rekordy: Speed of light

Evidence: 67 • authority: 72

Evidence: 61 • authority: 92

Fractal nature of galaxy clustering in the updated CfA redshift catalog.. We have recently argued that the expansion of the Universe is compatible not only with standard homogeneity, but also with fractal homogeneity in a hierarchical fractal cosmology. In this work we further test this paradigm using the galactic distances obtained from the Updated CfA Redshift Catalogs. We confirm that the observed multifractal spectrum is consistent with the weighted Cantor set models characteristic of turbulence in space magnetized plasmas such as the solar wind in heliosphere, the very local interstellar medium and even in laboratory experiments. The degree of multifractality is smaller than that found…

Evidence: 61 • authority: 72

The observable universe is a spherical region of the universe consisting of all matter that can be observed from Earth; the electromagnetic radiation from these astronomical objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion. The radius of this region is about 14.26 gigaparsecs (46.5 billion light-years or 4.40×1026 m). The word observable in this sense does not refer to the capability of modern technology to detect light or other information from an object, or whether there is anything to be detected. It refers to the physical limit created by the speed of light itself. No signal can travel faster than light and the universe has only…

Evidence: 54 • authority: 72

The Milky Way or Milky Way Galaxy, or simply the Galaxy, is the galaxy that includes the Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galaxy, which are so far away that they cannot be individually distinguished by the naked eye. The Milky Way is a barred spiral galaxy with a D25 isophotal diameter estimated at 26.8 ± 1.1 kiloparsecs (87,400 ± 3,600 light-years), but only about 1,000 light-years thick at the spiral arms (more at the bar). Recent simulations suggest that a dark matter area, also containing some visible stars, may extend up to a diameter of almost 2 million light-yea…

Evidence: 48 • authority: 72

Faster-than-light (superluminal or supercausal) travel and communication are the hypothetical propagation of matter or information faster than the speed of light in vacuum (c). The special theory of relativity implies that only particles with zero rest mass (i.e., photons) may travel at the speed of light, and that nothing may travel faster. Particles whose speed exceeds that of light (tachyons) have been hypothesized, but their existence would violate causality and would imply time travel. The scientific consensus is that they do not exist. According to all observations and current scientific theories, matter travels at slower-than-light (subluminal) speed with respect to the locally disto…

Evidence: 48 • authority: 88

Evidence: 48 • authority: 72

Evidence: 48 • authority: 72

The speed of light is the speed of electromagnetic waves. Light travels at slower speed inside materials like glass or water; its highest speed is in a vacuum. The speed of light in vacuum is a universal physical constant denoted c (in ISO and IEC standards c 0 {\displaystyle c_{0}} ), exactly equal to 299792458 m⋅s−1. It is exact because, by international agreement, a metre is defined as the length of the path travelled by light in vacuum during a time interval of 1⁄299792458 second. The value 299,792,458 metres per second is approximately 1 billion kilometres per hour; 700 million miles per hour. For other approximations of c, valid for various units and size scales see the infobox. The s…

Evidence: 42 • authority: 80

Evidence: 42 • authority: 92

The era of precision cosmology with voids.. Cosmic voids, the large underdense regions of our Universe, have emerged over the past decade as powerful cosmological laboratories: their simple dynamics, sensitivity to local gravitational effects and cosmic expansion, and ability to span large volumes, make them uniquely suited to test fundamental physics. Fueled by advances in theory, simulations, and observations, void science has matured into a precision tool for constraining the parameters of the standard cosmological model and its possible extensions. In this review, we provide a comprehensive description of the statistical tools developed to characterize voids, the theoretical models that…

Evidence: 36 • authority: 80

Code shines a light on distant galaxies

Evidence: 36 • authority: 92

Red novae, their progenitors, and remnants.. Red novae or luminous red novae are a class of optical transients that have emerged over the past two decades. They occupy an intermediate-luminosity regime between classical novae and supernovae and are characterized by cool, slowly expanding ejecta and a pronounced evolution toward red, dust-enshrouded remnants. These events are now widely interpreted as the outcome of binary coalescence involving non-compact stars, providing a rare opportunity to directly observe the dynamical phases of stellar mergers and their immediate aftermath. Observational studies of red novae provide a glimpse into the still poorly understood physics of unstable mass t…