mapy-i-pomiary: Comet

Evidence: 100 • authority: 72

A comet is an icy, small Solar System body or interstellar object that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or coma surrounding the nucleus, and sometimes a tail of gas and dust gas blown out from the coma. These phenomena are due to the effects of solar radiation and the outstreaming solar wind plasma acting upon the nucleus of the comet. Comet nuclei range from a few hundred meters to tens of kilometers across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times Earth's diameter, while the tail may stretch beyond on…

Evidence: 60 • authority: 72

Comets have been observed by humanity for thousands of years, but only in the past few centuries have they been studied as astronomical phenomena. Before modern times, great comets caused worldwide fear, considered bad omens foreboding disaster and turmoil; for example, the 1066 passage of Halley's Comet depicted as heralding the Norman conquest of England. As the science of astronomy developed planetary theories, understanding the nature and composition of comets became a challenging mystery and a large area of study. Halley's Comet, reappearing every 75–76 years, was pivotal to the study of comets and their orbits. Thinkers such as Immanuel Kant in the eighteenth century hypothesized abou…

Evidence: 60 • authority: 72

Chinese records of comets are the most extensive and accurate in existence from the ancient and medieval periods and stretch back across three millennia. Records exist at least as far back as 613 BC, and records may have been kept for many centuries earlier. There are continuous records all the way through to the nineteenth century and use substantially consistent methods throughout. Chinese data accuracy is unsurpassed in the ancient world and was not overtaken by Western accuracy until the fifteenth century or, in some respects, the twentieth century. Comets were observed in great detail because of their astrological significance. However, these observations are now of great use to modern…

Evidence: 52 • authority: 88

Comet Interceptor: A mission to an ancient world. Comets are the most pristine objects in our Solar System. Having spent most of their life at large distance from the Sun, where they remained mostly unaffected by solar radiation, comets are the most unaltered remnants from the era of planet formation. In June 2019, a multi-spacecraft project – Comet Interceptor – was selected by the European Space Agency (ESA) as its next planetary mission, and the first in its new class of Fast (F) projects [1]. The mission’s primary science goal is to characterise, for the first time, a long-period comet – preferably one which is dynamically new – or an interstellar object. A…

Evidence: 43 • authority: 72

Evidence: 43 • authority: 72

Evidence: 43 • authority: 80

Evidence: 43 • authority: 88