相关论文: The Habitable Epoch of the Early Universe
At high redshifts, the temperature of the cosmic microwave background (CMB) was higher than its value today. We explore the possibility that life may have arisen early because the higher CMB temperature would have supplied the requisite…
Is life most likely to emerge at the present cosmic time near a star like the Sun? We consider the habitability of the Universe throughout cosmic history, and conservatively restrict our attention to the context of "life as we know it" and…
The temperature of the cosmic microwave background (CMB) was equal to the surface temperature of Saturn's moon Titan, 94K, at a redshift z=33.5, after the first galaxies formed. Titan-like objects would have maintained this surface…
In popular cold dark matter cosmological scenarios, stars may have first appeared in significant numbers around a redshift of 10 or so, as the gas within protogalactic halos with virial temperatures in excess of 20,000 K (corresponding to…
A cosmological model, in which the cosmic microwave background (CMB) is a thermal radiation of intergalactic dust instead of a relic radiation of the Big Bang, is revived and revisited. The model suggests that a virtually transparent local…
The first galaxies formed at high redshifts, and were likely substantially less massive than typical galaxies in the local universe. We argue that (1) the reionization of a clumpy intergalactic medium by redshift z=6, (2) its enrichment by…
When galaxy formation started in the history of the Universe remains unclear. Studies of the cosmic microwave background indicate that the Universe, after initial cooling (following the Big Bang), was reheated and reionized by hot stars in…
The formation of the first stars and quasars marks the transition between the smooth initial state and the clumpy current state of the Universe. In popular CDM cosmologies, the first sources of light started to form at a redshift z=30 and…
First stars play crucial roles in development of the universe, influencing events like cosmic reionization and the chemical enrichment. While first stars are conventionally thought to form at around $z \sim 20-30$ in the standard $\Lambda$…
At the early stage of the Universe-evolution there were no stars and no galaxies, but only a uniform hot plasma consisting of free electrons and free nuclei. The Universe temperature was determined by the Stefan-Boltzmann law of…
Hydrogravitional-dynamics (HGD) cosmology of Gibson/Schild 1996 predicts that the primordial H-He^4 gas of big bang nucleosynthesis became proto-globular-star-cluster clumps of Earth-mass planets at 300 Kyr. The first stars formed from…
The so-called `impossibly early galaxy' problem, first identified via the Hubble Space Telescope's observation of galaxies at redshifts z > 10, appears to have been exacerbated by the more recent James Webb Space Telescope (JWST) discovery…
In popular cold dark matter cosmological scenarios, stars may have first appeared in significant numbers around a redshift of 10 or so, as the gas within protogalactic halos with virial temperatures in excess of 20,000 K (corresponding to…
We investigate the dust properties and star-formation signature of galaxies in the early universe by stacking 111227 objects in the recently released COSMOS catalogue on maps at wavelengths bracketing the peak of warmed dust emission. We…
The habitable zone is the circumstellar region in which a terrestrial-mass planet with an atmosphere can sustain liquid water on its surface. However, despite the usefulness of this concept, it is being found to be increasingly limiting in…
Employing hydrodynamic simulations of structure formation in a LCDM cosmology, we study the history of cosmic star formation from the "dark ages" at redshift z~20 to the present. In addition to gravity and ordinary hydrodynamics, our model…
Within the framework of an eternal inflationary scenario, a natural question regarding the production of eternal bubbles is the essential condition requires to have a universe capable of generating life. In either an open or a closed…
The history of life on Earth and in other potential life-bearing planetary platforms is deeply linked to the history of the universe. Since life as we know it relies on chemical elements forged in dying heavy stars, the universe needs to be…
The notion that dust might have formed the cosmic microwave background (CMB) has been strongly refuted on the strength of four decades of observation and analysis, in favour of recombination at a redshift z ~ 1080. But tension with the data…
We explore the conditions prevailing in primordial planets in the framework of the HGD cosmologies as discussed by Gibson and Schild. The initial stages of condensation of planet-mass H-4He gas clouds in trillion-planet clumps is set at…