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The hypothesis that one or more biodiversity drops in the Phanerozoic eon, evident in the geological record, might have been caused by the most powerful kind of stellar explosion so far known Gamma Ray Bursts (GRB) has been discussed in…
We continue our previous work on the potential short-term influence of a gamma ray bursts on Earth's biosphere, focusing on the only important short-term effect on life: the ultraviolet flash which occurs as a result of the retransmission…
Gamma-Ray Bursts (GRBs) are likely to have made a number of significant impacts on the Earth during the last billion years. We have used a two-dimensional atmospheric model to investigate the effects on the Earth's atmosphere of GRBs…
Gamma-ray bursts (GRBs) are likely to have made a number of significant impacts on the Earth during the last billion years. The gamma radiation from a burst within a few kiloparsecs would quickly deplete much of the Earth's protective ozone…
The aim of the present work is to study the potential short-term atmospheric and biospheric influence of Gamma Ray Bursts on the Earth. We focus in the ultraviolet flash at the planet's surface, which occurs as a result of the…
High-energy astrophysical events, particularly Gamma Ray Bursts (GRBs), have been proposed as significant contributors to mass extinction events on Earth-like planets in most of the galaxy, internal to our radius in it. This paper examines…
Gamma-ray bursts (hereafter GRB) produce a flux of radiation detectable across the observable Universe, and at least some of them are associated with galaxies. A GRB within our own Ggalaxy could do considerable damage to the Earth's…
We describe results of modeling the effects on Earth-like planets of long-duration gamma-ray bursts (GRBs) within a few kiloparsecs. A primary effect is generation of nitrogen oxide compounds which deplete ozone. Ozone depletion leads to an…
It is likely that one or more gamma-ray bursts within our galaxy have strongly irradiated the Earth in the last Gy. This produces significant atmospheric ionization and dissociation, resulting in ozone depletion and DNA-damaging ultraviolet…
Based on cosmological rates, it is probable that at least once in the last Gy the Earth has been irradiated by a gamma-ray burst in our Galaxy from within 2 kpc. Using a two-dimensional atmospheric model we have performed the first…
We present in this work a unified, quantitative synthesis of analytical and numerical calculations of the effects that could be caused on Earth by a Gamma-Ray Burst (GRB), considering atmospheric and biological implications. The main…
Gamma-Ray Bursts (GRBs) directed at Earth from within a few kpc may have damaged the biosphere, primarily though changes in atmospheric chemistry which admit greatly increased Solar UV. However, GRBs are highly variable in spectrum and…
Gamma ray bursts (GBRs) are a class of highly energetic explosions emitting radiation in a very short timescale of a few seconds and with a very narrow opening angle. Although, all GRBs observed so far are extragalactic in origin, there is…
It is known that a gamma ray burst (GRB) originating near the Earth could be devastating to life. The mechanism of ozone depletion and subsequent increased UVB exposure is the primary risk, but models also show increased nitrification…
It has been suggested that galactic shock asymmetry induced by our galaxy's infall toward the Virgo Cluster may be a source of periodicity in cosmic ray exposure as the solar system oscillates perpendicular to the galactic plane. Here we…
The continuous flux of Galactic cosmic rays that bombard Earth's atmosphere creates ionizing radiation that can damage the DNA of living organisms. While this radiation on Earth is relatively constant in the short term, large and long-scale…
One longstanding mystery in bio-evolution since Darwin's time is the origin of the Cambrian explosion that happened around 540 million years ago (Mya), where an extremely rapid increase of species occurred. Here we suggest that a nearby GRB…
We present a study of the effects of ultraviolet (UV) emission from active galactic nuclei (AGN) on the atmospheric composition of planets and potential impact on life. It is expected that all supermassive black holes, which reside at…
As a copious source of gamma-rays, a nearby Galactic Gamma-Ray Burst (GRB) can be a threat to life. Using recent determinations of the rate of GRBs, their luminosity function and properties of their host galaxies, we estimate the…
A planet having protective ozone within the collimated beam of a Gamma Ray Burst (GRB) may suffer ozone depletion, potentially causing a mass extinction event to existing life on a planet's surface and oceans. We model the dangers of long…