Earth Introduction Earth Introduction My view of our planet was a glimpse of divinity. -Edgar Mitchell, USA From the perspective we get on Earth, our planet appears to be big and sturdy with an endless ocean of air. Many dream of traveling in space and viewing the wonders of the universe. Earth is the 3rd planet from the Sun at a distance of about 150 million kilometers (93.2 million miles). Earth is the only planet in the solar system known to harbor life. From our journeys into space, we have learned much about our home planet. Besides affecting Earth's weather, solar activity gives rise to a dramatic visual phenomenon in our atmosphere. Animations of Earth Views of Earth The following set of images show some of the wonders of our planet, the Earth. Blue Marble West This spectacular "blue marble" image is the most detailed true-color image of the entire Earth to date. Blue Marble East This spectacular "blue marble" image is the most detailed true-color image of the entire Earth to date.
Pluto In 2015, the Pluto system is due to be visited by spacecraft for the first time. The New Horizons probe will perform a flyby during which it will attempt to take detailed measurements and images of the plutoid and its moons. Discovery Discovery photographs of Pluto In the 1840s, using Newtonian mechanics, Urbain Le Verrier predicted the position of the then-undiscovered planet Neptune after analysing perturbations in the orbit of Uranus. In 1906, Percival Lowell, a wealthy Bostonian who had founded the Lowell Observatory in Flagstaff, Arizona in 1894, started an extensive project in search of a possible ninth planet, which he termed "Planet X".[25] By 1909, Lowell and William H. Tombaugh's task was to systematically image the night sky in pairs of photographs taken two weeks apart, then examine each pair and determine whether any objects had shifted position. Name The discovery made headlines across the globe. ), but has a circle in place of the middle prong of the trident ( Other factors
Earth Earth Earth is a complex, dynamic system we do not yet fully understand. The Earth system, like the human body, comprises diverse components that interact in complex ways. We need to understand the Earth's atmosphere, lithosphere, hydrosphere, cryosphere, and biosphere as a single connected system. Our planet is changing on all spatial and temporal scales. This is a composite image of the North African Continent. A major component of NASA’s Earth Science Division is a coordinated series of satellite and airborne missions for long-term global observations of the land surface, biosphere, solid Earth, atmosphere, and oceans. The Foundational missions are those missions in development at the time the decadal survey was published and include CLARREO, Aquarius, Suomi National Polar-orbiting Partnership (S-NPP), Landsat Data Continuity Mission (LDCM), and Global Precipitation Measurement (GPM).
Jupiter Structure Jupiter is composed primarily of gaseous and liquid matter. It is the largest of four gas giants as well as the largest planet in the Solar System with a diameter of 142,984 km (88,846 mi) at its equator. Composition Jupiter's upper atmosphere is composed of about 88–92% hydrogen and 8–12% helium by percent volume or fraction of gas molecules. Based on spectroscopy, Saturn is thought to be similar in composition to Jupiter, but the other gas giants Uranus and Neptune have relatively much less hydrogen and helium.[21] Because of the lack of atmospheric entry probes, high-quality abundance numbers of the heavier elements are lacking for the outer planets beyond Jupiter. Mass Jupiter's diameter is one order of magnitude smaller (×0.10045) than the Sun, and one order of magnitude larger (×10.9733) than the Earth. Internal structure Above the layer of metallic hydrogen lies a transparent interior atmosphere of hydrogen. Atmosphere Cloud layers Great Red Spot and other vortices
Deimos Deimos was discovered by Asaph Hall, Sr. at the United States Naval Observatory in Washington, D.C on 12 August 1877, at about 07:48 UTC (given in contemporary sources as "11 August 14:40" Washington mean time, using an astronomical convention of beginning a day at noon, so 12 hours must be added to get the actual local mean time).[9][10][11][12] Hall also discovered Phobos on 18 August 1877, at about 09:14 GMT, after deliberately searching for Martian moons. It has an escape velocity of 5.6 m/s[3] and apparent magnitude of 12.45.[4] Only two geological features on Deimos have been given names. The craters Swift and Voltaire are named after writers who speculated on the existence of two Martian moons before Phobos and Deimos were discovered.[16] Deimos's orbit is nearly circular and is close to Mars's equatorial plane. Unlike Phobos, which orbits so fast that it actually rises in the west and sets in the east, Deimos rises in the east and sets in the west. ^ Jump up to: a b "Apsis".
Alpha Centauri Location of Alpha Centauri in Centaurus (right-click on starmap to enlarge) From Earth to Alpha Centauri. Alpha Centauri (α Centauri, α Cen; also known as Rigil Kent /ˈraɪdʒəl ˈkɛnt/—see Names) is the brightest star in the southern constellation of Centaurus, and the third brightest star in the night sky.[10][11] The Alpha Centauri system is located 1.34 parsecs or 4.37 light years from the Sun, making it the closest star system to the Solar System.[12] Although it appears to the unaided eye as a single object, Alpha Centauri is actually a binary star system (designated Alpha Centauri AB or α Cen AB) whose combined visual magnitude of −0.27 makes it the third brightest star (other than the Sun) seen from Earth after the −1.46 magnitude Sirius and the −0.72 magnitude Canopus. Its component stars are named Alpha Centauri A (α Cen A), with 110% of the mass and 151.9% the luminosity of the Sun, and Alpha Centauri B (α Cen B), at 90.7% of the Sun's mass and 44.5% of its luminosity.
Uranus Uranus is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. Uranus is similar in composition to Neptune, and both are of different chemical composition than the larger gas giants Jupiter and Saturn. For this reason, astronomers sometimes place them in a separate category called "ice giants". Uranus's atmosphere, although similar to Jupiter's and Saturn's in its primary composition of hydrogen and helium, contains more "ices" such as water, ammonia, and methane, along with traces of hydrocarbons.[12] It is the coldest planetary atmosphere in the Solar System, with a minimum temperature of 49 K (−224.2 °C), and has a complex, layered cloud structure, with water thought to make up the lowest clouds, and methane the uppermost layer of clouds.[12] In contrast, the interior of Uranus is mainly composed of ices and rock.[11] History Discovery The power I had on when I first saw the comet was 227. Naming Name Axial tilt
Mars Animation of Mars' rotation from the vantage of an observer who moves south, then north, to hover over both poles, showing the planet's major topographic features. Mars is currently host to five functioning spacecraft: three in orbit – the Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter – and two on the surface – Mars Exploration Rover Opportunity and the Mars Science Laboratory Curiosity. Defunct spacecraft on the surface include MER-A Spirit and several other inert landers and rovers such as the Phoenix lander, which completed its mission in 2008. Observations by the Mars Reconnaissance Orbiter have revealed possible flowing water during the warmest months on Mars.[25] In 2013, NASA's Curiosity rover discovered that Mars' soil contains between 1.5% and 3% water by mass (about two pints of water per cubic foot or 33 liters per cubic meter, albeit attached to other compounds and thus not freely accessible).[26] Physical characteristics Size comparison of Earth and Mars. Soil
Venus Venus is a terrestrial planet and is sometimes called Earth's "sister planet" because of their similar size, gravity, and bulk composition (Venus is both the closest planet to Earth and the planet closest in size to Earth). However, it has also been shown to be very 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 735 K (462 °C; 863 °F), Venus is by far the hottest planet in the Solar System. Physical characteristics Venus is one of the four terrestrial planets in the Solar System, meaning that, like Earth, it is a rocky body. Geography The Venusian surface was a subject of speculation until some of its secrets were revealed by planetary science in the 20th century. The longitudes of physical features on Venus are expressed relative to its prime meridian. Surface geology
Asteriod Belt The asteroid belt (shown in white) is located between the orbits of Mars and Jupiter. History of observation[edit] In an anonymous footnote to his 1766 translation of Charles Bonnet's Contemplation de la Nature,[8] the astronomer Johann Daniel Titius of Wittenberg[9][10] noted an apparent pattern in the layout of the planets. In 1800 the astronomer Baron Franz Xaver von Zach recruited 24 of his fellows into a club, the Vereinigte Astronomische Gesellschaft ("United Astronomical Society") which he informally dubbed the "Lilienthal Society"[11] for its meetings in Lilienthal, a small city near Bremen. Neither the appellation of planets, nor that of comets, can with any propriety of language be given to these two stars ... The discovery of Neptune in 1846 led to the discrediting of the Titius–Bode law in the eyes of scientists, because its orbit was nowhere near the predicted position. Origin[edit] Formation[edit] Evolution[edit] The asteroids are not samples of the primordial Solar System.
Mercury Mercury is gravitationally locked and rotates in a way that is unique in the Solar System. As seen relative to the fixed stars, it rotates exactly three times for every two revolutions[b] it makes around its orbit.[13] As seen from the Sun, in a frame of reference that rotates with the orbital motion, it appears to rotate only once every two Mercurian years. An observer on Mercury would therefore see only one day every two years. Because Mercury's orbit lies within Earth's orbit (as does Venus's), it can appear in Earth's sky in the morning or the evening, but not in the middle of the night. Internal structure Internal structure of Mercury: 1. Mercury's density can be used to infer details of its inner structure. Mercury's core has a higher iron content than that of any other major planet in the Solar System, and several theories have been proposed to explain this. Alternatively, Mercury may have formed from the solar nebula before the Sun's energy output had stabilized. Surface geology
Phobos Phobos (systematic designation: Mars I) is the larger and closer of the two natural satellites of Mars. Both moons were discovered in 1877. Phobos has dimensions of 27 × 22 × 18 km,[1] and is too small to be rounded under its own gravity. Its surface area is slightly less than the land area of Delaware. Faint dust rings produced by Phobos and Deimos have long been predicted but attempts to observe these rings have, to date, failed.[23] Recent images from Mars Global Surveyor indicate that Phobos is covered with a layer of fine-grained regolith at least 100 meters thick; it is hypothesized to have been created by impacts from other bodies, but it is not known how the material stuck to an object with almost no gravity.[24] The unique Kaidun meteorite is thought to be a piece of Phobos, but this has been difficult to verify since little is known about the detailed composition of the moon.[25][26] Labeled Map of Phobos - Moon of Mars (USGS).[30]