For the first time ever, our Cassini spacecraft dove through the narrow gap between Saturn and its rings on April 26. At 5 a.m. EDT, Cassini crossed the ring plane with its science instruments turned on and collecting data.
During this dive, the spacecraft was not in contact with Earth. The first opportunity to regain contact with the spacecraft is expected around 3 a.m. EDT on April 27.
This area between Saturn and its rings has never been explored by a spacecraft before. What we learn from these daring final orbits will further our understanding of how giant planets, and planetary systems everywhere, form and evolve.
So, you might be asking…how did this spacecraft maneuver its orbit between Saturn and its rings? Well…let us explain!
On April 22, Cassini made its 127th and final close approach to Saturn’s moon Titan. The flyby put the spacecraft on course for its dramatic last act, known as the Grand Finale.
As the spacecraft passed over Titan, the moon’s gravity bent its path, reshaping the robotic probe’s orbit slightly so that instead of passing just outside Saturn’s main rings, Cassini would begin a series of 22 dives between the rings and the planet.
With this assist, Cassini received a large increase in velocity of approximately 1,925 mph with respect to Saturn.
This final chapter of exploration and discovery is in many ways like a brand-new mission. Twenty-two times, the Cassini spacecraft will dive through the unexplored space between Saturn and its rings. What we learn from these ultra-close passes over the planet could be some of the most exciting revelations ever returned by the long-lived spacecraft.
Throughout these daring maneuvers, updates will be posted on social media at:
The Cassini spacecraft will begin its final series of orbits to cap a 13-year groundbreaking science mission known as the Grand Finale. For the first time ever in Cassini’s time at Saturn, the spacecraft will fly in between the planet’s rings and atmosphere. No spacecraft has ever before flown in this region of any of the solar system’s ringed planets.
After 23 orbits, Cassini will dive into Saturn’s upper atmosphere September 15 where it will be destroyed. In 2008, mission managers explored a range of End of Mission scenarios that would protect Saturn’s moon’s from Earthly contaminants before ultimately deciding on atmospheric reentry.
Cassini began her End of Mission manoeuvres on November 26, 2016, when it began the first of 20 ring-grazing orbits. A close flyby of Titan April 22 will alter the spacecraft’s trajectory to begin the first of 23 orbits in the Grand Finale, which will begin April 26.
Cassini launched from Earth on October 15, 1997, and entered Saturn orbit June 30, 2004. Six months later, on January 14, 2005, the European-built Huygens probe attached to the spacecraft landed on Titan, becoming the first probe to land in the outer solar system.
Originally scheduled for a four-year mission ending in 2008, Cassini received two mission extensions in 2008 and 2010, with the latter ending in 2017. With the spacecraft’s fuel reserves low, the Cassini team decided to end the mission.
This unprocessed image shows features in Saturn’s atmosphere from closer than ever before. The view was captured by our Cassini spacecraft during its first Grand Finale dive between the planet and its rings on April 26, 2017.
As Cassini dove through the gap, it came within about 1,900 miles (3,000 kilometers) of Saturn’s cloud tops (where the air pressure is 1 bar – comparable to the atmospheric pressure of Earth at sea level) and within about 200 miles (300 kilometers) of the innermost visible edge of the rings.
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 3,400 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 NASA 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 telescopes’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-200-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 last month; 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 has explored the Saturn system and its moons. 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. TESS and the James Webb Telescope are slated to launch in 2018, and WFIRST in the mid-2020s. 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.
We’re incredibly lucky to live on a planet
drenched in water, nestled in a perfect distance from our sun and wrapped with
magnetic fields keeping our atmosphere intact against harsh radiation and space
We know from recent research that life can
persist in the cruelest of environments here on Earth, which gives us hope to
finding life thriving on other worlds. While we have yet to find life outside
of Earth, we are optimistic about the possibilities, especially on other ocean
worlds right here in our solar system.
So…What’s the News?!
Two of our veteran missions are providing
tantalizing new details about icy, ocean-bearing moons of Jupiter and Saturn,
further enhancing the scientific interest of these and other “ocean worlds” in
our solar system and beyond!
scientists announce that a form of energy for life appears to exist in Saturn’s
moon Enceladus, and Hubble
researchers report additional evidence of plumes erupting from Jupiter’s moon
The Two Missions: Cassini and Hubble
spacecraft has found that hydrothermal vents in the ocean of Saturn’s icy moon Enceladus
are producing hydrogen gas, which could potentially provide a chemical energy
source for life.
Cassini discovered that this little moon of
Saturn was active in 2005. The discovery that Enceladus has jets of gas and icy
particles coming out of its south polar region surprised the world. Later we
determined that plumes of material are coming from a global ocean under the icy
crust, through large cracks known as “tiger stripes.”
We have more evidence now – this time sampled
straight from the plume itself – of hydrothermal activity, and we now know the
water is chemically interacting with the rock beneath the ocean and producing
the kind of chemistry that could be used by microbes IF they happened to be
This is the culmination of 12 years of
investigations by Cassini and a capstone finding for the mission. We now know Enceladus
has nearly all the ingredients needed for life as we know it.
The Cassini spacecraft made its deepest dive
through the plume on Oct. 28, 2015. From previous flybys, Cassini determined
that nearly 98% of the gas in the plume is water and the rest is a mixture of
other molecules, including carbon dioxide, methane and ammonia.
instruments provided evidence of hydrothermal activity in the ocean. What we
really wanted to know was…Is there hydrogen being produced that microbes could
use to make energy? And that’s exactly what we found!
To be clear…we haven’t discovered microbes at
Enceladus, but vents of this type at Earth host these kinds of life. We’re
cautiously excited at the prospect that there might be something like this at
Europa is one of the four major moons of
Jupiter, about the size of our own moon but very different in appearance. It’s
a cold, icy world with a relatively smooth, bright surface crisscrossed with
dark cracks and patches of reddish material.
What makes Europa interesting is that it’s believed
to have a global ocean, underneath a thick crust of ice. In fact, it’s got
about twice as much ocean as planet Earth!
In 2014, we detected evidence of intermittent
water plumes on the surface of Europa, which is interesting because they may
provide us with easier access to subsurface liquid water without having to
drill through miles of ice.
And now, in 2016, we’ve found one particular
plume candidate that appears to be at the same location that it
was seen in 2014.
This is exciting because if we can establish that a
particular feature does repeat, then it is much more likely to be real and we
can attempt to study and understand the processes that cause it to turn on or
This plume also happens to coincide with an
area where Europa is unusually warm as compared to the surrounding terrain. The
plume candidates are about 30 to 60 miles (50 to 100 kilometers) in height and are well-positioned for
observation, being in a relatively equatorial and well-determined location.
What Does All This Mean and What’s Next?
Hubble and Cassini are inherently different
missions, but their complementary scientific discoveries, along with the synergy
between our current and planned missions, will help us in finding out whether
we are alone in the universe.
Hubble will continue to observe Europa. If
you’re wondering how we might be able to get more information on the Europa
plume, the upcoming Europa Clipper mission
will be carrying
a suite of 9 instruments to investigate whether the mysterious icy moon could harbor conditions favorable for life. Europa Clipper is slated to launch in the 2020s.
This future mission will be able to study the
surface of Europa in great detail and assess the habitability of this moon.
Whether there’s life there or not is a question for this future mission to
Our solar system is a jewel box filled with a glittering variety of beautiful worlds–and not all of them are planets. This week, we present our solar system’s most marvelous moons.
1. Weird Weather: Titan
Saturn’s hazy moon Titan is larger than Mercury, but its size is not the only way it’s like a planet. Titan has a thick atmosphere, complete with its own “water cycle” – except that it’s way too cold on Titan for liquid water. Instead, rains of liquid hydrocarbons like ethane and methane fall onto icy mountains, run into rivers, and gather into great seas. Our Cassini spacecraft mapped the methane seas with radar, and its cameras even caught a glimpse of sunlight reflecting off the seas’ surface. Learn more about Titan: saturn.jpl.nasa.gov/science/titan/
2. Icy Giant: Ganymede
Jupiter’s moon Ganymede is the largest in the solar system. It’s bigger than Mercury and Pluto, and three-quarters the size of Mars. It’s also the only moon known to have its own magnetic field. Details: solarsystem.nasa.gov/planets/ganymede/indepth
3. Retrograde Rebel: Triton
Triton is Neptune’s largest moon, and the only one in the solar system to orbit in the opposite direction of its planet’s rotation, a retrograde orbit. It may have been captured from the Kuiper Belt, where Pluto orbits. Despite the frigid temperatures there, Triton has cryovolcanic activity – frozen nitrogen sometimes sublimates directly to gas and erupts from geysers on the surface. More on Triton: solarsystem.nasa.gov/planets/triton/indepth
4. Cold Faithful: Enceladus
The most famous geysers in our solar system (outside of those on Earth) belong to Saturn’s moon Enceladus. It’s a small, icy body, but Cassini revealed this world to be one of the solar system’s most scientifically interesting destinations. Geyser-like jets spew water vapor and ice particles from an underground ocean beneath the icy crust of Enceladus. With its global ocean, unique chemistry and internal heat, Enceladus has become a promising lead in our search for worlds where life could exist. Get the details: saturn.jpl.nasa.gov/science/enceladus/
5. Volcano World: Io
Jupiter’s moon Io is subjected to tremendous gravitational forces that cause its surface to bulge up and down by as much as 330 feet (100 m). The result? Io is the most volcanically active body in the Solar System, with hundreds of volcanoes, some erupting lava fountains dozens of miles high. More on Io’s volcanoes: solarsystem.nasa.gov/planets/io/indepth
6. Yin and Yang Moon: Iapetus
When Giovanni Cassini discovered Iapetus in 1671, he observed that one side of this moon of Saturn was bright and the other dark. He noted that he could only see Iapetus on the west side of Saturn, and correctly concluded that Iapetus had one side much darker than the other side. Why? Three centuries later, the Cassini spacecraft solved the puzzle. Dark, reddish dust in Iapetus’s orbital path is swept up and lands on the leading face of the moon. The dark areas absorb energy and become warmer, while uncontaminated areas remain cooler. Learn more: saturn.jpl.nasa.gov/news/2892/cassini-10-years-at-saturn-top-10-discoveries/#nine
7. A Double World: Charon and Pluto
At half the size of Pluto, Charon is the largest of Pluto’s moons and the largest known satellite relative to its parent body. The moon is so big compared to Pluto that Pluto and Charon are sometimes referred to as a double planet system. Charon’s orbit around Pluto takes 6.4 Earth days, and one Pluto rotation (a Pluto day) takes 6.4 Earth days. So from Pluto’s point of view Charon neither rises nor sets, but hovers over the same spot on Pluto’s surface, and the same side of Charon always faces Pluto. Get the details: www.nasa.gov/feature/pluto-and-charon-new-horizons-dynamic-duo
8. “Death Star” Moon: Mimas
Saturn’s moon Mimas has one feature that draws more attention than any other: the crater Herschel, which formed in an impact that nearly shattered the little world. Herschel gives Mimas a distinctive look that prompts an oft-repeated joke. But, yes, it’s a moon. More: olarsystem.nasa.gov/planets/mimas
9. Don’t Be Afraid, It’s Just Phobos
In mythology, Mars is a the god of war, so it’s fitting that its two small moons are called Phobos, “fear,” and Deimos, “terror.” Our Mars Reconnaissance Orbiter caught this look at Phobos, which is roughly 17 miles (27 km) wide. In recent years, NASA scientists have come to think that Phobos will be torn apart by its host planet’s gravity. Details: www.nasa.gov/feature/goddard/phobos-is-falling-apart
Although decades have passed since astronauts last set foot on its surface, Earth’s moon is far from abandoned. Several robotic missions have continued the exploration. For example, this stunning view of the moon’s famous Tycho crater was captured by our Lunar Reconnaissance Orbiter, which continues to map the surface in fine detail today. More: www.lroc.asu.edu/posts/902
Discover more lists of 10 things to know about our solar system HERE.
Reaching out into space yields benefits on Earth. Many of these have practical applications — but there’s something more than that. Call it inspiration, perhaps, what photographer Ansel Adams referred to as nature’s “endless prospect of magic and wonder."
Our ongoing exploration of the solar system has yielded more than a few magical images. Why not keep some of them close by to inspire your own explorations? This week, we offer 10 planetary photos suitable for wallpapers on your desktop or phone. Find many more in our galleries. These images were the result of audacious expeditions into deep space; as author Edward Abbey said, "May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view.”
1. Martian Selfie
This self-portrait of NASA’s Curiosity Mars rover shows the robotic geologist in the “Murray Buttes” area on lower Mount Sharp. Key features on the skyline of this panorama are the dark mesa called “M12” to the left of the rover’s mast and pale, upper Mount Sharp to the right of the mast. The top of M12 stands about 23 feet (7 meters) above the base of the sloping piles of rocks just behind Curiosity. The scene combines approximately 60 images taken by the Mars Hand Lens Imager, or MAHLI, camera at the end of the rover’s robotic arm. Most of the component images were taken on September 17, 2016.
NASA’s New Horizons spacecraft captured this high-resolution, enhanced color view of Pluto on July 14, 2015. The image combines blue, red and infrared images taken by the Ralph/Multispectral Visual Imaging Camera (MVIC). Pluto’s surface sports a remarkable range of subtle colors, enhanced in this view to a rainbow of pale blues, yellows, oranges, and deep reds. Many landforms have their own distinct colors, telling a complex geological and climatological story that scientists have only just begun to decode.
On July 19, 2013, in an event celebrated the world over, our Cassini spacecraft slipped into Saturn’s shadow and turned to image the planet, seven of its moons, its inner rings — and, in the background, our home planet, Earth. This mosaic is special as it marks the third time our home planet was imaged from the outer solar system; the second time it was imaged by Cassini from Saturn’s orbit, the first time ever that inhabitants of Earth were made aware in advance that their photo would be taken from such a great distance.
Before leaving the Pluto system forever, New Horizons turned back to see Pluto backlit by the sun. The small world’s haze layer shows its blue color in this picture. The high-altitude haze is thought to be similar in nature to that seen at Saturn’s moon Titan. The source of both hazes likely involves sunlight-initiated chemical reactions of nitrogen and methane, leading to relatively small, soot-like particles called tholins. This image was generated by combining information from blue, red and near-infrared images to closely replicate the color a human eye would perceive.
A huge storm churning through the atmosphere in Saturn’s northern hemisphere overtakes itself as it encircles the planet in this true-color view from Cassini. This picture, captured on February 25, 2011, was taken about 12 weeks after the storm began, and the clouds by this time had formed a tail that wrapped around the planet. The storm is a prodigious source of radio noise, which comes from lightning deep within the planet’s atmosphere.
Jupiter is still just as stormy today, as seen in this recent view from NASA’s Juno spacecraft, when it soared directly over Jupiter’s south pole on February 2, 2017, from an altitude of about 62,800 miles (101,000 kilometers) above the cloud tops. From this unique vantage point we see the terminator (where day meets night) cutting across the Jovian south polar region’s restless, marbled atmosphere with the south pole itself approximately in the center of that border. This image was processed by citizen scientist John Landino. This enhanced color version highlights the bright high clouds and numerous meandering oval storms.
X-rays stream off the sun in this image showing observations from by our Nuclear Spectroscopic Telescope Array, or NuSTAR, overlaid on a picture taken by our Solar Dynamics Observatory (SDO). The NuSTAR data, seen in green and blue, reveal solar high-energy emission. The high-energy X-rays come from gas heated to above 3 million degrees. The red channel represents ultraviolet light captured by SDO, and shows the presence of lower-temperature material in the solar atmosphere at 1 million degrees.
This image from NASA’s Mars Reconnaissance Orbiter shows Victoria crater, near the equator of Mars. The crater is approximately half a mile (800 meters) in diameter. It has a distinctive scalloped shape to its rim, caused by erosion and downhill movement of crater wall material. Since January 2004, the Mars Exploration Rover Opportunity has been operating in the region where Victoria crater is found. Five days before this image was taken in October 2006, Opportunity arrived at the rim of the crater after a drive of more than over 5 miles (9 kilometers). The rover can be seen in this image, as a dot at roughly the “ten o'clock” position along the rim of the crater. (You can zoom in on the full-resolution version here.)
Last, but far from least, is this remarkable new view of our home planet. Last week, we released new global maps of Earth at night, providing the clearest yet composite view of the patterns of human settlement across our planet. This composite image, one of three new full-hemisphere views, provides a view of the Americas at night from the NASA-NOAA Suomi-NPP satellite. The clouds and sun glint — added here for aesthetic effect — are derived from MODIS instrument land surface and cloud cover products.
At the top is a rough composite of the two lower images
taken by NASA’s Cassini spacecraft on 2017-01-30 and received on Earth 2017-02-01.
The bottom photo of Mimas and Pandora was taken earlier in the mission.
Having studied the Saturn system since 2004 the Cassini mission is now in its grand finale phase the highly productive mission will end this September (2017) with a dive into Saturn itself sparing the rings and moons from any accidental Earth-borne contamination after the craft exhausts the last of its fuel supply.
Image credits: NASA/composite by JN with Photoshop