galaxies in clusters 5–7 billion light-years away, researchers measured cluster speeds and found gravity weakens with distance consistent with Newtonian/Einsteinian gravity, strengthening the case for dark matter as the source of anomalous gravitational effects, though many questions remain. The study was published in Physical Review Letters.

via ScienceAlert|

#cosmology #dark-matter #galaxy-clusters

science2 months ago•7 min saved

Big G defies precision again as latest measurement clashes with CODATA

After a decade-long effort at the National Institute of Standards and Technology to measure Newton’s gravitational constant Big G, Schlamminger and colleagues report a value of 6.67387e-11 m^3 kg^-1 s^-2 that is about 0.0235% lower than the replicated result and inconsistent with the CODATA standard, highlighting the long-standing scatter in Big G measurements. The team blind-tested the experiment to avoid bias and published their findings in Metrologia, underscoring that precision metrology often raises questions and may point to small systematic biases rather than new physics.

via CNN|

#bigg #codata #fundamental-constants

science2 months ago•5 min saved

Tiny time fuzz hints at gravity-quantum link

Physicists show that spontaneous quantum-collapse models, possibly tied to gravity, would make time itself intrinsically uncertain, setting a fundamental limit on clock precision. The predicted effect is far too small to affect current technology, but it offers a testable path toward unifying quantum mechanics with gravity.

via ScienceDaily|

#clock-precision #gravity #quantum-collapse