Topic: Astronomy (Page 6)

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πŸ”— Canadian Hydrogen Intensity Mapping Experiment

πŸ”— Canada πŸ”— Astronomy πŸ”— Canada/British Columbia

The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is an interferometric radio telescope at the Dominion Radio Astrophysical Observatory in British Columbia, Canada which consists of four antennas consisting of 100 x 20 metre cylindrical parabolic reflectors (roughly the size and shape of snowboarding half-pipes) with 1024 dual-polarization radio receivers suspended on a support above them. The antenna receives radio waves from hydrogen in space at frequencies in the 400–800 MHz range. The telescope's low-noise amplifiers are built with components adapted from the cellphone industry and its data are processed using a custom-built FPGA electronic system and 1000-processor high-performance GPGPU cluster. The telescope has no moving parts and observes half of the sky each day as the Earth turns. It has also turned out to be a superior instrument for observing the recently discovered phenomenon of fast radio bursts (FRBs).

CHIME is a partnership between the University of British Columbia, McGill University, the University of Toronto and the Canadian National Research Council's Dominion Radio Astrophysical Observatory. A first light ceremony was held on 7 September 2017 to inaugurate the commissioning phase.

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πŸ”— Eltanin impact

πŸ”— Astronomy πŸ”— Geology

The Eltanin impact is thought to be an asteroid impact in the eastern part of the South Pacific Ocean during the Pliocene-Pleistocene boundary around 2.51 ± 0.07  million years ago. The location was at the edge of the Bellingshausen Sea 1,500Β km (950Β mi) southwest of Chile. The asteroid was estimated to be about one to fourΒ km (0.6 to 2.5Β mi) in diameter and the impact would have left a crater approximately 35Β km (22Β mi) across.

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πŸ”— Ali Qushji

πŸ”— Biography πŸ”— Biography/science and academia πŸ”— Astronomy πŸ”— Middle Ages πŸ”— Middle Ages/History


Ala al-DΔ«n Ali ibn Muhammed (1403 – 16 December 1474), known as Ali Qushji (Ottoman Turkish/Persian language: ΨΉΩ„ΫŒ Ω‚ΩˆΨ΄Ϊ†ΫŒ, kuşçu – falconer in Turkish; Latin: Ali Kushgii) was an astronomer, mathematician and physicist originally from Samarkand, who settled in the Ottoman Empire some time before 1472. As a disciple of Ulugh Beg, he is best known for the development of astronomical physics independent from natural philosophy, and for providing empirical evidence for the Earth's rotation in his treatise, Concerning the Supposed Dependence of Astronomy upon Philosophy. In addition to his contributions to Ulugh Beg's famous work Zij-i-Sultani and to the founding of Sahn-Δ± Seman Medrese, one of the first centers for the study of various traditional Islamic sciences in the Ottoman caliphate, Ali Kuşçu was also the author of several scientific works and textbooks on astronomy.

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πŸ”— Solar eclipse of August 12, 2026

πŸ”— Astronomy πŸ”— Astronomy/Eclipses

A total solar eclipse will occur at the Moon's descending node of the orbit on Wednesday, August 12, 2026, 2 days past perigee (Perigee on Monday, August 10, 2026), in North America and Europe. The total eclipse will pass over the Arctic, Greenland, Iceland, Atlantic Ocean and northern Spain. The points of greatest duration and greatest eclipse will be just 45Β km off the western coast of Iceland by 65Β°10.3' N and 25Β°12.3' W, where the totality will last 2m 18.21s. It will be the first total eclipse visible in Iceland since June 30, 1954, also Solar Saros series 126 (descending node), and the only one to occur in the 21st century as the next one will be in 2196.

Occurring only 2.3 days after perigee (Perigee on August 10, 2026), the Moon's apparent diameter will be larger. Lunar Perigee will occur on Monday, August 10, 2026, two days before the total solar eclipse.

The total eclipse will pass over northern Spain from the Atlantic coast to the Mediterranean coast as well as the Balearic Islands. The total eclipse will be visible from the cities of Valencia, Zaragoza, Palma and Bilbao but both Madrid and Barcelona will be just outside the path of totality.

The last total eclipse in continental Europe occurred on March 29, 2006 and in continental part of European Union it occurred on August 11, 1999. The last total solar eclipse happened in Spain on August 30, 1905 and followed a similar path across the country. The next total eclipse visible in Spain will happen less than a year later on 2 August 2027. A partial eclipse will cover more than 90% of the area of the sun in Ireland, Great Britain, Portugal, France, Italy, the Balkans and North Africa and to a lesser extent in most of Europe, North Africa and North America.

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πŸ”— The Theory of Interstellar Trade, Paul Krugman (1978)

πŸ”— Economics πŸ”— Literature πŸ”— Astronomy

The Theory of Interstellar Trade is a paper written in 1978 by the economist Paul Krugman. The paper was first published in March 2010 in the journal Economic Inquiry. He described the paper as something he wrote to cheer himself up when he was an "oppressed assistant professor" caught up in the academic rat race.

Krugman analyzed the question of

How should interest rates on goods in transit be computed when the goods travel at close to the speed of light? This is a problem because the time taken in transit will appear less to an observer traveling with the goods than to a stationary observer.

Krugman emphasized that in spite of its farcical subject matter, the economic analysis in the paper is correctly done. In his own words,

while the subject of this paper is silly, the analysis actually does make sense. This paper, then, is a serious analysis of a ridiculous subject, which is of course the opposite of what is usual in economics.

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πŸ”— Ton 618, 40B solar mass

πŸ”— Astronomy πŸ”— Astronomy/Astronomical objects

TON 618 (short for Tonantzintla 618) is a hyperluminous, broad-absorption-line, radio-loud quasar and Lyman-alpha blob located near the border of the constellations Canes Venatici and Coma Berenices, with the projected comoving distance of approximately 18.2 billion light-years from Earth. It possesses one of the most massive black holes ever found, at 40 billion Mβ˜‰.

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πŸ”— 774–775 carbon-14 spike

πŸ”— Environment πŸ”— Meteorology πŸ”— Astronomy πŸ”— Middle Ages πŸ”— Middle Ages/History πŸ”— Geology πŸ”— Glaciers πŸ”— Solar System

The 774–775 carbon-14 spike is an observed increase of 1.2% in the concentration of carbon-14 isotope in tree rings dated to 774 or 775, which is about 20 times as high as the normal background rate of variation. It was discovered during a study of Japanese cedar trees, with the year of occurrence determined through dendrochronology. A surge in beryllium isotope 10
Be
, detected in Antarctic ice cores, has also been associated with the 774–775 event. It is known as the Miyake event or the Charlemagne event and it produced the largest and most rapid rise in carbon-14 ever recorded.

The event appears to have been global, with the same carbon-14 signal found in tree rings from Germany, Russia, the United States, Finland and New Zealand.

The signal exhibits a sharp increase of around 1.2% followed by a slow decline (see Figure 1), which is typical for an instant production of carbon-14 in the atmosphere, indicating that the event was short in duration. The globally averaged production of carbon-14 for this event is calculated as Q = 1.3Γ—108 Β± 0.2Γ—108 atoms/cm2.

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πŸ”— Robert Burnham Jr

πŸ”— United States πŸ”— Biography πŸ”— Biography/science and academia πŸ”— Astronomy πŸ”— United States/Arizona πŸ”— Astronomy/Solar System

Robert Burnham Jr. (June 16, 1931 – March 20, 1993) was an American astronomer, best known for writing the classic three-volume Burnham's Celestial Handbook. He is the discoverer of numerous asteroids including the Mars crossing asteroid 3397Β Leyla, as well as six comets.

Burnham's late years were tragic; he died destitute and alone. However, he is remembered by a generation of deep sky observers for his unique contribution to astronomy, the Celestial Handbook. The main-belt asteroid 3467Β Bernheim was named in his honor.

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πŸ”— Happy (Summer|Winter) Solstice - 11:28 Zulu time.

πŸ”— Physics πŸ”— Astronomy πŸ”— Time πŸ”— Holidays πŸ”— Festivals

A solstice is an event occurring when the Sun appears to reach its most northerly or southerly excursion relative to the celestial equator on the celestial sphere. Two solstices occur annually, around June 21 and December 21. In many countries, the seasons of the year are determined by reference to the solstices and the equinoxes.

The term solstice can also be used in a broader sense, as the day when this occurs. The day of a solstice in either hemisphere has either the most sunlight of the year (summer solstice) or the least sunlight of the year (winter solstice) for any place other than the Equator. Alternative terms, with no ambiguity as to which hemisphere is the context, are "June solstice" and "December solstice", referring to the months in which they take place every year.

The word solstice is derived from the Latin sol ("sun") and sistere ("to stand still"), because at the solstices, the Sun's declination appears to "stand still"; that is, the seasonal movement of the Sun's daily path (as seen from Earth) pauses at a northern or southern limit before reversing direction.

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πŸ”— Berserker Hypothesis

πŸ”— Physics πŸ”— Astronomy

The berserker hypothesis, also known as the deadly probes scenario, is the idea that humans have not yet detected intelligent alien life in the universe because it has been systematically destroyed by a series of lethal Von Neumann probes. The hypothesis is named after the Berserker series of novels (1963-2005) written by Fred Saberhagen.

The hypothesis has no single known proposer, and instead is thought to have emerged over time in response to the Hart–Tipler conjecture, or the idea that an absence of detectable Von Neumann probes is contrapositive evidence that no intelligent life exists outside of the Sun's Solar System. According to the berserker hypothesis, an absence of such probes is not evidence of life's absence, since interstellar probes could "go berserk" and destroy other civilizations, before self-destructing.

In his 1983 paper "The Great Silence", astronomer David Brin summarized the frightening implications of the berserker hypothesis: it is entirely compatible with all the facts and logic of the Fermi paradox, but would mean that there exists no intelligent life left to be discovered. In the worst-case scenario, humanity has already alerted others to its existence, and is next in line to be destroyed.

There is no need to struggle to suppress the elements of the Drake equation in order to explain the Great Silence, nor need we suggest that no [intelligent aliens] anywhere would bear the cost of interstellar travel. It need only happen once for the results of this scenario to become the equilibrium conditions in the Galaxy. We would not have detected extra-terrestrial radio traffic – nor would any [intelligent aliens] have ever settled on Earth – because all were killed shortly after discovering radio.

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