A STELLAR VOYAGE

How far away is the moon really? Discover 15 space facts!

Credit: NASA

Since time immemorial, humanity has been fascinated by the vastness of the sky and the mysteries that lie beyond. This fascination bore countless stories, myths, and theories aiming to explain our place in the larger universe.

In this article, we will take a tour within the boundaries of our solar system. Join us on a journey of discovery through 15 celestial objects in our cosmic neighborhood and uncover some of the captivating stories behind them.

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The leader of the pack. It's the stellar centerpiece and namesake of the solar system, and it has inspired various myths in many cultures throughout human history. The Ancient Greeks, for example, believed that the god Helios drove a fiery chariot across the sky, thus explaining the apparent motion of the Sun from east to west.

The Sun is _massive_—it contains approximately 99.85% of the mass of the entire solar system. That is 333,000 times the mass of the Earth or 1047 times the mass of Jupiter, the largest of the planets and the second most massive object in the system.

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Mercury is the closest planet to the Sun and, since Pluto was reclassified as a dwarf planet in 2006, it is also the smallest planet in the solar system. It is barely larger than Earth's natural satellite, the Moon.

Named after the Roman messenger of the gods, Mercury does a lot to earn its name: it revolves around the Sun once every 88 Earth days, completing its orbit faster than any other planet.

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Venus is often referred to as Earth's twin planet because they are very similar in size and composition. However, we wouldn't recommend it as a vacation spot: Due to its incredibly dense atmosphere, Venus' mean surface temperature is close to 876°F.

Venus is a quirky planet—alongside Uranus, they are the only two planets that rotate clockwise on their axes. From the surface, the Sun would appear to rise from the west and set on the east. In addition, Venus moves around the Sun faster than it rotates on itself. That would make a year on Venus shorter than a day.

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Humanity's cradle and home and, so far, the only planet known to support life. Slightly larger than Venus, Earth is the largest of the inner planets—the four rocky planets on this side of the asteroid belt. Beyond the belt, in the outer solar system, roam the gas and ice giants.

Curiously, Earth is the only planet whose English name does not come from the name of a Roman or Greek deity. Instead, it has Old English roots, and it simply means "the ground."

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Earth's only natural satellite, a bright and familiar face in the night sky. As culturally significant as the Sun throughout humanity's history, its influence on life on Earth is undeniable and plain for all to see.

Our Moon is the fifth largest moon in the solar system. While it's close by in astronomical terms, it's still quite far—it sits a surprising 238,855 miles away from Earth. Thirty Earth-sized planets would fit in the distance between us and our closest celestial companion.

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The fourth planet from the Sun is easily recognizable in the night sky—it shines brightly and with a distinctly red coloration. This has earned Mars its nickname, "the Red Planet," a moniker fitting for a planet named after the Roman god of war.

Mars is one of the five planets—Mercury, Venus, Mars, Jupiter, and Saturn—that are visible to the naked eye. Ancient astronomers could tell them apart because of their constant movement against the sea of stars. That's the reason why the Ancient Greeks called these celestial objects planetes, meaning "wanderer."

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Separating the inner and the outer solar system you'll find the asteroid belt. This region is brimming with relatively small objects—much smaller than planets—called asteroids. It's been estimated that about 60% of the belt's total mass is contained within its four largest objects: Ceres, Vesta, Pallas, and Hygiea.

Ceres is, by some margin, the largest object in the asteroid belt. When it was first discovered in 1801, it was announced as a new planet. However, when more and more similar objects were discovered in the region, Ceres' classification was revised to that of an asteroid, and it ultimately became a dwarf planet in 2006.

Credit: Planet Volumes

Beyond the belt we step into a realm of giants, and Jupiter is chief among them. The second most massive object in the solar system—after the Sun itself—Jupiter is so large that it contains more than twice the mass of all the other planets combined. The entire circumference of the Earth would fit snugly on top of Jupiter's iconic Great Red Spot.

Jupiter is a gas giant and its stormy atmosphere, made primarily of hydrogen and helium, has been probed by automated spacecraft since NASA's Pioneer 10 approach in 1973. Since then, NASA has kept sending missions to Jupiter's region, and upcoming missions are scheduled for the future.

Credit: Kevin Gill from Nashua, NH, United States, CC BY-SA 2.0 <https://creativecommons.org/licenses/by-sa/2.0>, via Wikimedia Commons

We'll stay in Jupiter's neighborhood for a quick stop on Europa. Alongside Io, Ganymede, and Callisto, Europa is part of a select group called the Galilean moons. They are the largest of the more than 90 known moons of Jupiter.

The four Galilean moons are named in honor of Galileo Galilei, who first spotted them in 1610 with his homemade telescope. Nowadays, if you know where to look, they can be easily spotted with nothing but a pair of binoculars.

Europa has an icy surface that could hide a vast saltwater ocean beneath. According to NASA, this might make it a promising candidate as a place capable of supporting life beyond Earth.

Credit: NASA

Saturn is not the only planet to sport rings—all of the outer giants have them. It's a natural consequence of their size. However, none of them are so spectacular.

Saturn is the farthest and dimmest planet that can be seen in the night sky with the unaided eye. As such, it's the last one that humanity has known of since ancient times. It is named after the Roman god of time and agriculture.

The rings were first observed—you might have guessed it—by Galileo Galilei in 1610, but he was unable to identify them as such: He described them as Saturn's "ears." It wasn't until 1655 that Christiaan Huygens first described them as a disc surrounding the planet.

Credit: NASA/JPL-Caltech, Public domain, via Wikimedia Commons

Saturn's largest moon is only slightly smaller than Ganymede—Jupiter's largest moon—but it's still larger than the planet Mercury. On top of that, it's the only moon known to sustain a sizable atmosphere, and its icy crust is riddled with flowing rivers. However, instead of water, the rivers and seas on Titan's surface are primarily made up of methane and ethane.

Like Europa, Titan hides its water underneath a frozen shell—a vast subsurface ocean waiting to be explored. Who knows what mysteries lie beneath?

Credit: Planet Volumes

Uranus is a planetary oddball. Besides sharing Venus' retrograde rotation, its axis is so tilted that it appears to be spinning on its side. It's a very cold and windy planet, with winds that can reach up to 560 miles per hour.

Uranus and Neptune are classified as ice giants. Their size and composition differ vastly from that of Jupiter and Saturn, the gas giants. They are sizeably smaller, and they have much higher concentrations of water, ammonia, and methane. Astrophysicists call these substances _ices_—hence the name.

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We're approaching the end of our voyage, and we've finally reached the 8th and most distant planet in the solar system. The story of its discovery is unique among planets: Neptune's presence was mathematically predicted after observing unexplained disturbances in Uranus' orbit. Based on those predictions, Neptune was first observed in 1846 by astronomer Johann Galle.

The second of the ice giants, Neptune is a little smaller in volume than Uranus. However, it is also denser, and therefore slightly more massive. Its iconic blue color comes from traces of methane present in its atmosphere.

Credit: NASA

A small rocky world on the outskirts of our cosmic neighborhood. Long considered to be the solar system's ninth planet, Pluto's demotion to dwarf planet in 2006 caused ripples both in and out of the scientific community. Pluto sits in a region called the Kuiper Belt, a disc similar to the asteroid belt that encircles the outer solar system.

Pluto's classification history mirrors that of Ceres: as more and more objects of similar characteristics were found in the Kuiper Belt, scientists were forced to either accept them all as planets or to change the very definition of planet. They chose the latter and, sadly, Pluto just missed the criteria.

Credit: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute, Public domain, via Wikimedia Commons

Pluto is named after the Roman god of the underworld. It's only fitting that Charon, its largest moon, shares its name with the ferryman who carried the souls of the dead to the afterlife in Greek and Roman mythology.

Charon is uncharacteristically large for a moon: it has half the diameter and ⅛ of the mass of Pluto. On top of that, Charon and Pluto are mutually tidally locked, meaning that they always show each other the same face. Because of this unusual relationship, it's been argued that Pluto and Charon should be treated as a binary dwarf planet system.

Everyday expressions

Discover the fascinating origins of these 8 timeless English idioms

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Idioms are a rare breed, aren’t they? They confuse non-native speakers to no end, as they can’t simply be deduced from the meaning of individual words. After all, who in their right mind would accuse someone of stealing their intangible thunder? Or complain about having to burn lamp oil at midnight?

English speakers use these idioms all the time but rarely stop to figure out where they come from. If you were ever curious about how spilling beans might connect to confessing a secret, then this article is exactly what you need.

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The very literal origin of this idiom comes from the play "Appius and Virginia," written by English dramatist John Dennis in the early 1700s. For the production of his play, Dennis created a new method to imitate the sound of thunder. Sadly, "Appius and Virginia" had disappointing attendance and was canceled shortly after. However, Dennis soon after discovered that a production of Macbeth was using his thunder device, to critical acclaim. According to literary scholar Joseph Spence, Dennis angrily exclaimed, "Damn them! They will not let my play run, but they steal my thunder."

Credit: Yohan Cho

This idiom has a surprising lighthearted aspect to it. While its meaning entails soul-crushing defeat, one can’t help but also imagine a Groucho Marx-looking character chewing on a big cigar. And this lightheartedness might not be completely accidental: After all, this idiom comes from the cheerful world of carnival games.

In the late 19th century, carnival games were targeted for adults, not children. Therefore, instead of handing out oversized stuffed animals of undefined species, winners might receive objects like cigars as prizes. The idiom "close but no cigar" was born from those players that almost won, but didn’t earn a prize.

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The most widely accepted use of this idiom comes from America’s very own national pastime: baseball. In 1916, the New York Giants (now known as the San Francisco Giants) had an incredible winning streak of 26 consecutive games. The Giants believed that, if they were in the lead during the last inning of a game, moving a bag filled with extra baseballs off the field would secure their victory. They had "captured" the game in the bag. This team’s superstition has now evolved into an everyday idiom that means secured and complete success.

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Picture this: You are at work, hanging by the water cooler, and you are trying to get your favorite coworker to reveal a piece of office gossip that promises to be huge. We have all been there, but did you know that by asking your coworker to "spill the beans", you might be referencing one of the very first instances of democracy?

The origins of this idiom are still debated, but the consensus is that it most likely comes from a voting system from Ancient Greece. This process involved placing colored beans in a vase (white for yes, black for no). Tallying up the votes would then literally require someone to spill the vase and count each bean that was cast.

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Almost every student can attest to spending many sleepless nights burning the midnight oil in front of a seemingly endless pile of textbooks. While the origin of this idiom comes from oil lamps used in the 17th century, students all across the world still refer to this expression when talking about working late into the night.

The first known use of "burning the midnight oil" comes from a book written by English poet Francis Quarles in 1635. More recently, in 1972, country music legends Dolly Parton and Porter Wagoner recorded a collaborative studio album titled The Right Combination • Burning the Midnight Oil.

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While turning a blind eye might make us think about that lenient schoolteacher who occasionally gave us a pass on our missing homework, the most commonly accepted origin of this idiom comes from the nautical world. Specifically, from the iconic 18th century British Admiral Horatio Nelson.

In 1801, Nelson led the British attack alongside fellow Admiral Sir Hyde Parker in the Battle of Copenhagen. Nelson, who was blind in one eye, received a flag message from Parker that urged him to retreat. However, Nelson believed that the British fleet should continue to push forward, so he held his telescope to his blind eye and pretended he hadn’t seen Parker’s message.

Credit: Raimond Klavins

Weirdly enough, another unexpected nautical term has found its way into this list! While nowadays feeling "under the weather" means feeling ill, the origin of this idiom dates back to slang used by sailors as far back as the 19th century.

The term "under the weather bow" was used to refer to the side of the ship that was exposed the most during storms. Sailors would seek shelter in their cabins to avoid getting seasick, literally going under the ship’s deck to escape the weather. The first literary use of this term was by American author Donald Grant Mitchell in his 1855 book Fudge Doings. In the book, a character describes a nasty experience in a steamer as feeling "a little under the weather."

Credit: Carlos Felipe Ramírez Mesa

Throughout the years, countless parents have repeated the same question to their misbehaving children at the dinner table: "Were you raised by wolves?" And, while the current intention of these parents is to highlight bad manners and improper etiquette, it might hurt their case to learn that several outstanding characters from myths and literature were, in fact, raised by wolves.

Perhaps the first and most famous story of children raised by wolves is that of the founders of Ancient Rome, Romulus, and Remus. In the myth, the brothers are abandoned on the bank of a river, where they are found and nurtured by a she-wolf, before being eventually adopted by a shepherd. Furthermore, the protagonist of Rudyard Kipling’s 1894 novel The Jungle Book is a boy named Mowgli who is raised in the jungle by wolves.