Lunar water...

 Lunar water is water that is present on the Moon. Liquid water cannot persist on the surface of the Moon, and water vapor is broken down by sunlight, with hydrogen quickly lost to outer space. However, since the 1960s scientists have conjectured that water ice could survive in cold, permanently shadowed craters at the Moon's poles. Water molecules are also detected in the thin layer of gases above the lunar surface.

Black hole

 

A black hole is a region of spacetime where gravity is so strong that nothing, no particles or even electromagnetic radiation such as light, can escape from it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of no escape is called the event horizon.

Although it has a great effect on the fate and circumstances of an object crossing it, it has no locally detectable features according to general relativity. In many ways, a black hole acts like an ideal black body, as it reflects no light. Moreover, quantum field theory in curved spacetime predicts that event horizonts emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass.

This temperature is of the order of billionths of a kelvin for stellar black holes, making it essentially impossible to observe directly. Objects whose gravitational fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace. In 1916, Karl Schawarzschild found the first modern solution of general relativity that would characterize a black hole.

David Finkelstein, in 1958, first published the interpretation of "black hole" as a region of space from which nothing can escape. Black holes were long considered a mathematical curiosity; it was not until the 1960s that theoretical work showed they were a generic prediction of general relativity. The discovery of neutron stars by Jocelyn Bell Burnell in 1967 sparked interest in gravitationally collapsed compact objects as a possible astrophysical reality.

The first black hole known was Cygnus X-1, identified by serveral researchers independently in 1971. Black holes of stellar mass form when massive stars collapse at the end of their life cycle. After a black hole has formed, it can grow by absorbing mass from its surroundings. Supermassive black holes of millions of solar masses may form by absorbing other stars and merging with other black holes.

There is consensus that supermassive black holes exist in the centres of most galaxies. The presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as visible light. Any matter that falls onto a black hole can form an external accretion disk heated by friction, forming quasars, some of the brightest objects in the universe.

Stars passing too close to a supermassive black hole can be shredded into streamers that shine very brightly before being "swallowed". If other stars are orbiting a black hole, their orbits can determine the black hole's mass and location. Such observations can be used to exclude possible alternatives such as neutron stars. In this way, astronomers have identified numerous stellar black hole candidates in binary systems and established that the radio source known as Sagittarius A, at the core of the Milky Way galaxy, contains a supermassive black hole of about 4.3 million solar masses.

The National Aeronautics and Space Administration

 

NASA is an independent agency of the U.S. federal government responsible for the civilian space program, as well as aeronautics and space research. NASA was established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA). The new agency was to have a distinctly civilian orientation, encouraging peaceful applications in space science. Since its establishment, most US space exploration efforts have been led by NASA, including the Apollo Moon landing missions, the Skylab space station, and later the Space Shuttle.

NASA is supporting the International Space Station and is overseeing the development of the Orion spacecraft, the Space Launch System, and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program, which provides oversight of launch operations and countdown management for uncrewed NASA launches. NASA science is focused on better understanding Earth through the Earth Observing System; advancing heliophysics through the efforts of the Science Mission Directorate's Heliophysics Research Program.

Exploring bodies throughout the Solar System with advanced robotic spacecraft such as New Horizons; and researching astrophysics topics, such as the Big Bang, through the Great Observatories and associated programs. Since 2017, NASA's crewed spaceflight program has been the Artemis program, which involves the help of U.S. commercial spaceflight companies and international partners such as ESA, JAXA, and CSA. The goal of this program is to land "the first woman and the next man" on the lunar south pole region by 2024.

Polaris

Polaris, designated Ursae Minoris, commonly the North Star or Pole Star, is the brighest star in the constellation of Ursa Minor. It is very close to the north celestial pole, making it the current northern pole star. The revised Hipparcos parallax gives a distance to Polaris of about 433 light-years (133 parsecs), while calculations by other methods derive distances around 30% closer. 

Polaris is a triple star system, composed of the primary star, Polaris Aa (a yellow supergiant), in orbit with a smaller companion (Polaris Ab); the pair in orbit with Polaris B (discovered in August 1779 by William Herschel). There were once thought to be two more distant component, Polaris C and Polaris D, but these have been shown not to be physically associated with the Polaris system. 

Polaris Aa is a 5.4 solar mass F7 yellow supergiant of spectral type IB. It is the first classical Cepheid to have a mass determined from its orbit. The two smaller companions are Polaris B, a 1.39 F3 main-sequence star orbiting at a distance of 2400 astronomical units (AU), and Polaris Ab (or P), a very close F6 main-sequence star with an 18.8 AU radius orbit and 1.26.

Polaris B can be seen even with a modest telescope. William Herschel discovered the star in August 1779 using a reflecting telescope of his own, one of the best telescopes of the time. By examining the spectrum of Polaris A, it was also discovered in 1929 that it was a very close binary, with the secondary being a dwarf, which had been theorized in earlier observations. In January 2006, NASA, released images, from the Hubble telescope, that showed the three members of the Polaris ternary system.

Ab, the nearby dwarf star, is in an orbit of 18.5 AU (2.8 billion km) from Polaris Aa, about the distance between the Sun and Uranus, which explains why its light is swamped by its close and much brigher companion. Polaris Aa, the supergiant primary component, is a low-amplitude Population I classical Cepheid variable, although it was once thought to be a type II Cepheid due to its high galactic latitude. Cepheids constitute an important standard candle for determining distance, so Polaris, as the closest such star, is heavily studied.

Mars, the red planet.

Mars is the fourth planet from the Sun and the second smallest planet in the Solar System, after Mercury. Named after the Roman god of war, it is often referred to as the "Red Planet" because the iron oxide prevalent on its surface gives it a reddish appearance. Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the volcanoes, valleys, deserts, and polar ice caps of Earth.

The rotational period and seasonal cycles of Mars are likewise similar to those of Earth, as is the tilt that produces the seasons. Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System.

The smooth Boralis basin in the northern hemisphere covers 40% of the planet and may be a giant impact feature. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to Eureka, a Mars trojan.

Until the first succesful Mars flyby in 1.965 by Mariner 4, many speculated about the presence of liquid water on the planet's surface. This was based on observed periodic variations in light and dark patches, particularly in the polar latitudes, which appeared to be seas and continents; long, dark striations were interpreted by some as irrigation channels for liquid water.

These straight line features were later explained as optical illusions, though geological evidence gathered by unmanned missions suggests that Mars once had large-scale water coverage on its surface at some earlier stage of its life.

In 2.005, radar data revealed the presence of large quantities of water ice at the poles and at mid-latitudes. The Mars rover Spirit sampled chemical compounds containing water molecules in March 2.007. The Phoenix lander directly sampled water ice in shallow Martian soil on July 31, 2.008. Mars is host to seven functioning spacecraft: five in orbit.

2.001 - Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, MAVEN and Mars Orbiter Mission. And tow on the surface; Mars Exploration Rover Opportunity and the Mars Science Laboratory Curiosity.

Mars was the Roman counterpart of Ares...

The Earth

Earth, also called the world and, less frequently, Gaia and Terra in some works of science fiction, is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to accommodate life.

The earliest life on Earth arose at least 3,5 billion years ago. Earth's biodiversity has expanded continually except when interrupted by mass extinctions. Although scholars estimate that over 99% of all species of life that ever lived on Earth are extinct, there are still an estimated 10-14 million extant species, of which about 1,2 million have been documented and over 86% have not yet been described. 

Over 7,3 billion humans live on Earth and depend on its biosphere and minerals for their survival. Earth's human population is divided among about two hundred sovereign states which interact through diplomacy, conflict, travel, trade and communication media.

According to evidence from radiometric dating and other sources, Earth was formed about 4, 54 billion years ago. Within its first billion years, life appeared in its oceans and began to affect its atmophere and surface, promoting the proliferation of aerobic as well as anaerobic organisms and causin the formation of the atmophere's ozone layer.

Earth was a personified goddess in Germanic paganism: the Angles were listed by Tacitus as among the devotees of Nerthus, and later Norse mythology included Jöro, a giantess often given as the mother of Thor.

Venus

Venus is the second planet from the Sun, orbiting it every 224,7 Earth days. It has no natural satellite. It is named after the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of -4.6, bright enough to cast shadows. Because Venus is an inferior planet from Earth, it never appears to venture far from the Sun: its elongation reaches a maximum of 47.8º.

Venus is a terrestrial planet and is sometimes called Earth's "sister planet" because of their similar size, mass, proximity to the Sun and bulk composition. It is radically different from Earth in other respects. It has the densest atmosphere of the four terrestrial planets, consisting of more than 96% carbon dioxide.

The atmospheric pressure at the planet's surface is 92 times that of Earth's. With a mean surface temperature of 735K (462 ºC; 863 ºF), Venus is by far the hottest planet in the Solar System, even though Mercury is closer to the Sun. Venus has no carbon cycle that puts carbon into rock, nor does it seem to have any organic life to absorb carbon in biomass.

Venus is shrouded by an opaque layer of highly reflective clouds of sulfuric acid, preventing its surface from being seen from space in visible light. It may have had oceans in the past, but these would have vaporized as the temperature rose due to a runaway greenhouse effect. The water has most probably photodissociated, and, because of the lack of a planetary magnetic field, the free hydrogen has been swept into interplanetary space by the solar wind.

Venus's surface is a dry desertscape interspersed with slab-like rocks and periodically refreshed by volcanism. 

Mercury

Mercury is the smallest and closest to the Sun of the eight planets in the Solar System, with an orbital period of about 88 Earth days. Seen from Earth, it appears to move around its orbit in about 116 days, which is much fster than any other planet in the Solar System. It has no known natural satellites. The planet is named after the Roman deity Mercury, the messenger to the gods.

Because it has almost no atmosphere to retain heat, Mercury's surface experiences the greatest temperature variation of the planets in the Solar System, ranging from 100 K(-173 ºC and -280 ºC) at night to 700 K  (427 ºC; 800 ºF) during the day at some equatorial regions. The poles are constantly below 180 K (-93 ºC; -136 ºF).

Mercury's axis has the smallest tilt of any of the Solar System's planets (about 1/30 of a degree), but ithas the largest orbital eccentricity. At aphelion, Mercury is about 1,5 times as far from the Sun as it is at perihelion. Mercury's surface is heavily cratered and similar in appearance to the Moon, indicating that it has been geologically inactive for billions of years.