Weight on Other Planets

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Many children, and even adults, dream of visiting other planets and wonder what it would be like to stand on another planet. For one thing, your weight would be different on another planet, depending on a number of factors including the mass of the planet and how far you are away from the center of the planet.

Before we start, it’s important to understand that the kilogram is actually a measurement of your mass. And your mass doesn’t change when you go anywhere in the Universe and experience different amounts of gravity. Your weight is best measured in newtons. But since your bathroom doesn’t measure your weight in newtons, we’ll use kilograms. This is what your bathroom scale would say if you stepped on another world.

Mercury is the smallest planet in our Solar System, but it is dense. Because Mercury is so small, it has very little gravity. If you weighed 68 kg on Earth, you would only weigh 25.7 kg on Mercury. 

Venus is very close to Earth in size and mass. Venus’ mass is roughly 90% of the mass of the Earth. Thus, it is no surprise that someone would weigh a similar amount on Venus. Someone who weighed 68 kg on Earth would weigh 61.6 kg on Venus.

Mars is quite a bit smaller than Earth with only 11% of our planet’s mass. Mars is larger than Mercury, but it is not as dense as the smaller planet. If you weighed 68 kg on Earth then you would weigh 25.6 kg on Mars. Since Pluto was demoted to a dwarf planet, Mars became the planet where you would weigh the least.

Jupiter is the largest planet in our Solar System with the most mass. Because of Jupiter’s mass, you would weigh more on that planet than on any other one in our Solar System. If you weighed 68 kg on Earth then you would weigh 160.7 kg on Jupiter, over twice your normal weight. That is if you could actually stand on Jupiter’s surface, which is impossible because it is a gas giant, and gas giants do not have solid surfaces.

Saturn is a gas giant best known for its planetary rings system. It is also the second biggest planet in our Solar System. Despite its mass though, the planet has a very low density and a lower gravity than Earth. If you weighed 68 kg on Earth, you would weigh 72.3 kg on Saturn.

Uranus is a gas giant without a solid surface. Although Uranus is larger in size than Neptune, it has less mass and therefore less gravity. You would only weigh 60.4 kg on Uranus, if you weighed 68 kg on Earth.

Neptune, the last planet in our Solar System, is a gas giant. If you weighed 68 kg on Earth, then you would weigh 76.5 kg on Neptune if you could stand on the planet’s surface.

Although the Moon is not a planet, it is one of the few objects that astronauts have actually visited. Because the Moon is so small, it has a low density and low gravity. If you weighed 68 kg on Earth, then you would only weigh 11.2 kg on the Moon.

Universe Today has a number of articles to check out including weight on the moon and mass of the planets.

If you are looking for more information then determine your weight on other planets and facts about the planets.

Astronomy Cast has an episode on gravity.

Discovery of the Planets

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We actually only know the exact date of when a few of the planets were discovered. Five of the planets, not including Earth, have been known to exist for thousands of years  – Mercury, Mars, Venus, Jupiter, and Saturn. The Ancient Greeks and Romans wrote about the planets many centuries ago. Because the planets look like stars to the naked eye, that is where the term planets comes from. Because the planets move in the sky, they were termed wandering stars. The term planet comes from the Greek word for wanderer, “planetes.” Many ancient people thought that the planets were gods, so they gave them the names of their gods. All of the planets, except Earth have names of Roman deities.

The other three planets – Uranus, Neptune, and Pluto – were not discovered until at least the 1700’s. Pluto is no longer a planet since it was reclassified as a dwarf planet in 2006. It was known as the ninth planet for 70 years though, so its discovery will be included here. Uranus was discovered in 1781 by the famous astronomer Sir William Herschel, although that was not the first sighting of it. The planet had been sighted as early as 1690 by the English astronomer John Flamsteed. It was also sighted by Pierre Lemonier in the mid 1700’s. Sir Herschel at first thought that Uranus was a comet, but he noticed the irregularities early on and compared it to a planet in his notes.

Because Neptune cannot be seen without the help of a telescope, it was not discovered until after 1610, when Galileo created the telescope. Alexis Bouvard, a mathematician, saw that another planet had to be affecting Uranus’ orbit, so astronomers started looking for it. Two astronomers, John Couch Adams and Urbain Le Verrier, discovered Neptune independently or rather made the calculations and determined where Neptune could be found. The planet turned out to be 1° from Verrier’s calculations and 12° from Adams’. There was a dispute between France and England over who discovered the new planet because Adams and Verrier are from England and France respectively.

Pluto was the last planet discovered, although that distinction returned to Neptune when Pluto was reclassified as a dwarf planet. Pluto was discovered in 1930 by the astronomer Clyde Tombaugh. Many people had been searching for a ninth planet – the elusive planet X – for quite a while. Since Pluto was discovered near the calculated location of planet X, they thought the two planets were one and the same. Later, astronomers realized that there was no such planet X.

Universe Today has a number of articles on the planets including who discovered Neptune and the planets of our Solar System.

Check out these other articles including mathematical discovery of the planets and the planets.

Astronomy Cast has episodes on all of the planets including Mercury.

Names of the Planets

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You may recognize the names of the planets from your high school literature course or a history class. That is because many of the planets were first discovered by ancient civilizations, and so planets are named after their gods.

The Romans named Mercury after the messenger of the gods because it appears to move so quickly.

Venus was named after the Roman goddess of love because of its shining presence. The planet is the brightest object in the sky beside the Moon and the Sun. A number of other cultures also named Venus after their own gods or goddesses of love and war.

Earth is the only planet not named after a god. The name is based on Germanic and Old English words for “ground.”

Mars was named after the Roman god of war because of its red color, which reminded people of blood. Other civilizations also had names for the planet based on its color. The Egyptians called it “Her Desher,” which means “the red one.”

Jupiter was named after the king of the gods – Zeus by the Greeks and Jupiter by the Romans. Ancient civilizations most likely named this planet after the most powerful god because of its size. Jupiter is the largest and most massive planet in our Solar System.

Saturn was named after the father of the king of gods as well as being the god of agriculture and harvest. In mythology, Saturn had taken the position of king of the gods from his own father, Uranus, and then Jupiter overthrew him. Saturn is the last planet that can be seen from Earth without the aid of a telescope.

Uranus was not discovered until 1781 by Sir William Herschel, so it was not necessarily going to be named after a Roman god. In fact, Herschel named the planet “Georgium Sidus” in honor of George III who was King of England at the time. Others called the planet Herschel in honor of the astronomer who had discovered it. The name Uranus, which is the name of the Roman god who is the father of Jupiter, was suggested by the astronomer Johann Bode. That name was widely accepted in the mid 1800’s, and it fit in with the other planets, which all had names from mythology.

Neptune had been observed by a number of astronomers, but they believed it was a star. Two people, John Couch Adams and Urban Le Verrier, calculated the planet’s location. Johann Galle, the astronomer who discovered the planet using Verrier’s calculations, wanted to name the planet after Verrier. Many astronomers objected though, so it was named after Neptune the Roman god of the sea. The name was very fitting because the planet is a bright sea blue.

Universe Today has a number of articles on the planets including facts about the planets and the planets of the solar system.

If you are looking for more information on the planets take a look at the planets and interesting facts about the planets.

Astronomy Cast has episodes on all of the planets, so start with Mercury.

What are The Outer Planets of the Solar System?

Astronomers have divided the eight planets of our solar system into the inner planets and the outer planets. The 4 inner planets are the closest to the Sun, and the outer planets are the other four – Jupiter, Saturn, Uranus, and Neptune. The outer planets are also called the Jovian planets or gas giants. Like the inner planets, the outer planets have similar characteristics to one another.

The outer planets are so much larger than the inner planets that they make up 99 percent of the mass of the celestial bodies that orbit the Sun. Although mainly composed of gas, the outer planets also have other ingredients. Somewhere at the center is what scientist refer to as a rocky core, although it is actually composed of liquid heavy metals. While the inner planets have few or no moons, the outer planets have dozens each. The inner and outer planets are separated by the asteroid belt.

Jupiter is the largest planet in our Solar System with a mass more than three hundred times Earth’s mass. Jupiter is not only the largest planet, it also has the most moons – 63 identified so far. Jupiter is one of the brightest objects in the sky and has a very stormy atmosphere. One major storm, the Great Red Spot, is as big as the Earth.

Saturn is hard to miss with its distinctive, large rings. Although all of the outer planets have rings, Saturn’s are the most visible ones. Astronomers did not know that there any other planets with rings until 1977 when Uranus’ rings were discovered. Soon after that, astronomers discovered rings around both Jupiter and Neptune.

Uranus has the smallest mass of the outer planets, although in size it’s a little bigger than Uranus. It is the only planet to rotate on its side. Scientists are unsure why it rotates that way, although there are a couple theories. One suggests it suffered a major collision and another hypothesizes that smaller shifts during the planets’ formation caused its unusual rotation.

Neptune is the final outer planet in the solar system. Neptune’s winds are the fastest of any planets in the Solar System and can reach more than 1,200 miles per hour. While all of the outer planets’ atmospheres contain hydrogen and helium, Neptune and Uranus contain significant amounts of what astronomers call ices. These ices include water, ammonia, and methane. The methane in Neptune and Uranus is what gives the planets their blue color.

Check out these other articles from Universe Today on the outer solar system and the inner solar system.

If you are searching for more information, NASA has many articles, including one on the planets and Science Daily is also a rich resource for information on the outer planets.

Astronomy Cast has a number of episodes on the Jovian planets including this one on Jupiter.

Ten Interesting Facts About Uranus

The gas (and ice) giant known as Uranus is a fascinating place. The seventh planet from out Sun, Uranus is the third-largest in terms of size, the fourth-largest in terms of mass, and one of the least dense objects in our Solar System. And interestingly enough, it is the only planet in the Solar System that takes it name from Greek (rather than Roman) mythology.

But these basic facts really only begin to scratch the surface. When you get right down to it, Uranus is chock full of interesting and surprising details – from its many moons, to its ring system, and the composition of its aqua atmosphere. Here are just ten things about this gas/ice giant, and we guarantee that at least one of them will surprise you.

Continue reading “Ten Interesting Facts About Uranus”