query: what is the speed of earth around sun

pos: Earth's orbit As seen from Earth, the planet's orbital prograde motion makes the Sun appear to move with respect to other stars at a rate of about 1° (or a Sun or Moon diameter every 12 hours) eastward per solar day. Earth's orbital speed averages about 30 km/s (108,000 km/h; 67,000 mph), which is fast enough to cover the planet's diameter in 7 minutes and the distance to the Moon in 4 hours. From a vantage point above the north pole of either the Sun or Earth, Earth would appear to revolve in a counterclockwise direction around the Sun. From the same

pos: Specific energy more energy, typically moving with respect to the sun, when in our vicinity, at about the square root of two times the speed of the earth. This comes to 42 km/s, or a specific energy of 882 MJ/kg. The speed relative to the earth may be more or less, depending on direction. Since the speed of the earth around the sun is about 30 km/s, a comet's speed relative to the earth can range from 12 to 72 km/s, the latter corresponding to 2592 MJ/kg. If a comet with this speed fell to the earth it would gain another 63

pos: Earth's orbit As seen from Earth, the planet's orbital prograde motion makes the Sun appear to move with respect to other stars at a rate of about 1° (or a Sun or Moon diameter every 12 hours) eastward per solar day. Earth's orbital speed averages about 30 km/s (108,000 km/h; 67,000 mph), which is fast enough to cover the planet's diameter in 7 minutes and the distance to the Moon in 4 hours. From a vantage point above the north pole of either the Sun or Earth, Earth would appear to revolve in a counterclockwise direction around the Sun. From the same

neg: Ecliptic year, the Sun moves a little less than 1° eastward every day. This small difference in the Sun's position against the stars causes any particular spot on Earth's surface to catch up with (and stand directly north or south of) the Sun about four minutes later each day than it would if Earth would not orbit; a day on Earth is therefore 24 hours long rather than the approximately 23-hour 56-minute sidereal day. Again, this is a simplification, based on a hypothetical Earth that orbits at uniform speed around the Sun. The actual speed with which Earth orbits the Sun

neg: Horseshoe orbit viewed relative to the Earth. Its orbit around the Sun still takes only slightly more than one Earth year. Given enough time, the Earth and the satellite will be on opposite sides of the Sun. Eventually the satellite comes around to point D where Earth's gravity is now reducing the satellite's orbital velocity. This causes it to fall into a lower orbit, which actually increases the angular speed of the satellite around the Sun. This continues until point E where the satellite's orbit is now lower and faster than Earth's orbit, and it begins moving out ahead of Earth. Over

neg: Longitude by chronometer moment in time at which the sun passes through the sight tube on its descent from Zenith between a half-hour and hour later, the two times can be averaged to obtain a longitude sufficiently accurate for navigation (within 2nmi). Unfortunately, the Earth does not make a perfect circular orbit around the Sun. Due to the elliptical nature of the Earth’s orbit around the Sun, the speed of the Sun’s apparent orbit around the Earth varies throughout the year and that causes it to appear to speed up and slow down very slightly. Consequently, noon at the Prime Meridian is rarely

neg: Motion (physics) and their moons move with the sun. Thus, the solar system is moving. The Earth is rotating or spinning around its axis. This is evidenced by day and night, at the equator the earth has an eastward velocity of . The Earth is also orbiting around the Sun in an orbital revolution. A complete orbit around the sun takes one year, or about 365 days; it averages a speed of about . The Theory of Plate tectonics tells us that the continents are drifting on convection currents within the mantle causing them to move across the surface of the planet

neg: Edward W. Morley of the year, as the Earth revolved in its orbit around the Sun. These careful measurements were created to measure the differences in the speed of light in different directions. Michelson and Morley always found that the speed of light did not vary at all depending on the direction of measurement, or the position of the Earth in its orbit, deducing what we call a "null result" for their speed-of-light experiments. Neither he nor Michelson ever considered that these null results disproved the hypothesis of the existence of "luminiferous aether", in which electromagnetic waves were thought to be propagated. Their

neg: Day nearly constant (24 hours ± 30 seconds). This is the time as indicated by modern sundials. A further improvement defines a fictitious mean Sun that moves with constant speed along the celestial equator; the speed is the same as the average speed of the real Sun, but this removes the variation over a year as the Earth moves along its orbit around the Sun (due to both its velocity and its axial tilt). A "day", understood as the span of time it takes for the Earth to make one entire rotation with respect to the celestial background or a distant

neg: Speed of gravity many in the 19th century to criticize any model based on a finite speed of gravity, like electrical or mechanical explanations of gravitation. From a modern point of view, Laplace's analysis is incorrect. Not knowing about Lorentz' invariance of static fields, Laplace assumed that when an object like the Earth is moving around the Sun, the attraction of the Earth would not be toward the instantaneous position of the Sun, but toward where the Sun "had been" if its position was retarded using the relative velocity (this retardation actually "does" happen with the "optical" position of the Sun, and is

neg: STEREO and Spacecraft B will take 387 days. The A spacecraft/Sun/Earth angle will increase at 21.650 degree/year. The B spacecraft/Sun/Earth angle will change −21.999 degrees per year. Given that the length of Earth's orbit is around 940 million kilometres, both craft have an average speed, in a rotating geocentric frame of reference in which the sun is always in the same direction, of about 1.8 km/s, but the speed varies considerably depending on how close they are to their respective aphelion or perihelion (as well as on the position of Earth). Their current locations are shown here. Over time, the STEREO

neg: Speed of light of stars to move around. From the angular difference in the position of stars (maximally 20.5 arcseconds) it is possible to express the speed of light in terms of the Earth's velocity around the Sun, which with the known length of a year can be converted to the time needed to travel from the Sun to the Earth. In 1729, Bradley used this method to derive that light travelled 10,210 times faster than the Earth in its orbit (the modern figure is 10,066 times faster) or, equivalently, that it would take light 8 minutes 12 seconds to travel from the

neg: Hipparchus III.4) determined that spring (from spring equinox to summer solstice) lasted 94½ days, and summer (from summer solstice to autumn equinox) days. This is inconsistent with a premise of the Sun moving around the Earth in a circle at uniform speed. Hipparchus's solution was to place the Earth not at the center of the Sun's motion, but at some distance from the center. This model described the apparent motion of the Sun fairly well. It is known today that the planets, including the Earth, move in approximate ellipses around the Sun, but this was not discovered until Johannes Kepler published

neg: Moon Pluto, at 1/9 Pluto's mass. The Earth and the Moon's barycentre, their common centre of mass, is located (about a quarter of Earth's radius) beneath Earth's surface. The Earth revolves around the Earth-Moon barycentre once a sidereal month, with 1/81 the speed of the Moon, or about per second. This motion is superimposed on the much larger revolution of the Earth around the Sun at a speed of about per second. The Moon is in synchronous rotation as it orbits Earth; it rotates about its axis in about the same time it takes to orbit Earth. This results in it

neg: Adhik Maas AD) it would occur once, in 1963 AD. The Moon takes about 27.3 days to make one complete orbit around the earth. The earth orbits around the sun once every 365.2422 days (= earth’s orbital speed of 29.79 km per second). The earth and the moon in 27.3 days have moved as a system about 1/12 of the way around the sun. This means that from one full moon to the next full moon, the moon must travel 2.2 extra days before it appears again as a full moon, due to the curve of the earth’s orbit around the sun.

neg: Michelson–Morley experiment with aether. Because the speed of light is so great, and because material bodies pass through the "aether" without obvious friction or drag, it was assumed to have a highly unusual combination of properties. Designing experiments to test the properties of the aether was a high priority of 19th century physics. Earth orbits around the Sun at a speed of around , or . The Earth is in motion, so two main possibilities were considered: (1) The aether is stationary and only partially dragged by Earth (proposed by Augustin-Jean Fresnel in 1818), or (2) the aether is completely dragged by

neg: Apache Point Observatory Lunar Laser-ranging Operation this effect.) If the Moon just revolved around the Earth, there would be no way to tell what fraction of the Moon's or the Earth's gravity was caused by each form of mass, since only the total can be measured. However, the orbit of the Moon is also strongly affected by the gravity of the Sun—in essence, Earth and Moon are in free fall around the Sun. If the energy portion of mass behaves differently from the conventional portion, then the Earth and the Moon will fall differently toward the Sun, and the orbit of the Moon around the Earth

neg: Meteoroid are particles from comets, giving rise to meteor showers. Some meteoroids are fragments from bodies such as Mars or our moon, that have been thrown into space by an impact. Meteoroids travel around the Sun in a variety of orbits and at various velocities. The fastest move at about through space in the vicinity of Earth's orbit. This is escape velocity from the sun, equal to the square root of two times Earth's speed, and is the upper speed limit of objects in the vicinity of Earth, unless they come from interstellar space. Earth travels at about , so when

neg: Helios (spacecraft) a speed that counterbalances exactly the body of the probe. Synchronizing the speed is performed using data supplied by a Sun sensor. The maximum flow rate obtained with the large antenna gain is 4096 bits per second upstream. The reception and transmission of signals are supported by the Deep Space Network network antennas on Earth. To maintain its orientation during the mission, the spacecraft rotates continuously at 60 rpm around its main axis. The orientation control system eventually makes corrections to the speed and orientation of the probe shaft. To determine its orientation using a rude Sun sensor, a Sun

neg: Earth hours. Due to this motion, on average it takes 24 hours—a solar day—for Earth to complete a full rotation about its axis so that the Sun returns to the meridian. The orbital speed of Earth averages about , which is fast enough to travel a distance equal to Earth's diameter, about , in seven minutes, and the distance to the Moon, , in about 3.5 hours. The Moon and Earth orbit a common barycenter every 27.32 days relative to the background stars. When combined with the Earth–Moon system's common orbit around the Sun, the period of the synodic month, from

neg: Lagrangian point with regard to its orbit around the larger mass. The triangular points ( and ) are stable equilibria, provided that the ratio of is greater than 24.96. This is the case for the Sun–Earth system, the Sun–Jupiter system, and, by a smaller margin, the Earth–Moon system. When a body at these points is perturbed, it moves away from the point, but the factor opposite of that which is increased or decreased by the perturbation (either gravity or angular momentum-induced speed) will also increase or decrease, bending the object's path into a stable, kidney bean-shaped orbit around the point (as seen

neg: Aryabhata and a larger "śīghra" (fast). The positions and periods of the planets was calculated relative to uniformly moving points. In the case of Mercury and Venus, they move around the Earth at the same mean speed as the Sun. In the case of Mars, Jupiter, and Saturn, they move around the Earth at specific speeds, representing each planet's motion through the zodiac. Most historians of astronomy consider that this two-epicycle model reflects elements of pre-Ptolemaic Greek astronomy. Another element in Aryabhata's model, the "śīghrocca", the basic planetary period in relation to the Sun, is seen by some historians as a

neg: Gravity assist Mstislav Keldysh at the Steklov Institute of Mathematics, "inter alia" by Vsevolod Alexandrovich Egorov. A spacecraft traveling from Earth to an inner planet will increase its relative speed because it is falling toward the Sun, and a spacecraft traveling from Earth to an outer planet will decrease its speed because it is leaving the vicinity of the Sun. Although the orbital speed of an inner planet is greater than that of the Earth, a spacecraft traveling to an inner planet, even at the minimum speed needed to reach it, is still accelerated by the Sun's gravity to a speed notably

neg: Equation of time one year. If the Earth orbited the Sun with a constant speed, in a circular orbit in a plane perpendicular to the Earth's axis, then the Sun would culminate every day at exactly the same time, and be a perfect time keeper (except for the very small effect of the slowing rotation of the Earth). But the orbit of the Earth is an ellipse not centered on the Sun, and its speed varies between 30.287 and 29.291 km/s, according to Kepler's laws of planetary motion, and its angular speed also varies, and thus the Sun appears to move faster (relative

neg: Low head hydro power with speed and direction as caused by the gravitational forces of the sun and the moon, and centrifugal and inertial forces on the Earth's waters. Due to its proximity to the earth, the moon exerts roughly twice the tide raising force of the sun. The gravitational forces of the sun and moon and the centrifugal/inertial forces caused by the rotation of the earth around the center of mass of the earth-moon system create two "bulges" in the Earth's oceans: one closest to the moon, and the other on the opposite side of the globe.(CNW Group, 2008). This kind of energy

neg: Lunar theory P1 and P2, of the Moon in its orbit around the Earth, the respective vectors LS1 and LS2 for the perturbing acceleration due to the Sun. The Moon's position at P1 is fairly close to what it was at P in Newton's diagram; corresponding perturbation LS1 is like Newton's LS in size and direction. At another position P2, the Moon is farther away from the Sun than the Earth is, the Sun's attraction LQ2 on the Moon is weaker than the Sun's attraction SQ=SQ2 on the Earth, and then the resulting perturbation LS2 points obliquely away from the Sun. Constructions

neg: Sidereal time the moment when the Sun is exactly due south or north (depending on the observer's latitude and the season). A mean solar day (what we normally measure as a "day") is the average time between local solar noons ("average" since this varies slightly over the year). Earth makes one rotation around its axis in a sidereal day; during that time it moves a short distance (about 1°) along its orbit around the Sun. So after a sidereal day has passed, Earth still needs to rotate slightly more before the Sun reaches local noon according to solar time. A mean solar

neg: Gravity and events in the Universe including the Big Bang and what happened after it. In December 2012, a research team in China announced that it had produced measurements of the phase lag of Earth tides during full and new moons which seem to prove that the speed of gravity is equal to the speed of light. This means that if the Sun suddenly disappeared, the Earth would keep orbiting it normally for 8 minutes, which is the time light takes to travel that distance. The team's findings were released in the Chinese Science Bulletin in February 2013. In October 2017,

neg: 3753 Cruithne to "follow" each other in their paths around the Sun. This is why Cruithne is sometimes called "Earth's second moon". However, it does not orbit the Earth and is not a moon. In 2058, Cruithne will come within 0.09 AU () of Mars. Due to a high orbital eccentricity, Cruithne's distance from the Sun and orbital speed vary a lot more than the Earth's, so from the Earth's point of view Cruithne actually follows a kidney-bean-shaped horseshoe orbit ahead of the Earth, taking slightly less than one year to complete a circuit of the "bean". Because it takes slightly "less"

neg: Robert Bellarmine Paolo Antonio Foscarini in 1615: The Council [of Trent] prohibits interpreting Scripture against the common consensus of the Holy Fathers; and if Your Paternity wants to read not only the Holy Fathers, but also the modern commentaries on Genesis, the Psalms, Ecclesiastes, and Joshua, you will find all agreeing in the literal interpretation that the sun is in heaven and turns around the earth with great speed, and that the earth is very far from heaven and sits motionless at the center of the world.andI say that if there were a true demonstration that the sun is at the center

neg: Lunar day around the Sun at the same time, the Moon must travel further to return to the same phase. On average, this synodic period lasts 29 days, 12 hours, 44 minutes, and 3 seconds. This is the mean figure since the speed of the Earth–Moon system around the Sun varies slightly during a year due to the eccentricity of its elliptical orbit, variances in orbital velocity, and a number of other periodic and evolving variations about its observed, relative, mean values, which are influenced by the gravitational perturbations of the Sun and other bodies in the Solar System. As a result,

neg: De revolutionibus orbium coelestium divided into six "books" (sections or parts), following closely the layout of Ptolemy's "Almagest" which it updated and replaced: Copernicus argued that the universe comprised eight spheres. The outermost consisted of motionless, fixed stars, with the Sun motionless at the center. The known planets revolved about the Sun, each in its own sphere, in the order: Mercury, Venus, Earth, Mars, Jupiter, Saturn. The Moon, however, revolved in its sphere around the Earth. What appeared to be the daily revolution of the Sun and fixed stars around the Earth was actually the Earth's daily rotation on its own axis. Copernicus adhered

neg: Elliptic orbit radial elliptic trajectory is the solution of a two-body problem with at some instant zero speed, as in the case of dropping an object (neglecting air resistance). See also Free fall#Inverse-square law gravitational field. The Babylonians were the first to realize that the Sun's motion along the ecliptic was not uniform, though they were unaware of why this was; it is today known that this is due to the Earth moving in an elliptic orbit around the Sun, with the Earth moving faster when it is nearer to the Sun at perihelion and moving slower when it is farther away

neg: Delta-v budget table only give the Δv needed to get to the orbital distance of the planet. The speed relative to the planet will still be considerable, and in order to go into orbit around the planet either aerocapture is needed using the planet's atmosphere, or more Δv is needed. The New Horizons space probe to Pluto achieved a near-Earth speed of over 16 km/s which was enough to escape from the sun. (It also got a boost from a fly-by of Jupiter.) To get to the sun, it is actually not necessary to use a Δ"v" of 24 km/s. One can

neg: Horseshoe orbit the Sun. But Earth's gravity exerts an outward accelerating force, pulling the satellite into a higher orbit which (per Kepler's third law) decreases its angular speed. When the satellite gets to point B, it is traveling at the same speed as Earth. Earth's gravity is still accelerating the satellite along the orbital path, and continues to pull the satellite into a higher orbit. Eventually, at Point C, the satellite reaches a high and slow enough orbit such that it starts to lag behind Earth. It then spends the next century or more appearing to drift 'backwards' around the orbit when

neg: Retrograde and prograde motion than asteroids to be retrograde. Halley's Comet has a retrograde orbit around the Sun. Most Kuiper belt objects have prograde orbits around the Sun. The first Kuiper belt object discovered to have a retrograde orbit was . Other Kuiper belt objects with retrograde orbits are (471325) 2011 KT, , and 2011 MM. All of these orbits are highly tilted, with inclinations in the 100° - 125° range. Meteoroids in a retrograde orbit around the Sun hit the Earth with a faster relative speed than prograde meteoroids and tend to burn up in the atmosphere and are more likely to hit

neg: Saturn the Sun is over 1.4 billion kilometers (9 AU). With an average orbital speed of 9.68 km/s, it takes Saturn 10,759 Earth days (or about years) to finish one revolution around the Sun. As a consequence, it forms a near 5:2 mean-motion resonance with Jupiter. The elliptical orbit of Saturn is inclined 2.48° relative to the orbital plane of the Earth. The perihelion and aphelion distances are, respectively, 9.195 and 9.957 AU, on average. The visible features on Saturn rotate at different rates depending on latitude and multiple rotation periods have been assigned to various regions (as in Jupiter's case).

neg: Interplanetary spaceflight it must change its speed by another 2.3 km/s in order to match Mars' orbital speed around the Sun and enter an orbit around it. For comparison, launching a spacecraft into low Earth orbit requires a change in speed of about 9.5 km/s. For many years economical interplanetary travel meant using the Hohmann transfer orbit. Hohmann demonstrated that the lowest energy route between any two orbits is an elliptical "orbit" which forms a tangent to the starting and destination orbits. Once the spacecraft arrives, a second application of thrust will re-circularize the orbit at the new location. In the case

neg: Spherical Earth energy can also move water, rock, and soil to make the Earth slightly out of round. Earth undulates as the shape of its lowest potential energy changes daily due to the gravity of the Sun and Moon as they move around with respect to the Earth. This is what causes tides in the oceans' water, which can flow freely along the changing potential. The IAU definitions of planet and dwarf planet require that a Sun-orbiting body has undergone the rounding process to reach a roughly spherical shape, an achievement known as hydrostatic equilibrium. The same spheroidal shape can be seen

neg: Michelson–Morley experiment directions at various different times, it was thought to be possible to measure the motion of the Earth relative to the aether. The expected relative difference in the measured speed of light was quite small, given that the velocity of the Earth in its orbit around the Sun has a magnitude of about one hundredth of one percent of the speed of light. During the mid-19th century, measurements of aether wind effects of first order, i.e. effects proportional to "v"/"c" ("v" being Earth's velocity, "c" the speed of light) were thought to be possible, but no direct measurement of the

neg: Speed of light from the planet (or its moon) to Earth is shorter when the Earth is at the point in its orbit that is closest to its planet than when the Earth is at the farthest point in its orbit, the difference in distance being the diameter of the Earth's orbit around the Sun. The observed change in the moon's orbital period is caused by the difference in the time it takes light to traverse the shorter or longer distance. Rømer observed this effect for Jupiter's innermost moon Io and deduced that light takes 22 minutes to cross the diameter of the

neg: Dayton Miller time. Dayton Miller performed over 326,000 turns of interferometer with 16 readings each one, (more than 5,200,000 measurements). They showed what appeared to be a small amount of drift (about 9 km/s, 1/3 of the velocity of the earth around the sun): With white light and 32 m arms he could see nearly always the same result: The amplitude analysis suggests a drag of aether. But the analysis of phase suggests that the Solar System goes towards the constellation Dorado at a speed of 227 km/s. These results were presented by Miller as a positive indication of the existence of

neg: Tidal locking Librations are primarily caused by the Moon's varying orbital speed due to the eccentricity of its orbit: this allows up to about 6° more along its perimeter to be seen from Earth. Parallax is a geometric effect: at the surface of Earth we are offset from the line through the centers of Earth and Moon, and because of this we can observe a bit (about 1°) more around the side of the Moon when it is on our local horizon. It was thought for some time that Mercury was in synchronous rotation with the Sun. This was because whenever Mercury

neg: Analemma as the planet it accompanies, but with a different (usually greater) orbital eccentricity. It appears, when seen from the planet, to revolve around the planet once a year in the retrograde direction, but at varying speed and probably not in the ecliptic plane. Relative to its mean position, moving at constant speed in the ecliptic, the quasi-satellite traces an analemma in the planet's sky, going around it once a year. Analemma In astronomy, an analemma (; from Greek "analēmma" "support") is a diagram showing the position of the Sun in the sky, as seen from a fixed location on Earth

neg: Prague astronomical clock together they show the time in three different ways: Additionally, the distance of the Sun from the center of the dial shows the time of sunrise and sunset. The Sun and its hand are on the 365-tooth gear inside the machine. The movement of the Moon on the ecliptic is shown similarly to that of the Sun, although the speed is much faster (due to the Moon's own orbit around the Earth). The Moon's arm is on the 379-tooth gear inside the clock machine. The half-silvered, half-black sphere of the moon also shows the Lunar phase. The Moon has a

neg: Speed of light Sun to the Earth. An astronomical unit (AU) is approximately the average distance between the Earth and Sun. It was redefined in 2012 as exactly . Previously the AU was not based on the International System of Units but in terms of the gravitational force exerted by the Sun in the framework of classical mechanics. The current definition uses the recommended value in metres for the previous definition of the astronomical unit, which was determined by measurement. This redefinition is analogous to that of the metre, and likewise has the effect of fixing the speed of light to an exact

neg: Sun general vicinity as the Sun. The Sun's orbit around the Milky Way is perturbed due to the non-uniform mass distribution in Milky Way, such as that in and between the galactic spiral arms. It has been argued that the Sun's passage through the higher density spiral arms often coincides with mass extinctions on Earth, perhaps due to increased impact events. It takes the Solar System about 225–250 million years to complete one orbit through the Milky Way (a "galactic year"), so it is thought to have completed 20–25 orbits during the lifetime of the Sun. The orbital speed of the

neg: Newton's cannonball different path depending on its initial velocity. If the speed is low, it will simply fall back on Earth. (A and B) for example horizontal speed of 0 to 7,000 m/s for Earth. If the speed is the orbital speed at that altitude, it will go on circling around the Earth along a fixed circular orbit, just like the Moon. (C) for example horizontal speed of at approximately 7,300 m/s for Earth. If the speed is higher than the orbital velocity, but not high enough to leave Earth altogether (lower than the escape velocity), it will continue revolving around Earth

neg: Spherical Earth York, passengers saw a second sunset in the west. Because the speed of the Sun's shadow is slower in polar regions (due to the steeper angle), even a subsonic aircraft can overtake the sunset when flying at high latitudes. One photographer used a roughly circular route around the North Pole to take pictures of 24 sunsets in the same 24-hour period, pausing westward progress in each time zone to let the shadow of the Sun catch up. The surface of the Earth rotates at at 80° north or south, and at the equator. Because the Earth is spherical, long-distance travel

neg: King tide around the Sun in an elliptic orbit that takes a little over 365 days to complete. Its gravitational force is greatest when the Earth is at perihelion — closest to the Sun in early January — and least when the Earth is at aphelion — farthest from the Sun in early July. The king tides occur when the Earth, Moon and Sun are aligned at perigee and perihelion, resulting in the largest tidal range seen over the course of a year. So, tides are enhanced when the Earth is closest to the Sun around January 2 of each year. They

neg: Seconds pendulum 3. The equation of time is this difference, which is cyclical and does not accumulate from year to year. Mean time follows the mean sun. Jean Meeus describes the mean sun as follows: Consider a first fictitious Sun travelling along the "ecliptic" with a constant speed and coinciding with the true sun at the perigee and apogee (when the Earth is in perihelion and aphelion, respectively). Then consider a second fictitious Sun travelling along the "celestial equator" at a constant speed and coinciding with the first fictitious Sun at the equinoxes. This second fictitious sun is the "mean Sun"..." In

neg: Cosmic catastrophe Cosmic catastrophe The cosmic catastrophe is a thought experiment in which the sun were to instantaneously disappear. The question is what would then happen to the earth and the other planets orbiting the sun. According to Isaac Newton's classical theory of gravity, the planets would immediately cease to move in circular motion, and inertia would make them start traveling in a straight line. Albert Einstein saw a deficiency in Newton's theory. The finiteness of the speed of light would make it take a certain amount of time before the darkness from the sun's absence would reach the orbiting planet. Therefore,

neg: Cosmic catastrophe Only then, the planet would start to travel in a straight line. Cosmic catastrophe The cosmic catastrophe is a thought experiment in which the sun were to instantaneously disappear. The question is what would then happen to the earth and the other planets orbiting the sun. According to Isaac Newton's classical theory of gravity, the planets would immediately cease to move in circular motion, and inertia would make them start traveling in a straight line. Albert Einstein saw a deficiency in Newton's theory. The finiteness of the speed of light would make it take a certain amount of time before

neg: Messier 37 from Earth. Estimates of its age range from 347 million to 550 million years. It has 1,500 times the mass of the Sun and contains over 500 identified stars, with roughly 150 stars brighter than magnitude 12.5. M37 has at least a dozen red giants and its hottest surviving main sequence star is of stellar classification B9 V. The abundance of elements other than hydrogen and helium, what astronomers term metallicity, is similar to, if not slightly higher than, the abundance in the Sun. At its estimated distance of around from Earth, the cluster's angular diameter of 24 arcminutes corresponds

neg: Nicolaus Copernicus modern commentaries on Genesis, the Psalms, Ecclesiastes, and Joshua, you will find all agreeing in the literal interpretation that the sun is in heaven and turns around the earth with great speed, and that the earth is very far from heaven and sits motionless at the center of the world...Nor can one answer that this is not a matter of faith, since if it is not a matter of faith 'as regards the topic,' it is a matter of faith 'as regards the speaker': and so it would be heretical to say that Abraham did not have two children and

neg: HD 61005 in the Local Bubble - a region with a low concentration of dust clouds. HD 61005 is 115 light years from earth, has an apparent magnitude of 8.23 and a metallicity of 72.4% of the Sun. It is moving through the interstellar medium at a speed of 27.4 km/s relative to the Sun and is found in the night sky at right ascension 113.94248° and declination -32.20°. In 2007, a team of astronomers announced the discovery of a protoplanetary disk around HD 61005. The disk has an unusual shape, which may be due to the influence of the dense regions

neg: Cassiopeia (constellation) or Caph (meaning "hand"), is a white-hued star of magnitude 2.3, 54.7 ± 0.3 light-years from Earth. Around 1.2 billion years old, it has used up its core hydrogen and begun expanding and cooling off the main sequence. It is around 1.9 times as massive as the Sun, and around 21.3 times as luminous. Rotating at about 92% of its critical speed, Caph completes a full rotation every 1.12 days. This is giving the star an oblate spheroid shape with an equatorial bulge that is 24% larger than the polar radius. It is a Delta Scuti variable with a small

neg: Mechanics scientists reasoned that a cannonball falls down because its natural position is in the Earth; the sun, the moon, and the stars travel in circles around the earth because it is the nature of heavenly objects to travel in perfect circles. Often cited as father to modern science, Galileo brought together the ideas of other great thinkers of his time and began to calculate motion in terms of distance traveled from some starting position and the time that it took. He showed that the speed of falling objects increases steadily during the time of their fall. This acceleration is the

neg: Ole Rømer light to travel from the Sun to the Earth as 8 minutes and 12 seconds. Depending on the value assumed for the astronomical unit, this yields the speed of light as just a little more than 300,000 kilometres per second. The modern value is 8 minutes and 19 seconds, and a speed of 299,792.458 km/s. A plaque at the Observatory of Paris, where the Danish astronomer happened to be working, commemorates what was, in effect, the first measurement of a universal quantity made on this planet. In addition to inventing the first street lights in Copenhagen, Rømer also invented the

neg: Spherical Earth orbit around the Sun. The Earth always points in the same direction as it moves around the Sun, so for half the year (summer in the Northern Hemisphere), the North Pole is pointed slightly toward the Sun, keeping it in daylight all the time because the Sun lights up the half of the Earth that is facing it (and the North Pole is always in that half due to the tilt). For the other half of the orbit, the South Pole is tilted slightly toward the Sun, and it is winter in the Northern Hemisphere. This means that at the

neg: Newton's law of universal gravitation description of gravity is sufficiently accurate for many practical purposes and is therefore widely used. Deviations from it are small when the dimensionless quantities "φ"/"c" and "(v/c)" are both much less than one, where "φ" is the gravitational potential, "v" is the velocity of the objects being studied, and "c" is the speed of light. For example, Newtonian gravity provides an accurate description of the Earth/Sun system, since where "r" is the radius of the Earth's orbit around the Sun. In situations where either dimensionless parameter is large, then general relativity must be used to describe the system. General relativity

neg: Aberration of light worth noting that part of the original motivation of the search for stellar parallax was to test the Copernican theory that the Earth revolves around the Sun, but of course the existence of aberration also establishes the truth of that theory. The phenomenon of aberration became a driving force for many physical theories during the 200 years between its observation and the conclusive explanation by Albert Einstein. The first classical explanation was provided in 1729, by James Bradley as described above, who attributed it to the finite speed of light and the motion of Earth in its orbit around the

neg: Iota Reticuli Iota Reticuli Iota Reticuli (ι Reticuli) is a solitary, orange-hued star in the southern constellation of Reticulum. It is faintly visible to the naked eye, having a combined apparent visual magnitude of +4.97. Based upon an annual parallax shift of 10.22 mas as seen from Earth, it is located around 319 light years from the Sun. This is an evolved K-type giant star with a stellar classification of K4 III. Iota Reticuli is moving through the Galaxy at a speed of 80.9 km/s relative to the Sun. Its projected Galactic orbit carries it between 12,300 and 25,100 light years from

neg: Copernican heliocentrism was published during the year of his death, though he had arrived at his theory several decades earlier. The book marks the beginning of the shift away from a geocentric (and anthropocentric) universe with the Earth at its center. Copernicus held that the Earth is another planet revolving around the fixed sun once a year, and turning on its axis once a day. But while Copernicus put the Sun at the center of the celestial spheres, he did not put it at the exact center of the universe, but near it. Copernicus' system used only uniform circular motions, correcting what

neg: (469219) 2016 HO3 the best and most stable example to date of a near-Earth companion, or quasi-satellite. "Since loops around our planet, but never ventures very far away as we both go around the Sun, we refer to it as a quasi-satellite of Earth", said Paul Chodas, manager of NASA's Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena, California. In its yearly trek around the Sun, asteroid spends about half of the time closer to the Sun than Earth is (that is, the asteroid is inside the Earth's orbit) and passes ahead of our planet, and about half

neg: Myth of Er whorl of his celestial spindle were 8 "orbits", whereof each created a perfect circle. Each "orbit" is given different descriptions by Plato. Based on Plato's descriptions within the passage, the orbits can be identified as those of the classical planets, corresponding to the Aristotelian planetary spheres: The descriptions of the rims accurately fit the relative distance and revolution speed of the respective bodies as would appear to an observer from Earth (aside from the Moon, which revolves around the Earth slightly more slowly than the sun). Myth of Er The Myth of Er is a legend that concludes Plato's "Republic"

neg: Eclipse cycle Sun, Moon, and Earth has changed. As seen from the Earth, the time it takes for the Moon to return to a node, the draconic month, is less than the time it takes for the Moon to return to the same ecliptic longitude as the Sun: the synodic month. The main reason is that during the time that the Moon has completed an orbit around the Earth, the Earth (and Moon) have completed about of their orbit around the Sun: the Moon has to make up for this in order to come again into conjunction or opposition with the Sun.

neg: Theta Pyxidis Theta Pyxidis Theta Pyxidis (Theta Pyx, θ Pyxidis, θ Pyx) is a red M-type giant in the constellation Pyxis. It is approximately 500 ± 30 light years from Earth. It is of spectral type M1III and semi-regular variable with two measured periods of 13 and 98.3 days, and an average visual magnitude of 4.71, It shines with a luminosity approximately 970 times that of the Sun and has a surface temperature of 3825 K. It has a diameter around 54 times that of the Sun. Theta Pyxidis is moving through the Galaxy at a speed of 22.8 km/s relative to

neg: Rømer's determination of the speed of light (or K) for the various eclipses which might be observable. Finally, the distance between Earth and Jupiter can be calculated using standard trigonometry, in particular the law of cosines, knowing two sides (distance between the Sun and Earth; distance between the Sun and Jupiter) and one angle (the angle between Jupiter and Earth as formed at the Sun) of a triangle. The distance from the Sun to Earth was not well known at the time, but taking it as a fixed value "a", the distance from the Sun to Jupiter can be calculated as some multiple of "a". This model

neg: Solar time apparent time by about 14 minutes near February 6 and behind apparent time by about 16 minutes near November 3. The equation of time is this difference, which is cyclical and does not accumulate from year to year. Mean time follows the mean sun. Jean Meeus describes the mean sun as follows: Consider a first fictitious Sun travelling along the "ecliptic" with a constant speed and coinciding with the true sun at the perigee and apogee (when the Earth is in perihelion and aphelion, respectively). Then consider a second fictitious Sun travelling along the "celestial equator" at a constant speed

neg: Earth by the Apollo program. </math>, where "m" is the mass of Earth, "a" is an astronomical unit, and "M" is the mass of the Sun. So the radius in AU is about formula_1.</ref> Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. According to radiometric dating and other sources of evidence, Earth formed over 4.5 billion years ago. Earth's gravity interacts with other objects in space, especially the Sun and the Moon, Earth's only natural satellite. Earth revolves around the Sun in 365.26 days, a period known as an Earth year.

neg: Doppelgänger (1969 film) Lew Grade, who was Anderson's financier at his TV distributor ITC Entertainment, arranged a meeting with Kanter for Anderson to pitch a story concept concerning the hypothesis of a "replicated" or "mirror" Earth. According to Anderson, he "thought, rather naïvely, what if there was another planet the other side of the Sun, orbiting at exactly the same speed and the same size as Earth? That idea then developed into the planet being a replicated Earth and that's how it ended up, a mirrored planet ... We were perfectly poised – I was Lew Grade's golden boy and the <nowiki>[</nowiki>Century 21<nowiki>]</nowiki>

neg: Analemma the Sun, relative to its mean position, throughout the year. A date-marked diagram of the analemma, with equal scales in both north–south and east–west directions, can be used as a tool to estimate quantities such as the times of sunrise and sunset, which depend on the Sun's position. Generally, making these estimates depends on visualizing the analemma as a rigid structure in the sky, which moves around the Earth at constant speed so it rises and sets once a day, with the Sun slowly moving around it once a year. Some approximations are involved in the process, chiefly the use

neg: Axial precession for any object moving around the Earth, along or close to the ecliptic, notably, the Moon. The combined action of the Sun and the Moon is called the lunisolar precession. In addition to the steady progressive motion (resulting in a full circle in about 25,700 years) the Sun and Moon also cause small periodic variations, due to their changing positions. These oscillations, in both precessional speed and axial tilt, are known as the nutation. The most important term has a period of 18.6 years and an amplitude of 9.2 arcseconds. In addition to lunisolar precession, the actions of the other

neg: Counter-Earth Counter-Earth The Counter-Earth is a hypothesized by the pre-Socratic Greek philosopher Philolaus (c. 470 – c. 385 BC) to support his non-geocentric cosmology, in which all objects in the universe revolve around an unseen "Central Fire" (distinct from the Sun which also revolves around it). The Greek word Antichthon () means "Counter-Earth". In modern times a hypothetical planet always on the other side of the Sun from Earth has been called a "Counter-Earth", and has been a recurring theme in UFO claims, as well as in fiction (particularly science fiction). An astronomical system positing that the Earth, Moon, Sun, planets

neg: Ecliptic the movement of Earth around the Earth–Moon center of mass, the apparent path of the Sun wobbles slightly, with a period of about one month. Due to further perturbations by the other planets of the Solar System, the Earth–Moon barycenter wobbles slightly around a mean position in a complex fashion. The ecliptic is actually the apparent path of the Sun throughout the course of a year. Because Earth takes one year to orbit the Sun, the apparent position of the Sun takes one year to make a complete circuit of the ecliptic. With slightly more than 365 days in one

neg: Apparent retrograde motion the Sun undergoes apparent retrograde motion. This occurs because, from approximately four Earth days before perihelion until approximately four Earth days after it, Mercury's angular orbital speed exceeds its angular rotational velocity. Mercury's elliptical orbit is farther from circular than that of any other planet in the Solar System, resulting in a substantially higher orbital speed near perihelion. As a result, at specific points on Mercury's surface an observer would be able to see the Sun rise part way, then reverse and set before rising again, all within the same Mercurian day. Apparent retrograde motion Apparent retrograde motion is the

neg: Atmospheric escape loss of atmosphere. On Earth, for instance, the interaction between the solar wind and earth's magnetic field deflects the solar wind around the planet, with near total deflection at a distance of 10 Earth radii. This region of deflection is called a bow shock. Depending on planet size and atmospheric composition, however, a lack of magnetic field does not fully determine the fate of a planet's atmosphere. Venus, for instance, has no powerful magnetic field. Its close proximity to the Sun also increases the speed and number of particles, and would presumably cause the atmosphere to be stripped almost entirely,

neg: Aberration of light by the motion of an observer on Earth as the planet revolves around the Sun. Due to orbital eccentricity, the orbital velocity formula_4 of Earth (in the Sun's rest frame) varies periodically during the year as the planet traverses its elliptic orbit and consequently the aberration also varies periodically, typically causing stars to appear to move in small ellipses. Approximating Earth's orbit as circular, the maximum displacement of a star due to annual aberration is known as the "constant of aberration", conventionally represented by formula_22. It may be calculated using the relation formula_23 substituting the Earth's average speed in the

neg: Axis of evil (cosmology) apart, and these axes are aligned with the top/bottom divide. Lawrence Krauss is quoted as follows in a 2006 Edge.org article: "But when you look at CMB map, you also see that the structure that is observed, is in fact, in a weird way, correlated with the plane of the earth around the sun. Is this Copernicus coming back to haunt us? That's crazy. We're looking out at the whole universe. There's no way there should be a correlation of structure with our motion of the earth around the sun — the plane of the earth around the sun —

neg: Earth's orbit Earth's orbit All celestial bodies in the Solar System, including planets such as our own, orbit around the Solar System's centre of mass. The sun makes up 99.76% of this mass which is why the centre of mass is extremely close to the sun. Earth's orbit is the trajectory along which Earth travels around the Sun. The average distance between the Earth and the Sun is 149.60 million km (92.96 million mi), and one complete orbit takes days (1 sidereal year), during which time Earth has traveled 940 million km (584 million mi). Earth's orbit has an eccentricity of 0.0167.

neg: Earth's rotation given in mean solar time above to obtain their lengths in SI seconds (see Fluctuations in the length of day). The angular speed of Earth's rotation in inertial space is radians per SI second (mean solar second). Multiplying by (180°/π radians) × (86,400 seconds/mean solar day) yields 360.9856°/mean solar day, indicating that Earth rotates more than 360° relative to the fixed stars in one solar day. Earth's movement along its nearly circular orbit while it is rotating once around its axis requires that Earth rotate slightly more than once relative to the fixed stars before the mean Sun can pass

neg: Speed of light the closest star to Earth after the Sun, is around 4.2 light-years away. Radar systems measure the distance to a target by the time it takes a radio-wave pulse to return to the radar antenna after being reflected by the target: the distance to the target is half the round-trip transit time multiplied by the speed of light. A Global Positioning System (GPS) receiver measures its distance to GPS satellites based on how long it takes for a radio signal to arrive from each satellite, and from these distances calculates the receiver's position. Because light travels about () in one

neg: Apache Point Observatory Lunar Laser-ranging Operation Furthermore, both are in orbit around the Sun, meaning they are both falling towards the Sun at all times, even as they revolve around each other. If the Earth and the Moon were affected differently by the gravity of the Sun, this would directly affect the orbit of the Moon around the Earth. But as closely as scientists can measure, the orbit of the Moon is just as predicted from assuming that gravity acts the same on each — to within 1 part in , the Earth and the Moon fall towards the Sun in exactly the same way, despite

neg: Lunar month circular, the speed of Earth's progression around the Sun varies during the year. Thus, the angular rate is faster nearer periapsis and slower near apoapsis. The same is so for the Moon's orbit around the Earth. Because of these variations in angular rate, the actual time between lunations may vary from about 29.18 to about 29.93 days. The long-term average duration is days (29 d 12 h 44 min 2.8016 s). The synodic month is used to calculate eclipse cycles. It is customary to specify positions of celestial bodies with respect to the vernal equinox. Because of Earth's precession of

neg: Speed of gravity called annual solar aberration). Putting the Sun immobile at the origin, when the Earth is moving in an orbit of radius "R" with velocity "v" presuming that the gravitational influence moves with velocity "c", moves the Sun's true position ahead of its optical position, by an amount equal to "vR/c", which is the travel time of gravity from the sun to the Earth times the relative velocity of the sun and the Earth. The pull of gravity (if it behaved like a wave, such as light) would then be always displaced in the direction of the Earth's velocity, so that

neg: Aristotelian physics disk would have a different brightness than the point where a tangent plane reflects sunlight directly to the eye. A rough moon reflects in all directions equally, leading to a disk of approximately equal brightness which is what is observed. Galileo also observed that Jupiter has moons – i.e. objects revolving around a body other than the Earth – and noted the phases of Venus, which demonstrated that Venus (and, by implication, Mercury) traveled around the Sun, not the Earth. According to legend, Galileo dropped balls of various densities from the Tower of Pisa and found that lighter and heavier

neg: Rømer's determination of the speed of light not be fully explained for another century. The only solution available to Cassini and to other astronomers of his time was to issue periodic corrections to the tables of eclipses of Io to take account of its irregular orbital motion: periodically resetting the clock, as it were. The obvious time to reset the clock was just after the opposition of Jupiter to the Sun, when Jupiter is at its closest to Earth and so most easily observable. The opposition of Jupiter to the Sun occurred on or around 8 July 1676. Rømer's "aide-mémoire" lists two observation of emergences of Io

neg: Lunar month respect to the Sun as seen from the Earth. While the Moon is orbiting the Earth, the Earth is progressing in its orbit around the Sun. After completing a sidereal month, the Moon must move a little further to reach the new position having the same angular distance from the Sun, appearing to move with respect to the stars since the previous month. Therefore, the synodic month takes 2.2 days longer than the sidereal month. Thus, about 13.37 sidereal months, but about 12.37 synodic months, occur in a Gregorian year. Since Earth's orbit around the Sun is elliptical and not

neg: Dark Is the Sun to escape. Thomas M. Disch found himself unable to finish reading the novel, describing it as "meant for speed readers whose high-speed attention will construct from the asphalt of the prose a world of low resolution and high escapist involvement; not a novel but a daydream in remedial-reading." Dark Is the Sun Dark Is The Sun is a science fiction novel by American writer Philip José Farmer, first published in 1979. It tells the story of the people and creatures left on Earth when the Sun is dead and the universe is heading towards the Big Crunch. By the year

neg: 2003 YN107 2003 YN107 was discovered by the Lincoln Near Earth Asteroid Research (LINEAR) system in orbit around the Sun on 20 December 2003. Its diameter is approximately 10 to 30 metres. The object is on NASA's Earth Close Approach list, and is estimated to miss Earth by 0.01 AU. It revolves around the Sun on an Earth-like, almost circular, orbit. Its orbital period of 363.846 days also is very close to the sidereal year. From approximately 1997 to 2006, the asteroid remained within ) of Earth and it appeared to slowly orbit Earth. However, is no second moon, as it is

neg: Q0906+6930 this active galaxy is estimated to have taken around 12.3 billion light-years to reach us. But since this galaxy is receding from Earth at an estimated rate of 285,803 km/s (the speed of light is 299,792 km/s), the present (co-moving) distance to this galaxy is estimated to be around 26 billion light-years (7961 Mpc). Q0906+6930 Q0906+6930 is the most distant known blazar (redshift 5.47 / 12.2 billion light years), discovered in July, 2004. The engine of the blazar is a supermassive black hole (SMBH) approximately 2 billion times the mass of the Sun (the mass of the Milky Way Galaxy

neg: Earth Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. According to radiometric dating and other sources of evidence, Earth formed over 4.5 billion years ago. Earth's gravity interacts with other objects in space, especially the Sun and the Moon, Earth's only natural satellite. Earth revolves around the Sun in 365.26 days, a period known as an Earth year. During this time, Earth rotates about its axis about 366.26 times. Earth's axis of rotation is tilted with respect to its orbital plane, producing seasons on Earth. The gravitational interaction between Earth and

neg: Vela (constellation) faint emission nebula, believed to be the remains of a million-year-old supernova. Within it lie the smaller and younger Vela Supernova Remnant. This is the nebula of a supernova explosion that is believed to have been visible from Earth around 10,000 years ago. The remnant contains the Vela Pulsar, the first pulsar to be identified optically. Nearby is NGC 2736, also known as the Pencil Nebula. HH-47 is a Herbig-Haro Object, a young star around 1,400 light-years from the Sun that is ejecting material at tremendous speed (up to a million kilometres per hour) into its surrounds. This material glows

neg: Eclipse season seen from the sublunar point) depends on the apparent sizes of the Sun and Moon, which is a function of the elliptical distance of Earth from the Sun and of the Moon from Earth, respectively, as seen from Earth's surface. If the Earth had a perfectly circular orbit centered around the Sun, if the Moon's orbit was also perfectly circular and centered around the Earth, and if both orbits were coplanar (on the same plane) with each other, then two eclipses would happen every lunar month (29.53 days). A lunar eclipse would occur at every full moon, a solar eclipse

neg: Cosmological principle rested at the center of universe, Newton conceptualized the Earth as a sphere in orbital motion around the Sun within an empty space that extended uniformly in all directions to immeasurably large distances. He then showed, through a series of mathematical proofs on detailed observational data of the motions of planets and comets, that their motions could be explained by a single principle of "universal gravitation" that applied as well to the orbits of the Galilean moons around Jupiter, the Moon around the Earth, the Earth around the Sun, and to falling bodies on Earth. That is, he asserted the

neg: Sea A bulge is formed in the ocean at the place where the Earth is closest to the Moon, because it is also where the effect of the Moon's gravity is stronger. On the opposite side of the Earth, the lunar force is at its weakest and this causes another bulge to form. As the Moon rotates around the Earth, so do these ocean bulges move around the Earth. The gravitational attraction of the Sun is also working on the seas, but its effect on tides is less powerful than that of the Moon, and when the Sun, Moon and Earth

neg: Astronomical unit barycentric dynamical time, TDB). This is because the distance between Earth and the Sun is not fixed (it varies between and ) and, when Earth is closer to the Sun (perihelion), the Sun's gravitational field is stronger and Earth is moving faster along its orbital path. As the metre is defined in terms of the second and the speed of light is constant for all observers, the terrestrial metre appears to change in length compared to the "planetary metre" on a periodic basis. The metre is defined to be a unit of proper length, but the SI definition does not

neg: Mu Arae made by the Hipparcos astrometric satellite, Mu Arae exhibits a parallax of 64.47 milliarcseconds as the Earth moves around the Sun. When combined with the known distance from the Earth to the Sun, this means the star is located at a distance of 50.6 light years (15.51 parsecs). Seen from Earth it has an apparent magnitude of +5.12 and is visible to the naked eye. Asteroseismic analysis of the star reveals it is approximately 10% more massive than the Sun and significantly older, at around 6.34 billion years. The radius of the star is 36% greater than that of the

neg: 3753 Cruithne a long time. There is no danger of a collision with Earth for millions of years, if ever. Its orbital path and Earth's do not cross, and its orbital plane is currently tilted to that of the Earth by 19.8°. Cruithne, having a maximum near-Earth magnitude of +15.8, is fainter than Pluto and would require at least a reflecting telescope to be seen. Cruithne is in a normal elliptic orbit around the Sun. Its period of revolution around the Sun, approximately 364 days at present, is almost equal to that of the Earth. Because of this, Cruithne and Earth appear

neg: Near-Earth Object Camera by the Spitzer Space Telescope. The spacecraft would operate in a halo orbit around the Sun–Earth , and employ a Sun shield. This orbit would allow fast data downlink speeds to Earth, allowing full-frame images to be downloaded from the telescope. Near-Earth Object Camera The Near-Earth Object Camera (NEOCam) is a proposed space-based infrared telescope designed to survey the Solar System for potentially hazardous asteroids. NEOCam would survey from the Sun–Earth Lagrange point, allowing it to look close to the Sun and see objects inside Earth's orbit. NEOCam would be a successor to the WISE mission; the principal investigator is