Our Cassini spacecraft has been exploring Saturn, its stunning rings and its strange and beautiful moons for more than a decade.
Having expended almost every bit of the rocket propellant it carried to Saturn, operators are deliberately plunging Cassini into the planet to ensure Saturn’s moons will remain pristine for future exploration – in particular, the ice-covered, ocean-bearing moon Enceladus, but also Titan, with its intriguing pre-biotic chemistry.
Let’s take a look back at some of Cassini’s top discoveries:
Under its shroud of haze, Saturn’s planet-sized moon Titan hides dunes, mountains of water ice and rivers and seas of liquid methane. Of the hundreds of moons in our solar system, Titan is the only one with a dense atmosphere and large liquid reservoirs on its surface, making it in some ways more like a terrestrial planet.
Both Earth and Titan have nitrogen-dominated atmospheres – over 95% nitrogen in Titan’s case. However, unlike Earth, Titan has very little oxygen; the rest of the atmosphere is mostly methane and traced amounts of other gases, including ethane.
There are three large seas, all located close to the moon’s north pole, surrounded by numerous smaller lakes in the northern hemisphere. Just one large lake has been found in the southern hemisphere.
The moon Enceladus conceals a global ocean of salty liquid water beneath its icy surface. Some of that water even shoots out into space, creating an immense plume!
For decades, scientists didn’t know why Enceladus was the brightest world in the solar system, or how it related to Saturn’s E ring. Cassini found that both the fresh coating on its surface, and icy material in the E ring originate from vents connected to a global subsurface saltwater ocean that might host hydrothermal vents.
With its global ocean, unique chemistry and internal heat, Enceladus has become a promising lead in our search for worlds where life could exist.
Saturn’s two-toned moon Iapetus gets its odd coloring from reddish dust in its orbital path that is swept up and lands on the leading face of the moon.
The most unique, and perhaps most remarkable feature discovered on Iapetus in Cassini images is a topographic ridge that coincides almost exactly with the geographic equator. The physical origin of the ridge has yet to be explained…
It is not yet year whether the ridge is a mountain belt that has folded upward, or an extensional crack in the surface through which material from inside Iapetus erupted onto the surface and accumulated locally.
Saturn’s rings are made of countless particles of ice and dust, which Saturn’s moons push and tug, creating gaps and waves.
Scientists have never before studied the size, temperature, composition and distribution of Saturn’s rings from Saturn obit. Cassini has captured extraordinary ring-moon interactions, observed the lowest ring-temperature ever recorded at Saturn, discovered that the moon Enceladus is the source for Saturn’s E ring, and viewed the rings at equinox when sunlight strikes the rings edge-on, revealing never-before-seen ring features and details.
Cassini also studied features in Saturn’s rings called “spokes,” which can be longer than the diameter of Earth. Scientists think they’re made of thin icy particles that are lifted by an electrostatic charge and only last a few hours.
The powerful magnetic field that permeates Saturn is strange because it lines up with the planet’s poles. But just like Earth’s field, it all creates shimmering auroras.
Auroras on Saturn occur in a process similar to Earth’s northern and southern lights. Particles from the solar wind are channeled by Saturn’s magnetic field toward the planet’s poles, where they interact with electrically charged gas (plasma) in the upper atmosphere and emit light.
Saturn’s turbulent atmosphere churns with immense storms and a striking, six-sided jet stream near its north pole.
Saturn’s north and south poles are also each beautifully (and violently) decorated by a colossal swirling storm. Cassini got an up-close look at the north polar storm and scientists found that the storm’s eye was about 50 times wider than an Earth hurricane’s eye.
Unlike the Earth hurricanes that are driven by warm ocean waters, Saturn’s polar vortexes aren’t actually hurricanes. They’re hurricane-like though, and even contain lightning. Cassini’s instruments have ‘heard’ lightning ever since entering Saturn orbit in 2004, in the form of radio waves. But it wasn’t until 2009 that Cassini’s cameras captured images of Saturnian lighting for the first time.
Cassini scientists assembled a short video of it, the first video of lightning discharging on a planet other than Earth.
Cassini’s adventure will end soon because it’s almost out of fuel. So to avoid possibly ever contaminating moons like Enceladus or Titan, on Sept. 15 it will intentionally dive into Saturn’s atmosphere.
The spacecraft is expected to lose radio contact with Earth within about one to two minutes after beginning its decent into Saturn’s upper atmosphere. But on the way down, before contact is lost, eight of Cassini’s 12 science instruments will be operating! More details on the spacecraft’s final decent can be found HERE.
an earth moon’s heart is full, but she is hard like a forest floor. yet, every single day, new things grow in the forest, and form treetops and flora. it gives a home to forest animals and humans that dare to adventure into it. it’s alive and thriving, and so are earth moons.
an air moon’s heart is empty, but only because she is up in the clouds, running, dreaming, flying. she’s breathing in new experiences and emotions that don’t even exist yet. she’s found peter and she’s on her way to neverland as we speak, she doesn’t ever want to come down.
a fire moon’s heart is overflowing, you cannot keep her contained. she needs release, spirit, adventure. she’s sprinting through cities and setting everyone and everything in her way ablaze with stories, emotions and life. she’s reaching for the clouds and burning the planet to it’s core. she’s everywhere, everything and more.
a water moon’s heart is waiting at the bottom of the ocean. she’s seen everything the world has to offer and she’s not done yet. she’s catapulting into space. she’s created the oceans. she’s filled herself to the brim and she’s filling others too. she has so much to offer that her own tiny body cannot contain it all.
Is your favorite Star Wars planet a desert world or an ice planet or a jungle moon?
It’s possible that your favorite planet exists right here in our galaxy. Astronomers have found over 3,700 planets around other stars, called “exoplanets.”
Some of these alien worlds could be very similar to arid Tatooine, watery Scarif and even frozen Hoth, according to our scientists.
Find out if your planet exists in a galaxy far, far away or all around you. And May the Fourth be with you!
Planets With Two Suns
From Luke Skywalker’s home world Tatooine, you can stand in the orange glow of a double sunset. The same could said for Kepler-16b, a cold gas giant roughly the size of Saturn, that orbits two stars. Kepler-16b was the Kepler telescope’s first discovery of a planet in a “circumbinary” orbit (that is, circling both stars, as opposed to just one, in a double star system).
The best part is that Tatooine aka Kepler-16b was just the first. It has family. A LOT of family. Half the stars in our galaxy are pairs, rather than single stars like our sun. If every star has at least one planet, that’s billions of worlds with two suns. Billions! Maybe waiting for life to be found on them.
Mars is a cold desert planet in our solar system, and we have plenty of examples of scorching hot planets in our galaxy (like Kepler-10b), which orbits its star in less than a day)! Scientists think that if there are other habitable planets in the galaxy, they’re more likely to be desert planets than ocean worlds. That’s because ocean worlds freeze when they’re too far from their star, or boil off their water if they’re too close, potentially making them unlivable. Perhaps, it’s not so weird that both Luke Skywalker and Rey grew up on planets that look a lot alike.
An icy super-Earth named OGLE-2005-BLG-390Lb reminded scientists so much of the frozen Rebel base they nicknamed it “Hoth,” after its frozen temperature of minus 364 degrees Fahrenheit. Another Hoth-like planet was discovered in April 2017; an Earth-mass icy world orbiting its star at the same distance as Earth orbits the sun. But its star is so faint, the surface of OGLE-2016-BLG-1195Lb is probably colder than Pluto.
Both the forest moon of Endor and Takodana, the home of Han Solo’s favorite cantina in “Force Awakens,” are green like our home planet. But astrobiologists think that plant life on other worlds could be red, black, or even rainbow-colored!
In February 2017, the Spitzer Space Telescope discovered seven Earth-sized planets in the same system, orbiting the tiny red star TRAPPIST-1.
The light from a red star, also known as an M dwarf, is dim and mostly in the infrared spectrum (as opposed to the visible spectrum we see with our sun). And that could mean plants with wildly different colors than what we’re used to seeing on Earth. Or, it could mean animals that see in the near-infrared.
What About Moons?
In Star Wars, Endor, the planet with the cute Ewoks, is actually a habitable moon of a gas giant. Now, we’re looking for life on the moons of our own gas giants. Saturn’s moon Enceladus or Jupiter’s moon Europa are ocean worlds that may well support life. Our Cassini spacecraft explored the Saturn system and its moons, before the mission ended in 2017. Watch the video and learn more about the missions’s findings.
The next few years will see the launch of a new generation of spacecraft to search for planets around other stars. Our TESS spacecraft launched in April 2018, and will discover new exoplanets by the end of the year. The James Webb Space Telescope is slated to launch in 2020. That’s one step closer to finding life.
You might want to take our ‘Star Wars: Fact or Fiction?’ quiz. Try it! Based on your score you may obtain the title of Padawan, Jedi Knight, or even Jedi Master!
You don’t need to visit a galaxy far, far away to find wondrous worlds. Just visit this one … there’s plenty to see.
earlier this year i did extremely brief descriptions of the new/full moons just because but never shared so…
march 12th - healing but feels wronged april 11th - change, change, change may 10th - passionate and relationship-oriented june 9th - childish july 9th - TEMPERAMENTAL august 7th - condescending september 6th - euphoric october 5th - ostracizing november 4th - love on the edge december 3rd - destructive and nostalgic
march 27th - soulfully liberated, purpose oriented april 26th - unknowingly demanding, unsure whats gonna happen next may 25th - vastly abundant but suppressing, to act or not to act on opportunities june 23rd - lonely, confused, risky july 23rd - dramatic and blatantly erratic august 21st - wising up september 20th - communicative, a bit hazy (revelations) october 19th - ABSOLUTE MADNESS november 18th - social justice december 18th - cunning
The Voyager 1 and 2 spacecraft explored Jupiter, Saturn, Uranus and Neptune before starting their journey toward interstellar space. Here you’ll find some of those images, including “The Pale Blue Dot” – famously described by Carl Sagan – and what are still the only up-close images of Uranus and Neptune.
Photography of Jupiter began in January 1979, when images of the brightly banded planet already exceeded the best taken from Earth. They took more than 33,000 pictures of Jupiter and its five major satellites.
Erupting volcanoes on Jupiter’s moon Io, which has 100 times the volcanic activity of Earth.
Better understanding of important physical, geological, and atmospheric processes happening in the planet, its satellites and magnetosphere.
Jupiter’s turbulent atmosphere with dozens of interacting hurricane-like storm systems.
The Saturn encounters occurred nine months apart, in November 1980 and August 1981. The two encounters increased our knowledge and altered our understanding of Saturn. The extended, close-range observations provided high-resolution data far different from the picture assembled during centuries of Earth-based studies.
Saturn’s atmosphere is almost entirely hydrogen and helium.
Subdued contrasts and color differences on Saturn could be a result of more horizontal mixing or less production of localized colors than in Jupiter’s atmosphere.
An indication of an ocean beneath the cracked, icy crust of Jupiter’s moon Europa.
Winds blow at high speeds in Saturn. Near the equator, the Voyagers measured winds about 1,100 miles an hour.
The Voyager 2 spacecraft flew closely past distant Uranus, the seventh planet from the Sun. At its closest, the spacecraft came within 50,600 miles of Uranus’s cloud tops 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.
Revealed complex surfaces indicative of varying geologic pasts.
Detected 11 previously unseen moons.
Uncovered the fine detail of the previously known rings and two newly detected rings.
Showed that the planet’s rate of rotation is 17 hours, 14 minutes.
Found that the planet’s magnetic field is both large and unusual.
Determined that the temperature of the equatorial region, which receives less sunlight over a Uranian year, is nevertheless about the same as that at the poles.
Voyager 2 became the first spacecraft to observe the planet Neptune in the summer of 1989. Passing about 3,000 miles above Neptune’s north pole, Voyager 2 made its closest approach to any planet since leaving Earth 12 years ago. Five hours later, Voyager 2 passed about 25,000 miles from Neptune’s largest moon, Triton, the last solid body the spacecraft had the opportunity to study.
Discovered Neptune’s Great Dark Spot
Found that the planet has strong winds, around 1,000 miles per hour
Saw geysers erupting from the polar cap on Neptune’s moon Triton at -390 degrees Fahrenheit
Solar System Portrait
This narrow-angle color image of the Earth, dubbed ‘Pale Blue Dot’, is a part of the first ever ‘portrait’ of the solar system taken by Voyager 1.
The spacecraft acquired a total of 60 frames for a mosaic of the solar system from a distance of more than 4 billion miles from Earth and about 32 degrees above the ecliptic.
From Voyager’s great distance, Earth is a mere point of light, less than the size of a picture element even in the narrow-angle camera.
“Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.” - Carl Sagan
Both spacecraft will continue to study ultraviolet sources among the stars, and their fields and particles detectors will continue to search for the boundary between the Sun’s influence and interstellar space. The radioisotope power systems will likely provide enough power for science to continue through 2025, and possibly support engineering data return through the mid-2030s. After that, the two Voyagers will continue to orbit the center of the Milky Way.