How well do you know your astronomical neighborhood? Let’s go on a trip through our solar system and explore the weird, the wild, and the beautiful all around us. Today, we are learning all about Earth’s Moon.

Where is it?

Our Moon is 229,730 miles (369,714 km) from Earth. It’s the closest object to our planet in the solar system and it’s our only moon. It’s also the fifth-largest moon in the solar system.

What’s up with the name?

For once, we don’t have a complicated Greek or Roman mythology to dissect to get to the name. The word moon can be traced to the word mōna, an Old English word from medieval times. Mōna shares its origins with the Latin words metri, which means to measure, and mensis, which means month.

So, the moon is called the moon because it is used to measure the months.

Who “discovered” it?

This is another easy one. The moon has always been in the sky, for as long as humanity has existed. So the first humans would have “discovered” it simply by lifting their eyes to the heavens at night.

We could add a little color here and talk about how Neil Armstrong was the first person to explore the moon when he and Buzz Aldrin landed on its surface as part of Apollo 11 in 1969. We will discuss the Moon’s exploration more in a while.

Mountains of the Moon

What’s it made of?

Green cheese? Sorry, not at all. The Moon is very traditional. It has a core, mantle, and crust.

The Moon’s core is proportionally smaller than other terrestrial bodies’ cores. The solid, iron-rich inner core is 149 miles (240 kilometers) in radius. It is surrounded by a liquid iron shell 56 miles (90 kilometers) thick. A partially molten layer with a thickness of 93 miles (150 kilometers) surrounds the iron core.

The mantle extends from the top of the partially molten layer to the bottom of the Moon’s crust. It is most likely made of minerals like olivine and pyroxene, which are made up of magnesium, iron, silicon, and oxygen atoms.

The crust has a thickness of about 43 miles (70 kilometers) on the Moon’s near-side hemisphere and 93 miles (150 kilometers) on the far-side. It is made of oxygen, silicon, magnesium, iron, calcium, and aluminum, with small amounts of titanium, uranium, thorium, potassium, and hydrogen.

Long ago the Moon had active volcanoes, but today they are all dormant and have not erupted for millions of years.

Can we live there?

With the right protection, we can. NASA astronauts during the Apollo program stayed for days on the Moon and returned unharmed. A sustained human presence on the Moon would require a habitat to provide oxygen and shelter from radiation.

NASA’s Artemis program also envisions a Lunar Gateway space station orbiting the Moon that would be able to shuttle goods and astronauts down to the lunar surface, providing resupply missions for the permanent outpost.

Seems like science fiction? It may happen sooner than you think.

How long is a year there? What about a day?

The Moon makes a complete orbit around Earth in 27 Earth days and rotates or spins at that same rate, or in that same amount of time. Because Earth is moving as well – rotating on its axis as it orbits the Sun – from our perspective, the Moon appears to orbit us every 29 days.

Has NASA sent any missions there?

The Moon is the only other body in our solar system that has been explored by humans.

Twenty-four NASA astronauts have visited the Moon, on Apollo 11-17. NASA also sent Apollo 8 and 10 to orbit the Moon, preparing for the lunar landings.

We have talked extensively on this site about the Apollo missions. So, let’s explore NASA’s plans to return to the Moon with the Artemis Program.

With Artemis missions, NASA will land the first woman and first person of color on the Moon, using innovative technologies to explore more of the lunar surface than ever before. They will collaborate with commercial and international partners and establish the first long-term presence on the Moon.

The plan is to build an Artemis Base Camp on the surface and the Gateway in lunar orbit. These elements will allow our robots and astronauts to explore more and conduct more science than ever before.

Can I see it from here?

On a clear evening, you should be able to see the Moon, even if it’s in its waning stages.

Instead of leaving it simply at that, let’s explore the phases of our moon for a moment. Why does it look different at different points in the month?

The Moon is rotating at the same rate that it revolves around Earth (called synchronous rotation), so the same hemisphere faces Earth all the time. Some people call the far side – the hemisphere we never see from Earth – the “dark side” but that’s misleading.

As the Moon orbits Earth, different parts are in sunlight or darkness at different times. The changing illumination is why, from our perspective, the Moon goes through phases. During a “full Moon,” the hemisphere of the Moon we can see from Earth is fully illuminated by the Sun. And a “new Moon” occurs when the far side of the Moon has full sunlight, and the side facing us is having its night.

Are there any pretty pictures of it?

NASA has taken a ton of pictures of the Moon over the years. Here are a collection of some from orbit and from the surface.

[envira-gallery id=”52775″]

How well do you know your astronomical neighborhood? Let’s go on a trip through our solar system and explore the weird, the wild, and the beautiful all around us. Today, we are learning all about Europa.

Where is it?

Europa is one of Jupiter’s moons, orbiting Jupiter at about 417,000 miles (671,000 kilometers) from the planet. Light from the Sun takes about 45 minutes to reach Europa. Because of the distance, sunlight is about 25 times fainter at Jupiter and Europa than at Earth.

What’s up with the name?

Europa is named for a woman who, in Greek mythology, was abducted by the god Zeus – Jupiter in Roman mythology. Europa was a princess of Phoenecia and the mother of King Minos of Crete.

Zeus appeared to Europa as a white bull on the beach. When Europa climbed on the bull’s back, it plunged into the sea and swam away with her. Eventually, the two touched down on the island of Crete.

It’s there that Europa became the island’s first queen and, thus, had the future King Minos. Later, Minos would turn cruel and end up with the Minotaur as his son, building a labyrinth beneath his palace to hide the monster.

Whether its fitting that a moon of Jupiter, which is the Roman name for Zeus, is named after a woman Zeus kidnapped and isolated, who’s to say?

Who “discovered” it?

Our old friend Galileo Galilei discovered Europa on Jan. 8, 1610. It’s been a minute since we talked about Galileo, but it’s not surprising that he was the first to record and name Europa. His telescopes and observations were integral to our new understanding of the solar system.

That’s also why Jupiter’s four largest moons, including Europa, are known as Galillean moons.

What’s it made of?

Like our planet, Europa is thought to have an iron core, a rocky mantle, and an ocean of salty water. Unlike Earth, however, Europa’s ocean lies below a shell of ice probably 10 to 15 miles (15 to 25 kilometers) thick, and has an estimated depth of 40 to 100 miles (60 to 150 kilometers). While evidence for an internal ocean is strong, its presence awaits confirmation by a future mission.

Can we live there?

You know that possible internal ocean we just mentioned? It’s very important for the possibility of life on Europa. We may not be able to live there. But there may be life on Jupiter’s moon.

Life as we know it seems to have three main requirements: liquid water, the appropriate chemical elements, and an energy source.

Astrobiologists – scientists who study the origin, evolution, and future of life in the universe – believe Europa has abundant water and the right chemical elements, but an energy source on Europa has been difficult to confirm. On Earth, life forms have been found thriving near subterranean volcanoes, deep-sea vents, and other extreme environments. These “extremophile” life forms give scientists clues about how life may be able to survive beneath Europa’s ice shell.

If we eventually find some form of life at Europa (or Mars or Enceladus for that matter), it may look like microbes, or maybe something more complex. If it can be demonstrated that life formed independently in two places around the same star, it would then be reasonable to suspect that life springs up in the universe fairly easily once the necessary ingredients are present, and that life might be found throughout our galaxy and the universe.

How long is a year there? What about a day?

Europa orbits Jupiter every 3.5 days and is locked by gravity to Jupiter, so the same hemisphere of the moon always faces the planet. Jupiter takes about 4,333 Earth days (or about 12 Earth years) to orbit the Sun (a Jovian year). Jupiter’s equator (and the orbital plane of its moons) are tilted with respect to Jupiter’s orbital path around the Sun by only 3 degrees (Earth is tilted 23.5 degrees). This means Jupiter spins nearly upright so that the planet, as well as Europa and Jupiter’s other dozens of moons, do not have seasons as extreme as other planets do.

Has NASA sent any missions there?

There have been a few NASA missions to Jupiter that have studied Europa briefly. NASA’s Galileo spacecraft explored the Jupiter system from 1995 to 2003 and made numerous flybys of Europa.

Soon, though, NASA will be launching a mission specifically to the moon called the Europa Clipper. The Europa Clipper spacecraft will conduct a detailed survey of Jupiter’s moon Europa to determine whether the icy moon could harbor conditions suitable for life. The spacecraft, in orbit around Jupiter, will make about 40 to 50 close passes over Europa, shifting its flight path for each flyby to soar over a different location so that it eventually scans nearly the entire moon.

After each flyby, the spacecraft will send its haul of data back to Earth. The time between flybys will also give scientists time to study the data and consider adjusting the timing and trajectory of future flybys if they find regions that spark curiosity and need more study.

Can I see it from here?

Yes! Europa is one of four Jovian moons you can see with a telescope. When looking at Jupiter, Europa is usually the closest moon to the planet. The other four that are visible are Io, Callisto, and Ganymede.

 

What’s up with the name?

Pluto is the only world (so far) named by an 11-year-old girl. In 1930, Venetia Burney of Oxford, England, suggested to her grandfather that the new discovery be named for the Roman god of the underworld. He forwarded the name to the Lowell Observatory and it was selected.

Pluto, or Hades, is the god of the underworld. He rules over the afterlife and helps usher souls across the River Styx. The brother of Jupiter, or Zeus, Pluto was also the god of wealth because diamonds and other jewels come from underground.

In his Roman and Greek mythology, Pluto stole away the daughter of the goddess of the earth and tricked her to residing with him three months a year. These months were then why the earth goddess was inconsolable with grief, thus the earth itself is cold and icy. In other words, the mythologies used this story to explain the seasons and why winter exists.

Who “discovered” it?

Pluto was discovered on Feb. 18, 1930 at the Lowell Observatory in Flagstaff, Arizona, by astronomer Clyde W. Tombaugh, with contributions from William H. Pickering. This period in astronomy was one of intense planet hunting, and Pickering was a prolific planet predictor.

In 1906, Percival Lowell, a wealthy Bostonian who had founded the Lowell Observatory in Flagstaff, Arizona in 1894, started an extensive project in search of a possible ninth planet, which he termed “Planet X.” By 1909, Lowell and Pickering had suggested several possible celestial coordinates for such a planet.

The search for Planet X did not resume until 1929, when the job was handed to Clyde Tombaugh, a 23-year-old Kansan who had just arrived at the Lowell Observatory. Tombaugh’s task was to systematically image the night sky in pairs of photographs taken two weeks apart, then examine each pair and determine whether any objects had shifted position.

Using a machine called a blink comparator, he rapidly shifted back and forth between views of each of the plates to create the illusion of movement of any objects that had changed position or appearance between photographs.

On Feb. 18, after nearly a year of searching, Tombaugh discovered a possible moving object on photographic plates taken on Jan. 23 and Jan. 29.

Pluto officially became Pluto on March 24, 1930, when Burney’s suggestion was adopted and announced to the world.

What’s it made of?

Pluto is about two-thirds the diameter of Earth’s Moon and probably has a rocky core surrounded by a mantle of water ice. Interesting ices like methane and nitrogen frost coat the surface. Due to its lower density, Pluto’s mass is about one-sixth that of Earth’s Moon.

Pluto’s surface is characterized by mountains, valleys, plains, and craters. The temperature on Pluto can be as cold as -375 to -400 degrees Fahrenheit (-226 to -240 degrees Celsius).

Pluto has a thin, tenuous atmosphere that expands when it comes closer to the Sun and collapses as it moves farther away – similar to a comet. The main constituent is molecular nitrogen, though molecules of methane and carbon monoxide have also been detected.

When Pluto is close to the Sun, its surface ices sublimate (changing directly from solid to gas) and rise to temporarily form a thin atmosphere. Pluto’s low gravity (about 6% of Earth’s) causes the atmosphere to be much more extended in altitude than our planet’s atmosphere. Pluto becomes much colder during the part of each year when it is traveling far away from the Sun. During this time, the bulk of the planet’s atmosphere may freeze and fall as snow to the surface.

Can we live there?

You won’t find many places in our solar system less hospitable to life than Pluto. The surface of Pluto is extremely cold, so it seems unlikely that life could exist there. At such cold temperatures, water, which is vital for life as we know it, is essentially rock-like. Pluto’s interior is warmer, however, and some think there could even be an ocean deep inside.

Living and working on Pluto might be similar to being on the Moon, but the temperature extremes are so much worse, since it’s further from the Sun.

How long is a year there? What about a day?

Pluto’s orbit around the Sun is unusual compared to the planets: it’s both elliptical and tilted, like a comet. It takes Pluto about 248 years to orbit the Sun once.

One day on Pluto takes about 153 hours. Its axis of rotation is tilted 57 degrees, so it spins almost on its side. Pluto also rotates from east to west like Venus and Uranus.

 

Has NASA sent any missions there?

Pluto is so far away, it takes a very long time for spacecraft to reach it. That’s why it took a while for missions to first explore Pluto.

The most extensive mission sent to the dwarf planet was New Horizons.

New Horizons launched on Jan. 19, 2006; it swung past Jupiter for a gravity boost and scientific studies in February 2007, and conducted a six-month-long reconnaissance flyby study of Pluto and its moons in summer 2015, culminating with Pluto closest approach on July 14, 2015.

The spacecraft provided the first close-up images of Pluto and its moons and collecting other data that has transformed our understanding of these mysterious worlds on the solar system’s outer frontier.

In the years since that groundbreaking flyby, nearly every conjecture about Pluto possibly being an inert ball of ice has been thrown out the window or flipped on its head.

New Horizons at Pluto Artist Concept

Can I see it from here?

Not really. To catch a glimpse of the dwarf planet, you’ll need a telescope with at least an 8-inch diameter mirror, according to Sky and Telescope. Even at its brightest, Pluto is not visible to the naked eye and is about 27 million times fainter than Venus.

Are there any pretty pictures of it?

Of course! We recently got so many good shots of Pluto from the New Horizons mission.

[envira-gallery id=”52736″]

How well do you know your astronomical neighborhood? Let’s go on a trip through our solar system and explore the weird, the wild, and the beautiful all around us. Today, we are learning all about Neptune.

Where is it?

Neptune is the eighth planet of our solar system, sitting 2.8 miles from the sun and 2.5 miles from Earth. More than 30 times as far from the Sun as Earth, Neptune is the only planet in our solar system not visible to the naked eye.

Neptune is so far from the Sun that high noon on the big blue planet would seem like dim twilight to us. The warm light we see here on our home planet is roughly 900 times as bright as sunlight on Neptune.

Who “discovered” it?

Science is frequently amazing. But, from time to time, it’s good to take a step back and let some things fill us with awe.

To wit, the discovery of Neptune was the first done not by optics, but by mathematics.

Basically, astronomers studied Uranus’ orbit and theorized that there must be another planet nearby. That’s because of gravitational fluctuations, that, when they calculated it through Newtonain physics, suggested there was an undiscovered planet in the solar system.

Based on these calculations made by astronomer Urbain Le Verrier, fellow stargazer Johann Gottfried Galle used the Fraunhofer telescope at the Berlin Observatory and made the first observations of the new planet, only 1 degree from its calculated position. That fateful night happened on Sept. 23-24, 1846.

Is there a more pure expression of the scientific method than that? A theory is tested and proven with a new discovery.

It’s not often that the results of that test are the discovery of an entire planet in our neighborhood.

What’s up with the name?

With Neptune, we are back to the Roman pantheon. Neptune is the Roman god of the sea. His Greek counterpart is Poseidon. In both traditions, Neptune was also a god of horses. Interestingly, one of his enduring symbols was the trident, a three-pronged spear used for spear fishing.

Johann Gottfried Galle

Mosaic of Neptune (Regional Archeological Museum Antonio Salinas, Palermo)

Like Uranus, we have more detailed discussions about the naming of Neptune because it was discovered less than 200 years ago. Galle, who had been the first to observe it with a telescope, wanted to name it after Le Verrier.

LeVerrier himself first pushed the name Neptune, but quickly reverted to naming it after himself. Of course, nothing is simple and the scientific community debated it at the time, before most settled on Neptune as the official name by the end of 1846.

Because Neptune is the god of the sea, and the planet itself is icy blue, this felt fitting to astronomers of the day.

What’s it made of?

With a radius of 15,299.4 miles (24,622 kilometers), Neptune is about four times wider than Earth. Neptune’s atmosphere is made up mostly of hydrogen and helium with just a little bit of methane.

Neptune’s neighbor Uranus is a blue-green color due to such atmospheric methane, but Neptune is a more vivid, brighter blue, so there must be an unknown component that causes the more intense color.

Neptune is one of two ice giants in the outer solar system (the other is Uranus). Most (80% or more) of the planet’s mass is made up of a hot dense fluid of “icy” materials – water, methane, and ammonia – above a small, rocky core. Of the giant planets, Neptune is the densest.

Neptune does not have a solid surface. Its atmosphere (made up mostly of hydrogen, helium, and methane) extends to great depths, gradually merging into water and other melted ices over a heavier, solid core with about the same mass as Earth.

Scientists think there might be an ocean of super hot water under Neptune’s cold clouds. It does not boil away because incredibly high pressure keeps it locked inside.

It seems contradictory to view an ice giant like Neptune as having a superheated ocean under those blue clouds. But then again, that’s what makes our solar system so fascinating. We are constantly learning new and unexpected facts about our nearest neighbors.

Can we live there?

Doubtful. Much like fellow ice giant Uranus, Neptune would prove a challenging environment. The density of the atmosphere would put anyone on it’s sludgy surface at a great disadvantage. Then, there’s the wind.

Neptune is our solar system’s windiest world. Despite its great distance and low energy input from the Sun, Neptune’s winds can be three times stronger than Jupiter’s and nine times stronger than Earth’s.

These winds whip clouds of frozen methane across the planet at speeds of more than 1,200 miles per hour (2,000 kilometers per hour). Even Earth’s most powerful winds hit only about 250 miles per hour (400 kilometers per hour).

How long is a year there? What about a day?

One day on Neptune takes about 16 hours (the time it takes for Neptune to rotate or spin once). And Neptune makes a complete orbit around the Sun (a year in Neptunian time) in about 165 Earth years (60,190 Earth days).

Sometimes Neptune is even farther from the Sun than dwarf planet Pluto. Pluto’s highly eccentric, oval-shaped orbit brings it inside Neptune’s orbit for a 20-year period every 248 Earth years. This switch, in which Pluto is closer to the Sun than Neptune, happened most recently from 1979 to 1999. Pluto can never crash into Neptune, though, because for every three laps Neptune takes around the Sun, Pluto makes two. This repeating pattern prevents close approaches of the two bodies.

Has NASA sent any missions there?

Voyager 2 is the only spacecraft to fly by Neptune. No spacecraft has orbited this distant planet to study it at length and up close.

Voyager 2’s encounter with Neptune capped a 4.3 billion-mile (7 billion-kilometer) journey when, on Aug. 25, 1989, at 03:56 UT, it flew about 2,980 miles (4,800 kilometers) over the cloud tops of the giant planet, the closest of its four flybys. It was the first human-made object to fly by the planet. Its 10 instruments were still in working order at the time.

During the encounter, the spacecraft discovered six new moons (Proteus, Larissa, Despina, Galatea, Thalassa, and Naiad) and four new rings.

Neptune Small Dark Spot D2

The planet itself was found to be more active than previously believed, with 680-mile (1,100-kilometer) per hour winds. Hydrogen was found to be the most common atmospheric element, although the abundant methane gave the planet its blue appearance.

Images revealed details of the three major features in the planetary clouds—the Lesser Dark Spot, the Great Dark Spot, and Scooter.

Voyager photographed two-thirds of Neptune’s largest moon Triton, revealing the coldest known planetary body in the solar system and a nitrogen ice “volcano” on its surface. Spectacular images of its southern hemisphere showed a strange, pitted cantaloupe-type terrain.

Can I see it from here?

As we mentioned above, Neptune is the only planet in our solar system not visible to the naked eye.

Are there any pretty pictures of it?

Of course! There are many amazing shots of Neptune, though maybe not as many as some of the other planets that have seen more exploratory missions. Here are our favorites.

[envira-gallery id=”52708″]

How well do you know your astronomical neighborhood? Let’s go on a trip through our solar system and explore the weird, the wild, and the beautiful all around us. Today, we are learning all about Uranus.

Where is it?

Uranus is the seventh planet of our solar system, sitting 1.78 billion miles from the sun and 1.75 billion miles from Earth. From this distance, it takes sunlight 2 hours and 40 minutes to travel from the Sun to Uranus.

Who “discovered” it?

Uranus was the first planet found with the aid of a telescope. It was discovered in 1781 by astronomer William Herschel, although he originally thought it was either a comet or a star. Surprised it wasn’t our good friend Galileo? We are too. But, the distance to the planet made it much harder to see without aid of more sophisticated lenses.

It was two years after Herschel’s observation that the object was universally accepted as a new planet, in part because of observations by astronomer Johann Elert Bode. Rather than using advanced telescopes to more definitively mark Uranus as a planet, Bode’s contribution was one of research.

The German astronomer consulted older records and determined the object Herschel had found had been observed in old sky charts. Between 1690 and 1769, French astronomer Pierre Charles Le Monnier and English astronomer John Flamsteed observed what they thought was a star.

1785 portrait of William Herschel by Lemuel Francis Abbott

The reason they had mistaken it was that Uranus takes a glacial pace in orbiting the Sun. We will get into the details more later in this article, but Uranis takes about 84 years to make one orbit of the Sun. No wonder individual astronomers assumed it was as stationary as other stars.

What’s up with the name?

I know, this section usually comes before “Who discovered it?” but since Uranus was found relatively recently compared to the other planets in our solar system, the people who discovered it played a part in naming it.

Herschel tried unsuccessfully to name his discovery Georgium Sidus after King George III. Instead, the scientific community accepted Bode’s suggestion to name it Uranus, the Greek god of the sky, as suggested by Bode.

You also read that right. Uranus is the first non-Earth planet to be named after a Greek god, not its Roman counterpart. He is also one of the founding deities in the Greek pantheon. His family with Gaia beget the Titans, which included Cronus, or Saturn, who we recently discussed. That makes him the grandfather of Zeus, or Jupiter.

The radioactive element uranium was named after Uranus when it was discovered in 1789, just eight years after the planet was discovered.

What’s it made of?

Uranus is another gas giant, possessing the third-largest diameter of any planet in the solar system. With a radius of 15,759.2 miles (25,362 kilometers), Uranus is four times wider than Earth. If Earth was the size of a nickel, Uranus would be about as big as a softball.

Uranus is one of two ice giants in the outer solar system (the other is Neptune). Most (80% or more) of the planet’s mass is made up of a hot dense fluid of “icy” materials – water, methane, and ammonia – above a small rocky core. Near the core, it heats up to 9,000 degrees Fahrenheit (4,982 degrees Celsius).

Uranus is slightly larger in diameter than its neighbor Neptune, yet smaller in mass. It is the second least dense planet; Saturn is the least dense of all.

Uranus gets its blue-green color from methane gas in the atmosphere. Sunlight passes through the atmosphere and is reflected back out by Uranus’ cloud tops. Methane gas absorbs the red portion of the light, resulting in a blue-green color.

While not as striking in appearance as Saturn, Uranus does have two sets of rings. The inner system of nine rings consists mostly of narrow, dark grey rings. There are two outer rings: the innermost one is reddish like dusty rings elsewhere in the solar system, and the outer ring is blue like Saturn’s E ring.

Can we live there?

In short, no.

As an ice giant, Uranus doesn’t have a true surface. The planet is mostly swirling fluids. While a spacecraft would have nowhere to land on Uranus, it wouldn’t be able to fly through its atmosphere unscathed either. The extreme pressures and temperatures would destroy a metal spacecraft.

Think about how long it takes sunlight to reach Uranus. That means any warmth from the Sun is long extinguished as its rays journey to the ice giant. Hence the ice.

Uranus’ planetary atmosphere, with a minimum temperature of 49K (-224.2 degrees Celsius) makes it even colder than Neptune in some places. Wind speeds can reach up to 560 miles per hour (900 kilometers per hour) on Uranus, which also would prevent survival on the surface.

How long is a year there? What about a day?

One day on Uranus takes about 17 hours (the time it takes for Uranus to rotate or spin once). And Uranus makes a complete orbit around the Sun (a year in Uranian time) in about 84 Earth years (30,687 Earth days).

Uranus is the only planet whose equator is nearly at a right angle to its orbit, with a tilt of 97.77 degrees – possibly the result of a collision with an Earth-sized object long ago. This unique tilt causes the most extreme seasons in the solar system. For nearly a quarter of each Uranian year, the Sun shines directly over each pole, plunging the other half of the planet into a 21-year-long, dark winter.

Uranus is also one of just two planets that rotate in the opposite direction than most of the planets (Venus is the other one), from east to west.

Has NASA sent any missions there?

Voyager 2 is the only spacecraft to fly by Uranus. No spacecraft has orbited this distant planet to study it at length and up close. Voyager 2 launched on August 20, 1977, from Cape Canaveral, Florida aboard a Titan-Centaur rocket. Voyager 1 launched two weeks later, also from Florida, meaning Voyager 2 was actually first into orbit.

At its closest, the spacecraft came within 81,500 kilometers (50,600 miles) of Uranus’s cloudtops on Jan. 24, 1986.

Voyager 2 radioed thousands of images and voluminous amounts of other scientific data on the planet, its moons, rings, atmosphere, interior and the magnetic environment surrounding Uranus.

This archival photo shows engineers working on NASA’s Voyager 2 spacecraft on March 23, 1977.

Voyager 2’s images of the five largest moons around Uranus revealed complex surfaces indicative of varying geologic pasts. The cameras also detected 11 previously unseen moons.

Several instruments studied the ring system, uncovering the fine detail of the previously known rings and two newly detected rings. Voyager data showed that the planet’s rate of rotation is 17 hours, 14 minutes.

The spacecraft also found a Uranian magnetic field that is both large and unusual. In addition, the temperature of the equatorial region, which receives less sunlight over a Uranian year, is nevertheless about the same as that at the poles.

Can I see it from here?

Uranus is not visible to the naked eye, but can be seen with high-powered telescopes.

Are there any pretty pictures of it?

Of course! There are many amazing shots of Uranus, though maybe not as many as some of the other planets that have seen more exploratory missions. Here are our favorites.

[envira-gallery id=”52685″]

How well do you know your astronomical neighborhood? Let’s go on a trip through our solar system and explore the weird, the wild, and the beautiful all around us. Today, we are learning all about Jupiter.

Where is it?

Jupiter is the fifth planet of our solar system, sitting 468.1 million miles from the sun and 396.5 miles from Earth.

Jupiter is the first planet to make a pronounced jump in distance from the Sun. Jupiter is three times as far from the Sun as Mars and nearly five times as far as Earth. This distance creates a split in how we look at the solar system, with inner planets and outer planets. The inner planets are closer to the Sun and are smaller and rockier. The outer planets are further away, larger and made up mostly of gas.

How well do you know your astronomical neighborhood? Let’s go on a trip through our solar system and explore the weird, the wild, and the beautiful all around us. Today, we are learning all about Mars.

 

Where is it?

Mars is the fourth planet of our solar system, sitting 154.8 million miles from the sun and, at its closest, is 33.9 million miles from Earth.

What’s up with the name?

Mars was named by the ancient Romans for their god of war because its reddish color was reminiscent of blood. Other civilizations also named the planet for this attribute – for example, the Egyptians called it “Her Desher,” meaning “the red one.”

Mars is the Roman counterpart to Ares, the Greek god of war. However, the two were viewed very differently culturally. Ares is often seen in myths as a chaotic and villainous force, while Mars was viewed more positively by the Romans. This reflects the two civilizations outlooks on war and violence. Both valued peace, but the Romans recognized military power brought peace, usually through their legions.

Mars is also considered the father of Rome itself, as he is the father of founders of Rome Romulus and Remus. The Roman god’s name also forms the root of the word “martial,” meaning of or appropriate to war.

Who “discovered” it?

Mars is one of the “bright” planets, visible to the naked eye in the sky. It’s also unique in that its brightness varies throughout the year, appearing sometimes as bright as Jupiter and sometimes as dim as a star. Because it’s visible without optical enhancements, Mars was always known.

Much like Venus, the first person to see Mars through a telescope was astronomer Galileo Galilei. He took the first accurate observations of the planet in 1610.

What’s it made of?

The Red Planet is actually many colors. At the surface, we see colors such as brown, gold, and tan. The reason Mars looks reddish is due to oxidization – or rusting – of iron in the rocks, regolith (Martian “soil”), and dust of Mars. This dust gets kicked up into the atmosphere and from a distance makes the planet appear mostly red.

Mars has a dense core at its center between 930 and 1,300 miles (1,500 to 2,100 kilometers) in radius. It’s made of iron, nickel, and sulfur. Surrounding the core is a rocky mantle between 770 and 1,170 miles (1,240 to 1,880 kilometers) thick, and above that, a crust made of iron, magnesium, aluminum, calcium, and potassium. This crust is between 6 and 30 miles (10 to 50 kilometers) deep.

Mars has a thin atmosphere made up mostly of carbon dioxide, argon, nitrogen, and a small amount of oxygen and water vapor.

Can we live there?

Right now? No.

I know, I know. You may have seen the Matt Damon-starring movie The Martian, where his character, astronaut Mark Watney, devises a way to grow potatoes while stranded on Mars in 2035.

The science behind Andy Weir’s novel is solid, but our technology isn’t quite there yet. NASA is working on what a habitat on the Martian or lunar surface will look like. And in both situations, a habitat will absolutely be necessary.

The Martian surface currently doesn’t have enough atmosphere to support life, nor will the extreme temperature changes support it. The temperature on Mars can be as high as 70 degrees Fahrenheit (20 degrees Celsius) or as low as about -225 degrees Fahrenheit (-153 degrees Celsius). And because the atmosphere is so thin, heat from the Sun easily escapes this planet.

If you were to stand on the surface of Mars on the equator at noon, it would feel like spring at your feet (75 degrees Fahrenheit or 24 degrees Celsius) and winter at your head (32 degrees Fahrenheit or 0 degrees Celsius).

So, to survive on Mars, you would need a shelter to regulate those temperature swings and protect from the occasional dust storm. You’d also need to bring something to create and recycle both water and breathable air.

How long is a year there? What about a day?

A Martian day is about the same as an Earth day, taking a little more than 24 hours. But a Martian year is almost twice as long as an Earth year. Mars and Earth may only be 33.9 million miles apart, but since Mars is further away from the Sun, its orbit takes 687 Earth days to complete.

Has NASA sent any missions there?

Mars may be the most-explored object in our solar system (outside of Earth, of course). It’s also the only planet in the solar system inhabited entirely by robots. That fact would make many 50’s science fiction authors, like Ray Bradbury and Isaac Asimov, incredibly happy.

No planet beyond Earth has been studied as intensely as Mars. Recorded observations of Mars date as far back as the era of ancient Egypt over 4,000 years ago, when they charted the planet’s movements in the sky. Today, NASA has a fleet of robotic spacecraft studying Mars from all angles.

Mariner 4

Mariner 3 and 4 were identical spacecraft designed to carry out the first flybys of Mars. Mariner 3 was launched on November 5, 1964, but the shroud encasing the spacecraft atop its rocket failed to open properly, and Mariner 3 did not get to Mars. Three weeks later, on November 28, 1964, Mariner 4 was launched successfully on an eight-month voyage to the red planet.

The spacecraft flew past Mars on July 14, 1965, collecting the first close-up photographs of another planet. The pictures, played back from a small tape recorder over a long period, showed lunar-type impact craters (just beginning to be photographed at close range from the Moon), some of them touched with frost in the chill Martian evening. The Mariner 4 spacecraft was not expected to survive much longer than the eight months to its Mars flyby encounter, but actually lasted about three years in solar orbit, continuing long-term studies of the solar wind environment and making coordinated measurements with Mariner 5, a sister ship launched to Venus in 1967.