Related papers: Palaeolithic extinctions and the Taurid Complex
The Oort cloud is usually thought of as a collection of icy comets inhabiting the outer reaches of the Solar system, but this picture is incomplete. We use simulations of the formation of the Oort cloud to show that ~4% of the small bodies…
The cause of the glacial cycles remains a mystery. The origin is widely accepted to be astronomical since paleoclimatic archives contain strong spectral components that match the frequencies of Earth's orbital modulation. Milankovitch…
Among the near-Earth object (NEO) population there are comets and active asteroids which are sources of fragments that initially move together; in addition, some NEOs follow orbits temporarily trapped in a web of secular resonances. These…
Jupiter family comets contribute a significant amount of debris to near-Earth space. However, telescopic observations of these objects seem to suggest they have short physical lifetimes. If this is true, the material generated will also be…
We analyze a sample of 73 old long-period comets (LPCs) (orbital periods $200 < P < 1000$ yr) with perihelion distances $q < 2.5$ au, discovered in the period 1850-2014. We cloned the observed comets and also added fictitious LPCs with…
Sensitive high angular resolution ($\sim$ 2$"$) CO(2-1) line observations made with the Submillimeter Array (SMA) of the flow emanating from the high-mass star forming region DR21 located in the Cygnus X molecular cloud are presented. These…
Climate change is inducing a global atmospheric contraction above the tropopause (~10 km), leading to systematic decrease in neutral air density. The impact of climate change on small meteoroids has already been observed over the last two…
The discovery of close-to-star gas-giant exo-planets lends support to the idea of Earth's origin as a Jupiter-like gas giant and to the consequences of its compression, including whole-Earth decompression dynamics that gives rise, without…
We analyze findings of the Stardust mission that brought to the Earth dust from the 81P/Wild 2 coma. Just as the data of the Deep Impact mission to 9P/Tempel 1, they are at odds with the widely accepted condensation/sublimation comet…
With orbital periods longer than 200 years, most long-period comets (LPCs) remain undiscovered until they are in-bound towards perihelion. The comets that pass close to Earth's orbit are Potentially Hazardous Objects (PHOs). Those with…
The assumption that short-period (SP) comets are fragments of massive icy envelopes of Ganymede-like bodies saturated by products of ice electrolysis that underwent global explosions provides a plausible explanation of all known…
Comets are believed to be born in the outer Solar System where the temperature is assumed to have never exceeded T ~ 100 K. Surprisingly, observations and samples of cometary dust particles returned to Earth showed that they are in fact…
A numerical simulation of the Oort cloud is used to explain the observed orbital distributions and numbers of Jupiter-family and Halley-type short-period comets. Comets are given initial orbits with perihelion distances between 5 and 36 AU,…
We discuss a hypothetical existential threat from a 10 km diameter bolide discovered 6 months prior to impact with one case being a comet and the other being an asteroid. We show that an extension of our work on bolide fragmentation using…
The probability is investigated that the meteorites originating on Earth are transferred to other planets in our Solar System and to extra solar planets. We take the collisional Chicxulub crater event, and material that was ejected as an…
The essential features underlying the top-down scenarii for UHECR are discussed, namely, the stability (or lifetime) imposed to the heavy objects (particles) whatever they be: topological and non-topological solitons, X-particles, cosmic…
To date only very few meteor clusters have been instrumentally recorded. This means that every new detection is an important contribution to the understanding of these phenomena, which are thought to be evidence of the meteoroid…
We identify a sample of 27 long-period comets for which both non-gravitational accelerations and Lyman-alpha based gas production rates are available. Seven of the 27 comets (i.e. 25 percent) did not survive perihelion because of nucleus…
One of the longstanding debates in the history of paleontology focuses on the issue of whether or not there have been long term cycles (operating over tens of millions of years) in biodiversity and extinction. Here we consider the history…
The near-Earth objects (NEOs) (3200) Phaethon and (155140) 2005 UD are thought to share a common origin, with the former exhibiting dust activity at perihelion that is thought to directly supply the Geminid meteor stream. Both of these…