The Marvels Of Space
The marvels of space
Cassini Spacecraft: Top Discoveries
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:
Titan
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.
Enceladus
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.
Iapetus
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
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.
Auroras
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.
Turbulent Atmosphere
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.
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The wonders of Mars
1,000 Days in Orbit: MAVEN’s Top 10 Discoveries at Mars
On June 17, our MAVEN (Mars Atmosphere and Volatile Evolution Mission) will celebrate 1,000 Earth days in orbit around the Red Planet.
Since its launch in November 2013 and its orbit insertion in September 2014, MAVEN has been exploring the upper atmosphere of Mars. MAVEN is bringing insight to how the sun stripped Mars of most of its atmosphere, turning a planet once possibly habitable to microbial life into a barren desert world.
Here’s a countdown of the top 10 discoveries from the mission so far:
10. Unprecedented Ultraviolet View of Mars
Revealing dynamic, previously invisible behavior, MAVEN was able to show the ultraviolet glow from the Martian atmosphere in unprecedented detail. Nightside images showed ultraviolet “nightglow” emission from nitric oxide. Nightglow is a common planetary phenomenon in which the sky faintly glows even in the complete absence of eternal light.
9. Key Features on the Loss of Atmosphere
Some particles from the solar wind are able to penetrate unexpectedly deep into the upper atmosphere, rather than being diverted around the planet by the Martian ionosphere. This penetration is allowed by chemical reactions in the ionosphere that turn the charged particles of the solar wind into neutral atoms that are then able to penetrate deeply.
8. Metal Ions
MAVEN made the first direct observations of a layer of metal ions in the Martian ionosphere, resulting from incoming interplanetary dust hitting the atmosphere. This layer is always present, but was enhanced dramatically by the close passage to Mars of Comet Siding Spring in October 2014.
7. Two New Types of Aurora
MAVEN has identified two new types of aurora, termed “diffuse” and “proton” aurora. Unlike how we think of most aurorae on Earth, these aurorae are unrelated to either a global or local magnetic field.
6. Cause of the Aurorae
These aurorae are caused by an influx of particles from the sun ejected by different types of solar storms. When particles from these storms hit the Martian atmosphere, they can also increase the rate of loss of gas to space, by a factor of ten or more.
5. Complex Interactions with Solar Wind
The interactions between the solar wind and the planet are unexpectedly complex. This results due to the lack of an intrinsic Martian magnetic field and the occurrence of small regions of magnetized crust that can affect the incoming solar wind on local and regional scales. The magnetosphere that results from the interactions varies on short timescales and is remarkably “lumpy” as a result.
4. Seasonal Hydrogen
After investigating the upper atmosphere of the Red Planet for a full Martian year, MAVEN determined that the escaping water does not always go gently into space. The spacecraft observed the full seasonal variation of hydrogen in the upper atmosphere, confirming that it varies by a factor of 10 throughout the year. The escape rate peaked when Mars was at its closest point to the sun and dropped off when the planet was farthest from the sun.
3. Gas Lost to Space
MAVEN has used measurements of the isotopes in the upper atmosphere (atoms of the same composition but having different mass) to determine how much gas has been lost through time. These measurements suggest that 2/3 or more of the gas has been lost to space.
2. Speed of Solar Wind Stripping Martian Atmosphere
MAVEN has measured the rate at which the sun and the solar wind are stripping gas from the top of the atmosphere to space today, along with details of the removal process. Extrapolation of the loss rates into the ancient past – when the solar ultraviolet light and the solar wind were more intense – indicates that large amounts of gas have been lost to space through time.
1. Martian Atmosphere Lost to Space
The Mars atmosphere has been stripped away by the sun and the solar wind over time, changing the climate from a warmer and wetter environment early in history to the cold, dry climate that we see today.
Maven will continue its observations and is now observing a second Martian year, looking at the ways that the seasonal cycles and the solar cycle affect the system.
For more information about MAVEN, visit: www.nasa.gov/maven
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You gotta love gem fusions.
Chalcedony !
“blatherin blatherskite!”
Gizmoduck is on the town! Love the Ducktales reboot, the designs, the production quality, and the AMAZING voice cast!!!
Mysterious
Solar System: Things to Know This Week
Learn about the science of photonics to create space communications, get updates on Juno, mining data from Voyager for new discoveries and more.
1. Carried on a Beam of Light
One of our major priorities is to make space communications more efficient. While our communications systems have matured over the decades, they still use the same radio-frequency system developed in the earliest days of the agency. After more than 50 years, we’re investing in new ways to increase data rates while also finding more efficient communications systems. Photonics–generating, detecting and manipulating particles of light–may provide the solution.
+ See how it works
2. It’s No Joke: Two New Moons for the Seventh Planet
Voyager 2 spacecraft flew by Uranus 30 years ago, but researchers are still making discoveries using the data it gathered. A new study led by University of Idaho researchers suggests there could be two tiny, previously undiscovered moonlets orbiting near two of the planet’s rings.
+ Find out how they were discovered
3. Vortex of Mystery
As southern winter solstice approaches in the Saturn system, our Cassini spacecraft has revealed dramatic seasonal changes in the atmospheric temperature and composition of Saturn’s largest moon, Titan. Winter is taking a grip on Titan’s southern hemisphere, and a strong, whirling vortex has intensified in the upper atmosphere over the south pole.
+See more
4. The Spiders of Mars
Ten thousand volunteers viewing images of Martian south polar regions have helped identify targets for closer inspection, yielding new insights about seasonal slabs of frozen carbon dioxide and erosional features known as “spiders.” From the comfort of home, the volunteers have been exploring the surface of Mars by reviewing images from the Context Camera on our Mars Reconnaissance Orbiter and identifying certain types of seasonal terrains near Mars’ south pole.
+ Learn more and see how you can join in
5. Better Safe Than Sorry
On Oct. 18, when Juno’s onboard computer entered safe mode, early indications were a software performance monitor induced a reboot of the spacecraft’s onboard computer, turning off instruments and a few non-critical spacecraft components, and it confirmed the spacecraft was pointed toward the sun to ensure the solar arrays received power. On Oct. 24, the spacecraft left safe mode and has successfully completed a minor burn of its thruster engines in preparation for its next close flyby of Jupiter. The team is still investigating the cause of the reboot and assessing two main engine check valves. The burn, which lasted just over 31 minutes, changed Juno’s orbital velocity by about 5.8 mph (2.6 meters per second) and consumed about 8 pounds (3.6 kilograms) of propellant. Juno will perform its next science flyby of Jupiter on Dec. 11, with time of closest approach to the gas giant occurring at 12:03 p.m. EDT. The complete suite of Juno’s science instruments, as well as the JunoCam imager, will be collecting data during the upcoming flyby.
+ Get the details
Discover the full list of 10 things to know about our solar system this week HERE.
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Amazing.
The Moon Just Photobombed NASA’s Solar Dynamics Observatory
On May 25, 2017, the moon photobombed one of our sun-watching satellites by passing directly between the satellite and the sun.
The Solar Dynamics Observatory, or SDO, orbits Earth and watches the sun nearly 24/7 — except when another body, like the moon, gets in the way. These lunar photobombs are called transits, the generic term for when any celestial body passes in front of another.
Transits are one way we detect distant worlds. When a planet in another star system passes in front of its host star, it blocks some of the star’s light so the star appears slightly dimmer. By monitoring changes in a star’s light over time, scientists can deduce the presence of a planet, and even determine what its atmosphere is like. This method has been used to discover thousands of planets, including the TRAPPIST-1 planets.
SDO sees lunar transits about twice a year, and this one lasted about an hour with the moon covering about 89 percent of the sun at the peak of its journey across the sun’s face.
When they’re seen from Earth, we call lunar transits by another name: eclipses.
Solar eclipses are just a special kind of transit where the moon blocks all or part of our view of the sun. Since SDO’s view of the sun was only partially blocked, it saw a partial eclipse. Later this year, on Aug. 21, a total eclipse will be observable from the ground: The moon will completely block the sun’s face in some parts of the US, creating a total solar eclipse on a 70-mile-wide stretch of land, called the path of totality, that runs from Oregon to South Carolina.
Throughout the rest of North America — and even in parts of South America, Africa, Europe and Asia — the moon will partially obscure the sun, creating a partial eclipse. SDO will also witness this partial eclipse.
Total solar eclipses are incredible, cosmic coincidences: The sun is about 400 times wider than the moon, but it also happens to be 400 times farther away, so the sun and moon appear to be the same size in our sky. This allows the moon to completely block the sun when they line up just right.
Within the path of totality, the moon completely obscures the sun’s bright face, revealing the comparatively faint corona — the sun’s pearly-white outer atmosphere.
It’s essential to observe eye safety during an eclipse. You must use proper eclipse glasses or an indirect viewing method when any part of the sun’s surface is exposed, whether during the partial phases of an eclipse, or just on a regular day. If you’re in the path of totality, you may look at the eclipse ONLY during the brief moments of totality.
A total solar eclipse is one of nature’s most awe-inspiring sights, so make your plans now for August 21! You’ll also be able to see the eclipse cross the country that day through the eyes of NASA – including views of the partial eclipse from SDO – on NASA TV and at nasa.gov.
Learn more about the August eclipse — including where, when, and how to safely see it — at eclipse2017.nasa.gov and follow along on Twitter @NASASun.
Space 2017
Solar System: Things to Know This Week
See our home planet from Mars, learn about our latest Discovery missions, see stunning imagery from the Cassini mission and more!
1. Our Home
The powerful HiRISE camera on the Mars Reconnaissance Orbiter took this incredible image of our home and moon. The image combines two separate exposures taken on Nov. 20, 2016.
+ See more
2. Our Latest Missions of Discovery
We’ve selected two new missions to explore the early solar system. Lucy, a robotic spacecraft scheduled to launch in October 2021, is slated to arrive at its first destination, a main belt asteroid, in 2025. From 2027 to 2033, Lucy will explore six Jupiter Trojan asteroids. These asteroids are trapped by Jupiter’s gravity in two swarms that share the planet’s orbit, one leading and one trailing Jupiter in its 12-year circuit around the sun.
+Learn more
Psyche, targeted to launch in October 2023, will explore one of the most intriguing targets in the main asteroid belt–a giant metal asteroid, known as 16 Psyche. The asteroid is about 130 miles (210 kilometers) in diameter and thought to be comprised mostly of iron and nickel, similar to Earth’s core.
+ Details
3. Image From Cassini
Cassini took so many jaw-dropping photos last year, how could anyone choose just 10? Well, the Cassini team didn’t. Here are 17 amazing photos from Saturn and its moons last year.
4. The Colors of Mars
Impact craters have exposed the subsurface materials on the steep slopes of Mars. However, these slopes often experience rockfalls and debris avalanches that keep the surface clean of dust, revealing a variety of hues, like in this enhanced-color image from our Mars Reconnaissance Orbiter, representing different rock types.
+ Learn more
5. More From New Horizons
Even though our New Horizons mission flew by Pluto in 2015, the scientific discoveries keep coming. Using a model similar to what meteorologists use to forecast weather and a computer simulation of the physics of evaporating ices, scientists have found evidence of snow and ice features that, until now, had only been seen on Earth.
Discover the full list of 10 things to know about our solar system this week HERE.
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Beauty of space
What’s Up for December 2016?
What’s Up for December? Mars and Neptune above the crescent moon and a New Year’s Eve comet!
2016 ends with fireworks as three planets line up as if ejected from a Roman candle. Mercury, Venus and Mars are visible above the sunset horizon all month long.
As Venus climbs higher in the sky, it looks brighter and larger than it appeared last month.
On New Year’s Eve, Mars and Neptune appear very close to each other. Through telescopes, rusty red Mars and blue-green Neptune‘s colors contrast beautifully.
There are two meteor showers this month – the Geminds and the Ursids. The best time to see the reliable Geminids will be next year, when the full moon won’t be so bright and interfering. This year, however, we may luck out and see some of the brighter meteors on the evening of the 13th and the morning of the 14th.
The best time to view the Ursids, radiating from Ursa Minor, or the little Dipper, will be from midnight on the 21st until about 1 a.m. on the 22nd, before the moon rises. They may be active on the 23rd and 24th, too.
We haven’t had a good easy-to-see comet in quite a while, but beginning in December and through most of 2017 we will have several binocular and telescopic comets to view.
The first we’ll be able to see is Comet 45P/Honda-Mrkos-Pajdušáková, which will appear low on the western horizon on December 15th. On that date, the comet will pass the pretty globular cluster M75.
By the 21st, it will appear edge-on, sporting a bluish-green head and a thin, sharp view of the fan-shaped tail.
On New Years Eve, the comet and the crescent moon will rendezvous to say farewell to 2016. A “periodic” comet is a previously-identified comet that’s on a return visit. Periodic comet 45P returns to the inner solar system every 5.25 years, and that’s the one that will help us ring in the new year.
Watch the full What’s Up for December video:
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New things in space
Solar System: Things to Know This Week
Our Dawn mission to the asteroid belt is no ordinary deep space expedition.
Instead of traditional chemical rockets, the spacecraft uses sophisticated ion engines for propulsion. This enabled Dawn to become the first mission to orbit not one, but two different worlds — first the giant asteroid Vesta and now the dwarf planet Ceres. Vesta and Ceres formed early in the solar system’s history, and by studying them, the mission is helping scientists go back in time to the dawn of the planets. To mark a decade since Dawn was launched on Sept. 27, 2007, here are 10 things to know about this trailblazing mission.
1. Ion Engines: Not Just for Sci-Fi Anymore
Most rocket engines use chemical reactions for propulsion, which tend to be powerful but short-lived. Dawn’s futuristic, hyper-efficient ion propulsion system works by using electricity to accelerate ions (charged particles) from xenon fuel to a speed seven to 10 times that of chemical engines. Ion engines accelerate the spacecraft slowly, but they’re very thrifty with fuel, using just milligrams of xenon per second (about 10 ounces over 24 hours) at maximum thrust. Without its ion engines, Dawn could not have carried enough fuel to go into orbit around two different solar system bodies. Try your hand at an interactive ion engine simulation.
2. Time Capsules
Scientists have long wanted to study Vesta and Ceres up close. Vesta is a large, complex and intriguing asteroid. Ceres is the largest object in the entire asteroid belt, and was once considered a planet in its own right after it was discovered in 1801. Vesta and Ceres have significant differences, but both are thought to have formed very early in the history of the solar system, harboring clues about how planets are constructed. Learn more about Ceres and Vesta—including why we have pieces of Vesta here on Earth.
3. Portrait of a Dwarf Planet
This view of Ceres built from Dawn photos is centered on Occator Crater, home of the famous “bright spots.” The image resolution is about 460 feet (140 meters) per pixel.
Take a closer look.
4. What’s in a Name?
Craters on Ceres are named for agricultural deities from all over the world, and other features carry the names of agricultural festivals. Ceres itself was named after the Roman goddess of corn and harvests (that’s also where the word “cereal” comes from). The International Astronomical Union recently approved 25 new Ceres feature names tied to the theme of agricultural deities. Jumi, for example, is the Latvian god of fertility of the field. Study the full-size map.
5. Landslides or Ice Slides?
Thanks to Dawn, evidence is mounting that Ceres hides a significant amount of water ice. A recent study adds to this picture, showing how ice may have shaped the variety of landslides seen on Ceres today.
6. The Lonely Mountain
Ahuna Mons, a 3-mile-high (5-kilometer-high) mountain, puzzled Ceres explorers when they first found it. It rises all alone above the surrounding plains. Now scientists think it is likely a cryovolcano — one that erupts a liquid made of volatiles such as water, instead of rock. “This is the only known example of a cryovolcano that potentially formed from a salty mud mix, and that formed in the geologically recent past,” one researcher said. Learn more.
7. Shining a Light on the Bright Spots
The brightest area on Ceres, located in the mysterious Occator Crater, has the highest concentration of carbonate minerals ever seen outside Earth, according to studies from Dawn scientists. Occator is 57 miles (92 kilometers) wide, with a central pit about 6 miles (10 kilometers) wide. The dominant mineral of this bright area is sodium carbonate, a kind of salt found on Earth in hydrothermal environments. This material appears to have come from inside Ceres, and this upwelling suggests that temperatures inside Ceres are warmer than previously believed. Even more intriguingly, the results suggest that liquid water may have existed beneath the surface of Ceres in recent geological time. The salts could be remnants of an ocean, or localized bodies of water, that reached the surface and then froze millions of years ago. See more details.
8. Captain’s Log
Dawn’s chief engineer and mission director, Marc Rayman, provides regular dispatches about Dawn’s work in the asteroid belt. Catch the latest updates here.
9. Eyes on Dawn
Another cool way to retrace Dawn’s decade-long flight is to download NASA’s free Eyes on the Solar System app, which uses real data to let you go to any point in the solar system, or ride along with any spacecraft, at any point in time—all in 3-D.
10. No Stamp Required
Send a postcard from one of these three sets of images that tell the story of dwarf planet Ceres, protoplanet Vesta, and the Dawn mission overall.
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