Sun and Related Topics

Star

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Astronomical object comprising a luminous spheroid of plasma held together by its gravity.

Infrared image from NASA's Spitzer Space Telescope showing hundreds of thousands of stars in the Milky Way galaxy

Stellar evolution of low-mass (left cycle) and high-mass (right cycle) stars, with examples in italics

An example of a Hertzsprung–Russell diagram for a set of stars that includes the Sun (center) (see Classification)

Betelgeuse as seen by ALMA. This is the first time that ALMA has observed the surface of a star and resulted in the highest-resolution image of Betelgeuse available.

Onion-like layers at the core of a massive, evolved star just before core collapses

The Crab Nebula, remnants of a supernova that was first observed around 1050 AD

Artist's impression of the Sirius system, a white dwarf star in orbit around an A-type main-sequence star

This view of NGC 6397 includes stars known as blue stragglers for their location on the Hertzsprung–Russell diagram.

Some of the well-known stars with their apparent colors and relative sizes

The Pleiades, an open cluster of stars in the constellation of Taurus. These stars share a common motion through space.

Surface magnetic field of SU Aur (a young star of T Tauri type), reconstructed by means of Zeeman–Doppler imaging

The reflection nebula NGC 1999 is brilliantly illuminated by V380 Orionis. The black patch of sky is a vast hole of empty space and not a dark nebula as previously thought.

The asymmetrical appearance of Mira, an oscillating variable star

Internal structures of main sequence stars with masses indicated in solar masses, convection zones with arrowed cycles, and radiative zones with red flashes. Left to right, a red dwarf, a yellow dwarf, and a blue-white main sequence star

Overview of consecutive fusion processes in massive stars

The nearest star to Earth is the Sun.

Earth

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Planetary disk of a star, the inner ring has a radius equal to Earth and the Sun

Artist's impression of earth during the Archean eon, showing falling meteor, erupting volcano, round stromatolites, and barren landscape

Earth topological map, the area is redder if it is raised higher in real-life

Global map of heat flow from Earth's interior to the surface

Earth's major plates, which are: · · · · ·

Satellite picture of Upsala Glacier, showing mountains, icebergs, lakes, and clouds

Schematic of Earth's magnetosphere, with the solar wind flows from left to right

Earth's rotation imaged by Deep Space Climate Observatory, showing axis tilt

Illustration of the Earth, Earth's orbit, the Sun and the four seasons

Earth's axial tilt and its relation to the rotation axis and planes of orbit

A model of Vanguard 1, the oldest human-made object in Earth orbit

Water is transported to various parts of the hydrosphere via the water cycle

Top of Earth's blue-tinted atmosphere, with the Moon at the background

Fungi are one of the kingdoms of life on Earth.

Change in average surface air temperature since the industrial revolution, plus drivers for that change. Human activity has caused increased temperatures, with natural forces adding some variability.

Earthrise, taken in 1968 by William Anders, an astronaut on board Apollo 8

Hubble Space Telescope seen in orbit from Space Shuttle Atlantis

Processes leading to movements and phase changes in Earth's water

Tracy Caldwell Dyson in the Cupola module of the International Space Station observing the Earth below

Earth is the third planet from the Sun and the only astronomical object known to harbor life.

Solar wind

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Laboratory simulation of the magnetosphere's influence on the solar wind; these auroral-like Birkeland currents were created in a terrella, a magnetised anode globe in an evacuated chamber.

This is thought to show the solar wind from the star L.L. Orionis generating a bow shock (the bright Arc)

The heliospheric current sheet results from the influence of the Sun's rotating magnetic field on the plasma in the solar wind

Schematic of Earth's magnetosphere. The solar wind flows from left to right.

Apollo's Solar Wind Composition Experiment on the Lunar surface

An infographic featuring the outer regions of the heliosphere based on results from the Voyager spacecraft

Parker Solar Probe observed switchbacks — traveling disturbances in the solar wind that caused the magnetic field to bend back on itself.

The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona.

Venus

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Impact craters on the surface of Venus (false-colour image reconstructed from radar data)

Venus is the second planet from the Sun, orbiting approximately 1.6 times (yellow trail) in Earth's 365 days (blue trail).

Venus, pictured center-right, is always brighter than all other planets or stars as seen from Earth. Jupiter is visible at the top of the image.

The phases of Venus and evolution of its apparent diameter

The pentagram of Venus. Earth is positioned at the centre of the diagram, and the curve represents the direction and distance of Venus as a function of time.

The "black drop effect" as recorded during the 1769 transit

Galileo's discovery that Venus showed phases (although remaining near the Sun in Earth's sky) proved that it orbits the Sun and not Earth.

Modern telescopic view of Venus from Earth's surface

Artist's impression of Mariner 2, launched in 1962: a skeletal, bottle-shaped spacecraft with a large radio dish on top

Global false color view of Venus in ultraviolet radiation done by Mariner 10

180-degree panorama of Venus's surface from the Soviet Venera 9 lander, 1975. Black-and-white image of barren, black, slate-like rocks against a flat sky. The ground and the probe are the focus. Several lines are missing due to a simultaneous transmission of the scientific data.

Venus is portrayed just to the right of the large cypress tree in Vincent van Gogh's 1889 painting The Starry Night.

Venus is the second planet from the Sun and is named after the Roman goddess of love and beauty.

White dwarf

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Stellar core remnant composed mostly of electron-degenerate matter.

A comparison between the white dwarf IK Pegasi B (center), its A-class companion IK Pegasi A (left) and the Sun (right). This white dwarf has a surface temperature of 35,500 K.

The white dwarf cooling sequence seen by ESA's Gaia mission

Artist's impression of the WD J0914+1914 system.

Internal structures of white dwarfs. To the left is a newly formed white dwarf, in the center is a cooling and crystallizing white dwarf, and the right is a black dwarf.

Artist's impression of debris around a white dwarf

Comet falling into white dwarf (artist's impression)

The merger process of two co-orbiting white dwarfs produces gravitational waves

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A white dwarf is very dense: its mass is comparable to the Sun's, while its volume comparable to the Earth's. A white dwarf's faint luminosity comes from the emission of residual thermal energy; no fusion takes place in a white dwarf.

Mars

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A cross-section of underground water ice is exposed at the steep slope that appears bright blue in this enhanced-color view from the MRO. The scene is about 500 meters wide. The scarp drops about 128 meters from the level ground. The ice sheets extend from just below the surface to a depth of 100 meters or more.

A MOLA-based topographic map showing highlands (red and orange) dominating the Southern Hemisphere of Mars, lowlands (blue) the northern. Volcanic plateaus delimit regions of the northern plains, whereas the highlands are punctuated by several large impact basins.

Fresh asteroid impact on Mars at 3.34°N, 219.38°W. These before and after images of the same site were taken on the Martian afternoons of 27 and 28 March 2012 respectively (MRO).

Viking 1 image of Olympus Mons. The volcano and related terrain are approximately 550 km across.

Escaping atmosphere on Mars (carbon, oxygen, and hydrogen) by MAVEN in UV

Mars is about 143 e6mi from the Sun; its orbital period is 687 (Earth) days, depicted in red. Earth's orbit is in blue.

Viking 1 lander's sampling arm scooped up soil samples for tests (Chryse Planitia)

The descent stage of the Mars Science Laboratory mission carrying the Curiosity rover deploys its parachutes to decelerate itself before landing, photographed by Mars Reconnaissance Orbiter.

Animation of the apparent retrograde motion of Mars in 2003 as seen from Earth.

Mars distance from Earth in millions of km (Gm).

Martian tripod illustration from the 1906 French edition of The War of the Worlds by H. G. Wells

Curiosity view of Martian soil and boulders after crossing the "Dingo Gap" sand dune

Valles Marineris, taken by the Viking 1 probe

Edge-on view of Mars atmosphere by Viking 1 probe

Orbit of Mars and other Inner Solar System planets

Curiosity’s robotic arm showing drill in place, February 2013

Scoop of Mars soil by Curiosity, October 2012

Ingenuity helicopter on Mars, preparing for its first flight

Mars seen through an 16-inch amateur telescope, at 2020 opposition

Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, being larger than only Mercury.

Moon

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Earth's only natural satellite.

The Moon and selected moons of the Solar System, with Earth to scale. Nineteen moons are large enough to be round, several having subsurface oceans and one, Titan, having a considerable atmosphere.

Sketch by the Apollo 17 astronauts. The lunar atmosphere was later studied by LADEE.

Map of the near side of the Moon and its features, with major maria (blue) and craters (brown) marked.

The largest mare, the main dark region of the near side, is Oceanus Procellarum, with smaller mare, such as Imbrium and Serenitatis, that sit within its ring. Left of the centerline is Procellarum proper.

Lunar crater Daedalus on the Moon's far side

Lunar Reconnaissance Orbiter Wide Angle Camera image of the lunar swirl Reiner Gamma

Relative elemental composition of the lunar soil

DSCOVR satellite sees the Moon passing in front of Earth

Comparison between the Moon on the left, rotating tidally locked (correct), and with the Moon on the right, without rotation (incorrect).

Libration, the slight variation in the Moon's apparent size and viewing angle over a single lunar month as viewed from Earth's north.

During the lunar phases, only portions of the Moon can be observed from Earth.

Appearence of the Moon when visible at daytime

The Moon, tinted reddish, during a lunar eclipse

Galileo's sketches of the Moon from the ground-breaking Sidereus Nuncius, publishing among other findings the first descriptions of the Moons topography.

Map of the Moon by Johannes Hevelius from his Selenographia (1647), the first map to include the libration zones

First view in history of the far side of the Moon, taken by Luna 3, 7 October 1959

The first image from the lunar surface, photographed by Luna 9 in 1966.

A replica of Lunokhod 1, which reached the Moon becoming the first remote controled rover on an extraterrestrial surface (1970)

Earthrise, the first colour image of Earth taken by a human from the Moon, during Apollo 8 (1968) the first time a crewed spacecraft left Earth orbit and reached another astronomical body.

Neil Armstrong, the first human on the Moon, working at the Lunar Module Eagle, a first lunar base, during Apollo 11 (1969), the first Moon landing

One of the first moon rocks (Lunar basalt 70017, Apollo 17, 1972), which were collected during the Apollo missions.

NASA's Moon Mineralogy Mapper equipment on India's Chandrayaan-1 for the first time discovered in 2008 water-rich minerals (light blue), shown in blue around a small crater from which it was ejected.

Map of all soft landing sites on the near side of the Moon.

Remains of human activity, Apollo 17's Lunar Surface Experiments Package.

A photo of the reflector of the Lunar Laser Ranging Experiment of Apollo 11, still in use.

The Venus of Laussel (c. 25,000 BP) holding a crescent shaped horn, the 13 notches on the horn may symbolize the number of days from menstruation to ovulation, or of menstrual cycles or moons per year.

Scale model of the Earth–Moon system: Sizes and distances are to scale.

Day moon, the moon is visible during daylight almost every day.

The geologic map of the Moon at 1-2.5M scale by Chinese Academy of Sciences. See the original file for higher resolution.

Comparison of angular diameter of the Moon compared to other celestial objects (to get a true representation of this image view it at a size of 5 cm wide on your monitor and at 5.15 m distance).

Despite this, it is the brightest object in the sky after the Sun.

Helium

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Chemical element with the symbol He and atomic number 2.

Sir William Ramsay, the discoverer of terrestrial helium

The cleveite sample from which Ramsay first purified helium

Historical marker, denoting a massive helium find near Dexter, Kansas

The helium atom. Depicted are the nucleus (pink) and the electron cloud distribution (black). The nucleus (upper right) in helium-4 is in reality spherically symmetric and closely resembles the electron cloud, although for more complicated nuclei this is not always the case.

Binding energy per nucleon of common isotopes. The binding energy per particle of helium-4 is significantly larger than all nearby nuclides.

Helium discharge tube shaped like the element's atomic symbol

Liquefied helium. This helium is not only liquid, but has been cooled to the point of superfluidity. The drop of liquid at the bottom of the glass represents helium spontaneously escaping from the container over the side, to empty out of the container. The energy to drive this process is supplied by the potential energy of the falling helium.

Unlike ordinary liquids, helium II will creep along surfaces in order to reach an equal level; after a short while, the levels in the two containers will equalize. The Rollin film also covers the interior of the larger container; if it were not sealed, the helium II would creep out and escape.

Structure of the helium hydride ion, HHe+

Structure of the suspected fluoroheliate anion, OHeF−

The largest single use of liquid helium is to cool the superconducting magnets in modern MRI scanners.

A dual chamber helium leak detection machine

Because of its low density and incombustibility, helium is the gas of choice to fill airships such as the Goodyear blimp.

Its abundance is similar to this in both the Sun and in Jupiter, due to the very high nuclear binding energy (per nucleon) of helium-4, with respect to the next three elements after helium.