Usually when asked what planet is closest to Earth, most will answer Venus; however, this may not be accurate.
Mercury, Venus and Earth come first; Mars follows; then Jupiter, Saturn, Uranus and Neptune are seen setting and rising after the Sun. These inferior planets set and rise after him.
Mercury
Mercury, the closest and smallest planet to our Sun, is an intensely dense rocky world dotted with impact craters. It has an extremely thin atmosphere made up primarily of hydrogen, helium and oxygen atoms; and is tidally locked to it via its axis being in constant contact. Because its day only lasts 59 Earth days per year compared with 88 on earth; additionally its lack of tilt prevents full sun coverage at either pole, effectively eliminating seasons altogether.
Mercury, our fastest planet in our Solar System, goes through apparent retrograde motion three to four times per year. According to astrology, Mercury rules communication; those who believe in planetary horoscopes should expect communication difficulties or roadblocks during its apparent retrograde motion phase.
Since the dawn of space exploration, numerous probes have explored Mercury, Venus, Earth and Mars; Jupiter, Saturn, Uranus and Neptune; with possible signs of an additional ninth planet such as Nibiru or Planet X; with more exploration to be conducted beyond these four planets in an asteroid belt or into gas giants Neptune and Pluto.
Venus
Venus is our solar system’s hottest planet. Sometimes referred to as Earth’s twin planet, due to their similar sizes and densities, their two worlds couldn’t be any different – though their atmospheres might resemble each other closely – they couldn’t be further apart! Venus’ thick toxic atmosphere traps heat that almost matches that of the Sun itself while its surface area is 50 times drier than Chile’s Atacama Desert.
Venus may appear obscured by a thick cloud cover, yet radar observations reveal an intricate landscape filled with mountains, volcanoes and ridges. Most notable features are two bright spots rising through the clouds to nearly 11 kilometers (7 miles). These spots likely represent broken tectonic plates that have separated to form rift zones consisting of many valleys and ridges.
As with Mercury, Venus’s hostile environment renders life on this planet impossible. Its thick clouds wreak havoc with spacecraft and within minutes melt and burn any that land on the surface. Yet despite such difficulties, numerous robotic missions have visited Venus such as Soviet Russia’s Venera series and NASA’s Akatsuki missions.
Earth
According to Caltech (opens in new tab), Earth lies at just the right distance from the Sun for liquid water to remain stable on its surface, unlike Mercury, Venus, or Mars. Sunlight takes about eight minutes to reach Earth’s interior; an immense layer of silicate and basaltic rocks lies underneath a thick outer crust moving slowly due to plate tectonics.
Earth is tilted with respect to the ecliptic plane, altering how much sunlight each of its hemispheres receives throughout the year and giving us seasons. Our solar system’s only planet known to harbor life thrives thanks to abundant flora and fauna species as well as plentiful oxygen supplies as well as its magnetic field’s deflecting harmful cosmic radiation rays.
Jupiter, Saturn, Uranus and Neptune are collectively known as gas giants because their composition primarily comprises hydrogen, helium and ammonia atoms. Each planet takes approximately 84 Earth years to orbit the Sun; their rings, blue hues and unique axial tilts stand out among their competitors.
Mars
Mars is one of our closest planetary neighbors and is easily identified using a telescope. The red planet features iron oxide dust covering its surface, while its atmosphere consists of thin carbon dioxide clouds. Like Earth, Martian polar caps consist of water which vary seasonally – closer to the Sun the southern cap may become much larger; otherwise their sizes remain nearly equal throughout the year.
Mars, unlike Venus, is a true terrestrial planet and therefore habitable for short periods. It rotates every 687 days and boasts two natural satellites called Deimos and Phobos – as seen here at its closest approach to Earth.
However, Uranus falls outside the four inner planets due to its highly elliptical orbit that sometimes passes close to Earth than Neptune itself. Because of this phenomenon, astronomers use an algorithmic formula in order to identify which terrestrial planet lies closest.
Jupiter
Jupiter, our fifth planet from the Sun and a gas giant approximately twice as massive as all of our Solar System combined, features an atmosphere rich with helium that is enveloped by hydrogen-containing layers. Jupiter rotates extremely rapidly completing one day in about 10 hours which creates bands in its outer atmosphere that frequently interact with one another creating stormy and turbulent zones on its borders.
Planet Jupiter boasts a faint ring system and at least 79 moons, four of which can be spotted through binoculars or small telescopes and known as Galilean moons after Galileo Galilei in 1610. Io is home to one of our Solar System’s most active volcanic environments while Europa and Ganymede may hide liquid water oceans beneath their icy shells.
Scientists theorize that Jupiter formed from material left over from the Sun and its siblings’ creation, pulling in dust and gas as it collected in an area roughly two-and-a-half times the size of Earth before being shaped into its current form with its core of nickel and iron.
Saturn
Saturn is the second-largest planet in our Solar System and, similar to Jupiter, a gas giant. The rest of Saturn formed alongside other planets 4.5 billion years ago when gravity pulled swirling gas and dust together into our Solar System. Saturn primarily comprises hydrogen and helium molecules which gives its appearance a yellow hue.
Saturn rotates rapidly, covering one day of rotation every 10.6 hours. However, its density is extremely low – 764 times less dense than water! Furthermore, Saturn is currently locked into orbit around its parent planet Jupiter so only one side of Saturn appears visible to us.
Cassini probe identified and named 53 natural satellites of Jupiter that resemble the Solar System as part of its miniature nature, including Enceladus with an icy shell and cryovolcanoes spewing geyser-like jets of water vapor, ice particles and molecular hydrogen into space. Cassini also detected methane at fractured surfaces – perhaps suggesting an ocean of liquid water exists there! Whether or not life exists remains to be seen.
Uranus
Before recently, it was thought that there were only six planets in our Solar System; however, more dwarf planets have since been identified. Uranus is the seventh planet from our Sun and an ice giant planet.
Saturn stands out among its fellow gas giants due to its unique composition: most of its mass lies within a hot dense fluid of “icy” materials such as water, ammonia and methane that flows above a small rocky core. This gives it its distinct blue-green hue.
Uranus stands out among our Solar System planets with a dramatic 98-degree tilt that creates extreme seasons. One pole receives direct sunlight while the other experiences long, cold winters; then they swap places again.
Uranus currently boasts 27 known moons, such as Cordelia (named for the fairy queen in Shakespeare’s play, A Midsummer Night’s Dream). There is also a banded region called the southern collar which may host additional bodies but are difficult to detect from Earth. Astronomers believe there may be even more, though.
Neptune
Neptune, the eighth planet from the Sun, is an immense gas giant with an orbit that takes 165 years. Like Uranus, Neptune possesses 13 known satellites and lies 30 times further from our Sun than Earth does.
Neptune’s atmosphere consists mainly of hydrogen, helium and methane – with its absorption of red light causing its hue to change to blue – making the planet appear bluer than ever. Like Uranus and Saturn or Jupiter, Neptune also boasts rings; though their patterns are slightly diffuse.
Triton is the seventh-largest moon in our solar system and the biggest Neptune moon by volume. Unlike most of its fellow satellites, however, Triton orbits Neptune retrogradely, unlike all of its peers. Astronomers have identified 14 other Neptune satellites such as Naiad Thalassa Despina Larissa and Hippocamp. Neptune comes closest to our Sun at its perihelion while farthest at aphelion.
At night when looking up at the sky, Mercury, Venus, and Earth will appear close by – these inner planets are known as rocky planets.
One effective way of remembering this order is through mnemonic devices or learning it via song.
Mercury
Mercury, the smallest planet and closest planet to the Sun, orbits extremely elliptically and revolves around in 88 days, experiencing both scorching hot days and freezing cold nights due to being so close. Mercury’s name derives from Roman god of swift travel: Hermes.
Most people mistakenly believe Venus to be our closest planet; however, according to a new study published by Physics Today it could actually be Mercury. A team of scientists developed a computer simulation which tracked each planet for 10,000 years in our solar system; using this data they calculated how often each was near each other; they found Mercury closer on average than either Venus or Mars.
Reason being, other planets spend some time orbiting one side of the Sun while some on the other; therefore when at their perihelion (closest) alignment (closest to Earth), Venus becomes our closest neighbor; when they’re further from it (furthest from Sun), Mercury takes over as Earth’s closest planetary neighbor.
Venus
Venus, commonly referred to as Earth’s twin planet due to their similar sizes and densities, sits within our solar nebula system. Yet it couldn’t be further from our reality; with an overheated greenhouse atmosphere on Venus that produces temperatures high enough to melt lead.
At present, Jupiter is 75% illuminated, making it easily visible through even modest telescopes. On March 27, it reached its greatest eastern elongation point – this means it will now come closest to our planet from behind the Sun over the course of 8 1/2 months.
Most people mistakenly assume Venus is closer than Mars because of the frequency with which Venus passes by our planet; however, this calculation fails to take into account their average distances from the Sun. To gain a clearer idea of their movements over 10,000 years and what each planet was really up to close up, Stockman ran simulations over that span in which each close-by planet spent time as its closest neighbor with Earth; his results revealed Venus is actually closer than Mercury; on average Venus orbits at 96.6 million miles (179.9 million kilometers compared with 96.7 million miles for Mercury
Earth
Earth, our home planet in the Solar System, is perhaps best known to us all. It stands out as being unique due to the presence of liquid surface water – about 70% by volume! Additionally, its slow movements of tectonic plates create mountain ranges, volcanoes and earthquakes, while its protective magnetosphere deflects much of the damaging solar winds and cosmic radiation which reach Earth.
Though Earth is the largest of the inner rocky planets, Jupiter, Saturn, Uranus and Neptune dwarf it significantly in size and volume – you would need 57 Earths to fill Neptune!
Many are bewildered by the order of Earth’s closest planets. Unfortunately, due to their noncircular orbits and variable proximity of Mercury and Venus to our planet at different points, the answer varies each time a Mercury or Venus approaches us more closely than Mars does – or vice versa!
Venus may seem close to our home planet when discussing proximity, yet Mercury is actually our closest neighboring planet.
Mars
Most people consider Venus the closest planet to Earth, which may be true from an average distance perspective; however, an analysis of Mercury’s orbit shows it actually spends more time as our closest neighbor than Venus does.
Calculating distance between planets often involves subtracting their average distance from that of the Sun (more precisely, their average ecliptic longitude). But this method provides only an incomplete picture, since averages fail to take into account that planets have elliptical orbits – meaning they come closer together at times and further apart other times.
Phobos and Deimos, Mars’ two moons, are among the smallest in our Solar System. Each has an approximate diameter less than half that of Earth’s Moon; both may have formed from captured asteroids similar to how Earth’s Moon formed; both moons are tidally locked with Mars so one side always faces them, and will appear close together on June 2, rising about two hours before sunrise, and can be seen by naked eye.
Jupiter
Jupiter is by far the largest planet in our Solar System and by far the most massive object visible from Earth. A gas giant with at least 79 moons – four of which may pose challenges to existing theories on whether life exists beyond Earth – Jupiter offers us an intriguing window into space and time.
Jupiter’s rapid rotation, high winds and convective rise and fall of gases create an impressive structure of belts and zones visible through binoculars or small telescopes. Observers at mid-Northern latitudes will best view Jupiter in 2022 during late June/early July in Cetus (the Whale or Sea Monster), before it reaches its Northern stationary point in Taurus during September before beginning a slow retrograde motion against background stars before resuming East to West motion by November.
Due to Jupiter’s relatively shallow axial tilt (3o.1 from its orbit plane) and similar-sized moons, Jovian planets tend to present themselves in a relatively linear fashion in the night sky; however, mutual occultations/eclipse events occur frequently between them.
Saturn
Saturn was formed simultaneously with Jupiter 4.5 billion years ago during the early days of our Solar System’s formation, likely through accretion or gravity pulling asteroids and comets around which some then made contact with Earth, providing water supplies.
Saturn will make an apparition from 2023-2031 that spans Aquarius constellation and appears as dark dots against its background stars. After turning retrograde during the last quarter of 2025 and reaching opposition near Psc (Mu Piscium mag. +4.8) during December 2025. Reaching its Western stationary point by December 4th it resumes direct movement before disappearing again three and half months later on April 1st. 2028.
On its return to view in early June 2031 Saturn will be roughly 6deg south of Taurus’ most well-known star cluster – Pleiades/Hyades or Messier 45/M45). As with previous apparitions, Saturn’s brightness is strongly determined by its Ring Tilt; that is, how its plane tilts towards Earth.
Uranus
Uranus, the seventh planet from the Sun, is an immense gaseous cyan-colored ice giant with 13 moons and 13 rings – visible with naked eye under optimal viewing conditions.
William Herschel first observed an icy giant during a solar eclipse and became convinced it was a new planet. He reported his findings to the Royal Society and other scientists immediately confirmed his diagnosis. To please King George III of England, Herschel proposed calling the planet Georgium Sidus (“The Georgian Planet”); however, this suggestion never gained wide acceptance.
Astronomers have identified many distinctive aspects of Uranus. One such characteristic is its dramatic 98-degree tilt which brings about one of the most extreme solar system seasons – one pole experiences sunlight while its opposite receives total darkness for 21 years before this process reverses itself and sunlight returns.
Uranus’ magnetic field produces striking aurorae that do not align with its poles as on Earth and Jupiter, as well as an unusual corkscrew-shaped magnetosphere tail that extends millions of miles behind it – just like its planet itself, which tilts on one-third of its radius radius axis compared to one-third off center for Earth and Jupiter respectively. It also bears witness to rare and unique aurorae which don’t correspond with poles! Uranus stands out among its rivals thanks to its corkscrew-shaped magnetosphere tail that extends millions of miles further into space compared with Earth or Jupiter! Another peculiar feature is Uranus’ corkscrew-shaped tail that extends millions of miles into space behind it – its magnetic axis lies off-center by about one third radius which causes misalignments similar to Earth and Jupiter!