This controversial theory says the universe is subject to an ultimate, higher-order law that we can’t comprehend.
Category: space – Page 5
Time-delay snapshots enable scientists to identify dynamics in chaotic systems
Many of the world’s most important systems, such as the atmosphere, turbulent fluids, and even the motion of planets, behave unpredictably due to chaos and noise. Scientists often study these systems through their “invariant” measures, long-term statistical behaviors, rather than individual paths. While useful, these measures have a fundamental limitation: completely different systems can share the same statistics, making it impossible to identify the underlying dynamics.
Researchers led by mathematician Yunan Yang have introduced a new way forward, using time-delay snapshots. Their work, “Invariant Measures in Time-Delay Coordinates for Unique Dynamical System Identification,” was published in Physical Review Letters on Oct. 17.
An invariant measure is a way of assigning size or probability to parts of a system that remain unchanged when the system is transformed or evolves. Time-delay snapshots use invariant measures that are expressed in time-delay coordinates—linking present observations to their past values—and providing enough information to distinguish between systems.
AGI is still a decade away
Reinforcement learning is terrible — but everything else is worse.
Karpathy’s sharpest takes yet on AGI, RL, and the future of learning.
Andrej Karpathy’s vision of AGI isn’t a bang — it’s a gradient descent through human history.
Karpathy on AGI & Superintelligence.
* AGI won’t be a sudden singularity — it will blend into centuries of steady progress (~2% GDP growth).
* Superintelligence is uncertain and likely gradual, not an instant “explosion.”
Webb sheds more light on composition of planetary debris around nearby white dwarf
Using the James Webb Space Telescope (JWST), astronomers have performed infrared observations of a planetary debris disk around a nearby white dwarf known as GD 362. Results of the new observations, presented October 8 on the arXiv preprint server, yield important insights into the chemical composition of this disk.
White dwarfs (WDs) are stellar cores left behind after a star has exhausted its nuclear fuel. Due to their high gravity, they are known to have atmospheres of either pure hydrogen or pure helium.
However, there exists a small fraction of WDs that shows traces of heavier elements, and they are believed to be accreting planetary material. Studies of this material around WDs, which often forms dust disks, is essential to improving our knowledge of how planets form and evolve.
Gaia provides a deep look into the galactic open cluster NGC 2506
Using ESA’s Gaia satellite and NASA’s Transiting Exoplanet Survey Satellite (TESS), astronomers from the Ege University in Turkey and elsewhere have observed a galactic open cluster known as NGC 2506. Results of the observational campaign, published October 7 on the arXiv pre-print server, put more constraints on the properties of this cluster.
In general, groups of stars formed from the same giant molecular cloud and loosely gravitationally bound to each other are known as open clusters (OCs). Inspecting galactic OCs in detail could be crucial for improving our understanding of the formation and evolution of our Milky Way galaxy.
NGC 2,506 is a mildly-elongated OC estimated to be located some 12,700 light years away, near the galactic anti-center. It is a well-populated, metal-poor, intermediate-age cluster with a radius of about 18.5 light years.
Not So Dead After All: Astronomers Reveal the Secret Behind Inflated White Dwarfs
White dwarfs are the dense, compact remains left behind when stars exhaust their nuclear fuel, a process that will one day occur to our own Sun. These stellar remnants are known as degenerate stars because their internal physics defy normal expectations: as they gain mass, they actually become smaller in size.
Many white dwarfs exist in pairs, forming what are known as binary systems, where two stars orbit each other. Most of these systems are ancient by galactic standards and have cooled over time to surface temperatures near 4,000 Kelvin.
Yet, astronomers have recently identified a remarkable group of short-period binary systems in which the stars complete an orbit in less than an hour. Surprisingly, these white dwarfs appear to be about twice as large as models predict, with much higher surface temperatures ranging from 10,000 to 30,000 Kelvin.