Glossary

A paleoclimatology puzzle referring to the transition in the Earth climate cycles that occurred approximately 1 million years ago. Before this transition, ice core data from Antarctica shows climate was driven by regular ~41,000-year cycles (matching the obliquity cycle). After this point, dominant climate cycles shifted to ~100,000-year periodicities, which corresponds to the inclination cycle in the Holistic Universe Model. This shift suggests a fundamental change in how the Earth orbital parameters influenced climate, marking the beginning of the current balanced solar system configuration described in the Holistic Universe Model.

**1 296 000 arcseconds** = **1440 minutes** (our celestial sphere) = **24 hours** = **100%** of 1 circle or revolution. The sky can be divided into a number of degrees, arcseconds, minutes or hours of RA.

The figure-eight shaped curve that results from plotting the position of the Sun in the sky at the same time each day over the course of a year, as observed from a fixed location on Earth. The analemma's shape is determined by three factors: the dates of perihelion and aphelion, the orbital eccentricity, and the axial tilt (obliquity). The vertical extent of the analemma reflects the obliquity, while its asymmetric lobes result from the eccentricity and the timing of perihelion relative to the solstices. In the Holistic Universe Model, the analemma's shape shifts forward through time following the perihelion precession cycle of 18,636 years, with its width affected by eccentricity changes and its length modulated by the obliquity oscillation between ~22.36° and ~24.58° over the 298,176-year Holistic-Year.

The time between successive passages of the Moon through its perigee (closest point to Earth), approximately 27.5545536314 days. This period is slightly longer than the sidereal month because the Moon's line of apsides (connecting perigee and apogee) precesses forward in the same direction as the Moon's orbit due to apsidal precession.

The time required for the PERIHELION-OF-EARTH to return to the same fixed star – as viewed from the Earth. A MEAN time period equal to 365.261872819962 days (~31,558,467.2136858 seconds a year). This value is directly related to the 18,636 year Perihelion precession cycle. The J2000 value is ~31,558,432.3572673 seconds.

The point in an orbit where a celestial body is furthest from the Sun. For Earth, this currently occurs around July 4th. From Greek: ap (away from) + helios (Sun).

furthest transit point of the Moon with respect to Earth.

The gradual rotation of the Moon's line of apsides (the line connecting perigee and apogee) within its orbital plane. The Moon's apsidal precession has a duration of 8.8469024448 years as experienced on Earth and 8.8503161082 years against ICRF. Unlike nodal precession, the apsidal precession runs in the same direction as the Sun's orbit and Moon's orbit around Earth, which explains why the duration experienced on Earth is shorter than against ICRF (opposite to nodal precession).

The two extreme points in an elliptical orbit where a celestial body is closest to and farthest from the object it orbits. For Earth orbiting the Sun, the apsides are the perihelion (closest point) and aphelion (farthest point). The line connecting these two points is called the line of apsides. The term comes from Greek "hapsis" meaning "arch" or "vault."

It is an orbital element used for determining the inclination to the Ecliptic. It is the angle (starting from center of the orbit) between an orbiting body's periapsis and its ascending node. It is also known as the argument of perihelion or the argument of perifocus.

It is an orbital element used for determining the inclination to the Ecliptic. The ascending node is one of two places where an orbiting object passes through the reference plane, an imaginary flat surface which runs through the object being orbited around.

The average distance from Earth to the Sun with a J2000 value of 149,597,870.698828 km which is the distance of Earth to the PERIHELION-OF-EARTH (close to the Sun). This value is fluctuating across time with a MEAN value of 149,597,870.35 km.

The slow, continuous change in the orientation of Earth's rotational axis. Historically called "precession of the equinoxes" because the equinoxes move westward along the ecliptic. In the Holistic model, this is caused by Earth's clockwise orbit around the EARTH-WOBBLE-CENTER over approximately 22,937 years (currently experienced ~25,772 years).

The clockwise circular path our Earth travels in ~22,937 years around the EARTH-WOBBLE-CENTER which results in the visible precession "wobble" aka "Axial Precession" which will move Earth axial tilt compared to the Ecliptic up and down by ~0.564°. Currently in year 2000 AD Earth's axis is pointing to Polaris but e.g. in year ~2300 BC it was pointing to Thuban.

Current experienced value on 21 June 12:00 UTC was 23°26′21″ (23.4392298806°). The real MEAN value of the Axial Tilt is ~23.42723° and oscillating by ~0.564° (above and below). Since the Axial Tilt and Inclination Tilt work upon each other, this currently experienced ~23.44° does not only contain the axial tilt factor but also contains the inclination-tilt factor. The current Axial Tilt value is therefore actually ~23.355° so ~0.083° below the experienced axial tilt which is due to the inclination tilt above the mean value of the inclination tilt (~0.083°+ ~1.4951° = ~1.57869°). The net result is the Orbital inclination is currently ~0.012°

The common center of mass around which two or more celestial bodies orbit. In a two-body system like Earth-Moon, both bodies orbit their shared barycenter (located about 4,671 km from Earth's center, inside Earth). For the Sun and planets, the solar system's barycenter moves in a complex pattern around and sometimes outside the Sun due to the combined gravitational influence of all planets, particularly Jupiter and Saturn. The concept of a barycenter is fundamental to understanding orbital mechanics and is related to the perihelion points of planets shown in the Interactive 3D Solar System Simulation.

An orbit path that forms a perfect circle, with eccentricity = 0. In the Holistic Universe Model, the Sun's orbit around the Earth is modelled circular.

A mathematical phenomenon demonstrating that when a circle rolls around another circle of equal size, it completes exactly one more rotation than expected. In the Holistic Universe Model, this paradox explains two key observations: (1) Earth rotates exactly 1 time more than the number of days in a year because Earth both rotates on its axis AND orbits around a point, and (2) there is exactly 1 sidereal year less than the number of solar years in a Great Year (Axial Precession period) for the same reason. This extra rotation is not caused by physical forces but is a geometric consequence of orbital motion.

A cognitive bias that causes people to favor information that confirms their existing beliefs while ignoring or dismissing contradicting evidence. In scientific methodology, confirmation bias can lead researchers to unconsciously interpret data in ways that support their hypotheses.

An astronomical event where two or more celestial bodies appear close together in the sky as viewed from Earth. For planets relative to the Sun: inferior conjunction occurs when an inner planet (Mercury or Venus) passes between Earth and Sun, while superior conjunction occurs when a planet is on the opposite side of the Sun from Earth. The most famous planetary conjunction is the "Great Conjunction" of Jupiter and Saturn, which occurs approximately every 19.86 years when these two giant planets appear closest together in the sky.

Patterns of stars in the night sky that ancient astronomers grouped together and named after mythological figures, animals, or objects. The 88 officially recognized constellations divide the entire celestial sphere into distinct regions, serving both as a coordinate system for locating celestial objects and as a cultural record of how different civilizations interpreted the heavens. Twelve constellations along the ecliptic—the Sun's apparent annual path—form the zodiac, which has been used in astrology and astronomy for millennia. Due to axial precession, the constellation that appears behind the Sun on any given date gradually shifts over the approximately 22,937-year precession cycle, causing the astrological zodiac signs to become misaligned with their astronomical counterparts over time.

The moment when the Sun reaches its southernmost position in the sky, occurring around December 21-22. On this date, the Sun appears directly overhead at the Tropic of Capricorn (23.44°S latitude), marking the shortest day of the year in the Northern Hemisphere and the longest day in the Southern Hemisphere. In the Northern Hemisphere, the December solstice is called winter solstice; in the Southern Hemisphere, it is called summer solstice. That's why the hemisphere-neutral term "December solstice" is preferred. In the Holistic Universe Model, the December Solstice alignment with the longitude of perihelion around 1245 AD marks a key reference point when the solar year and sidereal year reflected their mean values.

used in astronomy as the celestial equivalent of terrestrial latitude.

The time difference ΔT = TT − UT between Universal Time (UT, defined by Earth's rotation) and Terrestrial Time (TT, independent of Earth's rotation). This difference results from variations in Earth's rotation speed over time. When Earth rotates slower than the standard 86,400 SI seconds per day, UT falls behind TT and ΔT increases. The value of Delta-T was approximately 0 around 1900 AD, and as of 2020, TT was ahead of UT by approximately 69 SI seconds. Delta-T is essential for converting between dynamical time (used for astronomical calculations) and observed time (based on Earth's actual rotation).

The point where an orbiting body crosses the reference plane (typically the ecliptic) moving from north to south. The opposite of the ascending node. Together with the ascending node, these two points define the line of nodes, which describes where an orbit intersects the reference plane. The descending node is used together with the ascending node to define the three-dimensional orientation of an orbit in space.

The time between successive passages of the Moon through the same node (the points where the Moon's orbit crosses the ecliptic plane), approximately 27.2122179337 days. This is shorter than the sidereal month because the lunar nodes precess westward (opposite to the Moon's orbital direction) due to nodal precession. The name comes from the ancient belief that eclipses were caused by a dragon eating the Sun or Moon.

The time for the Sun (as seen from Earth) to complete one revolution with respect to the same lunar node, approximately 346.62 days. This is shorter than a solar year because the lunar nodes precess westward. The Draconic year ICRF is 346.6074275875 days and the Draconic year Earth is 346.6217687161 days. Eclipse seasons occur when the Sun is near a lunar node, making the draconic year crucial for predicting eclipses.

A reference point representing the actual longitude of perihelion as measured from the EARTH-WOBBLE-CENTER, as opposed to the longitude of perihelion experienced on Earth (PERIHELION-OF-EARTH). Because Earth orbits the EARTH-WOBBLE-CENTER at a distance of ~0.00308211 AU, the actual movement of the perihelion position is different when measured from the EARTH-WOBBLE-CENTER compared to Earth's perspective. For example, on 21 June 2000 AD, while Earth experienced the longitude of perihelion at ~102.95°, the actual angle from the EARTH-WOBBLE-CENTER was ~105.8°. This difference explains why the currently experienced axial precession duration (~25,772 years) is longer than the mean value (~22,937 years).

A gravitational point that Earth orbits around. This point is used to simulate Axial precession (the "wobble" of Earth). Earth moves clockwise around this center on its Axial Precession Orbit (APO) in a period of approximately 22,937 years (currently experienced ~25,772 years) at a distance of 0.00308211 AU (461,077.09 km) from Earth.

A measure of how elliptical an orbit is. A value of 0 indicates a perfect circle, while values closer to 1 indicate increasingly elongated ellipses. In the Holistic Universe Model, the PERIHELION-OF-EARTH's orbit around the Sun combined with Earth's movement around the EARTH-WOBBLE-CENTER determines how Earth's effective eccentricity changes over time. The eccentricity therefore has a cycle similar to the 18,636 year Perihelion precession cycle.

A recurring period after which eclipses (both solar and lunar) repeat in a predictable pattern. Eclipse cycles occur because of the periodic alignment of the Sun, Earth, and Moon's orbital parameters. The most well-known eclipse cycle is the Saros cycle (approximately 18.6 years), but other cycles exist such as the Inex cycle, Metonic cycle, and others. Eclipse cycles are essential for predicting when and where eclipses will occur, and have been studied since ancient times.

The plane of Earth's orbit around the Sun (in heliocentric view) or the apparent path of the Sun across the sky as seen from Earth (in geocentric view). The ecliptic is tilted relative to Earth's equator by the obliquity angle.

An orbit path that forms an ellipse (oval shape) with eccentricity > 0. In elliptical orbits, the orbiting body moves faster when closer to the focus (perihelion) and slower when farther away (aphelion).

A standardized unit of time based on the fraction 1/86,400 of a mean solar day, originally defined to provide a uniform time scale for astronomical calculations. One Ephemeris Second equals one SI second. The value of 86,400 seconds per day was artificially chosen as a fixed standard and corresponds approximately to the length of a solar day around 1820 AD. In reality, the actual length of a solar day fluctuates both within a year and across long time periods. Modern astronomy uses this fixed 86,400-second standard as a reference, even though the true solar day length varies (currently ~86,400.003 SI seconds).

A specific moment in time used as a reference point for astronomical measurements. Orbital elements and positions are specified relative to a particular epoch (like J2000) and then calculated forward or backward in time.

The difference between apparent solar time (measured by a sundial) and mean solar time (measured by a clock running at a constant rate). This difference, which can range from approximately -14 to +16 minutes throughout the year, arises from two factors: the eccentricity of Earth's orbit (causing Earth to move faster near perihelion and slower near aphelion) and the obliquity of the ecliptic (causing the Sun's apparent motion along the ecliptic to project unequally onto the celestial equator). The equation of time is directly related to the analemma and explains why solar noon varies throughout the year. The Interactive 3D Solar System Simulation implicitly models this effect through its accurate representation of Earth's orbital mechanics.

The imaginary great circle around Earth that is equidistant from both poles, dividing Earth into the Northern and Southern hemispheres. The celestial equator is the projection of Earth's equator onto the celestial sphere. In astronomical coordinate systems, the equatorial frame (or equatorial coordinate system) uses the celestial equator as its fundamental plane, with Right Ascension measured along the equator and Declination measured perpendicular to it. The equatorial frame is essential for expressing positions of celestial objects and is used in the Interactive 3D Solar System Simulation to calculate RA and Dec values.

The two times per year (around March 21 and September 22) when Earth's equatorial plane passes through the center of the Sun, resulting in approximately equal day and night lengths. The equinoxes move westward along the ecliptic due to Axial precession.

The mathematical relationship between the durations of Axial Precession and Inclination Precession cycles, expressed as a Fibonacci ratio of 3:13. This means that 13 Axial Precession cycles (13 × ~22,937 = 298,176 years) occur in the same time as 3 Inclination Precession cycles (3 × 99,392 = 298,176 years), resulting in a repeating pattern of 16 Perihelion Precession cycles within one Holistic-Year. This Fibonacci connection reveals the elegant mathematical structure underlying all precession movements in the solar system.

A cycle related to the Moon's phases and orbital mechanics. In the Holistic Universe Model, the Full Moon cycle ICRF is 411.7665207232 days and the Full Moon cycle Earth is 411.7867608414 days. This represents the time between alignments of the lunar phases with specific orbital configurations.

A theory of gravitation developed by Albert Einstein between 1907 and 1915, describing gravity not as a force but as a curvature of spacetime caused by mass and energy. One of its key proofs was explaining the anomalous precession of Mercury's perihelion (~43 arc-seconds per century).

A frame of reference of the solar system that puts Earth at the center, and has Sun and Moon orbiting the Earth with other planets revolving around the Sun

The long-term increase in Earth's average surface temperature, particularly the warming trend observed since the late 19th century. While modern climate discussions focus on anthropogenic (human-caused) factors, the Holistic Universe Model emphasizes that climate has always changed naturally due to orbital mechanics. Temperature records only extend reliably to around 1880 AD—a very short period compared to the precession cycles of tens of thousands of years. Since 1880 AD coincides with the end of the Little Ice Age, using this date as a baseline may overstate the warming trend when viewed in the context of longer natural climate cycles.

A mathematical ratio approximately equal to 1.618 (represented by the Greek letter Phi, φ), found throughout nature in spiral patterns, plant growth, and astronomical phenomena. The golden ratio appears in the Fibonacci sequence, where the ratio of consecutive numbers approaches φ. In the Holistic Universe Model, the solar system's precession cycles follow Fibonacci ratios on timescales, reflecting this fundamental principle of proportion and balance found throughout nature - from nautilus shells and sunflower seeds to galaxy spirals and hurricane formations.

The fundamental force of attraction between objects with mass

~22,937 years = the full time period for the Earth to complete one APO. This old term of the Axial precession (precession of the equinoxes) is related to Plato and can be seen as a popular term for Axial Precession.

The calendar system introduced by Pope Gregory XIII in 1582, and now used as the civil calendar in most countries worldwide. It refines the Julian calendar by omitting 3 leap days every 400 years, resulting in an average year length of 365.2425 days. This value was chosen to keep the calendar aligned with the March equinox. However, since the actual solar year length (~365.24219 days in 2000 AD) differs slightly from the Gregorian value, the calendar gradually drifts relative to the astronomical seasons. In the Holistic Universe Model, this drift is predicted to cause the June solstice to occur around June 18 by the year 10,564 AD—approximately 3.5 days earlier than today's date of June 20-21.

A model or frame of reference where the Sun is at the center and planets orbit around it. The standard modern astronomical model. From Greek: helios (sun) + centric (center).

The solar system is a remarkably complex yet balanced system. Despite this complexity, its primary movements can be modelled by simulating just two interacting forces: Axial precession, which moves clockwise, and Inclination precession, which moves counter clockwise. The Holistic Universe Model explores these forces in detail, offering insight into the dynamic equilibrium governing our solar system and its impact on our Earth.

The complete cycle period of 13 APO (Axial Precession Orbit) or 3 IPO (Inclination Precession Orbit) to meet each other again. This period is 298,176 years and shows on historic temperature/CO2 graphs as measured on e.g. Antarctica.

International Celestial Reference Frame - A system of distant quasars used as fixed reference points for measuring positions and motions of celestial objects. Provides an inertial (non-rotating) reference frame for astronomical measurements.

New term for what is currently called "apsidal precession" / "precession of the ecliptic" caused by the Inclination Precession Orbit (IPO). The Inclination Precession is the counterclockwise movement of the PERIHELION-OF-EARTH around the Sun. This motion occurs over 99,392 years (currently experienced ~112,000 years on Earth) to revolve once relative to the ICRF and ~59,635 years (currently experienced ~70,000 years) against the ecliptic.

The counter clockwise circular path the PERIHELION-OF-EARTH travels in 99,392 Years around the Sun resulting in the "Inclination Precession" which will move Earth inclination tilt compared to the Ecliptic up and down by ~0.564°.

Inclination to the invariable plane. Current experienced value on 01 January 2000 AD 12:00 UTC was ~1.57869°. The real MEAN value of the Inclination Tilt is ~1.4951° and oscillating by ~0.564° (above and below) so from ~0.931° to ~2.059°.

when a body (e.g. Venus) is aligned with the Sun while transiting closest to Earth.

The plane passing through the barycenter of the Solar System perpendicular to its total angular momentum vector. Unlike the ecliptic (Earth's orbital plane), the invariable plane represents the weighted average of all planetary orbital planes and remains essentially fixed in space. In the Holistic Universe Model, Earth's orbital plane is tilted relative to the invariable plane by a mean value of approximately 1.4951° with an amplitude of ~0.564°, creating the inclination precession cycle of 99,392 years. This exact tilt placement is a distinctive feature of the model and represents a prediction that could be confirmed by future astronomical observations.

Julian epoch 2000.0 - A standard reference epoch used in astronomy, corresponding to January 1, 2000, 12:00 TT (Terrestrial Time). Used as a baseline for measuring positions and motions of celestial objects.

A calendar system introduced in 46 BC by Julius Caesar to reform the Roman calendar. The Julian calendar established a year length of 365.25 days by adding a leap day every four years. While a significant improvement over earlier Roman calendars, this calculation was slightly too long (the actual solar year is approximately 365.2422 days), causing the calendar to drift by about 1 day every 128 years. By 325 AD, the March equinox had drifted from March 25 to approximately March 21. The Julian calendar remained in use in Western civilization until replaced by the Gregorian calendar in 1582 AD.

A continuous count of days since the beginning of the Julian Period on January 1, 4713 BC (Julian calendar) at noon Universal Time. The Julian day number (JD) provides an unambiguous date reference used by astronomers to avoid confusion between different calendar systems. For example, June 21, 2000 AD at 00:00 UTC corresponds to Julian day 2451716.5. The fractional part represents the time of day, with .0 being noon and .5 being midnight. Julian days are essential for astronomical calculations spanning long time periods and are used as the primary date input in the Interactive 3D Solar System Simulation.

The moment when the Sun reaches its northernmost position in the sky, occurring around June 20-21. On this date, the Sun appears directly overhead at the Tropic of Cancer (23.44°N latitude), marking the longest day of the year in the Northern Hemisphere and the shortest day in the Southern Hemisphere. In the Northern Hemisphere, the June solstice is called summer solstice; in the Southern Hemisphere, it is called winter solstice. That's why the hemisphere-neutral term "June solstice" is preferred. In the Holistic Universe Model, the June Solstice of year 2000 AD is used as a key reference point for calculating orbital parameters.

Three fundamental laws of planetary motion discovered by Johannes Kepler in the early 17th century: (1) First Law - Planets orbit in ellipses with the Sun at one focus, (2) Second Law - A line from the Sun to a planet sweeps equal areas in equal times (meaning planets move faster when closer to the Sun), (3) Third Law - The square of the orbital period is proportional to the cube of the semi-major axis (T² ∝ a³). The Interactive 3D Solar System Simulation implements Kepler's Third Law directly for calculating orbital elements, while simplifying the first two laws by using circular orbits with constant speeds.

A fundamental principle in physics describing the attenuation of light (or other electromagnetic radiation) as it passes through a substance. In climate science, this law explains why the greenhouse effect of CO2 is logarithmic rather than linear: as CO2 concentration increases, each additional unit of CO2 has a diminishing effect on heat absorption because the relevant infrared wavelengths become increasingly saturated. This means doubling CO2 from 200 to 400 PPM has a larger warming effect than doubling from 400 to 800 PPM.

The most recent period in Earth's climate history when ice sheets were at their greatest extent, occurring approximately 26,500 to 19,000 years ago (peaking around 20,000 BC). During the LGM, ice sheets covered large portions of North America, Northern Europe, and Asia, sea levels were approximately 125 meters lower than today, and global average temperatures were about 6°C colder than present. In the Holistic Universe Model, the end of the LGM around 20,496 BC correlates with the maximum inclination tilt, combined with rising obliquity, providing a mechanistic explanation for the rapid warming that ended this glacial period.

A correction day added to the calendar to keep the calendar year synchronized with the astronomical year. Because the length of a solar year is not a whole number of days (~365.242 days), a leap day (typically February 29th) is periodically inserted to prevent the solstices and equinoxes from drifting through the calendar over time. In the Gregorian calendar, leap days are added in years divisible by 4, except for years divisible by 100 (unless also divisible by 400), resulting in an average calendar year of 365.2425 days.

It is an orbital element used for determining the inclination to the Ecliptic. It is the angle from a specified reference direction, called the origin of longitude, to the direction of the ascending node.

An orbital element (symbol: ϖ) that measures the angular position of the perihelion point along the ecliptic, measured from a reference direction (typically the March equinox). Calculated as ϖ = Ω + ω (longitude of ascending node + argument of periapsis). Specifically in the Holistic Universe Model, this value indicates the position of the PERIHELION-OF-EARTH as seen from Earth and changes over time due to Perihelion Precession, completing a full 360° cycle in 18,636 years (currently experienced ~21,000 years).

A type of calendar based on the cycles of the Moon's phases, typically measuring time from new moon to new moon (approximately 29.5 days per lunar month). A lunar year of 12 lunar months is approximately 354 days, about 11 days shorter than a solar year. As a result, lunar calendars drift relative to the seasons, with dates cycling through all seasons over approximately 33 years. The Islamic Hijri calendar is an example of a pure lunar calendar. Lunar calendars do not keep solstices or equinoxes on fixed dates.

The time interval between successive occurrences of the same lunar phase, most commonly measured from new moon to new moon. Also known as the synodic month, this period averages approximately 29.53 days. The lunar month is the basis for lunar and lunisolar calendars, where each month begins with a new moon or the first visible crescent. The term "synodic" comes from the Greek word for "meeting," referring to the Moon's apparent meeting with the Sun in the sky at each new moon. The lunar month is longer than the Moon's orbital period around Earth (the sidereal month of ~27.32 days) because Earth is also moving along its orbit, requiring additional time for the Moon to return to the same phase relative to the Sun.

A phenomenon occurring approximately every 18.6 years when the Moon's declination range (the variation in how far north or south the Moon appears in the sky) reaches either its maximum (major lunar standstill) or minimum (minor lunar standstill). This occurs due to the Moon's nodal precession cycle. During a major standstill, the Moon rises and sets at its most extreme positions on the horizon, while during a minor standstill, the Moon's rising and setting positions are closest together. Ancient monuments like Stonehenge and Chimney Rock were aligned to observe these events.

A type of calendar that combines lunar months with periodic adjustments to stay aligned with the solar year and seasons. Lunisolar calendars follow the Moon's phases for determining months but add an extra (intercalary) month approximately every 2-3 years to prevent the calendar from drifting too far from the seasons. Examples include the Hebrew calendar, Chinese calendar, and Hindu calendar. While lunisolar calendars keep the seasons roughly aligned, the year length varies (some years have 12 months, others have 13), and the background stars still shift over time due to precession.

In the Northern Hemisphere, the March equinox is called the vernal or spring equinox. In the Southern Hemisphere, the reverse is true. That's why the term March equinox is preferred over vernal equinox.

The mean angular velocity of Earth represents the average rate at which Earth rotates over a long period. This value discards the slight variations in Earth's rotation speed over time. The mean angular velocity of Earth's rotation about its axis is 7.29215170117725 × 10^-5 radians per second. The mean angular velocity is typically expressed with greater precision to account for observed variations, while the nominal value is a simplified version. The mean value is directly related to the MEAN length of the solar day and MEAN length of the sidereal day and MEAN length of sidereal day (which is Earth's MEAN rotation period).

Long-term variations in Earth's climate caused by changes in orbital parameters: eccentricity, obliquity, and precession. Named after Serbian scientist Milutin Milanković who first calculated their effects on Earth's climate.

Movements compared to the path of the Sun. This is how we experience all precession movements on Earth.

Movements compared to the fixed stars. This is how someone who looks at the total solar system relative to the fixed stars would observe all precession movements.

A proposed redefinition of the SI second to align with the mean length of day in the Holistic Universe Model. The current SI second is defined as 9,192,631,770 periods of caesium-133 radiation, resulting in a day of approximately 86,400 SI seconds. The proposed NEWSI second would be defined as 9,192,585,572 periods of caesium-133 radiation, making each NEWSI second slightly shorter than an SI second. This would result in exactly 86,400 NEWSI seconds per mean day (equivalent to 86,399.5657965675 SI seconds), allowing Delta-T to oscillate evenly around zero across ages rather than growing infinitely negative over time.

The gradual rotation of the Moon's orbital plane around Earth. The Moon's orbital plane is tilted about 5.1° relative to the ecliptic, and the line of nodes (where the Moon's orbit intersects the ecliptic) rotates westward completing a full cycle in approximately 18.6 years. This precession has a duration of 18.5999625725 years against ICRF and 18.6150580597 years as experienced on Earth. The nodal precession is responsible for the Lunar Standstill phenomenon and is crucial for predicting eclipses. The nodal precession runs in the direction opposite to the Sun's apparent orbit around Earth.

The nominal angular velocity (ΩN) refers to the idealized or standardized rotation rate used for practical timekeeping and calculations. It assumes a perfectly consistent rotation without accounting for minor fluctuations. The current fixed ΩN is however the reference angular velocity corresponding to the epoch 1820. The value is therefore directly connected to the artificially chosen length of a stellar day. The nominal angular velocity is often taken as approximately 7.2921151467064 × 10^-5 radians per second which is the value consistent with the Ratio mean solar day/stellar day (1.002 737 811 911 354 48). [See useful constants](https://hpiers.obspm.fr/eop-pc/index.php?index=constants&lang=en). Since the stellar day is fluctuating also the nominal angular velocity is fluctuation.

The total result of the Axial Tilt and Inclination Tilt resulting in the actual angle of tilt of Earth's axis of rotation relative to the plane of its orbit (the ecliptic). Currently about 23.44 degrees and this will oscillate and return to the same pattern in a period of 298,176 years between ~22.36° and ~24.58° in cycles of 37,272 years (currently experienced ~41,000 years).

A problem-solving principle attributed to the 14th-century philosopher William of Ockham, stating that "of two competing theories, the simpler explanation of an entity is to be preferred." In scientific methodology, this principle suggests that when multiple hypotheses explain the same observations, the one with the fewest assumptions should be selected. The Holistic Universe Model embraces this principle by explaining multiple astronomical phenomena (obliquity, eccentricity, inclination, precession movements, and length of days & years) through just two interacting forces, rather than treating each as independent, unconnected cycles.

An astronomical event where an outer planet (Mars, Jupiter, Saturn, etc.) is positioned directly opposite the Sun as seen from Earth, appearing highest in the sky at midnight. At opposition, a planet is closest to Earth and appears brightest, making it optimal for observation. The angular distance between the planet and the Sun is 180°. Mars opposition occurs approximately every 779.926 days (about 2 years and 50 days), while Jupiter opposition occurs approximately every 398.88 days.

A set of six parameters that uniquely define the size, shape, and orientation of an orbit around a celestial body: (1) semi-major axis (size of orbit), (2) eccentricity (shape of orbit), (3) inclination (tilt relative to reference plane), (4) longitude of ascending node (orientation of orbit intersection), (5) argument of periapsis (orientation of closest approach), and (6) true anomaly or mean anomaly (position along orbit). These parameters allow calculation of the position and velocity of an orbiting body at any point in time and are fundamental to the Interactive 3D Solar System Simulation.

The branch of physics that studies the motions of celestial bodies under the influence of gravitational forces. Includes calculations of orbits, trajectories, and interactions between multiple bodies.

The scientific study and reconstruction of past climates using indirect evidence such as ice cores, tree rings, sediment layers, pollen records, and isotope ratios. Paleoclimate models attempt to understand climate patterns over geological timescales spanning thousands to millions of years. Ice core data from Antarctica and Greenland provide particularly valuable records of temperature and atmospheric CO2 concentrations extending back approximately 800,000 years. In the Holistic Universe Model, paleoclimate data showing ~100,000-year climate cycles provides supporting evidence for the inclination precession cycle of 99,392 years as a primary driver of ice ages.

A unit of astronomical distance equal to approximately 30,856,775,814,671.9 km or about 3.26 light-years. One parsec is the distance at which one astronomical unit (AU) subtends an angle of one arcsecond. The term combines "parallax" and "arcsecond." The relation to a parsec is: 648000 / π × 1 AU = 206,264.806247096 AU.

The partially shadowed outer region of a shadow cast by an opaque object, where only part of the light source is blocked. In the context of eclipses: During a lunar eclipse, the penumbra is the outer part of Earth's shadow where the Sun is only partially blocked, causing a subtle darkening of the Moon. During a solar eclipse, the penumbra is the area on Earth's surface where observers see a partial eclipse. The penumbra is distinguished from the umbra, which is the darker central shadow where the light source is completely blocked.

closest transit point of the Moon with respect to Earth.

The point in an orbit where a celestial body is closest to the Sun. For Earth, this currently occurs around January 3rd. From Greek: peri (near) + helios (Sun).

The combined cycle where Earth (moving clockwise around the EARTH-WOBBLE-CENTER) and the PERIHELION-OF-EARTH (moving counterclockwise around the Sun) meet each other. This motion occurs over 18,636 years (currently experienced ~21,000 years).

The combined cycle where Earth (moving clockwise around the EARTH-WOBBLE-CENTER) and the PERIHELION-OF-EARTH (moving counterclockwise around the Sun) meet each other. This motion occurs over 18,636 years (currently experienced ~21,000 years).

The gradual rotation of Mercury's orbital ellipse around the Sun, causing its perihelion point to shift over time. The observed precession rate around 1900 AD was approximately ~5599 arcseconds per century (~570 of Mercury + ~5029 of Earth axial precession movement). Classical Newtonian mechanics accounts for about ~530 arcseconds (of the expected ~570 arcseconds) per century due to gravitational perturbations from other planets, leaving approximately ~40 arcseconds per century unexplained by classical theory. This ~40 arcsecond discrepancy was historically cited as evidence for Einstein's General Theory of Relativity since 1915 AD. However, in the Holistic Universe Model, the observed perihelion precession of Mercury is fully explained by the clockwise movement of the PERIHELION-OF-MERCURY, combined with Earth's wobble and the movement of the PERIHELION-OF-EARTH around the Sun which changes Earths orientation axis, without requiring relativistic corrections. The Interactive 3D Solar System Simulation calculates Mercury's perihelion data directly using the apparentRaFromPdA function in Three.js.

A proposed calendar system that redefines year numbering based on the perihelion precession cycle. In this system, year 0 corresponds to December 14, 1245 AD (making 1246 AD = year 0 PY), when the perihelion aligned with the December solstice. Under this system, 2030 AD would become Perihelion Year (PY) 784. This calendar would track the 18,636-year perihelion precession cycle, helping future generations understand and measure the actual duration of this astronomical cycle and its effects on season lengths, eccentricity, and year/day lengths.

A gravitational point that Earth orbits around yearly, close to the Sun, resulting in the perihelion and aphelion of the Sun on Earth. This point is at a distance of 0.01370018 AU (2,049,517.75 km) from the Sun and moves counterclockwise around the Sun in approximately 99,392 years (currently experienced ~112,000 years). It can be considered as the center-point of Earth's orbit around the Sun.

A geological period lasting from approximately 299 to 252 million years ago, ending with the largest mass extinction in Earth's history known as the "Great Dying" or Permian-Triassic extinction event. During this extinction, approximately 96% of marine species and 70% of terrestrial vertebrate species went extinct. The Permian Period had significantly higher atmospheric CO2 levels (1,000-2,000+ PPM) than today's ~425 PPM, demonstrating that current CO2 levels are historically low on geological timescales.

The time required for the PERIHELION OF A PLANET to return to the same fixed star – as viewed from the Earth. This cycle differs per planet. This value can fluctuate across time for a specific planet, but in the long run it returns to this mean value.

The North Star - currently Earth's celestial pole is pointing to the star Polaris. Due to Axial precession, different stars occupy this position over the approximately 22,937-year precession cycle (currently experienced ~25,772 years).

A unit of measurement expressing concentration as parts per million, commonly used to measure atmospheric gas concentrations. For atmospheric CO2, 1 PPM means one molecule of CO2 per million molecules of air. Current atmospheric CO2 is approximately 425 PPM (as of 2024), while during the Last Glacial Maximum it dropped to approximately 170 PPM—dangerously close to the ~150 PPM threshold below which plant life cannot survive through photosynthesis. Historically, CO2 levels have ranged from 170 PPM to over 2,000 PPM across geological time.

"precession" is generally known as "backwards drift" because the term is most commonly used in "precession of the equinoxes". What is confusing is that sometimes precession is also "forward drifting" (in case of inclination precession). In both cases it is a moving factor. In this book I only make a distinction between Axial Precession (BACKWARD in time) and Inclination Precession (FORWARD in time) as the drivers of all currently known precession movements.

a celestial body is said to be "in prograde mode" when it moves in the same direction as the Sun.

used in astronomy as the celestial equivalent of terrestrial longitude.

A coordinate system or set of axes used to measure positions, velocities, and other properties of objects. Different reference frames can give different perspectives on the same motions. Examples include heliocentric, geocentric, and ICRF.

a celestial body is said to be "in retrograde mode" when it moves in the opposed direction of the Sun.

A calendar system introduced in 1923 AD, co-designed by Milutin Milankovitch (the scientist behind the Milankovitch cycles). It refines the leap year rules to produce an average year length of 365.2422222 days, making it more accurate than the Gregorian calendar (365.2425 days) for keeping the March equinox fixed on March 21. The Revised Julian calendar will not diverge from the Gregorian calendar until the year 2800 AD. Despite its superior accuracy, it has only been adopted by a few Orthodox churches and countries.

An updated interpretation of the classical Milankovitch cycles presented in the Holistic Universe Model, incorporating two key modifications: (1) the inclusion of Inclination Precession (~99,392 years), which was not studied by Milankovitch but is proposed as the primary driver of ~100,000-year climate cycles, and (2) revised values for eccentricity, obliquity, and precession based on the interconnected model where all orbital parameters are mathematically related through Fibonacci ratios. Unlike the original Milankovitch theory where precession, eccentricity, obliquity, and inclination are treated as independent unconnected cycles, the Revised Milankovitch cycles demonstrate how these movements are all connected within the 298,176-year Holistic-Year cycle.

A lunar cycle of approximately 6,166.8448471122 days (16.8842582106 years) that represents a specific alignment period in the Moon's orbital mechanics. In the Holistic Universe Model, there are 1,103.75 Royer cycles per perihelion precession cycle of 18,636 years.

A period of approximately 18 years, 11 days, and 8 hours (6585.32 days) after which eclipses repeat with nearly identical geometry. The Saros cycle is one of the most famous eclipse cycles and results from the combination of the Moon's synodic month, draconic month, and anomalistic month aligning after this period. After one Saros cycle, the Sun, Earth, and Moon return to approximately the same relative positions, producing a very similar eclipse. The cycle was known to ancient Babylonian astronomers and is still used today to predict eclipses.

In the Northern Hemisphere, the September equinox is called the autumnal or fall equinox. In the Southern Hemisphere, the reverse is true. That's why the term September equinox is preferred over autumnal equinox.

A numeral system with sixty as its base, inherited from ancient Babylonian mathematics. In astronomy, sexagesimal notation is used to express angles and time in degrees/hours, minutes, and seconds format. For example, Right Ascension is expressed as hours:minutes:seconds (e.g., 12h34m56s) and Declination as degrees:arcminutes:arcseconds (e.g., +23°26'21"). This notation divides each unit into 60 subunits: 1 hour = 60 minutes = 3600 seconds, and 1 degree = 60 arcminutes = 3600 arcseconds. The Interactive 3D Solar System Simulation converts raw radian values to sexagesimal format for display in the Celestial Positions menu.

The SI (International System of Units) second is the base unit of time in the International System of Units. Since 1967, it has been defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the caesium-133 atom at a temperature of 0 K. This atomic definition provides an extremely precise and reproducible standard for timekeeping. One SI second equals one Ephemeris Second. The fixed value of 86,400 SI seconds per day is used as the standard reference for astronomical calculations, though the actual length of a solar day fluctuates around this value.

The sidereal day is the sidereal rotation period of Earth measured relative to the moving vernal equinox. The vernal equinoxes moves because of Axial precession (a.k.a. precession of the equinoxes). The sidereal day is connected to the solar day and the solar year. The J2000 value is ~86,164.0905326261 SI seconds with WRONG LOD fixed to 86,400 sec/day and 86,164.0935657957 SI seconds with REAL LOD. This value is fluctuating across time in the same way [the length of day is fluctuating](https://en.wikipedia.org/wiki/Day_length_fluctuations). The MEAN value in REAL LOD is 86,163.6575681587 seconds.

The time it takes for the Moon to complete one orbit around Earth relative to the fixed stars (ICRF), approximately 27.3216583887 days. This is shorter than the synodic month (29.53 days) because it measures the Moon's position against the stellar background rather than relative to the Sun. As Earth moves along its orbit, additional time is needed for the Moon to return to the same phase relative to the Sun.

a celestial body completes a "sidereal" period each time it aligns again with a given star.

The time required the Sun takes to return to the same fixed star – as seen on Earth. A MEAN time period equal to the value it had IN SECONDS in 1246 AD (when the longitude of perihelion was in line with the December Solstice) which according to science was ~31,558,149.6846777 seconds a year. The J2000 value of the sidereal year is 31,558,149.7591855 seconds a year, which is ~1224.54 seconds longer than the current Solar year but fluctuating across the ages.

A type of calendar designed to keep a specific solar event (such as an equinox or solstice) fixed on the same date each year. Solar calendars are based on the tropical (solar) year—the time it takes for the Sun to return to the same position relative to Earth's seasons (approximately 365.2422 days). The Julian, Gregorian, and Revised Julian calendars are all solar calendars designed to keep the March equinox near March 21. Because solar calendars follow the Sun's apparent motion rather than the Moon's phases or the position of stars, the background constellations gradually shift over time due to axial precession.

The solar day is the time it takes for the Sun to return to the same position in the sky, from one noon to the next. In simpler terms, it's the length of time between two successive moments when the Sun is directly overhead. On average, a solar day lasts about 24 hours—this is the basis for how we set our clocks and structure our daily lives. Currently, the J2000 length of a solar day is slightly longer than 86,400 SI seconds (86,400.0030498014 SI seconds a day). However, this value fluctuates both within a single year and over long periods. As a result, leap seconds are occasionally added to ensure the solar day remains aligned with the 86,400-second standard. These adjustments help track the difference between the time experienced on Earth (Universal Time, UT) and the ´fixed" stars (Terrestrial Time, TT). This difference is known as Delta T (ΔT)](https://en.wikipedia.org/wiki/%CE%94T_(timekeeping). The MEAN value of the solar day over long periods of time is 86,399.5657965675 SI seconds a day.

The angle subtended by Earth's equatorial radius as seen from the center of the Sun, approximately 8.794143836 arcseconds. Solar parallax is used to determine the Earth-Sun distance: the distance to the Sun equals the radius of Earth divided by the solar parallax, times the conversion factor from arcseconds to radians (206,264.806247096).

also known as "Tropical year". The time it takes for Earth to complete one full orbit around the Sun, returning to the exact same position in the sky as seen on Earth. In simpler terms, it's the time between two spring equinoxes (when day and night are roughly equal). A MEAN time period equal to the value it had IN DAYS beginning of 1246 AD (when the longitude of perihelion was in line with the December Solstice) which is 365.242273019961 days per year (6,806,655 solar days in 18,636 years). The J2000 value of the Solar year is 31,556,925.2259806 seconds. The Solar year in seconds is currently calculated against the fixed 86,400 seconds a day but this length of day value is fluctuating not only within the year but also across the ages.

The two times per year (around June 21 and December 21) when the Sun reaches its highest or lowest point in the sky at noon, marking the longest and shortest days of the year. These dates are determined by Earth's tilt relative to the ecliptic.

A theory developed by Albert Einstein in 1905 describing the relationship between space and time. It is based on two postulates: the laws of physics are the same for all observers in uniform motion, and the speed of light in a vacuum is constant for all observers. Along with General Relativity, it forms the foundation of modern physics.

A theoretical type of calendar that fixes a specific date to the position of background stars (constellations) rather than to solar events or lunar phases. Also known as a sidereal calendar. In such a system, a date like March 21 would always align with the same constellation (e.g., Pisces). However, because star calendars would follow the sidereal year rather than the tropical (solar) year, the solstices and equinoxes would gradually drift through the calendar over the approximately 22,937-year axial precession cycle. No major civilization has adopted a pure star calendar, likely because seasonal alignment is more practical for agriculture and daily life than stellar alignment.

The stellar day is the sidereal rotation period of Earth relative to the fixed inertial frame of background stars. The time that it takes for the Earth to rotate 360 degrees relative to distant "fixed" stars. The period is measured as the Earth Rotation Angle (ERA). formerly the stellar angle. An increase of 360° in the ERA is a full rotation of the Earth. The stellar day is directly connected to the Nominal Angular Velocity which is consistent with the definition of the Nominal Angular velocity (ΩN) of Earth. The current fixed ΩN is however the reference angular velocity corresponding to the epoch 1820. Most sources mention therefore this value as set to 86,164.0989036905 seconds. The length of a Stellar day is however also fluctuating in time in the same way [the length of day is fluctuating](https://en.wikipedia.org/wiki/Day_length_fluctuations) will fluctuate in time. The stellar day is directly connected to the length of the sidereal year. The J2000 value is 8.37 SI milliseconds longer than the sidereal day which is 86,164.0989054839 (with WRONG LOD fixed to 86,400 sec/day). The MEAN value is 86,163.6669758971 seconds, so around 9.4 ms longer than the MEAN Sidereal day.

when a body (e.g. Venus) is aligned with the Sun while transiting furthest from Earth.

a celestial body completes a "synodic" period each time it aligns again with the Sun.

A theoretical uniform time scale that is independent of Earth's rotation, fixed at exactly 86,400 SI seconds per day. TT coincidentally aligned with the mean Solar day around 1820 AD. It can be considered as ICRF time or atomic time, remaining constant regardless of fluctuations in Earth's actual rotation (Length of Day changes). TT is more suitable for predicting astronomical events because it provides a stable, unchanging reference. The difference between TT and Universal Time (UT, which tracks Earth's actual rotation) is measured as Delta-T (ΔT).

The starting point of the 298,176-year Holistic-Year cycle, showing as 3 times ~100k year cycles as identified on historical temperature graphs from ice core data. The Balanced Year represents the moment when Earth's maximum Axial tilt and minimum Inclination tilt are in exact opposite position and therefore level out on the mean Axial tilt of Earth's movement in the ecliptic plane. The current cycle began in 268,976 BC, and the next Balanced Year will occur in 29,200 AD.

A cross-browser JavaScript library and application programming interface (API) used to create and display animated 3D computer graphics in a web browser using WebGL. Three.js allows developers to create complex 3D scenes, including geometries, materials, lights, and cameras, without dealing with the low-level WebGL API directly. The Interactive 3D Solar System Simulation of the Holistic Universe Model is built entirely in Three.js, enabling real-time visualization of planetary orbits, precession movements, and celestial positions directly in the browser.

Differential gravitational forces caused by the variation in gravitational pull across an extended object. In standard astronomy, tidal forces from the Sun and Moon on Earth's equatorial bulge are said to cause Axial precession.

The passage of a celestial body directly between a larger body and the observer, appearing to move across the face of the larger body. Mercury and Venus transits across the Sun can be observed from Earth and are relatively rare events used historically to calculate the Earth-Sun distance. Mercury transits occur about 13-14 times per century, while Venus transits occur in pairs separated by 8 years, with over a century between pairs. Transit data is valuable for validating planetary orbital parameters in the Interactive 3D Solar System Simulation.

The time for the Moon to return to the same ecliptic longitude relative to the vernal equinox, approximately 27.3215761379 days. This is very close to the sidereal month but slightly shorter due to the precession of the equinoxes.

The darkest, central part of a shadow where the light source is completely blocked by an opaque object. In the context of eclipses: During a lunar eclipse, the umbra is the dark inner region of Earth's shadow where sunlight is completely blocked, causing the Moon to appear dark red or copper-colored during totality. During a solar eclipse, the umbra is the dark shadow on Earth's surface where observers experience a total eclipse. Only observers within the umbra see a total eclipse, while those in the surrounding penumbra see a partial eclipse.

Constant velocity - moving at the same speed without acceleration or deceleration. In the Holistic model, the Sun moves at uniform speed in its circular orbit around the PERIHELION-OF-EARTH, unlike the variable speed in elliptical orbits.

A time standard based on Earth's actual rotation relative to distant celestial objects. Universal Time represents the observed rotation angle of the Earth relative to an inertial reference frame. Unlike Terrestrial Time (TT), which is fixed at 86,400 SI seconds per day, UT varies because Earth's rotation speed is not constant - sometimes a day is longer than 86,400 SI seconds and sometimes it is shorter. UT is the time scale that corresponds to the actual day-night cycle as experienced on Earth. The difference between TT and UT is called Delta-T (ΔT).

The primary time standard by which the world regulates clocks and time. UTC is based on International Atomic Time (TAI) with leap seconds added at irregular intervals to compensate for the Earth's slowing rotation and keep it close to mean solar time at 0° longitude (Greenwich Mean Time). Unlike Universal Time (UT), which is based on Earth's actual rotation, UTC maintains a constant rate using atomic clocks. UTC is the time standard commonly used across the world and is the basis for civil timekeeping in most countries. The acronym UTC is a compromise between the English "CUT" (Coordinated Universal Time) and the French "TUC" (Temps Universel Coordonné).

Variations Séculaires des Orbites Planétaires (Secular Variations of Planetary Orbits) - A highly accurate analytical solution for computing the positions and orbital elements of the planets in our solar system. VSOP87 was developed by French astronomers Pierre Bretagnon and Gérard Francou and published in 1987. It provides mathematical formulas (based on periodic terms) to calculate planetary positions, orbital eccentricity, inclination, and other parameters across time. The theory is valid for several thousand years around the J2000 epoch and is widely used in astronomical software and ephemeris calculations.

The terminology used by Copernicus to describe the apparent movement of the Earth in the phenomenon known as the "Precession of the Equinoxes". This movement is simulated by Earth orbiting the EARTH-WOBBLE-CENTER in its Axial Precession Orbit (APO).

A sudden return to near-glacial conditions that occurred approximately 12,900 to 11,700 years ago (around 10,900 to 9,700 BC), interrupting the warming trend following the Last Glacial Maximum. Named after a cold-tolerant wildflower (Dryas octopetala) that became common during this period. In the Holistic Universe Model, this cold snap correlates with the maximum obliquity around 9,800 BC, demonstrating how the obliquity cycle can cause rapid climate oscillations even during an overall warming trend.

The apparent path our Sun travels across the celestial sphere over the course of the year through the 12 constellations.

The twelve 30-degree divisions of the ecliptic used in astronomy and astrology (Aries, Taurus, Gemini, etc.). Due to Axial precession, the equinoxes move westward through these signs over approximately 22,937 years (currently experienced ~25,772 years).