Solar system
The solar system is the planetary system that gravitationally binds a set of astronomical objects that revolve directly or indirectly in an orbit around a single star known as the Sun.
The star concentrates 99.86% of the mass of the solar system, and most of the remaining mass is concentrated in eight planets whose orbits are practically circular and transit within an almost flat disk called the ecliptic plane The four closest, considerably smaller planets, Mercury, Venus, Earth, and Mars, also known as the terrestrial planets, are composed primarily of rock and metal. Jovians", more massive than the terrestrials, are composed of ice and gases. The two largest, Jupiter and Saturn, are made mostly of helium and hydrogen. Uranus and Neptune, called ice giants, are made mostly of frozen water, ammonia, and methane.
The Sun is the only celestial body in the solar system that emits its own light, due to the thermonuclear fusion of hydrogen and its transformation into helium in its core. The solar system formed about 4.6 billion years ago from the collapse of a molecular cloud. The residual material originated a protoplanetary circumstellar disk in which the physical processes that led to the formation of the planets occurred. The solar system is currently located in the Local Interstellar Cloud that is located in the Local Bubble of the Orion arm of the spiral Milky Way galaxy, about 28,000 light-years from its center.
The solar system is also home to several regions made up of small objects. The asteroid belt, located between Mars and Jupiter, is similar to the terrestrial planets in that it is made up primarily of rock and metal. In this belt is the dwarf planet Ceres. Beyond Neptune's orbit are the Kuiper belt, the scattered disk, and the Oort cloud, which include trans-Neptunian objects made mostly of water, ammonia, and methane. In this place there are four dwarf planets: Haumea, Makemake, Eris and Pluto, which was considered the ninth planet in the solar system until 2006. This type of celestial body located beyond the orbit of Neptune is also called plutoids, which together to Ceres, they are large enough to have become rounded by the effects of their gravity, but differ mainly from planets in that they have not emptied their orbit of neighboring bodies.
In addition to the thousands of small objects in these two zones, some dozens of which are dwarf planet candidates, there are other groups such as comets, centaurs, and cosmic dust that travel freely between regions. Six planets and four dwarf planets have natural satellites. The solar wind, a flow of plasma from the Sun, creates a bubble of stellar wind in the interstellar medium known as the heliosphere, which extends to the edge of the scattered disk. The Oort cloud, which is believed to be the source of long-period comets, is the boundary of the solar system, its edge located one light-year from the Sun.
At the beginning of 2016, a study was published according to which there may be a ninth planet in the solar system, which they gave the provisional name of Phattie. It is estimated that the size of Phattie would be between that of Neptune and the Earth and that the hypothetical planet would have a gaseous composition.
Discoveries and exploration
Some of the oldest civilizations conceived the universe from a geocentric perspective, as in Babylonia where their world view was represented in this way. In the West, the pre-Socratic Greek Anaximander declared the Earth to be the center of the universe, he imagined it as a drum-shaped pillar balanced at its four most distant points, which, in his opinion, allowed it to have stability. Pythagoras and his followers spoke for the first time of the planet as a sphere, based on the observation of eclipses; and in the fourth century BC. C. Plato together with his student Aristotle wrote texts of the geocentric model of Anaximander, fusing it with the Pythagorean sphere. But it was the work of the Hellenic astronomer Claudius Ptolemy, especially his publication called the Almagest expounded in the second century AD, which served for a period of nearly 1,300 years as the standard on which both European and Islamic astronomers relied.
Although the Greek Aristarchus presented in the 3rd century B.C. C. to the heliocentric theory and later the Hindu mathematician Aryabhata did the same, no astronomer really challenged the geocentric model until the arrival of the Pole Nicolás Copernicus who caused a true revolution in this branch worldwide, for which he is considered the father of modern astronomy. This is because, unlike his predecessors, his work achieved wide diffusion despite the fact that it was conceived to circulate privately; Pope Clement VII requested information on this text in 1533 and Luther in 1539 described him as an "upstart astrologer who claims to prove that the Earth is what rotates". The work of Copernicus grants two movements to the Earth, one of rotation on its own axis every 24 hours and one of translation around the Sun every year, with the particularity that this was circular and not elliptical as we describe it today.
In the 17th century, the work of Copernicus was promoted by scientists such as Galileo Galilei, who, helped with a new invention, the telescope, discovers that natural satellites rotate around Jupiter, which greatly affected the conception of the geocentric theory since that these celestial bodies did not orbit the Earth; which caused a great conflict between the Church and the scientists who promoted this theory, which culminated in the arrest and sentence of the court of the inquisition to Galileo for heresy when his idea was contrasted with the classical religious model. His contemporary Johannes Kepler, from the study of the circular orbit, tried to explain the planetary translation without achieving any results, so he reformulated his theories and published, in the year 1609, the now-known laws of Kepler in his work Astronomia nova, in which he establishes an elliptical orbit which was confirmed when he successfully predicted the transit of Venus in 1631. Together with them, the British scientist Isaac Newton formulated and explained planetary motion through its laws and the development of the concept of gravity. However, heliocentrism would not be experimentally supported until decades later with the discovery of the aberration of light by the English astronomer James Bradley in 1725, and the measurement of stellar parallax by the German mathematician Friedrich Bessel in 1838.
In 1655, the Dutch scientist Christiaan Huygens discovered the satellite Titan and the true nature of Saturn's rings, and described for the first time the real dimensions of the then-known solar system (6 planets and 6 moons). coined the term "solar system". British scientist Edmund Halley devoted his studies mainly to the analysis of the orbits of comets. new characteristics of the celestial bodies that exist.
In the middle of the 20th century, on April 12, 1961, cosmonaut Yuri Gagarin became the first man in space; the US mission Apollo 11, commanded by Neil Armstrong, landed on the Moon on July 16 of 1969. Currently, the solar system is studied with the help of ground-based telescopes, space observatories and space missions.
General characteristics
The planets and asteroids orbit around the Sun, approximately in the same plane and following elliptical orbits (counterclockwise, if they were observed from the North Pole of the Sun); although there are exceptions, such as Halley's Comet, which rotates clockwise. The plane in which the Earth revolves around the Sun is called the plane of the ecliptic, and the other planets orbit in roughly the same plane. Although some objects orbit with a large degree of inclination with respect to it, such as Pluto, which has an inclination with respect to the axis of the ecliptic of 17º, as well as a significant part of the Kuiper belt objects.
Based on their characteristics, the bodies that are part of the solar system are classified as follows:
- The Sun, a G2 spectral star containing more than 99.86 % of the system mass. With a diameter of 1 400 000 km, it consists of 75% hydrogen, 20% helium and 5% oxygen, carbon, iron and other elements.
- Them planets, divided into inner planets (also called terrestrial or theoric) and external or giant planets. Among the latter, Jupiter and Saturn are called giant gaseous, while Uranus and Neptune are often named giant ice cream. All the giant planets have rings around them.
- Them dwarf planets are bodies whose mass allows them to have spherical form, but it is not enough to have attracted or expelled all the bodies around them. They are: Pluto (up to 2006 was considered the ninth planet of the solar system), Ceres, Makemake, Eris and Haumea.
- Them satellites are larger bodies that orbit the planets; some are large, like the Moon, on Earth; Ganymede, in Jupiter, or Titan, on Saturn.
- Them minor bodies They constitute the rest of the celestial objects and according to the definition of the UAI are subdivided into:
- Them asteroids are smaller bodies concentrated mostly on the asteroid belt between the orbits of Mars and Jupiter. Its size varies from 50 m to 1000 km in diameter.
- Them Transneptunian objects are frozen objects of stable orbits belonging to the outer zone of the solar system. They are located in regions such as the Kuiper belt, the scattered disk and the Oort cloud.
- Them kites are small iced objects made up of ice, dust and rocks. They usually have very eccentric orbits. They originate in Kuiper's belt and Oort's cloud.
- Them meteoroids are objects less than 50 m in diameter, but greater than cosmic dust particles. They are usually fragments of comets, asteroids and larger objects.
The interplanetary space around the Sun contains scattered material from the evaporation of comets and the escape of material from different massive bodies. Interplanetary dust (sort of interstellar dust) is made up of solid microscopic particles. Interplanetary gas is a tenuous flow of gas and charged particles that form a plasma that is ejected by the Sun in the solar wind. The outer limit of the solar system is defined through the region of interaction between the solar wind and the interstellar medium originated from the interaction with other stars. The region of interaction between the two winds is called the heliopause and determines the limits of influence of the Sun. The heliopause can be found at about 100 AU (15,000 million kilometers from the Sun).
Planetary systems detected around other stars appear very different from the solar system, although only a few high-mass planets around other stars can be detected with available means. Therefore, it does not seem possible to determine to what extent the solar system is characteristic or atypical among the planetary systems in the universe.
Formation and evolution
The solar system was formed 4.568 million years ago by the gravitational collapse of a part of a giant molecular cloud. This primordial cloud was several light-years across and likely gave birth to several stars. As is normal for molecular clouds, it consisted mostly of hydrogen, some helium, and small amounts of heavy elements from previous stellar generations. As the region—known as the protosolar nebula—developed into the solar system, it collapsed, and conservation of angular momentum caused it to rotate faster. The center, where most of the mass accumulated, became increasingly hotter than the surrounding disk. As the contracting nebula rotated faster, it began to flatten into a protoplanetary disk with a diameter of about 200 AU and a hot, dense protostar at the center. Planets formed by accretion from this disk in which gas and dust gravitationally attracted to each other coalesce to form larger and larger bodies. In this scenario, hundreds of protoplanets could have arisen in the early solar system that eventually merged or were destroyed, leaving planets, dwarf planets, and other minor bodies.
Thanks to their higher boiling points, only metals and silicates could exist in solid form near the Sun, in the hot inner solar system; these were finally the components of Mercury, Venus, Earth and Mars: the rocky planets. Because the metals were only a small part of the solar nebula, the terrestrial planets could not be made very large. The giant planets (Jupiter, Saturn, Uranus, and Neptune) formed farther out, beyond the frost line: the boundary between the orbits of Mars and Jupiter where temperatures are low enough for volatile compounds to remain solid. The ices that make up these planets were more abundant than the metals and silicates that made up the inner terrestrial planets, allowing them to grow massive enough to capture vast atmospheres of hydrogen and helium—the lightest and most abundant elements. The remaining remnants that did not become planets clustered in regions such as the asteroid belt, the Kuiper belt, and the Oort cloud. The Nice model explains the appearance of these regions and proposes that the outer planets could have formed in places different from the current ones they would have reached after multiple gravitational interactions.
After fifty million years, the hydrogen density and pressure at the center of the protostar became so great that thermonuclear fusion began. The temperature, reaction rate, pressure, and density increased until reaching the hydrostatic equilibrium: the thermal pressure equaled the force of gravity. At that time, the Sun entered the main sequence. The time it will be on the main sequence will be about ten billion years; by comparison, all phases prior to thermonuclear ignition lasted about two billion years. The solar wind formed the heliosphere, which swept the remnants of gas and dust from the protoplanetary disk (and ejected them into interstellar space), ending the planetary formation process. Since then, the Sun has been getting brighter and brighter; it is now 70% brighter than it was when it entered the main sequence.
The solar system will continue more or less as we know it until all the hydrogen in the Sun's core has been converted to helium, which will be five billion years from now. This will mark the end of the Sun's stay in the main sequence. At that time the core will collapse and the energy production will be much higher than at present. The outer layers will expand to about 260 times its current diameter, making it a red giant. The large increase in its surface area will make it much colder (on the order of 2600 K). The expanding Sun is expected to vaporize Mercury and Venus and render Earth uninhabitable by moving the habitable zone beyond the orbit of Mars. Ultimately, the core will be hot enough to fuse helium; the Sun will burn helium for a fraction of the time it was burning hydrogen. The Sun does not have enough mass to start the fusion of heavy elements, so nuclear reactions in the core will slow down. The outer layers will be lost to space in the form of a planetary nebula, returning some of the material from which the Sun was formed—enriched with heavy elements such as carbon—to the interstellar medium and leaving behind a white dwarf with half the original mass. of the Sun and the size of the Earth (an extraordinarily dense object).
Solar system objects
The main objects in the solar system are:
| Solar system |  |
|---|---|
| Planets and dwarf planets | Sun - Mercury - Venus - Earth - Mars - Ceres - Jupiter - Saturn - Uranus - Neptune - Pluto - Haumea - Makemake - Eris - Sedna - Phattie |
| Natural satellite | Terrestrial - Marcianas - Asteroidales - Jovianas - Saturnianas - Uranianas - Neptunianas - Plutonianas - Haumeanas - Eridiana |
Center Star
The Sun is the sole and central star of the solar system; therefore, it is the closest star to Earth and the star with the greatest apparent brightness. Its presence or its absence in the terrestrial sky determine, respectively, the day and the night. The energy radiated by the Sun is used by photosynthetic beings, which constitute the base of the trophic chain, and is therefore the main source of energy for life. It also provides the energy that keeps climate processes running. The Sun is a star that is in the phase called the main sequence, with a spectral type G2, which formed about 5 billion years ago, and will remain on the main sequence for about another 5 billion years.
Despite being a medium-sized star, it is the only one whose circular shape can be seen with the naked eye, with an angular diameter of 32′35″ of arc at perihelion and 31′31″ at aphelion, which gives an average diameter of 32′03″. Coincidentally, the combination of sizes and distances of the Sun and the Moon from Earth make them appear approximately the same apparent size in the sky. This allows for a wide range of different solar eclipses (total, annular, or partial).
Planetary systems have been discovered that have more than one central star (star system).
Planets
The eight planets that make up the solar system are, from least to greatest distance from the Sun, the following: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
Planets are bodies that revolve in orbits around the star, have enough mass for their gravity to overcome rigid body forces, so that they assume a hydrostatic equilibrium (nearly spherical) shape, and have cleared the neighborhood of its orbit of planetesimals (orbital dominance).
The inner planets are Mercury, Venus, Earth and Mars and have a solid surface. The outer planets are Jupiter, Saturn, Uranus and Neptune, also called gas planets because they contain gases such as helium, hydrogen and methane in their atmospheres, and the structure of their surface is not known with certainty.
On August 24, 2006, the International Astronomical Union (IAU) excluded Pluto as a planet from the solar system, and classified it as a dwarf planet.
At the beginning of 2016, a study was published according to which there may be a ninth planet in the solar system, which they gave the provisional name of Phattie. That study focused on explaining the orbits of many of the Kuiper belt objects, which differ greatly from the orbits that are calculated, including well-known objects such as Sedna. Therefore, the idea of the existence of an unknown object perturbing these orbits originally arose. Using mathematical models, computer simulations were carried out, and it was determined that the possible planet would have an eccentric orbit at a distance of between 700 and 200 AU from the Sun, and would take about ten to twenty thousand years to go around.
Distances of the planets
The orbits of the major planets are ordered at increasing distances from the Sun, so that the distance of each planet is about twice that of the planet immediately before it, although this does not fit all planets. This relationship is expressed by the Titius-Bode law, an approximate mathematical formula that indicates the distance of a planet from the Sun, in Astronomical Units (AU):
- a=0,4+0,3× × k{displaystyle a=0.4+0,3times k,!}
- where k{displaystyle k} = 0, 1, 2, 4, 8, 16, 32, 64, 128.
Where Mercury's orbit is at k = 0 and semi-major axis 0.4 AU, Mars' orbit is k = 4 to 1.6 AU, and Ceres (the largest asteroid) is k = 8. Actually the orbits of Mercury and Mars meet at 0.38 and 1.52 AU. This law does not hold for all planets, for example Neptune is much closer than this law predicts. There is no explanation of the Titius-Bode law and many scientists consider it to be just a coincidence.
Main features
The main characteristics of the planets of the solar system are:
| Planet | Yes. | Equatorial diameter♪ | Equatorial diameter (km) | Masa♪ | Orbital radio (UA) | Orbital period (years) | Rotation period (days) | Incl.** | Sat.*** | Composition of the atmosphere | Image |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Mercury |  | 0.39 | 4878 | 0.06 | 0.39 | 0.24 | 58.6667 | 7° | 0 | Traces of hydrogen and helium |  |
| Venus |  | 0.95 | 12100 | 0.82 | 0.72 | 0.615 | 243 | 3.4° | 0 | 96 % CO2, 3 % nitrogen,0.1 % water |  |
| Earth |  | 1,00 | 12756 | 1,00 | 1,00 | 1,00 | 1,00 | 0° | 1 | 78 % nitrogen, 21 % oxygen, 1 % argon |  |
| Mars |  | 0.53 | 6787 | 0.11 | 1.52 | 1.88 | 1.03 | 1.9° | 2 | 95% CO2, 1.6 % argon, 3 % nitrogen |  |
| Jupiter |  | 11,2 | 142984 | 318 | 5,20 | 11,86 | 0.414 | 1.3° | 79 | 90% hydrogen, 10% helium, traces of methane |  |
| Saturn |  | 9,41 | 120536 | 95 | 9.54 | 29,46 | 0.426 | 2.5° | 82 | 96 % hydrogen, 3 % helium, 0.5 % methane | .jpg){kind=small} |
| Uranus |  | 3,98 | 51108 | 14,6 | 19,19 | 84,01 | 0.718 | 0.8° | 27 | 84 % hydrogen, 14 % helium, 2 % methane |  |
| Neptune |  | 3,81 | 49538 | 17,2 | 30.06 | 164.79 | 0.6745 | 1.8° | 14 | 74 % hydrogen, 25 % helium, 1 % methane |  |
* Diameter and mass are expressed relative to the Earth ** Orbit inclination (relative to the ecliptic) *** Natural satellites
Dwarf Planets
The five dwarf planets in the solar system, from least to greatest distance from the Sun, are: Ceres, Pluto, Haumea, Makemake, and Eris.
Dwarf planets are those that, unlike planets, have not cleaned up the neighborhood of their orbit.
Shortly after its discovery in 1930, Pluto was classified as a planet by the International Astronomical Union (IAU). However, after the discovery of other large bodies later, a debate was opened in order to reconsider said decision. On August 24, 2006, at the XXVI General Assembly of the IAU in Prague, it was decided that the number of planets should not be increased to twelve, but should be reduced from nine to eight, and the new category of dwarf planet was then created., in which Pluto would be classified, which therefore ceased to be considered a planet because, as it is a trans-Neptunian object belonging to the Kuiper belt, it has not cleaned the vicinity of its orbit of small objects.
| Planet dwarf | Average diameter♪ | Diameter (km) | Masa♪ | Orbital radio (UA) | Orbital period (years) | Rotation period (days) | Natural satellites | Image |
|---|---|---|---|---|---|---|---|---|
| Ceres | 0.074 | 952,4 | 0,00016 | 2,766 | 4.599 | 0.3781 | 0 |  |
| Pluto | 0.22 | 2370 | 0.0021 | 39,482 | 247,92 | -6,3872 | 5 |  |
| Haumea | 0.09 | 1300-1900 | 0.0007 | 43,335 | 285,4 | 0.167 | 2 |  |
| Makemake | 0.12 | 1.420 ± 60 | 0.0007 | 45,792 | 309,9 | 0.9375 | 1 |  |
| Eris | 0.19 | 2326 | 0.0028 | 67.668 | 557 | 1.0417 | 1 |  |
* Diameter and mass are expressed here with reference to Earth data.
Large satellites of the solar system
Some satellites in the solar system are so large that if they were in direct orbit around the Sun, they would be classified as planets or dwarf planets; Because they orbit the major planets, these bodies can be called "secondary planets." The following list includes the satellites of the solar system that maintain a hydrostatic balance:
| Satellite | Planet | Diameter (km) | Orbital period | Image |
|---|---|---|---|---|
| Moon | Earth | 3476 | 27d 7h 43,7m |  |
| Io | Jupiter | 3643 | 1d 18h 27,6m |  |
| Europe | Jupiter | 3122 | 3,551181 d |  |
| Ganymede | Jupiter | 5262 | 7d 3h 42,6m |  |
| Calisto | Jupiter | 4821 | 16,6890184 d |  |
| Titan | Saturn | 5162 | 15d 22h 41m |  |
| Tetis | Saturn | 1062 | 1,888 d |  |
| Dione | Saturn | 1118 | 2,736915 d |  |
| Rea | Saturn | 1529 | 4.518 d |  |
| Jápeto | Saturn | 1436 | 79d 19h 17m |  |
| Mimas | Saturn | 416 | 22 h 37 min |  |
| Ice cream. | Saturn | 499 | 32 h 53 m |  |
| Miranda | Uranus | 472 | 1,413 d |  |
| Ariel | Uranus | 1162 | 2.52 d | .jpg) |
| Umbriel | Uranus | 1172 | 4,144 d |  |
| Titania | Uranus | 1577 | 8,706 d | _color,_cropped.jpg) |
| Oberón | Uranus | 1523 | 13,46 d |  |
| Triton | Neptune | 2707 | -5877 d |  |
| Caronte | Pluto | 1207 | 6,387 230 d |  |
Minor Corps
The minor bodies of the solar system are grouped into:
- asteroid belt
- Transneptunian objects and Kuiper Belt
- Oort Cloud
A small Solar System body (CMSS or SSSB, small Solar System body) is, according to the resolution of the IAU (International Astronomical Union) of August 22, 2006, a celestial body that orbits around the Sun and that is not a planet, nor a dwarf planet, nor a satellite:
_(pd).jpg)
All other objects [referred to those that are neither dwarf planets nor satellites], and orbiting around the Sun, should be collectively referred to as "small bodies of the solar system" (Small Solar-System Bodies).
These currently include most of the asteroids of the solar system, most transneptunian objects (NATOs), comets, and other small bodies.
Therefore, according to the IAU definition, they are minor bodies of the solar system, regardless of their orbit and composition:
- The asteroids
- Comets
- The meteoroids
According to the definitions of planet and dwarf planet, which take into account the sphericity of the object due to its great mass, it can be defined as a "minor body of the solar system", by exclusion, any celestial body that, without being a satellite, has not attained sufficient size or mass to assume an essentially spherical shape.
According to some estimates, the mass required to reach the condition of sphericity would be around 5 x 1020 kg, with a minimum diameter of around 800 km. However, characteristics such as the chemical composition, temperature, density or rotation of the objects can significantly vary the minimum sizes required, for which reason it was rejected to assign a priori values to the definition, leaving the individual resolution of each case to observation. direct.
According to the IAU, some of the largest minor bodies in the solar system could be reclassified in the future as dwarf planets, after examination to determine if they are in hydrostatic equilibrium, that is, if they are large enough for their gravity to overcome the forces of the rigid body until it has assumed an essentially spherical shape.
Excepting the trans-Neptunian objects, the largest minor bodies in the solar system are Vesta and Pallas, with just over 500 km in diameter.
| Minor planets | Equatorial diameter (km) | Mass (M)) | Orbital radio (UA) | Orbital period (years) | Rotation period (days) | Image |
|---|---|---|---|---|---|---|
| Vesta | 578×560×458 | 0,000 23 | 2.36 | 3,63 | 0.22226 |  |
| Orcus | 840 - 1880 | 0,000 10 - 0.001 17 | 39,47 | 248 | ? |  |
| Ixion | ~822 | 0,000 10 - 0,000 21 | 39,49 | 248 | ? |  |
| 2002 UX25 | 910 | 0,000 123 | 42.9 | 277 | 0.599 - 0.699 |  |
| 2002 TX300 | 900 | ? | 43,102 | 283 | ? |  |
| Varuna | 900 - 1060 | 0,000 05 - 0,000 33 | 43.129 | 283 | 0.132 or 0.264 |  |
| 1996 TO66 | 902? | ? | 43.2 | 285 | 7.92 | _1996_TO66.png){kind=small} |
| Quaoar | 1280 | 0,000 17 - 0,000 44 | 43,376 | 285 | 0.7366 |  |
| 2002 AW197 | 734 | ? | 47,0 | 325 | 8,86 |  |
| 2002 TC302 | 584,1 +105.6 −88.0 | 0.003 98 | 55.535 | 413,86 | ? | |
| Gonggong | 1280 | - | 67.21 | 550 | 0.93 | .jpg) |
| Sedna | 1180 - 1800 | 0,000 14 - 0.001 02 | 502,040 | 11500 | ~0.41 |  |
| 2018 VG18 | 500 | ? | ? | ? | ? |
The astronomical dimension of distances in space
To have a notion of the astronomical dimension of distances in space, it is interesting to make a scale model that allows a clearer perception of it. Imagine a reduced model in which the Sun is represented by a ball 220 mm in diameter. At that scale, Earth would be 23.6m away and a sphere just 2mm in diameter (the Moon would be about 5cm from Earth and about 0.5mm in diameter). Jupiter and Saturn would be little balls about 2 cm in diameter, at 123 and 226 m from the Sun, respectively. Pluto would be 931 m from the Sun, with about 0.3 mm in diameter. As for the nearest star (Proxima Centauri), it would be 6,332 km from the Sun, and the star Sirius, 13,150 km.
If it took 1 and a quarter hours to go from Earth to the Moon (at about 257,000 km/h), it would take about 3 (Earth) weeks to go from Earth to the Sun, about 3 months to go to Jupiter, 7 months to Saturn and about two and a half years to reach Pluto and leave the solar system. From there, at that speed, it would take about 17,600 years to reach the nearest star, and 35,000 years to reach Sirius.
A more exact comparative scale can be obtained by comparing the Sun to a compact disc 12 cm in diameter. At this scale, Earth would be just over a millimeter in diameter (1.1mm) and 6.44 meters from the Sun. The diameter of the largest star in the known Universe, Stephenson 2-18, would be 258 meters. (Picture that massive star almost three house blocks in size, compared to our 12cm star.) The outer orbit of Eris would move 625.48 meters away from the Sun. There a great void awaits us until the nearest star, Proxima Centauri, 1645.6 km away. From there, the galactic distances exceed the size of the Earth (even using the same scale). With a Sun the size of a compact disc, the center of the galaxy would be almost 11 million kilometers away and the diameter of the Milky Way would be almost 39 million kilometers. There would be a huge gap, since the Andromeda galaxy would be 1028 million kilometers away, almost the actual distance between the Sun and Saturn.
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