You're using an outdated browser. Please upgrade to a modern browser for the best experience.
Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort by:
Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)
Filter:
All Topic Review Biography Peer Reviewed Entry Video Entry
Topic Review
List of Unnumbered Minor Planets: 2001 S–Y
This is a partial list of unnumbered minor planets for principal designations assigned between 16 September 2001 and 31 December 2001 (S–Z).
  • 694
  • 29 Nov 2022
Topic Review
(6545) 1986 TR6
(6545) 1986 TR6, provisional designation 1986 TR6, is a Jupiter trojan from the Greek camp, approximately 53 kilometers (33 miles) in diameter. It was discovered on 5 October 1986, by Slovak astronomer Milan Antal at the Piwnice Astronomical Observatory in Poland. The dark D-type asteroid has a rotation period of 16.3 hours and belongs to the 90 largest Jupiter trojans. It has not been named since its numbering in September 1995.
  • 680
  • 09 Nov 2022
Topic Review
List of Unnumbered Minor Planets: 2002 A–O
This is a partial list of unnumbered minor planets for principal designations assigned between 1 January 2002 and 31 July 2002 (A–O).
  • 677
  • 29 Nov 2022
Topic Review
Shallow Geological Structures of CE-4 Landing Site
China has successfully carried out five lunar exploration missions since 2007. These missions indicate that China has successfully implemented a three-step lunar exploration program of “orbiting, landing, and returning”. Among them, the Lunar Penetrating Radar (LPR) carried by the Yutu-2 rover in the Chang’E-4 (CE-4) mission is the only one still operating on the far side of the Moon.
  • 674
  • 31 Oct 2023
Topic Review
Alternative General-Relativity-related experiments and Particle Physics
The use of quantum optical systems for investigation in General Relativity ad related theories, of which General Relativity is the weak-field limit is exposed; the analyses are based on the comparison of the properties of Astrophysical systems inferred form the quantum-optics techniques, which can compare Planck-scale physics.
  • 659
  • 12 Nov 2024
Topic Review
Valley Network
Valley networks are branching networks of valleys on Mars that superficially resemble terrestrial river drainage basins. They are found mainly incised into the terrain of the martian southern highlands, and are typically - though not always - of Noachian age (approximately four billion years old). The individual valleys are typically less than 5 kilometers wide, though they may extend for up to hundreds or even thousands of kilometers across the martian surface. The form, distribution, and implied evolution of the valley networks are of great importance for what they may tell us about the history of liquid water on the martian surface, and hence Mars' climate history. Some authors have argued that the properties of the networks demand that a hydrological cycle must have been active on ancient Mars, though this remains contentious. Objections chiefly arise from repeated results from models of martian paleoclimate suggesting high enough temperatures and pressures to sustain liquid water on the surface have not ever been possible on Mars. The advent of very high resolution images of the surface from the HiRISE, THEMIS and Context (CTX) satellite cameras as well as the Mars Orbital Laser Altimeter (MOLA) digital terrain models have drastically improved our understanding of the networks in the last decade.
  • 654
  • 25 Oct 2022
Topic Review
List of Unnumbered Minor Planets: 2004 A–Q
This is a partial list of unnumbered minor planets for principal designations assigned between 1 January 2004 and 31 August 2004 (A–Q).
  • 646
  • 24 Nov 2022
Topic Review
List of Unnumbered Minor Planets: 2002 P–Q
This is a partial list of unnumbered minor planets for principal designations assigned between 1 August 2002 and 31 August 2002 (P–Q).
  • 635
  • 10 Nov 2022
Topic Review
TAUVEX
The Tel Aviv University Ultraviolet Explorer, or TAUVEX (Hebrew: טאווקס‎), is a space telescope array conceived by Noah Brosch of Tel Aviv University and designed and constructed in Israel for Tel Aviv University by El-Op, Electro-Optical Industries, Ltd. (a division of Elbit systems) acting as Prime Contractor, for the exploration of the ultraviolet (UV) sky. TAUVEX was selected in 1988 by the Israel Space Agency (ISA) as its first priority scientific payload. Although originally slated to fly on a national Israeli satellite of the Ofeq series, TAUVEX was shifted in 1991 to fly as part of a Spektr-RG international observatory, a collaboration of many countries with the Soviet Union (Space Research Institute) leading. Due to repeated delays of the Spektr project, caused by the economic situation in the post-Soviet Russia, ISA decided to shift TAUVEX to a different satellite. In early-2004 ISA signed an agreement with the Indian Space Research Organisation (ISRO) to launch TAUVEX on board the India n technology demonstrator satellite GSAT-4. The launch vehicle slated to be used was the GSLV with a new, cryogenic, upper stage. TAUVEX was a scientific collaboration between Tel Aviv University and the Indian Institute of Astrophysics in Bangalore. Its Principal Investigators were Noah Brosch at Tel Aviv University and Jayant Murthy at the Indian Institute of Astrophysics. Originally, TAUVEX was scheduled to be launched in 2008, but various delays caused the integration with GSAT-4 to take place only in November 2009 for a launch the following year. ISRO decided in January 2010 to remove TAUVEX from the satellite since the Indian-built cryogenic upper stage for GSLV was deemed under-powered to bring GSAT-4 to a geosynchronous orbit. GSAT-4 was subsequently lost in the 15 April 2010 launch failure of GSLV. On 13 March 2011 TAUVEX was returned to Israel and was stored at the Prime Contractor facility pending an ISA decision about its future. In 2012 ISA decided to terminate the TAUVEX project, against the recommendation of a committee it formed to consider its future that recommended its release for a high-altitude balloon flight.
  • 623
  • 10 Nov 2022
Topic Review
List of Jupiter Trojans (Trojan Camp) (300001–400000)
This is a partial list of Jupiter's L5 trojans (60° behind Jupiter) with numbers 300001–400000 (also see main page).
  • 620
  • 24 Nov 2022
Topic Review
Space Apps
Space Apps is annual NASA's global hackathon, first held in April 2012, and serves as innovation incubation and civic engagement program. NASA and its partners put out challenges relating to current work for which space enthusiasts around the world of all backgrounds can develop innovative solutions (which can be more than just apps!), particularly focusing on use of NASA data and promoting education. The project, formerly run by NASA's Office of the Chief Information Officer, is part of NASA's Earth Science Mission Directorate and is a part of the Open Government Initiative founded under President Barack Obama "creating an unprecedented level of openness in Government." It also fulfills the United States’ commitments to the Open Government Partnership.
  • 610
  • 08 Nov 2022
Topic Review
Venus In Situ Atmospheric and Geochemical Explorer
Venus In Situ Atmospheric and Geochemical Explorer (VISAGE) is a proposed Venus lander mission that would perform atmospheric and surface science investigations. The mission was proposed in 2017 to NASA's New Frontiers program to compete for funding and development, but it was not selected.
  • 593
  • 07 Nov 2022
Topic Review
A Short History of the Universe
This is the current state of the science regarding the birth and evolution of our universe. A few presumptions are not yet 100% secure and may still need to be amended in the future - and there are even some non-standard models that have a completely different approach to explaining the history of the universe. But the most convincing and most widely accepted hypothesis amongst scientists is the Big Bang Theory that will be described in this article. With this information at the back of your mind, let's start with the beginning, 13.8 billion years ago. 
  • 593
  • 25 Mar 2025
Topic Review
Exoplanets
One of the most fundamental questions any human being can ask is: are we alone in the universe? The knowledge about the existence and characteristics of exoplanets is indispensable for giving us an answer. Everything that we have learned up to now indicates that life might exist on millions and billions of other planets in our galaxy alone: there is the pure mind-blowing number of exoplanets that orbit other stars in the habitable zone; in the entire universe there is an abundance of water, oxygen, carbon and all the other main elements that make up life as we know it; and life on Earth itself evolved relatively quickly after the formation of the solar system was completed. Anyhow, our current instruments do not yet allow us to detect life on other planets, but there is a whole lot of other information that we have been able to find out already. So let's have a closer look at exoplanets to better understand them. 
  • 587
  • 23 Apr 2025
Topic Review
EnVision (Spacecraft)
EnVision is a proposed orbital mission to Venus that would perform high-resolution radar mapping and atmospheric studies. The mission would help scientists understand the relationships between its geological activity and the atmosphere, and it would investigate why Venus and Earth took such different evolutionary paths. The mission is studied by ESA in collaboration with NASA, with the potential sharing of responsibilities currently under assessment.
  • 587
  • 27 Oct 2022
Topic Review
Electromagnetic Spectrum
The electromagnetic spectrum is the range of all possible wavelengths of electromagnetic radiation, ranging from high energy gamma rays through visible light and down to low energy radio waves. Various astronomical phenomena can only be observed via specific wavelengths different from visible light. By scanning the sky in the complete spectrum of electromagnetic radiation via optical telescopes, X-ray telescopes, microwave telescopes and radio telescopes, astronomers gather information that wouldn't be accessible if they were just observing via visible light. Visible light is a small fraction of the entire electromagnetic spectrum with wavelengths ranging from 380 nm (nanometres or 10-9 m) to 740 nm.
  • 583
  • 24 Apr 2025
Topic Review
SDSS J001820.5-093939.2
SDSS J001820.5–093939.2 or SDSS J0018-0939 for short is a star system approximately 1000 light-years away near the constellation Cetus. SDSS J0018-0939 is a cool main-sequence star. It is the first star found proposed to be a massive second generation star.
  • 579
  • 18 Oct 2022
Topic Review
Micro-Imaging Dust Analysis System
The Micro-Imaging Dust Analysis System (MIDAS) is one of several instruments on the European Space Agency's Rosetta mission which studied in-situ the environment around the active comet 67P/Churyumov–Gerasimenko as it flew into the inner Solar System. MIDAS is an atomic force microscope (AFM) designed to collect dust particles emitted from the comet, and then scan them with a very sharp needle-like tip to determine their 3D structure, size and texture with very high resolution (4 nanometers).
  • 545
  • 20 Oct 2022
Topic Review
Atmospheric Transparency at Candidate Sites for Sub-Millimeter-Wave Telescopes
Radio astronomical observations at millimeter and submillimeter wavelengths are a very important tool for astrophysical research. However, there is a huge area in northeastern Eurasia, including the whole Russian territory, which lacks sufficiently large radio telescopes effectively operating at these wavelengths. 
  • 534
  • 03 Nov 2023
Topic Review
Northern Light (Spacecraft)
Northern Light was a concept mission for a robotic mission to Mars that would consist of a lander and a rover, being studied by a consortium of Canadian universities, companies and organisations. The primary contractor for the spacecraft was Thoth Technology Inc. The spacecraft would consist of four parts: an apogee kick engine to provide orbital injection for a cruise vehicle that carries the Northern Light lander and the Beaver Rover to a direct rendezvous with Mars using a Hohmann transfer orbit. Atmospheric entry would be achieved by a heat shield, parachute and airbag deployment system. The lander would transfer the rover to the Martian surface. Once deployed on the Martian surface, the lander contacts Earth directly to the 46 m parabolic antenna located at the Algonquin Radio Observatory. The Beaver Rover was proposed to have a maximum range of 1000 metres (0.62 mile) from the landing site. It would have operated under battery, utilizing tools and sensors to investigate surface rocks that may contain the presence of photosynthetic life.
  • 528
  • 03 Nov 2022
  • Page
  • of
  • 13
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of COVID-19
Encyclopedia of Engineering
Encyclopedia of Social Sciences
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Academic Video Service
Feedback