How Long Is A Year On The Other Planets? - Universe Today Universe Today How Long Is A Year On The Other Planets? Article Updated: 29 Jan , 2016 by Matt Williams Here on Earth, we to end to not give our measurements of time much thought. Unless we’re griping about Time Zones, enjoying the extra day of a Leap Year, or contemplating the rationality of Daylight Savings Time, we tend to take it all for granted. But when you consider the fact that increments like a year are entirely relative, dependent on a specific space and place, you begin to see how time really works. Here on Earth, we consider a year to be 365 days. Unless of course it’s a Leap Year, which takes place every four years (in which it is 366). But the actual definition of a year is the time it takes our planet to complete a single orbit around the Sun. So if you were to put yourself in another frame of reference – say, another planet – a year would work out to something else. Let’s see just how long a year is on the other planets, shall we?

A Year On Mercury: To put it simply, Mercury has an orbital period of 88 days (87.969 to be exact), which means a single year is 88 Earth days – or the equivalent of about 0.241 Earth years. But here’s the thing. Because of Mercury’s slow rotation (once every 58.646 days) and its rapid orbital speed (47.362 km/s), one day on Mercury actually works out to 175.96 Earth days. MESSENGER maps of Mercury – a monochrome map at 250 m/pixel and an eight-color (left), 1-km/pixel color map. Small gaps will be filled in during the next solar day (right). Credit: NASA/Johns Hopkins University APL/Carnegie Institution of Washington So basically, a single year on Mercury is half as long as a Mercurian (aka. Hermian) day. This is due to Mercury being the closest planet to the Sun, ranging from 46,001,200 km at perihelion to 69,816,900 km at aphelion.

At that distance, the planet shoots around the Sun faster than any other in our Solar System and has the shortest year. In the course of a year, Mercury experiences intense variations in surface temperature – ranging from 80 °K (-193.15 °C;-315.67 °F) to 700 °K (426.85 °C; 800.33 °F). However, this is due to the planet’s varying distance from the Sun and its spin, which subjects one side to extended periods of extremely hot temperatures and one side to extended periods of night. Mercury’s low axial tilt (0.034°) and its rapid orbital period means that there really is no seasonal variation on Mercury. Basically, one part of the year is as hellishly hot, or horribly cold, as any other. A Year On Venus: The second closest planet to our Sun, Venus completes a single orbit once ever 224.7 days. This means that a single year on Venus works out to about 0.6152 Earth years. But, once again, things are complicated by the fact that Venus has an unusual rotation period.

In fact, Venus takes 243 Earth days to rotate once on its axis – the slowest rotation of any planet – and its rotation is retrograde to its orbital path. The planet Venus, as imagined by the Magellan 10 mission. Credit: NASA/JPL Combined with its orbital period, this means that a single solar day on Venus (the time between one sunup to the next) is 117 Earth days. So basically, a single year on Venus is lasts 1.92 Venusian (aka. Cytherean) days. Again, this would make for some confusing time-cycles for any humans trying to make a go of it on Venus! Also, Venus has a very small axial tilt – 3° compared to Earth’s 23.5° – and its proximity to the Sun makes for a much shorter seasonal cycle – 55-58 days compared to Earth’s 90-93 days. Add to that its unusual day-night cycle, variations are very slight. In fact, the temperate on Venus is almost always a brutal 736 K (463 °C ; 865 degrees °F), which is hot enough to melt lead!

A Year On Earth: Comparatively speaking, a year on Earth is pretty predictable, which is probably one of the reasons why life is able to thrive here. In short, our planet takes 365.2564 solar days to complete a single orbit of the Sun, which is why we add an extra day to the calendar every four years (i.e. a Leap Year, which 2016 happens to be). But because our axis is tilted, there is considerable variation in the seasons during the course of a year. During the winter, when one hemisphere is pointed away from the Sun, the Sun’s distance from the equator changes by up to 23.5°. As a result, between the summer and winter, the length of days and nights, temperatures, and seasons will go through significant changes. Above the Arctic Circle, an extreme case is reached where there is no daylight at all for part of the year – up to six months at the North Pole itself, in what is known as a “polar night”. In the southern hemisphere the situation is exactly reversed, with the South Pole experiencing a midnight sun, a day of 24 hours, again reversing with the South Pole.

Every six months, the order of this is reversed. A Year On Mars: Mars has one of the highest eccentricities of any planet in the Solar System, ranging from 206,700,000 km at perihelion and 249,200,000 km at aphelion. This large variation and its greater distance from the Sun, leads to a rather long year. Basically, Mars takes the equivalent of 687 (Earth) days to complete a single orbit around the Sun, which works out to to 1.8809 Earth years, or 1 year, 320 days, and 18.2 hours. On the other hand, Mars has a rotation period that is very similar to Earth’s – 24 hours, 39 minutes, and 35.244 seconds. So while the days on Mars are only slightly longer, the seasons are generally twice as long. But this is mitigated by the fact that seasonal changes are far greater on Mars, owing to its eccentricity and greater axial tilt (25.19°).

During the winter, the global atmospheric pressure on Mars is 25% lower than during summer. This is due to temperature variations and the complex exchange of carbon dioxide between the Martian dry-ice polar caps and its CO2 atmosphere. As a result, Martian seasons vary greatly in duration than those on Earth, change roughly every six months, and do not start on the same Earth day every Martian year. Mars 2001 Global Dust Storm, as captured by the Hubble Space Telescope. Credit: NASA/J. Bell (Cornell)/M. Wolff (SSI)/Hubble Heritage Team (STScI/AURA) A Year On Jupiter: Jupiter is another interesting case. Whereas the gas giant only takes 9 hours 55 minutes and 30 seconds to rotate once on its axis, it also takes alson 11.8618 Earth years to complete an orbit around the Sun. This means that a year on Jupiter is not only the equivalent of 4,332.59 Earth days, but 10,475.8 Jovian days. That’s a lot of sunrises!

Much like Venus, Jupiter has an axial tilt of only 3 degrees, so there is literally no seasonal variation between the hemispheres. In addition, temperature variations are due to chemical compositions and depths rather than seasonal cycles. So while it does have “seasons”, which change very slowly due to its distance from the Sun – each season lasts 3 years – they are not similar to what terrestrial planets experience. A Year On Saturn: Much like its fellow gas giant Jupiter, Saturn takes it time completing a single orbit of the Sun, but rotates on its axis very rapidly. All told, a year on the planet lasts the equivalent of 10,759 Earth days (or about 29 1?2 years). But since it only takes 10 hours, and 33 minutes to complete a single rotation on its axis, a year on Saturn works out to 24,491.07 Saturnian (aka. Cronian) days. This portrait looking down on Saturn and its rings was created from images obtained by NASA’s Cassini spacecraft on Oct. 10, 2013. Credit: NASA/JPL-Caltech/Space Science Institute/G.

Ugarkovic Due to its axial tilt of almost 27 degrees (slightly more than Mars), Saturn experiences some rather long seasonal changes. But due to it being a gas giant, this does not result in variations in temperature. Combined with its distance from the Sun (at an average distance of 1,429.39 million km or 9.5 AU), a single season lasts more than seven years. A Year On Uranus: Uranus has some of the strangest annual and seasonal variations of any planet in the Solar System. For one, the gas/ice giant takes about 84 Earth years (or 30,688.5 Earth days) to rotate once around the Sun. But since the planet takes 17 hours, 14 minutes and 24 seconds to complete a single rotation on its axis, a year on Uranus lasts 42,718 Uranian days. However, this is confounded due to Uranus’ axial tilt, which is inclined at 97.77° towards the Sun. This results in seasonal changes that are quite extreme, and unique to Uranus. In short, when one hemisphere is pointed towards the Sun (i.e.

in summer), it will experience 42 years of continuous light. In winter, the situation is reversed, with this same hemisphere experiencing 42 years of continuous darkness. A Year On Neptune: Given its distance from the Sun, Neptune has the longest orbital period of any planet in the Solar System. As such, a year on Neptune is the longest of any planet, lasting the equivalent of 164.8 years (or 60,182 Earth days). But since Neptune also takes comparatively little time to rotate once on its axis (16 hours, 6 minutes and 36 seconds), a single year lasts a staggering 89,666 Neptunian days. Reconstruction of Voyager 2 images showing the Great Black spot (top left), Scooter (middle), and the Small Black Spot (lower right). Credit: NASA/JPL What’s more, with an axial tilt close to Earth and Mars’ (28.5 degrees), there is some seasonal variation on the planet. Essentially, a single season lasts more than 40 years. But like all gas/ice giants, this does not result in noticeable temperature variations. What planet has the longest year?

| Reference.com What planet has the longest year? A: Quick Answer As the furthest orbiting planet in the Solar System, Neptune has the longest year, taking 164.8 Earth years to complete a single orbit of the Sun. Prior to its reclassification as a dwarf planet in 2006, Pluto was the planet with the longest year, equal to about 248 Earth years. Full Answer University Today explains that the length of a year increases in relation to distance from the Sun. The closest planet to the Sun, Mercury, has the shortest year, equivalent to 88 Earth days. A year on Venus equals 224.7 Earth days, and a year on Mars equals 687 Earth days. Jupiter's year equals 11.9 Earth years, Saturn's equals 29.7 Earth years, and Uranus' equals 84.3 Earth years. What planet has the longest period of revolution? | Socratic What planet has the longest period of revolution? Start with a one sentence answer Then teach the underlying concepts Don't copy without citing sources Write a one sentence answer...

Answer: I want someone to double check my answer Describe your changes (optional) 200 Cancel Dr. $ Share Oct 1, 2015 The planet in our solar system that has the longest period of revolution is Neptune. A Neptunian year is around 164.8 Earth years. Was this helpful? Let the contributor know! Yes Planets - Zoom Astronomy Your age on the Planets The Planets (plus the Dwarf Planet Pluto) Our solar system consists of the sun, eight planets, moons, many dwarf planets (or plutoids), an asteroid belt, comets, meteors, and others. The sun is the center of our solar system ; the planets, their moons, a belt of asteroids , comets , and other rocks and gas orbit the sun. The eight planets that orbit the sun are (in order from the sun): Mercury , Venus , Earth , Mars , Jupiter , Saturn , Uranus , Neptune . Another large body is Pluto , now classified as a dwarf planet or plutoid. A belt of asteroids (minor planets made of rock and metal) lies between Mars and Jupiter.

These objects all orbit the sun in roughly circular orbits that lie in the same plane, the ecliptic (Pluto is an exception; it has an elliptical orbit tilted over 17° from the ecliptic). Easy ways to remember the order of the planets (plus Pluto) are the mnemonics: "My Very Excellent Mother Just Sent Us Nine Pizzas" and "My Very Easy Method Just Simplifies Us Naming Planets" The first letter of each of these words represents a planet - in the correct order. The largest planet is Jupiter. It is followed by Saturn, Uranus, Neptune, Earth, Venus, Mars, Mercury, and finally, tiny Pluto (the largest of the dwarf planets). Jupiter is so big that all the other planets could fit inside it. The Inner Planets vs. the Outer Planets The inner planets (those planets that orbit close to the sun) are quite different from the outer planets (those planets that orbit far from the sun). The inner planets are: Mercury, Venus, Earth, and Mars. They are relatively small, composed mostly of rock, and have few or no moons. The outer planets include: Jupiter, Saturn, Uranus, Neptune, and Pluto (a dwarf planet).

They are mostly huge, mostly gaseous, ringed, and have many moons (again, the exception is Pluto, the dwarf planet, which is small, rocky, and has four moons). Temperatures on the Planets Generally, the farther from the Sun, the cooler the planet. Differences occur when the greenhouse effect warms a planet (like Venus) surrounded by a thick atmosphere. Density of the Planets The outer, gaseous planets are much less dense than the inner, rocky planets. The Earth is the densest planet. Saturn is the least dense planet; it would float on water. The Mass of the Planets Jupiter is by far the most massive planet; Saturn trails it. Uranus, Neptune, Earth, Venus, Mars, and Pluto are orders of magnitude less massive. Gravitational Forces on the Planets The planet with the strongest gravitational attraction at its surface is Jupiter. Although Saturn, Uranus, and Neptune are also very massive planets, their gravitational forces are about the same as Earth. This is because the gravitational force a planet exerts upon an object at the planet's surface is proportional to its mass and to the inverse of the planet's radius squared.

A Day on Each of the Planets A day is the length of time that it takes a planet to rotate on its axis (360°). A day on Earth takes almost 24 hours. The planet with the longest day is Venus ; a day on Venus takes 243 Earth days. (A day on Venus is longer than its year; a year on Venus takes only 224.7 Earth days). The planet with the shortest day is Jupiter ; a day on Jupiter only takes 9.8 Earth hours! When you observe Jupiter from Earth, you can see some of its features change. The Average Orbital Speed of the Planets As the planets orbit the Sun , they travel at different speeds. Each planet speeds up when it is nearer the Sun and travels more slowly when it is far from the Sun (this is Kepler's Second Law of Planetary Motion ). The Planets in Our Solar System Planet (or Dwarf Planet) In 2005, a large object beyond Pluto was observed in the Kuiper belt. A few astronomers think that there might be another planet or companion star orbiting the Sun far beyond the orbit of Pluto. This distant planet/companion star may or may not exist.

The hypothesized origin of this hypothetical object is that a celestial object, perhaps a hard-to-detect cool, brown dwarf star (called Nemesis ), was captured by the Sun's gravitational field. This planet is hypothesized to exist because of the unexplained clumping of some long-period comet's orbits. The orbits of these far-reaching comets seem to be affected by the gravitational pull of a distant, Sun-orbiting object. Planet Activities and Quizzes Neptune Neptune Neptune Planet Neptune Neptune, the farthest planet in our Solar System (sorry, Pluto is not designated as a planet any more), has the longest year of all the planets. One orbit around the Sun takes almost 165 Earth years instead of just one year here on Earth. Like Uranus, Neptune shines so blue due to traces of methane in the topmost layer of its atmosphere. Methane molecules absorb the red part and reflect the blue frequencies of the sunlight. Whilst the surface of neighbouring Uranus is nearly featureless, Neptune has many observable surface features caused by an active weather system. During the Voyager 2 flyby in 1989 the Great Dark Spot - a storm system like the Great Red Spot on Jupiter - was observed.

Neptune is the absolute record holder when it comes to storms, and wind speeds can reach up to 2100 km/h (1300 mph), almost reaching supersonic speeds. Under these conditions the ‘moderate' wind speeds of the most extreme tornado measured here on Earth (480 km/h) would feel like a light breeze. The internal structure of Neptune is a bit different from those of the other gas giants: an atmosphere of gas (mainly hydrogen, helium and methane) overlays a huge ocean of liquid water and ammonia. This ocean makes up most of the mass of the planet. Like the other gas giants Neptune is also believed to have a solid core made of iron, nickel and silicates (rock). The conditions in the centre of Neptune are quite extreme: a pressure of 7 million bar causes temperatures to rise above 5000 K, which is still much lower than the 40 million bar and 36000 K inside the super-massive planet Jupiter. Like all the other gas giants, Neptune has a ring system, but it's so faint that it hadn't been definitely confirmed before 1989 when Voyager 2 had its flyby.

Name How Long Is A Day On The Other Planets Of The Solar System? - Universe Today Universe Today How Long Is A Day On The Other Planets Of The Solar System? Article Updated: 24 Jan , 2016 by Matt Williams Here on Earth, we tend to take time for granted, never suspected that the increments with which we measure it are actually quite relative. The ways in which we measure our days and years, for example, are actually the result of our planet’s distance from the Sun, the time it takes to orbit, and the time it takes to rotate on its axis. The same is true for the other planets in our Solar System. While we Earthlings count on a day being about 24 hours from sunup to sunup, the length of a single day on another planet is quite different. In some cases, they are very short, while in others, they can last longer than years – sometimes considerably! Let’s go over how time works on other planets and see just how long their days can be, shall we?

A Day On Mercury: Mercury is the closest planet to our Sun, ranging from 46,001,200 km at perihelion (closest to the Sun) to 69,816,900 km at aphelion (farthest). Since it takes 58.646 Earth days for Mercury to rotate once on its axis – aka. its sidereal rotation period – this means that it takes just over 58 Earth days for Mercury to experience a single day. However, this is not to say that Mercury experiences two sunrises in just over 58 days. Due to its proximity to the Sun and rapid speed with which it circles it, it takes the equivalent of 175.97 Earth days for the Sun to reappear in the same place in the sky. Hence, while the planet rotates once every 58 Earth days, it is roughly 176 days from one sunrise to the next on Mercury. Images of Mercury’s northern polar region, provided by MESSENGER. Credit: NASA/JPL What’s more, it only takes Mercury 87.969 Earth days to complete a single orbit of the Sun (aka.

its orbital period). This means a year on Mercury is the equivalent of about 88 Earth days, which in turn means that a single Mercurian (or Hermian) year lasts just half as long as a Mercurian day. What’s more, Mercury’s northern polar regions are constantly in the shade. This is due to it’s axis being tilted at a mere 0.034° (compared to Earth’s 23.4°), which means that it does not experience extreme seasonal variations where days and nights can last for months depending on the season. On the poles of Mercury, it is always dark and shady. So you could say the poles are in a constant state of twilight. A Day On Venus: Also known as “Earth’s Twin”, Venus is the second closest planet to our Sun – ranging from 107,477,000 km at perihelion to 108,939,000 km at aphelion. Unfortunately, Venus is also the slowest moving planet, a fact which is made evident by looking at its poles.

Whereas every other planet in the Solar System has experienced flattening at their poles due to the speed of their spin, Venus has experienced no such flattening. Venus has a rotational velocity of just 6.5 km/h (4.0 mph) – compared to Earth’s rational velocity of 1,670 km/h (1,040 mph) – which leads to a sidereal rotation period of 243.025 days. Technically, it is -243.025 days, since Venus’ rotation is retrograde. This means that Venus. rotates in the direction opposite to its orbital path around the Sun. The planet Venus, as imagined by the Magellan 10 mission. Credit: NASA/JPL So if you were above Venus’ north pole and watched it circle around the Sun, you would see it is moving clockwise, whereas its rotation is counter-clockwise. Nevertheless, this still means that Venus takes over 243 Earth days to rotate once on its axis, which means that many, many days pass between one sunrise and the next.

This may seem odd, until you consider that a single Venusian (or Cytherean) year works out to 224.701 Earth days. Yes, Venus takes a little more than 224 days to complete a single orbital period, but over 243 days to experience a single day and night cycle. So basically, a single Venusian day is longer than a Venusian year! Good thing Venus has other things in common With Earth, because it is sure isn’t its diurnal cycle! A Day On Earth: When we think of a day on Earth, we tend to think of it as a simple 24 hour interval. In truth, it takes the Earth exactly 23 hours 56 minutes and 4.1 seconds to rotate once on its axis. Meanwhile, on average, a solar day on Earth is 24 hours long, which means it takes that amount of time for the Sun to appear in the same place in the sky. Between these two values, we say a single day and night cycle lasts an even 24. At the same time, there are variations in the length of a single day on the planet based on seasonal cycles.

Due to Earth’s axial tilt, the amount of sunlight experienced in certain hemispheres will vary. The most extreme case of this occurs at the poles, where day and night can last for days or months depending on the season. At the North and South Poles during the winter, a single night can last up to six months, which is known as a “polar night”. During the summer, the poles will experience what is called a “midnight sun”, where a day lasts a full 24 hours. So really, days are not as simple as we like to imagine. But compared to the other planets in the Solar System, time management is still easier here on Earth. A Day On Mars: In many respects, Mars can also be called “Earth’s Twin”. In addition to having polar ice caps, seasonal variations , and water (albeit frozen) on its surface, a day on Mars is pretty close to what a day on Earth is. Essentially, Mars takes 24 hours 37 minutes and 22 seconds to complete a single rotation on its axis. This means that a day on Mars is equivalent to 1.025957 days.

The seasonal cycles on Mars, which are due to it having an axial tilt similar to Earth’s (25.19° compared to Earth’s 23.4°), are more similar to those we experience on Earth than on any other planet. As a result, Martian days experience similar variations, with the Sun rising sooner and setting later in the summer and then experiencing the reverse in the winter. However, seasonal variations last twice as long on Mars, thanks to Mars’ being at a greater distance from the Sun. This leads to the Martian year being about two Earth years long – 686.971 Earth days to be exact, which works out to 668.5991 Martian days (or Sols). As a result, longer days and longer nights can be expected last much longer on the Red Planet. Something for future colonists to consider! Sunrise at Gale Crater on Mars. Gale is at center top with the mound in the middle, called Mt. Sharp (Aeolis Mons.) A Day On Jupiter: Given the fact that it is the largest planet in the Solar System, one would expect that a day on Jupiter would last a long time.

But as it turns out, a Jovian day is officially only 9 hours, 55 minutes and 30 seconds long, which means a single day is less than a third the length of an Earth day. This is due to the gas giant having a very rapid rotational speed, which is 12.6 km/s (45,300 km/h, or 28148.115 mph) at the equator. This rapid rotational speed is also one of the reasons the planet has such violent storms. Note the use of the word officially. Since Jupiter is not a solid body, its upper atmosphere undergoes a different rate of rotation compared to its equator. Basically, the rotation of Jupiter’s polar atmosphere is about 5 minutes longer than that of the equatorial atmosphere. Because of this, astronomers use three systems as frames of reference. System I applies from the latitudes 10° N to 10° S, where its rotational period is the planet’s shortest, at 9 hours, 50 minutes, and 30 seconds.

System II applies at all latitudes north and south of these; its period is 9 hours, 55 minutes, and 40.6 seconds. System III corresponds to the rotation of the planet’s magnetosphere, and it’s period is used by the IAU and IAG to define Jupiter’s official rotation (i.e. 9 hours 44 minutes and 30 seconds) Jupiter and Io capturing the Sun. Image Credit: NASA/JPL So if you could, theoretically, stand on the cloud tops of Jupiter (or possibly on a floating platform in geosynchronous orbit), you would witness the sun rising an setting in the space of less than 10 hours from any latitude. And in the space of a single Jovian year, the sun would rise and set a total of about 10,476 times. A Day On Saturn: Saturn’s situation is very similar to that of Jupiter’s. Despite its massive size, the planet has an estimated rotational velocity of 9.87 km/s (35,500 km/h, or 22058.677 mph).

As such Saturn takes about 10 hours and 33 minutes to complete a single sidereal rotation, making a single day on Saturn less than half of what it is here on Earth. Here too, this rapid movement of the atmosphere leads to some super storms , not to mention the hexagonal pattern around the planet’s north pole and a vortex storm around its south pole. And, also like Jupiter, Saturn takes its time orbiting the Sun. With an orbital period that is the equivalent of 10,759.22 Earth days (or 29.4571 Earth years), a single Saturnian (or Cronian) year lasts roughly 24,491 Saturnian days. However, like Jupiter, Saturn’s atmosphere rotates at different speed depending on latitude, which requires that astronomers use three systems with different frames of reference. System I encompasses the Equatorial Zone, the South Equatorial Belt and the North Equatorial Belt, and has a period of 10 hours and 14 minutes. System II covers all other Saturnian latitudes, excluding the north and south poles, and have been assigned a rotation period of 10 hr 38 min 25.4 sec.

System III uses radio emissions to measure Saturn’s internal rotation rate, which yielded a rotation period of 10 hr 39 min 22.4 sec. This portrait looking down on Saturn and its rings was created from images obtained by NASA’s Cassini spacecraft on Oct. 10, 2013. Credit: NASA/JPL-Caltech/Space Science Institute/G. Ugarkovic Using these various systems, scientists have obtained different data from Saturn over the years. For instance, data obtained during the 1980’s by the Voyager 1 and 2 missions indicated that a day on Saturn was 10 hours 39 minutes and 24 seconds long. In 2004, data provided by the Cassini-Huygens space probe measured the planet’s gravitational field, which yielded an estimate of 10 hours, 45 minutes, and 45 seconds (± 36 sec). In 2007, this was revised by researches at the Department of Earth, Planetary, and Space Sciences, UCLA, which resulted in the current estimate of 10 hours and 33 minutes.

Much like with Jupiter, the problem of obtaining accurate measurements arises from the fact that, as a gas giant, parts of Saturn rotate faster than others. A Day On Uranus: When we come to Uranus, the question of how long a day is becomes a bit complicated. One the one hand, the planet has a sidereal rotation period of 17 hours 14 minutes and 24 seconds, which is the equivalent of 0.71833 Earth days. So you could say a day on Uranus lasts almost as long as a day on Earth. It would be true, were it not for the extreme axial tilt this gas/ice giant has going on. With an axial tilt of 97.77°, Uranus essentially orbits the Sun on its side. This means that either its north or south pole is pointed almost directly at the Sun at different times in its orbital period. When one pole is going through “summer” on Uranus, it will experience 42 years of continuous sunlight. When that same pole is pointed away from the Sun (i.e. a Uranian “winter”), it will experience 42 years of continuous darkness. Uranus as seen by NASA’s Voyager 2.

Credit: NASA/JPL Hence, you might say that a single day – from one sunrise to the next – lasts a full 84 years on Uranus! In other words, a single Uranian day is the same amount of time as a single Uranian year (84.0205 Earth years). In addition, as with the other gas/ice giants, Uranus rotates faster at certain latitudes. Ergo, while the planet’s rotation is 17 hours and 14.5 minutes at the equator, at about 60° south, visible features of the atmosphere move much faster, making a full rotation in as little as 14 hours. A Day On Neptune: Last, but not least, we have Neptune. Here too, measuring a single day is somewhat complicated. For instance, Neptune’s sidereal rotation period is roughly 16 hours, 6 minutes and 36 seconds (the equivalent of 0.6713 Earth days). But due to it being a gas/ice giant, the poles of the planet rotate faster than the equator.

Whereas the planet’s magnetic field has a rotational speed of 16.1 hours, the wide equatorial zone rotates with a period of about 18 hour. Meanwhile, the polar regions rotate the fastest, at a period of 12 hours. This differential rotation is the most pronounced of any planet in the Solar System, and it results in strong latitudinal wind shear. Reconstruction of Voyager 2 images showing the Great Black spot (top left), Scooter (middle), and the Small Black Spot (lower right). Credit: NASA/JPL In addition, the planet’s axial tilt of 28.32° results in seasonal variations that are similar to those on Earth and Mars. The long orbital period of Neptune means that the seasons last for forty Earth years. But because its axial tilt is comparable to Earth’s, the variation in the length of its day over the course of its long year is not any more extreme. As you can see from this little rundown of the different planets in our Solar System, what constitutes a day depends entirely on your frame of reference. In addition to it varying depending on the planet in question, you also have to take into account seasonal cycles and where on the planet the measurements are being taken from.

As Einstein summarized, time is relative to the observer. Based on your inertial reference frame, its passage will differ. And when you are standing on a planet other than Earth, your concept of day and night, which is set to Earth time (and a specific time zone) is likely to get pretty confused! We have written many interesting articles about how time is measured on other planets here at Universe Today. For example, here’s How Long Is A Year On The Other Planets? , Which Planet Has the Longest Day? , The Rotation of Venus , How Long Is A Day on Mars? and How Long Is A Day On Jupiter? . If you are looking for more information, check out Our Solar System at Space.com Astronomy Cast has episodes on all the planets, including Episode 49: Mercury , and Episode 95: Humans to Mars, Part 2 – Colonists Share this: “Since it takes 58.646 Earth days for Mercury to rotate once on its axis – aka. its sidereal rotation period – this means that it takes just over 58 Earth days for Mercury to experience a single sunrise and sunset.” Sorry, Matt, but this is precisely incorrect, and I stopped reading at this point.

1) Sideral = stars; solar = Sol/The Sun. Mercury’s sidereal day/rotation period is indeed 58.646 Earth days. This means that it takes 58.646 Earth days for background stars (NOT the Sun) to rise, set, and then rise again. 2) “Days” are measured from sunrise to sunrise, not sunrise to sunset as you’ve indicated; if you think about the 24hrs of a Terran solar day you will see instantly that this is true. 3) Mercury’s solar day is heavily influenced by the Mercury’s speedy orbit around the sun; while Mercury rotates, it also revolves, leading to a Nabooan solar day of ~176 Earth days. This same effect of rotation + revolution is why sidereal and solar days are different in the first place — Earth’s solar day is ~24hrs, while its sidereal day is ~4min shorter — and is why the stars visible in our night sky locally change from season to season.

4) Finally, the effect of revolution + Mercury’s noticeably elliptical orbit + rotation leads to some bizarre timing when it comes local sunrise, sunset, noon, and midnight in various places on the planet as well. In some places, one ends up with Sol crossing overhead three separate times between local sunrise & sunset; in others “Sunrise” is spread out over weeks (Earth reckoning) as Sol rises above the horizon, then sets completely, then rises again to cross the sky, only to perform the same dance in reverse upon “Sunset” (set, rise again, set again). Thought we maybe discussed this once before, somewhere…. What does Neptune look like? | Reference.com What does Neptune look like? A: Quick Answer Neptune is an ice giant planet that is blue in color and is the fourth-largest planet in the Solar System. When looking at Neptune with smaller detail, an observer will see the planet's blueness as largely smooth and uniform. When looking with more detail, however, the striations on the planet's surface that are caused by storms in Neptune's atmosphere are more apparent.

Full Answer While many planets in the Solar System have variations of color and texture on their surfaces, Neptune looks a lot like a smooth blue marble, though some images, such as those from NASA's Voyager spacecraft, show that the planet's blue surface is marked by white and light blue cloud systems, creating round, striped shapes. In addition to being defined by its blueness, Neptune also has a few characteristic physical features, including what NASA refers to as the Great Dark Spot, which is a storm that creates a darker blue-gray spot on the planet's surface. Neptune does have rings, but those rings are not typically visible because they're so small. This eighth planet from the Sun also has 13 known moons that accompany it in its orbit. Sometimes described as Uranus' twin, Neptune is the furthest planet from the Sun. It secured this spot after Pluto was reclassified as a dwarf planet in 2006. Interplanetary Seasons | Science Mission Directorate Science Mission Directorate Jun 19, 2000 Interplanetary Seasons Every planet in the solar system has seasons. Most have four like the Earth -- called Winter, Spring, Summer and Fall -- but that's where the similarities end.

Extraterrestrial seasons are hardly noticeable on some planets (Venus), mindbogglingly extreme on others (Uranus) and in some cases simply impossible to define (Mercury). The table below gives the dates of the seasons for 8 of the 9 planets in the solar system. Only Pluto is missing. It's so far away that we don't know much about seasons on that distant world. In the table the equinoxes and solstices are named after the corresponding season in the northern hemisphere. This is the convention that astronomers often use to discuss planetary seasons. When the north pole of a planet is tilted toward the sun, astronomers call it the Summer Solstice; when the south pole is tilted toward the sun it is called the Winter Solstice. Nevertheless, the seasons are always opposite in the two hemispheres. On Earth, for example, when it is summer in New York, it is winter in Sydney. On a spring day in Paris, autumn leaves are falling in Argentina, and so on... When the Vernal Equinox takes place on March 20, Earth will join Venus and Jupiter as the only planets in the solar system where it is now northern Spring.

Seasons on Other Planets 2003 (Table note: seasonal names refer to the northern hemisphere of each planet.) Planetary seasons are caused by two factors: axial tilt and variable distance from the sun (orbital eccentricity). Earth's orbit is nearly circular and so has little effect on climate. It's our planet's axial tilt that causes almost all seasonal changes. When the north pole is tilted toward the Sun, it's northern summer. Six months later the north pole tilts away from the Sun and we experience northern winter. The other two planets where it is northern spring, Jupiter and Venus, have very small axial tilts -- just 3 degrees compared to Earth's 23.5 degree tilt. Seasonal changes on those planets are correspondingly small. Spring on Venus isn't much different from autumn. The planet's dense, acidic atmosphere produces a runaway greenhouse effect that keeps the surface at 750 K year-round -- that's hot enough to melt lead. Spring fever on Venus is really hot! Our second-nearest planetary neighbor Mars has the highest orbital eccentricity of any world except Pluto. Its distance from the Sun varies between 1.64 and 1.36 AU over the Martian year.

This large variation, combined with an axial tilt greater than Earth's gives rise to seasonal changes far greater than we experience even in Antarctica. Right: Over the past six months, the southern hemisphere of Mars has passed through spring and into summer. Spring started in early August 1999 and summer arrived toward the end of December 1999. Mars Global Surveyor is in a polar orbit, thus the spacecraft's camera has had an excellent view of seasonal changes. Shown here are three views of the same portion the layered terrain near the Martian south pole. They show how the landscape thaws and defrosts as summer approaches. [ more information ] From the point of view of an Earth-dweller, one of the strangest effects of seasons on Mars is the change in atmospheric pressure. During winter the global atmospheric pressure on Mars is 25% lower than during summer. This happens because of the eccentricity of Mars's orbit and a complex exchange of carbon dioxide between Mars's dry-ice polar caps and its CO2 atmosphere. Around the summer solstice when the Martian north pole is tilted away from the sun, the northern polar cap expands as carbon dioxide in the polar atmosphere freezes.

At the other end of the planet the southern polar cap melts, giving CO2 back to the atmosphere. This process reverses half a year later at the winter solstice. At first it might seem that these events occurring at opposite ends of Mars would simply balance out over the course of the Martian year, having no net effect on climate. But they don't. That's because Mars is 10% closer to the Sun in winter than it is in summer. At the time of the winter solstice the northern polar cap absorbs more CO2 than the southern polar cap absorbs half a year later. The difference is so great that Mars's atmosphere is noticeably thinner during winter. Seasons on Mars vs. Seasons on Earth Season Length of Season on Earth (Earth Days) Length of Season on Mars (Martian Days) 89 154 Above: The orbit of Mars is very eccentric, unlike Earth's which is more nearly circular. Its orbital motion is slowest when it is at aphelion (the farthest point from the Sun) and fastest at perihelion (the closest point to the Sun). This effect, combined with the planet's axial tilt, makes Martian seasons vary in duration more than those on Earth.

The length of the seasons in this table are give in Earth days and Martian days. The two are almost exactly the same duration. An Earth day is 24 hours long, a Martian day is 24.6 hours long. [ more information ] Martian seasons are peculiar by Earth standards, but they probably pale in comparison to seasons on Uranus. Like Earth, the orbit of Uranus is nearly circular so it keeps the same distance from the Sun throughout its long year. But, Uranus's spin axis is tilted by a whopping 82 degrees! This gives rise to extreme 20-year-long seasons and unusual weather. For nearly a quarter of the Uranian year (equal to 84 Earth years), the sun shines directly over each pole, leaving the other half of the planet plunged into a long, dark, frigid winter. Left: A dramatic time-lapse movie by NASA's Hubble Space Telescope shows seasonal changes on Uranus. Once considered one of the blander-looking planets, Uranus is now revealed as a dynamic world with the brightest clouds in the outer Solar System. more info . The Northern Hemisphere of Uranus is just now coming out of the grip of its decades-long winter.

As the sunlight reaches some latitudes for the first time in years, it warms the atmosphere and triggers gigantic springtime storms comparable in size to North America with temperatures of 300 degrees below zero. In the animation pictured left the bright clouds are probably made of crystals of methane, which condense as warm bubbles of gas well up from deep in the atmosphere of Uranus. Uranus does not have a solid surface, but is instead a ball of mostly hydrogen and helium. Absorption of red light by methane in the atmosphere gives the planet its cyan color. Uranus was discovered March 13, 1781, by William Herschel. Early visual observers reported Jupiter-like cloud belts on the planet, but when NASA's Voyager 2 flew by in 1986, Uranus appeared as featureless as a cue ball. In the past 13 years, the planet has moved far enough along its orbit for the sun to shine at mid-latitudes in the Northern Hemisphere. By the year 2007, the sun will be shining directly over Uranus' equator. Parents and Educators: Please visit Thursday's Classroom for lesson plans and activities related to this story.

Mercury's seasons -- if they can be called that -- are also remarkable. Until the 1960's it was thought that Mercury's "day" was the same length as its "year" keeping the same face to the Sun much as the Moon does to the Earth. This was shown to be incorrect by Doppler radar observations. We now known that Mercury rotates three times during two of its years. Mercury is the only body in the solar system tidally locked into an orbital-to-rotational resonance with a ratio other than 1:1. This fact and the high eccentricity of Mercury's orbit would produce very strange effects for an observer on Mercury's surface. [ ref ] At some longitudes the observer would see the Sun rise and then gradually increase in apparent size as it slowly moved toward the zenith. At that point the Sun would stop, briefly reverse course, and stop again before resuming its path toward the horizon and decreasing in apparent size. All the while the stars would be moving three times faster across the sky. Observers at other points on Mercury's surface would see different but equally bizarre motions.

Temperature variations on Mercury are the most extreme in the solar system ranging from 90 K at night to 700 K during the day. Web Links

Question: Which planet in our solar has the longest year, equal to 164 Earth years?
Answer: Neptune