The Sun is near the inner rim of the Orion Arm, within the Local Fluff of the Local Bubble, and in the Gould Belt. Based upon studies of stellar orbits around Sgr A* by Gillessen and associates (2016), the Sun lies at an estimated distance of from the Galactic Center. Boehle and associates (2016) found a smaller value of , also using a star orbit analysis. The Sun is currently above, or north of, the central plane of the Galactic disk. The distance between the local arm and the next arm out, the Perseus Arm, is about . The Sun, and thus the Solar System, is located in the Milky Way's galactic habitable zone.
Sun's location and neighborhood
Milky Way
Milky Way | Sun's location and neighborhood
The Solar System, is located in the Milky Way's galactic habitable zone. It is located at a radius of about 27,000 light-years from the Galactic Center, on the inner edge of the Orion Arm. The Solar System is located at a radius of about 27,000 light-years from the Galactic Center, on the inner edge of the Orion Arm, one of the spiral-shaped concentrations of gas and dust. The Milky Way is the galaxy that contains our Solar System
where is the solar system located in our galaxy
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The Solar System is located in the Milky Way, a barred spiral galaxy with a diameter of about 100,000 light-years containing more than 100 billion stars. The Sun resides in one of the Milky Way's outer spiral arms, known as the Orion–Cygnus Arm or Local Spur. The Sun lies between 25,000 and 28,000 light-years from the Galactic Centre, and its speed within the Milky Way is about 220 km/s, so that it completes one revolution every 225–250 million years. This revolution is known as the Solar System's galactic year. The solar apex, the direction of the Sun's path through interstellar space, is near the constellation Hercules in the direction of the current location of the bright star Vega.
Solar System | Galactic context
The Sun is near the inner rim of the Orion Arm, within the Local Fluff of the Local Bubble, and in the Gould Belt. Based upon studies of stellar orbits around Sgr A* by Gillessen and associates (2016), the Sun lies at an estimated distance of from the Galactic Center. Boehle and associates (2016) found a smaller value of , also using a star orbit analysis. The Sun is currently above, or north of, the central plane of the Galactic disk. The distance between the local arm and the next arm out, the Perseus Arm, is about . The Sun, and thus the Solar System, is located in the Milky Way's galactic habitable zone.
Milky Way | Sun's location and neighborhood
The Milky Way is rotating around its dense galactic center, thus the sun is moving in a circle within the galaxy's gravity. Away from the central bulge, or outer rim, the typical stellar velocity is between . All planets and their moons move with the sun. Thus, the solar system is moving.
Motion | Sun and solar system
The Solar System orbits within the Milky Way, a barred spiral galaxy that is a prominent member of the Local Group of galaxies. It is a rotating mass of gas, dust, stars and other objects, held together by mutual gravitational attraction. As the Earth is located within the dusty outer arms, there are large portions of the Milky Way that are obscured from view. In the center of the Milky Way is the core, a bar-shaped bulge with what is believed to be a supermassive black hole at its center. This is surrounded by four primary arms that spiral from the core.
Astronomy | Galactic astronomy
The plane of the ecliptic lies at an angle of about 60° to the galactic plane. The Solar System's location in the Milky Way is a factor in the evolutionary history of life on Earth. Its orbit is close to circular, and orbits near the Sun are at roughly the same speed as that of the spiral arms. Therefore, the Sun passes through arms only rarely. Because spiral arms are home to a far larger concentration of supernovae, gravitational instabilities, and radiation that could disrupt the Solar System, this has given Earth long periods of stability for life to evolve.
Solar System | Galactic context
The apex of the Sun's way, or the solar apex, is the direction that the Sun travels through space in the Milky Way. The general direction of the Sun's Galactic motion is towards the star Vega near the constellation of Hercules, at an angle of roughly 60 sky degrees to the direction of the Galactic Center. The Sun's orbit about the Milky Way is expected to be roughly elliptical with the addition of perturbations due to the Galactic spiral arms and non-uniform mass distributions. In addition, the Sun passes through the Galactic plane approximately 2.7 times per orbit. This is very similar to how a simple harmonic oscillator works with no drag force (damping) term.
Milky Way | Sun's location and neighborhood
The Sun lies close to the inner rim of the Milky Way's Orion Arm, in the Local Interstellar Cloud or the Gould Belt, at a distance of from the Galactic Center. The Sun is contained within the Local Bubble, a space of rarefied hot gas, possibly produced by the supernova remnant Geminga, or multiple supernovae in subgroup B1 of the Pleiades moving group. The distance between the local arm and the next arm out, the Perseus Arm, is about 6,500 light-years. The Sun, and thus the Solar System, is found in what scientists call the galactic habitable zone. The "Apex of the Sun's Way", or the solar apex, is the direction that the Sun travels relative to other nearby stars.
Sun | Motion and location
The Milky Way is the galaxy that contains our Solar System. Milky Way may also refer to:
Milky Way (disambiguation) | Introduction
These oscillations were until recently thought to coincide with mass lifeform extinction periods on Earth. However, a reanalysis of the effects of the Sun's transit through the spiral structure based on CO data has failed to find a correlation.
Milky Way | Sun's location and neighborhood
The Sun orbits the center of the Milky Way, and it is presently moving in the direction of the constellation of Cygnus. A simple model of the motion of a star in the galaxy gives the galactic coordinates , , and as: where , , and are the respective velocities with respect to the local standard of rest, and are the Oort constants, formula_4 is the angular velocity of galactic rotation for the local standard of rest, formula_5 is the "epicyclic frequency", and ν is the vertical oscillation frequency. For the sun, the present values of , , and are estimated as formula_6 km/s, and estimates for the other constants are = 15.5 km/s/kpc, = −12.2 km/s/kpc, κ = 37 km/s/kpc, and ν=74 km/s/kpc.
Sun | Orbit in Milky Way
The distribution of the different types of galaxies in the universe depends on their location within galaxy clusters, with elliptical galaxies found mostly close to their centers.
Planetary system | Galactic distribution of planets
The Solar System is in the Local Interstellar Cloud or Local Fluff. It is thought to be near the neighbouring G-Cloud but it is not known if the Solar System is embedded in the Local Interstellar Cloud, or if it is in the region where the Local Interstellar Cloud and G-Cloud are interacting. The Local Interstellar Cloud is an area of denser cloud in an otherwise sparse region known as the Local Bubble, an hourglass-shaped cavity in the interstellar medium roughly 300 light-years (ly) across. The bubble is suffused with high-temperature plasma, that suggests it is the product of several recent supernovae.
Solar System | Neighbourhood
We take and to be zero and is estimated to be 17 parsecs. This model implies that the Sun circulates around a point that is itself going around the galaxy. The period of the Sun's circulation around the point is formula_7. which, using the equivalence that a parsec equals 1 km/s times 0.978 million years, comes to 166 million years, shorter than the time it takes for the point to go around the galaxy. In the () coordinates, the Sun describes an ellipse around the point, whose length in the direction is and whose width in the direction is The ratio of length to width of this ellipse, the same for all stars in our neighborhood, is formula_10 The moving point is presently at
Sun | Orbit in Milky Way
The Sun is from the Galactic Center. This value is estimated using geometric-based methods or by measuring selected astronomical objects that serve as standard candles, with different techniques yielding various values within this approximate range. In the inner few kpc (around 10,000 light-years radius) is a dense concentration of mostly old stars in a roughly spheroidal shape called the bulge. It has been proposed that the Milky Way lacks a bulge formed due to a collision and merger between previous galaxies, and that instead it only has a "pseudobulge" formed by its central bar. However, confusion in the literature between the (peanut shell)-shaped structure created by instabilities in the bar, versus a possible bulge with an expected half-light radius of 0.5 kpc, abounds.
Milky Way | Galactic Center
Much of the Solar System is still unknown. The Sun's gravitational field is estimated to dominate the gravitational forces of surrounding stars out to about two light years (125,000 AU). Lower estimates for the radius of the Oort cloud, by contrast, do not place it farther than 50,000 AU. Despite discoveries such as Sedna, the region between the Kuiper belt and the Oort cloud, an area tens of thousands of AU in radius, is still virtually unmapped. There are also ongoing studies of the region between Mercury and the Sun. Objects may yet be discovered in the Solar System's uncharted regions.
Solar System | Boundaries
Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis, observations by Edwin Hubble showed that the Milky Way is just one of many galaxies. The Milky Way is a barred spiral galaxy with an estimated visible diameter between 170,000 and 200,000 light-years (ly). It is estimated to contain 100–400 billion stars and at least that number of planets. The dark matter halo around the Milky Way may span as much as 2 million light years. The Solar System is located at a radius of about 27,000 light-years from the Galactic Center, on the inner edge of the Orion Arm, one of the spiral-shaped concentrations of gas and dust.
Milky Way | Introduction
HD 30963 is close to the orbit that the solar system is traversing in the Milky Way. The sun will be close to the current location of HD 30963 in about 18.5 million years. Interstellar absorption lines for Na I are present for velocities lower than 10 km/s.
HD 30963 | Introduction
The Solar System also lies well outside the star-crowded environs of the galactic centre. Near the centre, gravitational tugs from nearby stars could perturb bodies in the Oort cloud and send many comets into the inner Solar System, producing collisions with potentially catastrophic implications for life on Earth. The intense radiation of the galactic centre could also interfere with the development of complex life. Even at the Solar System's current location, some scientists have speculated that recent supernovae may have adversely affected life in the last 35,000 years, by flinging pieces of expelled stellar core towards the Sun, as radioactive dust grains and larger, comet-like bodies.
Solar System | Galactic context
The Sun is the star at the center of the Solar System. The Sun may also refer to:
The Sun | Introduction
With a galactic latitude of 4 degrees and galactic longitude 71 degrees, this system lies inward along the same Orion Spur in which the Sun is located within the Milky Way, near where the spur approaches the Sagittarius Arm. Cygnus X-1 has been described as belonging to the Sagittarius Arm, though the structure of the Milky Way is not well established.
Cygnus X-1 | Binary system
The Sun is the star at the center of the Solar System. Sun may also refer to:
Sun (disambiguation) | Introduction
The Solar System comprises the Sun and the objects that orbit it, either directly or indirectly. Solar System may also refer to:
Solar System (disambiguation) | Introduction
The Solar System is located within a structure called the Local Bubble, a low-density region of the galactic interstellar medium. Within this region is the Local Interstellar Cloud, an area of slightly higher hydrogen density. The Sun is near the edge of the Local Interstellar Cloud. It is thought to have entered the region at some point between 44,000 and 150,000 years ago and is expected to remain within it for another 10,000 to 20,000 years. The cloud has a temperature of about , about the same temperature as the surface of the Sun. However, its specific heat capacity is very low because it is not very dense, with .
Local Interstellar Cloud | Structure
4 billion solar masses) than the black hole at our Milky Way's center, one of the largest known. The physics that creates the jets is poorly understood, with a likely energy source being matter ejected perpendicular to the accretion disc of the central black hole.
Hercules A | Galaxy
Therefore, the Sun's vertical position cannot alone explain such periodic extinctions, and that extinctions instead occur when the Sun passes through the galaxy's spiral arms. Spiral arms are home not only to larger numbers of molecular clouds, whose gravity may distort the Oort cloud, but also to higher concentrations of bright blue giants, which live for relatively short periods and then explode violently as supernovae.
Formation and evolution of the Solar System | Galactic interaction
Although the vast majority of galaxies in the Universe are moving away from the Milky Way, the Andromeda Galaxy, the largest member of the Local Group of galaxies, is heading toward it at about 120 km/s. In 4 billion years, Andromeda and the Milky Way will collide, causing both to deform as tidal forces distort their outer arms into vast tidal tails. If this initial disruption occurs, astronomers calculate a 12% chance that the Solar System will be pulled outward into the Milky Way's tidal tail and a 3% chance that it will become gravitationally bound to Andromeda and thus a part of that galaxy.
Formation and evolution of the Solar System | Galactic collision and planetary disruption
The Milky Way is the galaxy that contains our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. The term "Milky Way" is a translation of the Latin ', from the Greek (', "milky circle"). From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe.
Milky Way | Introduction
The Milky Way is the second-largest galaxy in the Local Group (after the Andromeda Galaxy), with its stellar disk approximately in diameter and, on average, approximately thick. The Milky Way is approximately 890 billion times the mass of the Sun. To compare the relative physical scale of the Milky Way, if the Solar System out to Neptune were the size of a US quarter (), the Milky Way would be approximately the size of the contiguous United States. There is a ring-like filament of stars rippling above and below the relatively flat galactic plane, wrapping around the Milky Way at a diameter of , which may be part of the Milky Way itself.
Milky Way | Size and mass
DENIS-P J082303.1-491201 (also known as DENIS J082303.1-491201, DE0823-49), is a binary system of two brown dwarfs, located away from the Earth. The system is located in the constellation Vela. The primary has a spectral class of L1.5, a mass of and a temperature of . The secondary is also a brown dwarf but with a spectral type of L5.5, a mass of , and a temperature of . The mass ratio is around 0.64 to 0.74. The system has an orbital period of 248 days. The age of the system is estimated to be around 80 to 500 million years old, a relatively young object in the solar neighbourhood, however it does not seem to belong to have any association with any moving groups.
DENIS J082303.1−491201 | Introduction
History of the Solar System
Outline of the Solar System | History of the Solar System
According to the idea, the solar system had its origin in a gigantic star into which a smaller, dead, waterlogged star fell. This impact caused a huge explosion that flung fragments of the smaller star out into interstellar space where the water condensed and froze into giant blocks of ice. A ring of such blocks formed, that we now call the Milky Way, as well as a number of solar systems among which was our own, but with many more planets than currently exist. Interplanetary space is filled with traces of hydrogen gas, which cause the planets to slowly spiral inwards, along with ice blocks.
Welteislehre | Premise
This motion is towards a point in the constellation Hercules, near the star Vega. Within of the Sun there are 315 known stars in 227 systems, as of 2000, including 163 single stars. It is estimated that a further 130 systems within this range have not yet been identified. Out to , there may be up to 7,500 stars, of which around 2,600 are known. The number of substellar objects in that volume are expected to be comparable to the number of stars. Of the 50 nearest stellar systems within 17 light-years from Earth (the closest being the red dwarf Proxima Centauri at approximately 4.2 light-years), the Sun ranks fourth in mass.
Sun | Motion and location
The resulting disk of stars can be seen as a band on the sky from our perspective inside the disk. In a treatise in 1755, Immanuel Kant elaborated on Wright's idea about the structure of the Milky Way. The first project to describe the shape of the Milky Way and the position of the Sun was undertaken by William Herschel in 1785 by counting the number of stars in different regions of the sky. He produced a diagram of the shape of the galaxy with the Solar System close to the center. Using a refined approach, Kapteyn in 1920 arrived at the picture of a small (diameter about 15 kiloparsecs) ellipsoid galaxy with the Sun close to the center.
Galaxy | Milky Way
The models of the Solar System, in order:
Sagan Planet Walk | Model gallery
The Solar System is the gravitationally bound system of the Sun and the objects that orbit it, either directly or indirectly. Of the objects that orbit the Sun directly, the largest are the eight planets, with the remainder being smaller objects, the dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly—the moons—two are larger than the smallest planet, Mercury. The Solar System formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority of the system's mass is in the Sun, with the majority of the remaining mass contained in Jupiter.
Solar System | Introduction
A different method by Harlow Shapley based on the cataloguing of globular clusters led to a radically different picture: a flat disk with diameter approximately 70 kiloparsecs and the Sun far from the center. Both analyses failed to take into account the absorption of light by interstellar dust present in the galactic plane, but after Robert Julius Trumpler quantified this effect in 1930 by studying open clusters, the present picture of our host galaxy, the Milky Way, emerged.
Galaxy | Milky Way
The Solar System travels alone through the Milky Way in a circular orbit approximately 30,000 light years from the Galactic Centre. Its speed is about 220 km/s. The period required for the Solar System to complete one revolution around the Galactic Centre, the galactic year, is in the range of 220–250 million years. Since its formation, the Solar System has completed at least 20 such revolutions. Various scientists have speculated that the Solar System's path through the galaxy is a factor in the periodicity of mass extinctions observed in the Earth's fossil record. One hypothesis supposes that vertical oscillations made by the Sun as it orbits the Galactic Centre cause it to regularly pass through the galactic plane.
Formation and evolution of the Solar System | Galactic interaction
If placed at the center of the Solar system its photosphere would engulf the orbit of Saturn and reach to about 3/4 the distance to Uranus orbit.
WOH G17 | Introduction
The following works or series use multiple planets and other locations within the Solar System as their primary settings:
Solar System in fiction | Works
If placed at the center of the Solar System, the star's surface would engulf the orbit of Jupiter.
WOH G64 | Introduction
While stellar crowding proves disadvantageous to habitability, so too does extreme isolation. A star as metal-rich as the Sun would probably not have formed in the very outermost regions of the Milky Way given a decline in the relative abundance of metals and a general lack of star formation. Thus, a "suburban" location, such as the Solar System enjoys, is preferable to a Galaxy's center or farthest reaches.
Planetary habitability | The galactic neighborhood
HD 199942 is a binary star system in the northern constellation of Equuleus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.98. The system is located at a distance of approximately 184 light years based on parallax, and it has an absolute magnitude of 1.59. It is drifting closer with a radial velocity of −26 km/s. This system is moving through the galaxy at a velocity of relative to the Sun. Its galactic orbit carry it somewhere between 25100-22000 light years from the galactic core, and it'll come at its closest to the Sun 2.1 million years from now, at a distance of .
HD 199942 | Introduction
J1808−5104 is an ultra metal-poor (UMP) star, one that has a metallicity [Fe/H] less than , 1/10,000th of the levels in the sun. It is a single-lined spectroscopic binary, with radial velocity variations in its spectral absorption lines interpreted as orbital motion of the visible star. The companion is invisible, but inferred from the orbit. J1808−5104 is the brightest UMP star, as a binary system, known, and is part of the "thin disk" of the Milky Way, the part of the galaxy in which the Sun is located, but unusual for such a metal-poor and old star. At , the star is the oldest known thin-disk star, and several billion years older than most estimates for the age of the Milky Way's thin disk.
2MASS J18082002−5104378 | System
Mercury and Venus).
Solar System | Inner planets
Thus the Sun moves towards the apex (a relatively local point) at about our spiral arm's orbital speed. The sun's motion in the Milky Way is not confined to the galactic plane; it also shifts ("bobs") up and down with respect to the plane over millions of years.
Solar apex | Direction
The galactic coordinate system uses the approximate plane of our galaxy as its fundamental plane. The Solar System is still the center of the coordinate system, and the zero point is defined as the direction towards the galactic center. Galactic latitude resembles the elevation above the galactic plane and galactic longitude determines direction relative to the center of the galaxy.
Celestial coordinate system | Galactic system
However, their eccentric mutual orbit causes their distance to vary between 5.5 AUs at periastron, to 13.5 at apastron. This system is orbiting through the Milky Way at a distance from the core that varies from 7–9 kpc with an orbital eccentricity of 0.126–0.130. The closest approach to the Sun will occur in about 88,600 years when this system will come within 1.95 parsecs.
Kruger 60 | Description
The Greek philosopher Democritus (450–370 BCE) proposed that the bright band on the night sky known as the Milky Way might consist of distant stars. Aristotle (384–322 BCE), however, believed the Milky Way to be caused by "the ignition of the fiery exhalation of some stars that were large, numerous and close together" and that the "ignition takes place in the upper part of the atmosphere, in the region of the World that is continuous with the heavenly motions." The Neoplatonist philosopher Olympiodorus the Younger (–570 CE) was critical of this view, arguing that if the Milky Way is sublunary (situated between Earth and the Moon) it should appear different at different times and places on Earth, and that it should have parallax, which it does not.
Galaxy | Milky Way
The "Probability" trilogy takes place in a galaxy that has been colonized by humans. This was made possible by the space tunnels, a network of FTL warp gates that were created by a now-lost progenitor race. Humanity is not united under a common government and political system; instead, the various governments in the Solar System and beyond have united as the "Solar Alliance Defense Network" in light of the war against the Fallers. The Terrans have also discovered a number of alien races, most of them vastly similar in body format, living conditions and even DNA, leading to the hypothesis that the aforementioned progenitor race seeded the galaxy with sentient life, which then evolved according to the conditions on each planet.
Probability Sun | Setting
The stars that were monitored in this astronomical survey were all located in the Sagittarius-I Window. The Sagittarius Window is a rare view to the Milky Way's central bulge stars: our view to most of the galaxy's central stars is generally blocked by lanes of dust. These stars in the galaxy's central bulge region are approximately 27,000 light years from Earth.
Sagittarius Window Eclipsing Extrasolar Planet Search | Area examined
In September 2005, a massive planet was found orbiting the star surrounded by a disk. However, by next month, the disk was disproved because the infrared radiation is actually coming from the background galaxy passing very close to its star in apparent distance.
HD 33564 | Planetary system
Unlike planets, these objects basically appear to move in straight lines, so for normal use no complicated calculation is needed to find their mean position.
Apparent place | Solar System objects
The galactic coordinate system is a celestial coordinate system in spherical coordinates, with the Sun as its center, the primary direction aligned with the approximate center of the Milky Way galaxy, and the fundamental plane parallel to an approximation of the galactic plane but offset to its north. It uses the right-handed convention, meaning that coordinates are positive toward the north and toward the east in the fundamental plane.
Galactic coordinate system | Introduction
In particular, both display the radio jets characteristic of many active galactic nuclei. The distance from the Solar System is probably about 11,000 light years, or approximately half-way from the Sun to the Galactic Center, but a closer distance of ~2800 ly is not ruled out. GRO J1655-40 and its companion are moving through the Milky Way at around 112 km/s (250,000 miles per hour), in a galactic orbit that depends on its exact distance, but is mostly interior to the "Solar circle", "d"~8,500 pc, and within 150 pc (~500 ly) of the galactic plane. For comparison, the Sun and other nearby stars have typical speeds on the order of 20 km/s relative to the average velocity of stars moving with the galactic disk's rotation in the solar neighborhood, which supports the idea that the black hole formed from the collapse of the core of a massive star.
GRO J1655-40 | Introduction
This article describes extreme locations of the Solar System. Entries listed in bold are Solar System-wide extremes.
List of Solar System extremes | Introduction
In 2009, a gas giant planet was found in orbit around the star.
HD 148156 | Planetary system
This came as a surprise: according to standard cosmology, the satellite galaxies should form in dark matter halos, and they should be widely distributed and moving in random directions. This discrepancy is still not fully explained.
Milky Way | Environment
In astronomy, Galactocentrism is the theory that the Milky Way Galaxy, home of Earths Solar System, is at or near the center of the Universe. Observations by William Herschel in 1785 suggested that the Milky Way was a disk-shaped galaxy with the sun in a central position. Although heliocentric, Herschel's observations were the first attempt at an observational cosmology. Herschel's heliocentric theory was overthrown by astronomer Harlow Shapley's work on globular clusters in 1918. Shapley's research marked the transition from heliocentrism to galactocentrism, placing the Galactic Center of the Milky Way Galaxy far away from the sun, towards Sagittarius. Heber Doust Curtis and Edwin Hubble further refuted the heliocentric view of the universe by showing that spirals are themselves far-flung galactic systems.
Galactocentrism | Introduction
At this distance or beyond, the orbits of most halo objects would be disrupted by the Magellanic Clouds. Hence, such objects would probably be ejected from the vicinity of the Milky Way. The integrated absolute visual magnitude of the Milky Way is estimated to be around −20.9. Both gravitational microlensing and planetary transit observations indicate that there may be at least as many planets bound to stars as there are stars in the Milky Way, and microlensing measurements indicate that there are more rogue planets not bound to host stars than there are stars. The Milky Way contains at least one planet per star, resulting in 100–400 billion planets, according to a January 2013 study of the five-planet star system Kepler-32 with the Kepler space observatory.
Milky Way | Contents
The Milky Way and the Andromeda Galaxy are a binary system of giant spiral galaxies belonging to a group of 50 closely bound galaxies known as the Local Group, surrounded by a Local Void, itself being part of the Virgo Supercluster. Surrounding the Virgo Supercluster are a number of voids, devoid of many galaxies, the Microscopium Void to the "north", the Sculptor Void to the "left", the Bootes Void to the "right" and the Canes-Major Void to the South. These voids change shape over time, creating filamentous structures of galaxies. The Virgo Supercluster, for instance, is being drawn towards the Great Attractor, which in turn forms part of a greater structure, called Laniakea.
Milky Way | Environment
Following are the longest, widest, and deepest rifts and valleys in various worlds of the Solar System.
List of largest rifts, canyons and valleys in the Solar System | Introduction
The Sun's motion with respect to the LSR is called the "peculiar solar motion". The components of space velocity in the Milky Way's Galactic coordinate system are usually designated U, V, and W, given in km/s, with U positive in the direction of the Galactic Center, V positive in the direction of galactic rotation, and W positive in the direction of the North Galactic Pole. The peculiar motion of the Sun with respect to the LSR is with statistical uncertainty (+0.69−0.75, +0.47−0.47, +0.37−0.36) km/s and systematic uncertainty (1, 2, 0.5) km/s. (Note that V is 7 km/s larger than estimated in 1998 by Dehnen et al.)
Stellar kinematics | Space velocity
Beyond Neptune, the Solar System continues into the Kuiper belt, the scattered disc, and the Oort cloud, three sparse populations of small icy bodies thought to be the points of origin for most observed comets. At their distance from the Sun, accretion was too slow to allow planets to form before the solar nebula dispersed, and thus the initial disc lacked enough mass density to consolidate into a planet. The Kuiper belt lies between 30 and 55 AU from the Sun, while the farther scattered disc extends to over 100 AU, and the distant Oort cloud begins at about 50,000 AU.
Formation and evolution of the Solar System | Planetary migration
The rest frame of the center of mass of our solar system isn't a perfect inertial frame of reference since our solar system orbits around the center of the Milky Way. An estimation for the time of period of circulation is 230 million years (estimations vary between 225 and 250 million years). As the estimation for the distance between our solar system and the center of the Milky Way is about 28000 Ly, the assumed orbital speed of our solar system is formula_80. This would cause an aberration ellipse with a major semiaxis of 2,6' (arcminutes). Therefore, in one year the aberration angle could change (at max.) formula_81 = 4,3 µas (microarcseconds).
Stellar aberration (derivation from Lorentz transformation) | Stellar aberration due to the orbit of our solar system around the center of the Milky Way
Astronomers are confident that the Milky Way galaxy has a supermassive black hole at its center, 26,000 light-years from the Solar System, in a region called Sagittarius A* because: Infrared observations of bright flare activity near Sagittarius A* show orbital motion of plasma with a period of at a separation of six to ten times the gravitational radius of the candidate SMBH. This emission is consistent with a circularized orbit of a polarized "hot spot" on an accretion disk in a strong magnetic field. The radiating matter is orbiting at 30% of the speed of light just outside the innermost stable circular orbit.
Supermassive black hole | In the Milky Way
Stars brighter and hotter than the Sun are rare, whereas substantially dimmer and cooler stars, known as red dwarfs, make up 85% of the stars in the Milky Way. The Sun is a population I star; it has a higher abundance of elements heavier than hydrogen and helium ("metals" in astronomical parlance) than the older population II stars. Elements heavier than hydrogen and helium were formed in the cores of ancient and exploding stars, so the first generation of stars had to die before the Universe could be enriched with these atoms. The oldest stars contain few metals, whereas stars born later have more.
Solar System | Sun
The Sun is moved by the gravitational pull of the planets. One can think of the barycentre of the Solar System as being stationary (or as moving in a steady motion around the galaxy). The centre of the sun is always within 2.2 solar radii of the barycentre. This motion of the Sun is mainly due to Jupiter, Saturn, Uranus, and Neptune. For some periods of several decades, the motion is rather regular, forming a trefoil pattern, whereas between these periods it appears more chaotic. After 179 years (nine times the synodic period of Jupiter and Saturn) the pattern more or less repeats, but rotated by about 24°.
Sun | Motion in the Solar System
The model places the Milky Way galaxy relatively near the center of the cosmos. Humphreys' proposal has been criticized by other scientists and old earth creationists, such as Hugh Ross and Samuel R. Conner. Humphreys has replied to Ross' and Conner's critiques. In 1998, physicist Dave Thomas wrote that in Humphreys' thousands-of-years-old universe, he "has his astronomy backwards - the Kuiper Belt contains the remains of the 'volatile' (icy) planetesimals that were left over from the formation of the solar system - numbering in the hundreds of millions. If anything, it is the Kuiper Belt that supplies the more remote hypothesized Oort Cloud, as some icy chunks are occasionally flung far away by interactions with large planets."
Russell Humphreys | Cosmology
In 2009, two gas giant planets were found in orbit around the star.
BD−08°2823 | Planetary system
Clicking on the "Friz-finder" will determine whether Ms. Frizzle is anywhere on the current planet. If she is, then the game is completed, but if she is not then the user will have to collect another token to activate the "Friz-finder" to try again.
The Magic School Bus Lost in the Solar System | Software adaptation
Two scientists with the Harvard–Smithsonian Center for Astrophysics stated that when, and even whether, the two galaxies collide will depend on Andromeda's transverse velocity. Based on current calculations they predict a 50% chance that in a merged galaxy, the Solar System will be swept out three times farther from the galactic core than its current distance. They also predict a 12% chance that the Solar System will be ejected from the new galaxy sometime during the collision. Such an event would have no adverse effect on the system and the chances of any sort of disturbance to the Sun or planets themselves may be remote.
Andromeda–Milky Way collision | Fate of the Solar System
The principal component of the Solar System is the Sun, a G2 main-sequence star that contains 99.86% of the system's known mass and dominates it gravitationally. The Sun's four largest orbiting bodies, the giant planets, account for 99% of the remaining mass, with Jupiter and Saturn together comprising more than 90%. The remaining objects of the Solar System (including the four terrestrial planets, the dwarf planets, moons, asteroids, and comets) together comprise less than 0.002% of the Solar System's total mass. Most large objects in orbit around the Sun lie near the plane of Earth's orbit, known as the ecliptic.
Solar System | Structure and composition
Estimates of have been affected by discoveries that the Solar System's orbit is circular in the galaxy, at such a distance that it remains out of the spiral arms for tens of millions of years (evading radiation from novae). Also, Earth's large moon may aid the evolution of life by stabilizing the planet's axis of rotation.
Drake equation | Fraction of the above that develops intelligent life,
The myriad of stars that exist beyond our solar system are also shown. The Galilean moons of Jupiter, as well as moons of Earth, Saturn, Neptune and Uranus are included, as are Saturn's rings. A comet with an eccentric orbit is also present - perhaps Halley's comet which had last been seen in 1835.
Ellen Harding Baker | Solar System Quilt
The following is a list of Solar System objects by orbit, ordered by increasing distance from the Sun. Most named objects in this list have a diameter of 500 km or more. The Solar System also contains:
List of Solar System objects | Introduction
The Sun is a star located at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma and magnetic fields. It has a diameter of about , around 109 times that of Earth, and its mass (1.989 kilograms, approximately 330,000 times that of Earth) accounts for some 99.86% of the total mass of the Solar System. Chemically, about three quarters of the Sun's mass consists of hydrogen, while the rest is mostly helium. The remaining 1.69% (equal to 5,600 times the mass of Earth) consists of heavier elements, including oxygen, carbon, neon and iron.
Solar phenomena | Sun
On 2 October 1962, the universe underwent a change – instantly, the continents of the Earth were no longer wrapped onto a spherical planet but were on the surface of an Alderson disk. Measurements on Cepheid variable stars indicate that the Alderson disk is located in the Lesser Magellanic Cloud, and that the epoch is roughly 800,000 years later than the calendar date (give or take 100,000 to 200,000 years). In the sky, the stars of the Milky Way are reddened and metal-depleted, evidence that it is now controlled by a Type-III civilisation capable of controlling the resources of an entire galaxy.
Missile Gap | Plot
The point at which the Solar System ends and interstellar space begins is not precisely defined because its outer boundaries are shaped by two forces, the solar wind and the Sun's gravity. The limit of the solar wind's influence is roughly four times Pluto's distance from the Sun; this "heliopause", the outer boundary of the heliosphere, is considered the beginning of the interstellar medium. The Sun's Hill sphere, the effective range of its gravitational dominance, is thought to extend up to a thousand times farther and encompasses the hypothetical Oort cloud.
Solar System | Farthest regions
Based upon blackbody models, it is orbiting from the host star with a mean temperature of 280 K. There may be an additional, 60 K debris disk orbiting at a distance of .
HD 45184 | Planetary system
ULAS J0015+01 is, at the current time, 900,000 light years away from the Milky Way galaxy. The Milky Way's disk is 180,000 light years in diameter, putting it far beyond the Milky Way stellar disk, or only 3 times closer than the Andromeda galaxy. In comparison, in distance to the Milky Way's satellite galaxy, the Large Magellanic Cloud, is only 160,000 light-years from Earth. ULAS J0015+01 and ULAS J0744+25 are not technically in a galaxy, but they are both classified as being in the Milky Way's outer halo, which stretches at least 500,000 light years away. These stars were both the first to be discovered beyond 200 kpc.
ULAS J0015+01 | Distance
Along with the characteristics of planets and their star systems, the wider galactic environment may also impact habitability. Scientists considered the possibility that particular areas of galaxies (galactic habitable zones) are better suited to life than others; the Solar System in which we live, in the Orion Spur, on the Milky Way galaxy's edge is considered to be in a life-favorable spot: Thus, relative isolation is ultimately what a life-bearing system needs. If the Sun were crowded amongst other systems, the chance of being fatally close to dangerous radiation sources would increase significantly. Further, close neighbors might disrupt the stability of various orbiting bodies such as Oort cloud and Kuiper belt objects, which can bring catastrophe if knocked into the inner Solar System.
Planetary habitability | The galactic neighborhood
HD 128429 is a binary star system located at a distance of 88 light years from the Sun in the southern zodiac constellation of Libra. It has a yellow-white hue and is just barely visible to the naked eye with an apparent visual magnitude of 6.20. The system is drifting closer to the Sun with a radial velocity of −66 km/s and has a high proper motion, traversing the celestial sphere at the rate of per year. It is a high velocity star system with a net heliocentric velocity of 158.8 km/s. The system is orbiting the through the galaxy with a high eccentricity of 0.62, which carries it from as close as 4.1 out to away from the Galactic center.
HD 128429 | Introduction
In this mode it is possible to zoom away from the Solar System, through the Milky Way, and out into the cosmos to see a hypothetical view of the entire known universe. Other bodies, spacecraft and orbital reference frames can be added and visualized in the Solar System Mode using the layer manager. Users can query the Minor Planet Center for the orbits of minor bodies in the solar system, such as Sandbox
WorldWide Telescope | Solar System
He argues that the difficulty inherent in the development of eukaryotic cells represents such a barrier to the emergence of intelligent life that Earth may be the only planet where this has taken place in the Milky Way galaxy. In this episode Brian also tells us how Kepler observes into deep space seeking other solar systems just like our very own – How many potential 'earth-like' planets are there in the galaxy?
Human Universe | 3. "Are We Alone?"
The outermost planet orbits at a distance similar to the distance of Venus to the Sun and is situated well in the system's liquid water habitable zone.
HD 40307 | Planetary system
Knowledge of the location of Earth has been shaped by 400 years of telescopic observations, and has expanded radically since the start of the 20th century. Initially, Earth was believed to be the center of the Universe, which consisted only of those planets visible with the naked eye and an outlying sphere of fixed stars. After the acceptance of the heliocentric model in the 17th century, observations by William Herschel and others showed that the Sun lay within a vast, disc-shaped galaxy of stars. By the 20th century, observations of spiral nebulae revealed that the Milky Way galaxy was one of billions in an expanding universe, grouped into clusters and superclusters.
Location of Earth | Introduction
Cox then relates the Voyager missions and their continuing exploration of the massive reach of the Sun's gravitational forces on objects in the farthest regions of the Solar System. Finally, in the clear skies of the Atacama Desert, at the Paranal Observatory he is able to observe, with the naked eye, the myriad of stars on the Milky Way and relates the meaning of their diverse colours as mapped on the Hertzsprung–Russell diagram.
Wonders of the Solar System | 1. "Empire of the Sun"
This makes the Milky Way difficult to see from brightly lit urban or suburban areas, but very prominent when viewed from rural areas when the Moon is below the horizon. Maps of artificial night sky brightness show that more than one-third of Earth's population cannot see the Milky Way from their homes due to light pollution. As viewed from Earth, the visible region of the Milky Way's galactic plane occupies an area of the sky that includes 30 constellations. The Galactic Center lies in the direction of Sagittarius, where the Milky Way is brightest. From Sagittarius, the hazy band of white light appears to pass around to the galactic anticenter in Auriga.
Milky Way | Appearance
The stars and gas in the Milky Way rotate about its center differentially, meaning that the rotation period varies with location. As is typical for spiral galaxies, the orbital speed of most stars in the Milky Way does not depend strongly on their distance from the center. Away from the central bulge or outer rim, the typical stellar orbital speed is between . Hence the orbital period of the typical star is directly proportional only to the length of the path traveled. This is unlike the situation within the Solar System, where two-body gravitational dynamics dominate, and different orbits have significantly different velocities associated with them.
Milky Way | Galactic rotation
The orbits of Solar System planets are nearly circular. Compared to other systems, they have smaller orbital eccentricity. Although there are attempts to explain it partly with a bias in the radial-velocity detection method and partly with long interactions of a quite high number of planets, the exact causes remain undetermined.
Solar System | Comparison with extrasolar systems
HD 206610, a K0 star located 194 parsecs from Earth, is host to one planet, HD 206610 b. The host star is larger than the Sun; more massive at 1.56 solar masses and larger at 6.1 solar radii. The planet was discovered by the radial velocity method in 2010 and has a mass of 2.2 Jupiter masses. It orbits every 610 days at a distance of 1.68 AU. Much closer to its sun is WASP-47 b, which orbits every 4.15 days only 0.052 AU from its sun, yellow dwarf (G9V) WASP-47. WASP-47 is close in size to the Sun, having a radius of 1.15 solar radii and a mass even closer at 1.08 solar masses.
Aquarius (constellation) | Planetary systems
The planets were originally thought to have formed in or near their current orbits. This has been questioned during the last 20 years. Currently, many planetary scientists think that the Solar System might have looked very different after its initial formation: several objects at least as massive as Mercury were present in the inner Solar System, the outer Solar System was much more compact than it is now, and the Kuiper belt was much closer to the Sun.
Formation and evolution of the Solar System | Subsequent evolution
The following outline is provided as an overview of and topical guide to the Solar System: Solar System – gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly. Of those objects that orbit the Sun directly, the largest eight are the planets (including Earth), with the remainder being significantly smaller objects, such as dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly, the moons, two are larger than the smallest planet, Mercury.
Outline of the Solar System | Introduction
Formation and evolution of the Solar System –
Outline of the Solar System | Formation and evolution of the Solar System
The inner Solar System is the region comprising the terrestrial planets and the asteroid belt. Composed mainly of silicates and metals, the objects of the inner Solar System are relatively close to the Sun; the radius of this entire region is less than the distance between the orbits of Jupiter and Saturn. This region is also within the frost line, which is a little less than 5 AU (about 700 million km) from the Sun.
Solar System | Inner Solar System
The Galactic Center is marked by an intense radio source named Sagittarius A* (pronounced Sagittarius A-star). The motion of material around the center indicates that Sagittarius A* harbors a massive, compact object. This concentration of mass is best explained as a supermassive black hole (SMBH) with an estimated mass of 4.1–4.5 million times the mass of the Sun. The rate of accretion of the SMBH is consistent with an inactive galactic nucleus, being estimated at around per year. Observations indicate that there are SMBHs located near the center of most normal galaxies. The nature of the Milky Way's bar is actively debated, with estimates for its half-length and orientation spanning from and 10–50 degrees relative to the line of sight from Earth to the Galactic Center.
Milky Way | Galactic Center
The largest nearby star is Sirius, a bright main-sequence star roughly 8.6 light-years away and roughly twice the Sun's mass and that is orbited by a white dwarf, Sirius B. The nearest brown dwarfs are the binary Luhman 16 system at 6.6 light-years. Other systems within ten light-years are the binary red-dwarf system Luyten 726-8 (8.7 ly) and the solitary red dwarf Ross 154 (9.7 ly). The closest solitary Sun-like star to the Solar System is Tau Ceti at 11.9 light-years. It has roughly 80% of the Sun's mass but only 60% of its luminosity. The closest known free-floating planetary-mass object to the Sun is WISE 0855−0714, an object with a mass less than 10 Jupiter masses roughly 7 light-years away.
Solar System | Neighbourhood
In 2009, a gas giant was found in orbit around the star using the radial velocity method. It has an orbital period of and has at least 68% of the mass of Jupiter.
HD 8535 | Planetary system
This is a list of known galaxies within 3.8 megaparsecs (12 million light-years) of the Solar System, in ascending order of heliocentric distance, or the distance to the Sun. This encompasses all of the about 50 major Local Group galaxies, and some that are members of neighboring galaxy groups, the M81 Group and the Centaurus A/M83 Group, and some that are currently not in any defined galaxy group. The list aims to reflect current knowledge: not all galaxies within the 3.8 Mpc radius have been discovered. Nearby dwarf galaxies are still being discovered, and galaxies located behind the central plane of the Milky Way are extremely difficult to discern.
List of nearest galaxies | Introduction
Active star formation takes place in the disk (especially in the spiral arms, which represent areas of high density), but does not take place in the halo, as there is little cool gas to collapse into stars. Open clusters are also located primarily in the disk. Discoveries in the early 21st century have added dimension to the knowledge of the Milky Way's structure. With the discovery that the disk of the Andromeda Galaxy (M31) extends much farther than previously thought, the possibility of the disk of the Milky Way extending farther is apparent, and this is supported by evidence from the discovery of the Outer Arm extension of the Cygnus Arm and of a similar extension of the Scutum–Centaurus Arm.
Milky Way | Halo