Related papers: Comets, historical records and vedic literature
Equation of motion for a comet in the Oort cloud is numerically solved. Orbital evolution of the comet under the action of the gravity of the Sun and the Galaxy is presented for various initial conditions. Oscillations of the Sun with…
We review the literature for perceptions of meteors in the Maori cultures of New Zealand. We examine representations of meteors in religion, story, and ceremony. We find that meteors are sometimes personified as gods or children, or are…
This monograph presents a study of the nature and origin of meteorites, asteroids and comets; and of the consequences of encounters of these cosmic objects with the Earth. The purpose of this monograph is mainly of divulgation for…
NASA's Stardust mission returned rocky material from the coma of comet 81P/Wild 2 (pronounced "Vilt 2") to Earth for laboratory study on January 15, 2006. Comet Wild 2 contains volatile ices and likely accreted beyond the orbit of Neptune.…
Coins of Armenian king Tigranes II the Great (95-55 BC), silver and copper-bronze tetradrachms and drachms, clearly reveal a star with a tail on the royal tiara which may be associated with the Halley's comet passage of 87 BC. If so, one…
When the EPOXI spacecraft flew by Comet 103P/Hartley 2, it observed large particles floating around the comet nucleus. These particles are likely low-density, centimeter- to decimeter-sized clumps of ice and dust. While the origin of these…
This paper describes progress achieved in early investigations of the orbital motion and light curve of comet C/2026 A1 (MAPS), the third ground-based discovery of a Kreutz sungrazer in the 21st century. The highly unusual trait of the…
For much of February 2023, the world was in panic as repeated balloon-like unidentified flying objects (UFOs) were reported over numerous countries by governments that often responded with military action. As a result, most of these craft…
Comets contain abundant amounts of organic and inorganic species. Many of the volatile molecules in comets have also been observed in the interstellar medium and some of them even with similar relative abundances, indicating formation under…
We present the results of our orbital computations in support of the recently proposed contact-binary model for the Kreutz sungrazer system (Sekanina 2021, 2022). We demonstrate that comet Ikeya-Seki (C/1965 S1) previously passed perihelion…
Some examples of the events associated with falls of rocks and iron terrestrial origin from the sky are considered (in scientific publications they are often called as meteor-wrongs or pseudo-meteorites). Their possible connections with…
Ice naturally forms in the disordered or ``amorphous'' state when accreted from vapor at temperatures and pressures found in the interstellar medium and in the frigid, low density outer regions of the Sun's protoplanetary disk. It is…
This note is about three interesting 15th and 16th century sightings of comets in Kashmiri chronicles. We provide reasons for their identification as the 1468 S1, 1531 (Halley's), and 1533 M1 comets.
We review the current state of knowledge of the long-term evolution of the small bodies that give rise to comets and exocomets, as well as their reservoirs. The active cometary phase is only transitory, and bodies that become comets pass…
The shape of the heliosphere, regarded as comet-like since the 1960s, has recently been the subject of intense debate in the last decade. There is disagreement whether the heliospheric tail extends to $\sim$10,000 au in a comet-like shape…
Comets, asteroids and moons that orbit stars and planets exterior to our solar system are prefixed with "exo". While the existence of these objects is certain, our understanding of their physical properties, composition, and diversity is…
There is an unceasing incoming flux of extraterrestrial materials reaching the Earth's atmosphere. Some of these objects produce luminous columns when they ablate during the hypersonic encounter with air molecules. A few fireballs occur…
Comets are made of volatile and refractory material and naturally experience various degrees of sublimation as they orbit around the Sun. This gas release, accompanied by dust, represents what is traditionally described as activity.…
We investigate the time sequence for the appearance of jets and molecular tori in the transition of stars from the Asymptotic Giant Branch to the planetary nebula phase. Jets and tori are prominent features of this evolution, but their…
Cosmology from the Top Down.