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What Cassini Saw - Incredible 4K Video of the planet Saturn
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By NASA
Artist’s concept of a young, newly discovered planet, exposed to observation by a warped debris disk. Credit: Robert Hurt, Caltech-IPAC. The discovery
A huge planet with a long name – IRAS 04125+2902 b – is really just a baby: only 3 million years old. And because such infant worlds are usually hidden inside obscuring disks of debris, it is the youngest planet so far discovered using the dominant method of planet detection.
Key facts
The massive planet, likely still glowing from the heat of its formation, lies in the Taurus Molecular Cloud, an active stellar nursery with hundreds of newborn stars some 430 light-years away. The cloud’s relative closeness makes it a prime target for astronomers. But while the cloud offers deep insight into the formation and evolution of young stars, their planets are usually a closed book to telescopes like TESS, the Transiting Exoplanet Survey Satellite. These telescopes rely on the “transit method,” watching for the slight dip in starlight when a planet crosses the face of its host star. But such planetary systems must be edge-on, from Earth’s vantage point, for the transit method to work. Very young star systems are surrounded by disks of debris, however, blocking our view of any potentially transiting planets.
A research team has just reported an extraordinary stroke of luck. Somehow, the outer debris disk surrounding this newborn planet, IRAS 04125+2902 b, has been sharply warped, exposing the baby world to extensive transit observations by TESS.
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While the warped outer disk is a great coincidence, it’s also a great mystery. Possible explanations include a migration of the planet itself, moving closer to the star and, in the process, diverging from the orientation of the outer disk – so that, from Earth, the planet’s orbit is edge-on, crossing the face of the star, but the outer disk remains nearly face-on to us. One problem with this idea: Moving a planet so far out of alignment with its parent disk would likely require another (very large) object in this system. None has been detected so far.
The system’s sun happens to have a distant stellar companion, also a possible culprit in the warping of the outer disk. The angle of the orbit of the companion star, however, matches that of the planet and its parent star. Stars and planets tend to take the gravitational path of least resistance, so such an arrangement should push the disk into a closer alignment with the rest of the system – not into a radical departure.
Another way to get a “broken” outer disk, the study authors say, would not involve a companion star at all. Stellar nurseries like the Taurus Molecular Cloud can be densely packed, busy places. Computer simulations show that rains of infalling material from the surrounding star-forming region could be the cause of disk-warping. Neither simulations nor observations have so far settled the question of whether warped or broken disks are common or rare in such regions.
Fun facts
Combining TESS’s transit measurements with another way of observing planets yields more information about the planet itself. We might call this second approach the “wobble” method. The gravity of a planet tugs its star one way, then another, as the orbiting planet makes its way around the star. And that wobble can be detected by changes in the light from the star, picked up by specialized instruments on Earth. Such “radial velocity” measurements of this planet reveal that its mass, or heft, amounts to no more than about a third of our own Jupiter. But the transit data shows the planet’s diameter is about the same. That means the planet has a comparatively low density and, likely, an inflated atmosphere. So this world probably is not a gas giant like Jupiter. Instead, it could well be a planet whose atmosphere will shrink over time. When it finally settles down, it could become a gaseous “mini-Neptune” or even a rocky “super-Earth.” These are the two most common planet types in our galaxy – despite the fact that neither type can be found in our solar system.
The discoverers
A science team led by astronomer Madyson G. Barber of the University of North Carolina at Chapel Hill published the study, “A giant planet transiting a 3 Myr protostar with a misaligned disk,” in the journal Nature in November 2024.
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By NASA
2 min read
NASA-Funded Study Examines Tidal Effects on Planet and Moon Interiors
NASA-supported scientists have developed a new method to compute how tides affect the interiors of planets and moons. Importantly, the new study looks at the effects of body tides on objects that don’t have a perfectly spherical interior structure, which is an assumption of most previous models.
The puzzling, fascinating surface of Jupiter’s icy moon Europa looms large in this newly-reprocessed color view, made from images taken by NASA’s Galileo spacecraft in the late 1990s. This is the color view of Europa from Galileo that shows the largest portion of the moon’s surface at the highest resolution. NASA/JPL-Caltech/SETI Institute Body tides refer to the deformations experienced by celestial bodies when they gravitationally interact with other objects. Think of how the powerful gravity of Jupiter tugs on its moon Europa. Because Europa’s orbit isn’t circular, the crushing squeeze of Jupiter’s gravity on the moon varies as it travels along its orbit. When Europa is at its closest to Jupiter, the planet’s gravity is felt the most. The energy of this deformation is what heats up Europa’s interior, allowing an ocean of liquid water to exist beneath the moon’s icy surface.
“The same is true for Saturn’s moon Enceladus.” says co-author Alexander Berne of CalTech in Pasadena and an affiliate at NASA’s Jet Propulsion Laboratory in Southern California. “Enceladus has an ice shell that is expected to be much more non-spherically symmetric than that of Europa.”
The body tides experienced by celestial bodies can affect how the worlds evolve over time and, in cases like Europa and Enceladus, their potential habitability for life as we know it. The new study provides a means to more accurately estimate how tidal forces affect planetary interiors.
In this movie Europa is seen in a cutaway view through two cycles of its 3.5 day orbit about the giant planet Jupiter. Like Earth, Europa is thought to have an iron core, a rocky mantle and a surface ocean of salty water. Unlike on Earth, however, this ocean is deep enough to cover the whole moon, and being far from the sun, the ocean surface is globally frozen over. Europa’s orbit is eccentric, which means as it travels around Jupiter, large tides, raised by Jupiter, rise and fall. Jupiter’s position relative to Europa is also seen to librate, or wobble, with the same period. This tidal kneading causes frictional heating within Europa, much in the same way a paper clip bent back and forth can get hot to the touch, as illustrated by the red glow in the interior of Europa’s rocky mantle and in the lower, warmer part of its ice shell. This tidal heating is what keeps Europa’s ocean liquid and could prove critical to the survival of simple organisms within the ocean, if they exist. The giant planet Jupiter is now shown to be rotating from west to east, though more slowly than its actual rate. NASA/JPL-Caltech The paper also discusses how the results of the study could help scientists interpret observations made by missions to a variety of different worlds, ranging from Mercury to the Moon to the outer planets of our solar system.
The study, “A Spectral Method to Compute the Tides of Laterally Heterogeneous Bodies,” was published in The Planetary Science Journal.
For more information on NASA’s Astrobiology Program, visit:
https://science.nasa.gov/astrobiology
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Karen Fox / Molly Wasser
Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
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Last Updated Nov 07, 2024 Related Terms
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By NASA
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Preparations for Next Moonwalk Simulations Underway (and Underwater)
A SWOT data visualization shows water on the northern side of Greenland’s Dickson Fjord at higher levels than on the southern side on Sept. 17, 2023. A huge rockslide into the fjord the previous day led to a tsunami lasting nine days that caused seismic rumbling around the world. NASA Earth Observatory Data from space shows water tilting up toward the north side of the Dickson Fjord as it sloshed from south to north and back every 90 seconds for nine days after a 2023 rockslide.
The international Surface Water and Ocean Topography (SWOT) satellite mission, a collaboration between NASA and France’s CNES (Centre National d’Études Spatiales), detected the unique contours of a tsunami that sloshed within the steep walls of a fjord in Greenland in September 2023. Triggered by a massive rockslide, the tsunami generated a seismic rumble that reverberated around the world for nine days. An international research team that included seismologists, geophysicists, and oceanographers recently reported on the event after a year of analyzing data.
The SWOT satellite collected water elevation measurements in Dickson Fjord on Sept. 17, 2023, the day after the initial rockslide and tsunami. The data was compared with measurements made under normal conditions a few weeks prior, on Aug. 6, 2023.
In the data visualization (above), colors toward the red end of the scale indicate higher water levels, and blue colors indicate lower-than-normal levels. The data suggests that water levels at some points along the north side of the fjord were as much as 4 feet (1.2 meters) higher than on the south.
“SWOT happened to fly over at a time when the water had piled up pretty high against the north wall of the fjord,” said Josh Willis, a sea level researcher at NASA’s Jet Propulsion Laboratory in Southern California. “Seeing the shape of the wave — that’s something we could never do before SWOT.”
In a paper published recently in Science, researchers traced a seismic signal back to a tsunami that began when more than 880 million cubic feet of rock and ice (25 million cubic meters) fell into Dickson Fjord. Part of a network of channels on Greenland’s eastern coast, the fjord is about 1,772 feet (540 meters) deep and 1.7 miles (2.7 kilometers) wide, with walls taller than 6,000 feet (1,830 meters).
Far from the open ocean, in a confined space, the energy of the tsunami’s motion had limited opportunity to dissipate, so the wave moved back and forth about every 90 seconds for nine days. It caused tremors recorded on seismic instruments thousands of miles away.
From about 560 miles (900 kilometers) above, SWOT uses its sophisticated Ka-band Radar Interferometer (KaRIn) instrument to measure the height of nearly all water on Earth’s surface, including the ocean and freshwater lakes, reservoirs, and rivers.
“This observation also shows SWOT’s ability to monitor hazards, potentially helping in disaster preparedness and risk reduction,” said SWOT program scientist Nadya Vinogradova Shiffer at NASA Headquarters in Washington.
It can also see into fjords, as it turns out.
“The KaRIn radar’s resolution was fine enough to make observations between the relatively narrow walls of the fjord,” said Lee-Lueng Fu, the SWOT project scientist. “The footprint of the conventional altimeters used to measure ocean height is too large to resolve such a small body of water.”
More About SWOT
Launched in December 2022 from Vandenberg Space Force Base in California, SWOT is now in its operations phase, collecting data that will be used for research and other purposes.
The SWOT satellite was jointly developed by NASA and CNES, with contributions from the Canadian Space Agency (CSA) and the UK Space Agency. NASA’s Jet Propulsion Laboratory, managed for the agency by Caltech in Pasadena, California, leads the U.S. component of the project. For the flight system payload, NASA provided the KaRIn instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations. CNES provided the Doppler Orbitography and Radioposition Integrated by Satellite (DORIS) system, the dual frequency Poseidon altimeter (developed by Thales Alenia Space), the KaRIn radio-frequency subsystem (together with Thales Alenia Space and with support from the UK Space Agency), the satellite platform, and ground operations. CSA provided the KaRIn high-power transmitter assembly. NASA provided the launch vehicle and the agency’s Launch Services Program, based at Kennedy Space Center in Florida, managed the associated launch services.
To learn more about SWOT, visit:
https://swot.jpl.nasa.gov
News Media Contacts
Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307 / 626-379-6874
jane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov
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Last Updated Oct 31, 2024 Related Terms
SWOT (Surface Water and Ocean Topography) Earth Earth Science Earth Science Division Jet Propulsion Laboratory Explore More
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Preparations for Next Moonwalk Simulations Underway (and Underwater)
A natural color view from Cassini of Saturn with its Titan moon in the foreground in August 2012. Titan’s diameter is 50% larger than Earth’s moon.Credit: NASA NASA’s ambitious Cassini mission to Saturn in the late 1990s was one of the agency’s greatest accomplishments, providing unprecedented revelations about the esoteric outer planet and its moons. The complex undertaking was also a tremendous, yet bittersweet, achievement for the Lewis Research Center (today, NASA’s Glenn Research Center in Cleveland), which oversaw the rockets that propelled Cassini to Saturn. Cassini brought a close to over 35 years of Lewis’ management of NASA’s launch vehicles.
Cassini Mission: 5 Things to Know About NASA Lewis’ Last Launch
1. NASA Lewis Launched the Largest and Most Complex Deep-Space Mission to Date
In the early 1980s, NASA began planning the first-ever in-depth study of the planet Saturn. The mission would use the Cassini orbiter designed by NASA’s Jet Propulsion Laboratory in Southern California and the European Space Agency’s Huygens lander. It was one of the heaviest and most complex interplanetary spacecraft ever assembled. Cassini’s plutonium power system and intricate flight path further complicated the mission.
NASA Lewis was responsible for managing the launches of government missions involving the Centaur upper stage and the Atlas and Titan boosters. Cassini’s 6-ton payload forced Lewis to use the U.S. Air Force’s three-stage Titan IV, the most powerful vehicle available, and pair it with the most advanced version of the Centaur, referred to as G-prime.
The Titan IV shroud in the Space Power Facility in October 1990. It was only the second test since the world-class facility had been brought back online after over a decade in standby conditions.Credit: NASA/Quentin Schwinn 2. Lewis Performed Hardware Testing for the Cassini Launch
One of NASA Lewis’ primary launch responsibilities was integrating the payload and upper stages with the booster. This involved balancing weight requirements, providing adequate insulation for Centaur’s cryogenic propellants, determining correct firing times for the stages, and ensuring that that the large shroud, which encapsulated both the upper stage and payload, jettisoned cleanly after launch.
By the time of Cassini, the center had been testing shrouds (including the Titan III fairing) in simulated space conditions for over 25 years. NASA’s Space Power Facility possesses the world’s largest vacuum chamber and was large enough to accommodate the Titan IV’s 86-foot-tall, 16-foot-diameter fairing. In the fall of 1990, the shroud was installed in the chamber, loaded with weights that simulated the payload, and subjected to atmospheric pressures found at an altitude of 72 miles.
The system was successfully separated in less than half a second. Using simulated Cassini and Centaur vehicles, NASA engineers also redesigned a thicker thermal blanket that would protect Cassini’s power system from acoustic vibrations during liftoff.
Members of NASA Lewis’ Launch Vehicle Directorate pose with a Centaur model in May 1979 to mark the 50th successful launch of the Atlas/Centaur.Credit: NASA/Martin Brown 3. Lewis Personnel Assisted with the Launch
In late August 1997, a group of NASA Lewis engineers traveled to NASA’s Kennedy Space Center in Florida to make final preparations for the Cassini launch, working with Air Force range safety personnel at Patrick Air Force Base to ensure a safe launch under all circumstances.
After an aborted launch two days earlier, the vehicle was readied for another attempt in the evening of October 14. Lewis personnel took stations in the Launch Vehicle Data Center inside Hangar AE to monitor the launch vehicle’s temperature, pressure, speed, trajectory, and vibration during the launch. The weather was mild, and the countdown proceeded into the morning hours of October 15 without any major issues.
At 4:43 a.m. EDT, Titan’s first stage and the two massive solid rocket motors roared to life, and the vehicle rose into the dark skies over Florida. The Lewis launch team monitored the flight as the vehicle exited Earth’s atmosphere, Titan burned through its stages, and Centaur sent Cassini out of Earth orbit and on its 2-billion-mile journey to Saturn. After a successful spacecraft separation, Lewis’ responsibilities were complete. The launch had gone exceedingly well.
This illustration depicts the Cassini orbiter with the Huygens lander descending to the Titan moon (left) and Saturn in the background.Credit: NASA 4. Cassini-Huygens Brought a Close to Decades of Lewis Launch Operations
Cassini-Huygens was NASA Lewis’ 119th and final launch, and it brought to a close the center’s decades of launch operations. The center had been responsible for NASA’s upper-stage vehicles since the fall of 1962. The primary stages were the Agena, which had 28 successful launches, and Centaur, which has an even more impressive track record and remains in service today.
While Lewis continued to handle vehicle integration and other technical issues for launches of NASA payloads, in the 1980s, NASA began transferring launch responsibilities to commercial entities. In the mid-1990s, NASA underwent a major realignment that consolidated all launch vehicle responsibilities at NASA Kennedy.
So it was with mixed emotions that around 20 Lewis employees and retirees gathered at the Cleveland center in the early morning hours of Oct. 15, 1997, to watch the Cassini launch. The group held its cheers for 40 minutes after liftoff until Lewis’ responsibilities concluded for the last time with the safe separation of Cassini from Centaur. “In many ways, this is the end of an era, across the agency and, in particular, here at Lewis,” noted one engineer from the Launch Vehicle and Transportation Office.
The Titan IV/Centaur lifts off from Launch Complex 40 at Cape Canaveral on Oct. 15, 1997. NASA Lewis engineers were monitoring the launch from Hangar AE, roughly 3.5 miles to the south. Credit: NASA 5. Cassini Made Groundbreaking Discoveries That Inform Today’s NASA Missions
Cassini’s seven-year voyage to Saturn included flybys of Venus (twice), Earth, and Jupiter so that the planets’ gravitational forces could accelerate the spacecraft. Cassini entered Saturn’s orbit in June 2004 and began relaying data and nearly half a million images back to Earth. Huygens separated from the spacecraft and descended to the surface of the Saturn’s largest moon, Titan, in January 2005. It was the first time a vehicle ever landed on a celestial body in the outer solar system.
Cassini went on to make plunges into the planet’s upper atmosphere and through Saturn’s rings. Scientific information on the mysterious planet, its moons, and rings led to the publication of nearly 4,000 technical papers. After over 13 years and nearly 300 orbits, on Sept. 15, 2017, NASA intentionally sent Cassini plummeting into the atmosphere where it burned up, ending its remarkable mission.
NASA engineers used their experiences from the Cassini mission to help design the Europa Clipper, which is intended to perform flybys of Jupiter’s moon Europa. Europa Clipper launched on Oct. 14.
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Read the “Sending Cassini to Saturn” Series from NASA Glenn Visit NASA’s Cassini-Huygens Website Visit the European Space Agency’s Cassini-Huygens Website Watch NASA Coverage of the Cassini Launch See NASA Glenn’s Historic Centaur Rocket Display
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