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The zodiac is a belt-shaped region of the sky that extends approximately 8° north or south (as measured in celestial latitude) of the ecliptic, the apparent path of the Sun across the celestial sphere over the course of the year. The paths of the Moon and visible planets are within the belt of the zodiac. In Western astrology, and formerly astronomy, the zodiac is divided into twelve signs, each occupying 30° of celestial longitude and roughly corresponding to the following star constellations: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces. These astrological signs form a celestial coordinate system, or more specifically an ecliptic coordinate system, which takes the ecliptic as the origin of latitude and the Sun's position at vernal equinox as the origin of longitude.

7.4K
31 Oct 2022

Topic Review

Zeta Ursae Majoris

Mizar is a 2nd magnitude star in the handle of the Big Dipper asterism in the constellation of Ursa Major. It has the Bayer designation ζ Ursae Majoris (Latinised as Zeta Ursae Majoris). It forms a well-known naked eye double star with the fainter star Alcor, and is itself a quadruple star system. The whole system lies about 83 light-years away from the Sun, as measured by the Hipparcos astrometry satellite, and is part of the Ursa Major Moving Group.

626
29 Sep 2022

Biography

Yury Viktorovich Romanenko (Russian: Ю́рий Ви́кторович Романе́нко, Jurij Viktorovič Romanenko; born August 1, 1944) is a former Soviet cosmonaut, twice Hero of the Soviet Union (March 16, 1978 and September 26, 1980). Over his career, Yury Romanenko spent a total of 430 days 20 hours 21 minutes 30 seconds in space and 18 hours in space walks.[1] In 1987 he was a reside

372
07 Dec 2022

Biography

Prof. Dr. Yuri N. Gnedin was an outstanding astrophysicist whose scientific interests and expertise were extraordinarily wide. He was an expert in theoretical investigation of the polarized radiation transfer, generation of high-energy radiation in close binary star systems and galactic nuclei, and cyclotron lines in spectra of accreting neutron stars. Prof. Dr. Yuri N. Gnedin developed the pion

640
20 Dec 2022

Topic Review

Yellow Supergiant Star

A yellow supergiant (YSG) is a star, generally of spectral type F or G, having a supergiant luminosity class (e.g. Ia or Ib). They are stars that have evolved away from the main sequence, expanding and becoming more luminous. Yellow supergiants are smaller than red supergiants; naked eye examples include Polaris. Many of them are variable stars, mostly pulsating Cepheids such as δ Cephei itself.

1.4K
03 Nov 2022

Topic Review

Yajnavalkya's 95 Years Cycle of Synchronisation

Yajnavalkya's 95 Years Cycle of Synchronisation is the model proposed by the great Indian philosopher Yajnavalkya which explains the mathematical concept of the synchronisation of the motions of the Sun and the Moon. Yajnavalkya invented the 95 years of the periodic cycle, when the solar and lunar motions get synchronised. This 95 years of the periodic cycle is also known as Yajnavalkya Cycle.

425
25 Dec 2023

Topic Review

Wide Field Infrared Survey Telescope

The Wide Field Infrared Survey Telescope (WFIRST) is a NASA infrared space observatory currently under development. WFIRST was recommended in 2010 by United States National Research Council Decadal Survey committee as the top priority for the next decade of astronomy. On February 17, 2016, WFIRST was approved for development and launch. WFIRST is based on an existing 2.4 m wide field-of-view telescope and will carry two scientific instruments. The Wide-Field Instrument is a 288-megapixel multi-band near-infrared camera, providing a sharpness of images comparable to that achieved by the Hubble Space Telescope (HST) over a 0.28 square degree field of view, 100 times larger than that of the HST. The Coronagraphic Instrument is a high-contrast, small field-of-view camera and spectrometer covering visible and near-infrared wavelengths using novel starlight-suppression technology. The design of WFIRST is based on one of the proposed designs for the Joint Dark Energy Mission between NASA and DOE. WFIRST adds some extra capabilities to the original JDEM proposal, including a search for extra-solar planets using gravitational microlensing. In its present incarnation (2015), a large fraction of its primary mission will be focused on probing the expansion history of the Universe and the growth of cosmic structure with multiple methods in overlapping redshift ranges, with the goal of precisely measuring the effects of dark energy, the consistency of general relativity, and the curvature of spacetime. On February 12, 2018, development on the WFIRST mission was proposed to be terminated in the President's FY19 budget request, due to a reduction in the overall NASA astrophysics budget and higher priorities elsewhere in the agency. However, in March 2018 Congress approved funding to continue making progress on WFIRST until at least September 30, 2018, in a bill stating that Congress "rejects the cancellation of scientific priorities recommended by the National Academy of Sciences decadal survey process".[needs update] In testimony before Congress in July 2018, NASA administrator Jim Bridenstine proposed slowing down the development of WFIRST in order to accommodate a cost increase in the James Webb Space Telescope (JWST), which would result in decreased[clarification needed] funding for WFIRST in 2020/2021. In the President's FY2020 budget request, termination of WFIRST was proposed again, due to cost overruns and higher priority for JWST.. The telescope received $511 million for FY2020.

917
29 Nov 2022

Topic Review

White holes are regions of space-time that although matter may come out, no matter is able to enter; or in other words, they have gravitational features opposite to those of black holes. White holes exist in the solutions to Einstein's general theory of relativity and the maximal extension of the Schwarzschild metric. The term "white hole" was coined by Soviet cosmologist Igor Novikov in 1965 after his theorization on the existence.

476
15 Oct 2023

Biography

Wendy Laurel Freedman (born July 17, 1957) is a Canadian-American astronomer, best known for her measurement of the Hubble constant, and as director of the Carnegie Observatories in Pasadena, California, and Las Campanas, Chile. She is now the John & Marion Sullivan University Professor of Astronomy and Astrophysics at The University of Chicago.[1] Her principal research interests are in observa

886
24 Nov 2022

Topic Review

Water Ice Resources on Shallow Subsurface of Mars

The planet Mars is the most probable among the terrestrial planets in our solar system to support human settlement or colonization in the future. The detection of water ice or liquid water on the shallow subsurface of Mars is a crucial scientific objective for both the Chinese Tianwen-1 and United States Mars 2020 missions, which were launched in 2020. Both missions were equipped with Rover-mounted ground-penetrating radar (GPR) instruments, specifically the RoPeR on the Zhurong rover and the RIMFAX radar on the Perseverance rover. The in situ radar provides unprecedented opportunities to study the distribution of shallow subsurface water ice on Mars with its unique penetrating capability. The presence of water ice on the shallow surface layers of Mars is one of the most significant indicators of habitability on the extraterrestrial planet.

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27 Mar 2024

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