NASA’s Juno Mission Spots Jupiter’s Tiny Moon Amalthea
NASA’s Juno mission captured these views of Jupiter during its 59th close flyby of the giant planet on March 7, 2024. They provide a good look at Jupiter’s colorful belts and swirling storms, including the Great Red Spot. Close examination reveals something more: two glimpses of the tiny moon Amalthea (see Figure B below).
Figure B NASA’s Juno mission captured these views of Jupiter during its 59th close flyby of the giant planet on March 7, 2024. They provide a good look at Jupiter’s colorful belts and swirling storms, including the Great Red Spot. Close examination reveals something more: two glimpses of the tiny moon Amalthea.Image data: NASA/JPL-Caltech/SwRI/MSSS. Image processing by Gerald Eichstädt
With a radius of just 52 miles (84 kilometers), Amalthea has a potato-like shape, lacking the mass to pull itself into a sphere. In 2000, NASA’s Galileo spacecraft revealed some surface features, including impact craters, hills, and valleys. Amalthea circles Jupiter inside Io’s orbit, which is the innermost of the planet’s four largest moons, taking 0.498 Earth days to complete one orbit.
Amalthea is the reddest object in the solar system, and observations indicate it gives out more heat than it receives from the Sun. This may be because, as it orbits within Jupiter’s powerful magnetic field, electric currents are induced in the moon’s core. Alternatively, the heat could be from tidal stresses caused by Jupiter’s gravity.
At the time that the first of these two images was taken, the Juno spacecraft was about 165,000 miles (265,000 kilometers) above Jupiter’s cloud tops, at a latitude of about 5 degrees north of the equator.
Citizen scientist Gerald Eichstädt made these images using raw data from the JunoCam instrument, applying processing techniques to enhance the clarity of the images.
JunoCam’s raw images are available for the public to peruse and process into image products at https://missionjuno.swri.edu/junocam/processing. More information about NASA citizen science can be found at https://science.nasa.gov/citizenscience and https://www.nasa.gov/solve/opportunities/citizenscience.
More information about Juno is at https://www.nasa.gov/juno and https://missionjuno.swri.edu. For more about this finding and other science results, see https://www.missionjuno.swri.edu/science-findings.
Image credit:
Image data: NASA/JPL-Caltech/SwRI/MSSS
Image processing by Gerald Eichstädt
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NASA’s Webb Hints at Possible Atmosphere Surrounding Rocky Exoplanet
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NASA’s Webb Hints at Possible Atmosphere Surrounding Rocky Exoplanet This artist’s concept shows what the exoplanet 55 Cancri e could look like. Observations by NASA’s Webb telescope suggest it may be surrounded by an atmosphere rich in carbon dioxide or carbon monoxide, which could have bubbled up from of an ocean of magma on the planet’s surface.
While the planet is too hot to be habitable, detecting its atmosphere could provide insights into the early conditions of Earth, Venus, and Mars.
Researchers using NASA’s James Webb Space Telescope may have detected atmospheric gases surrounding 55 Cancri e, a hot rocky exoplanet 41 light-years from Earth. This is the best evidence to date for the existence of any rocky planet atmosphere outside our solar system.
Renyu Hu from NASA’s Jet Propulsion Laboratory in Southern California is lead author on a paper published today in Nature. “Webb is pushing the frontiers of exoplanet characterization to rocky planets,” Hu said. “It is truly enabling a new type of science.”
Super-Hot Super-Earth 55 Cancri e55 Cancri e, also known as Janssen, is one of five known planets orbiting the Sun-like star 55 Cancri, in the constellation Cancer. With a diameter nearly twice that of Earth and density slightly greater, the planet is classified as a super-Earth: larger than Earth, smaller than Neptune, and likely similar in composition to the rocky planets in our solar system.
Data from the Mid-Infrared Instrument on NASA’s Webb telescope shows the decrease in brightness of the 55 Cancri system as the rocky planet 55 Cancri e moves behind the star, a phenomenon known as a secondary eclipse. The data indicates that the planet’s dayside temperature is about 2,800 degrees Fahrenheit.
To describe 55 Cancri e as “rocky,” however, could leave the wrong impression. The planet orbits so close to its star (about 1.4 million miles, or one-twenty-fifth the distance between Mercury and the Sun) that its surface is likely to be molten — a bubbling ocean of magma. With such a tight orbit, the planet is also likely to be tidally locked, with a dayside that faces the star at all times and a nightside in perpetual darkness.
In spite of numerous observations since it was discovered to transit in 2011, the question of whether or not 55 Cancri e has an atmosphere — or even could have one given its high temperature and the continuous onslaught of stellar radiation and wind from its star — has gone unanswered.
“I’ve worked on this planet for more than a decade,” said Diana Dragomir, an exoplanet researcher at the University of New Mexico and co-author on the study. “It’s been really frustrating that none of the observations we’ve been getting have robustly solved these mysteries. I am thrilled that we’re finally getting some answers!”
Unlike the atmospheres of gas giant planets, which are relatively easy to spot (the first was detected by NASA’s Hubble Space Telescope more than two decades ago), thinner and denser atmospheres surrounding rocky planets have remained elusive.
Previous studies of 55 Cancri e using data from NASA’s now-retired Spitzer Space Telescope suggested the presence of a substantial atmosphere rich in volatiles (molecules that occur in gas form on Earth) like oxygen, nitrogen, and carbon dioxide. But researchers could not rule out another possibility: that the planet is bare, save for a tenuous shroud of vaporized rock, rich in elements like silicon, iron, aluminum, and calcium. “The planet is so hot that some of the molten rock should evaporate,” explained Hu.
Measuring Subtle Variations in Infrared ColorsTo distinguish between the two possibilities, the team used Webb’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument) to measure 4- to 12-micron infrared light coming from the planet.
A thermal emission spectrum of the exoplanet 55 Cancri e — captured by the NIRCam instrument, GRISM Spectrometer, and MIRI Low-Resolution Spectrometer on NASA’s Webb telescope — shows that the planet may be surrounded by an atmosphere rich in carbon dioxide or carbon monoxide and other volatiles.
Although Webb cannot capture a direct image of 55 Cancri e, it can measure subtle changes in light from the system as the planet orbits the star.
By subtracting the brightness during the secondary eclipse, when the planet is behind the star (starlight only), from the brightness when the planet is right beside the star (light from the star and planet combined), the team was able to calculate the amount of various wavelengths of infrared light coming from the dayside of the planet.
This method, known as secondary eclipse spectroscopy, is similar to that used by other research teams to search for atmospheres on other rocky exoplanets, like TRAPPIST-1 b.
Cooler Than ExpectedThe first indication that 55 Cancri e could have a substantial atmosphere came from temperature measurements based on its thermal emission, or heat energy given off in the form of infrared light. If the planet is covered in dark molten rock with a thin veil of vaporized rock or no atmosphere at all, the dayside should be around 4,000 degrees Fahrenheit (~2,200 degrees Celsius).
“Instead, the MIRI data showed a relatively low temperature of about 2,800 degrees Fahrenheit [~1540 degrees Celsius],” said Hu. “This is a very strong indication that energy is being distributed from the dayside to the nightside, most likely by a volatile-rich atmosphere.” While currents of lava can carry some heat around to the nightside, they cannot move it efficiently enough to explain the cooling effect.
When the team looked at the NIRCam data, they saw patterns consistent with a volatile-rich atmosphere. “We see evidence of a dip in the spectrum between 4 and 5 microns — less of this light is reaching the telescope,” explained co-author Aaron Bello-Arufe, also from NASA JPL. “This suggests the presence of an atmosphere containing carbon monoxide or carbon dioxide, which absorb these wavelengths of light.” A planet with no atmosphere or an atmosphere consisting only of vaporized rock would not have this specific spectral feature.
“We’ve spent the last 10 years modeling different scenarios, trying to imagine what this world might look like,” said co-author Yamila Miguel from the Leiden Observatory and the Netherlands Institute for Space Research (SRON). “Finally getting some confirmation of our work is priceless!”
Bubbling Magma OceanThe team thinks that the gases blanketing 55 Cancri e would be bubbling out from the interior rather than being present ever since the planet formed. “The primary atmosphere would be long gone because of the high temperature and intense radiation from the star,” said Bello-Arufe. “This would be a secondary atmosphere that is continuously replenished by the magma ocean. Magma is not just crystals and liquid rock; there’s a lot of dissolved gas in it, too.”
While 55 Cancri e is far too hot to be habitable, researchers think it could provide a unique window for studying interactions between atmospheres, surfaces, and interiors of rocky planets, and perhaps provide insights into the early conditions of Earth, Venus, and Mars, which are thought to have been covered in magma oceans far in the past.
“Ultimately, we want to understand what conditions make it possible for a rocky planet to sustain a gas-rich atmosphere: a key ingredient for a habitable planet,” said Hu.
This research was conducted as part of Webb’s General Observers (GO) Program 1952. Analysis of additional secondary eclipse observations of 55 Cancri e are currently in progress.
More About the MissionThe James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.
MIRI was developed through a 50-50 partnership between NASA and ESA. A division of Caltech in Pasadena, California, JPL led the U.S. efforts for MIRI, and a multinational consortium of European astronomical institutes contributes for ESA. George Rieke with the University of Arizona is the MIRI science team lead. Gillian Wright is the MIRI European principal investigator.
The MIRI cryocooler development was led and managed by JPL, in collaboration with Northrop Grumman in Redondo Beach, California, and NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
News Media ContactsLaura Betz / Rob Gutro
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Margaret Carruthers / Christine Pulliam
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mcarruthers@stsci.edu / cpulliam@stsci.edu
Calla Cofield
Jet Propulsion Laboratory, Pasadena, Calif.
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Share Details Last Updated May 08, 2024 Related Terms- 55 Cancri e
- Exoplanet Atmosphere
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A secondary atmosphere on the rocky Exoplanet 55 Cancri eNew NASA Black Hole Visualization Takes Viewers Beyond the Brink
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New NASA Black Hole Visualization Takes Viewers Beyond the BrinkEver wonder what happens when you fall into a black hole? Now, thanks to a new, immersive visualization produced on a NASA supercomputer, viewers can plunge into the event horizon, a black hole’s point of no return.
In this visualization of a flight toward a supermassive black hole, labels highlight many of the fascinating features produced by the effects of general relativity along the way. Produced on a NASA supercomputer, the simulation tracks a camera as it approaches, briefly orbits, and then crosses the event horizon — the point of no return — of a monster black hole much like the one at the center of our galaxy. Credit: NASA’s Goddard Space Flight Center/J. Schnittman and B. PowellView the plunge in 360 video on YouTube
“People often ask about this, and simulating these difficult-to-imagine processes helps me connect the mathematics of relativity to actual consequences in the real universe,” said Jeremy Schnittman, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who created the visualizations. “So I simulated two different scenarios, one where a camera — a stand-in for a daring astronaut — just misses the event horizon and slingshots back out, and one where it crosses the boundary, sealing its fate.”
The visualizations are available in multiple forms. Explainer videos act as sightseeing guides, illuminating the bizarre effects of Einstein’s general theory of relativity. Versions rendered as 360-degree videos let viewers look all around during the trip, while others play as flat all-sky maps.
To create the visualizations, Schnittman teamed up with fellow Goddard scientist Brian Powell and used the Discover supercomputer at the NASA Center for Climate Simulation. The project generated about 10 terabytes of data — equivalent to roughly half of the estimated text content in the Library of Congress — and took about 5 days running on just 0.3% of Discover’s 129,000 processors. The same feat would take more than a decade on a typical laptop.
The destination is a supermassive black hole with 4.3 million times the mass of our Sun, equivalent to the monster located at the center of our Milky Way galaxy.
“If you have the choice, you want to fall into a supermassive black hole,” Schnittman explained. “Stellar-mass black holes, which contain up to about 30 solar masses, possess much smaller event horizons and stronger tidal forces, which can rip apart approaching objects before they get to the horizon.”
This occurs because the gravitational pull on the end of an object nearer the black hole is much stronger than that on the other end. Infalling objects stretch out like noodles, a process astrophysicists call spaghettification.
The simulated black hole’s event horizon spans about 16 million miles (25 million kilometers), or about 17% of the distance from Earth to the Sun. A flat, swirling cloud of hot, glowing gas called an accretion disk surrounds it and serves as a visual reference during the fall. So do glowing structures called photon rings, which form closer to the black hole from light that has orbited it one or more times. A backdrop of the starry sky as seen from Earth completes the scene.
Tour an alternative visualization that tracks a camera as it approaches, falls toward, briefly orbits, and escapes a supermassive black hole. This immersive 360-degree version allows viewers to look around during the flight. Credit: NASA’s Goddard Space Flight Center/J. Schnittman and B. PowellView the flyby explainer on YouTube
As the camera approaches the black hole, reaching speeds ever closer to that of light itself, the glow from the accretion disk and background stars becomes amplified in much the same way as the sound of an oncoming racecar rises in pitch. Their light appears brighter and whiter when looking into the direction of travel.
The movies begin with the camera located nearly 400 million miles (640 million kilometers) away, with the black hole quickly filling the view. Along the way, the black hole’s disk, photon rings, and the night sky become increasingly distorted — and even form multiple images as their light traverses the increasingly warped space-time.
In real time, the camera takes about 3 hours to fall to the event horizon, executing almost two complete 30-minute orbits along the way. But to anyone observing from afar, it would never quite get there. As space-time becomes ever more distorted closer to the horizon, the image of the camera would slow and then seem to freeze just shy of it. This is why astronomers originally referred to black holes as “frozen stars.”
At the event horizon, even space-time itself flows inward at the speed of light, the cosmic speed limit. Once inside it, both the camera and the space-time in which it’s moving rush toward the black hole’s center — a one-dimensional point called a singularity, where the laws of physics as we know them cease to operate.
“Once the camera crosses the horizon, its destruction by spaghettification is just 12.8 seconds away,” Schnittman said. From there, it’s only 79,500 miles (128,000 kilometers) to the singularity. This final leg of the voyage is over in the blink of an eye.
In the alternative scenario, the camera orbits close to the event horizon but it never crosses over and escapes to safety. If an astronaut flew a spacecraft on this 6-hour round trip while her colleagues on a mothership remained far from the black hole, she’d return 36 minutes younger than her colleagues. That’s because time passes more slowly near a strong gravitational source and when moving near the speed of light.
“This situation can be even more extreme,” Schnittman noted. “If the black hole were rapidly rotating, like the one shown in the 2014 movie ‘Interstellar,’ she would return many years younger than her shipmates.”
Download high-resolution video and images from NASA’s Scientific Visualization Studio
By Francis Reddy
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
Claire Andreoli
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- Astrophysics
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Hubble Views a Galaxy with a Voracious Black Hole
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Hubble Views a Galaxy with a Voracious Black Hole This NASA Hubble Space Telescope image features the spiral galaxy NGC 4951, located roughly 50 million light-years away from Earth.
Bright, starry spiral arms surround an active galactic center in this new NASA Hubble Space Telescope image of the galaxy NGC 4951.
Located in the Virgo constellation, NGC 4951 is located roughly 50 million light-years away from Earth. It’s classified as a Seyfert galaxy, which means that it’s an extremely energetic type of galaxy with an active galactic nucleus (AGN). However, Seyfert galaxies are unique from other sorts of AGNs because the galaxy itself can still be clearly seen – different types of AGNs are so bright that it’s nearly impossible to observe the actual galaxy that they reside within.
AGNs like NGC 4951 are powered by supermassive black holes. As matter whirls into the black hole, it generates radiation across the entire electromagnetic spectrum, making the AGN shine brightly.
Hubble helped prove that supermassive black holes exist at the core of almost every galaxy in our universe. Before the telescope launched into low-Earth orbit in 1990, astronomers only theorized about their existence. The mission verified their existence by observing the undeniable effects of black holes, like jets of material ejecting from black holes and disks of gas and dust revolving around those black holes at very high speeds.
These observations of NGC 4951 were taken to provide valuable data for astronomers studying how galaxies evolve, with a particular focus on the star formation process. Hubble gathered this information, which is being combined with observations with the James Webb Space Telescope (JWST) to support a JWST Treasury program. Treasury programs collect observations that focus on the potential to solve multiple scientific problems with a single, coherent dataset and enable a variety of compelling scientific investigations.
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Hubble Hunts Visible Light Sources of X-Rays
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Hubble Hunts Visible Light Sources of X-Rays This NASA/ESA Hubble Space Telescope image features the dwarf galaxy IC 776. ESA/Hubble & NASA, M. Sun
This NASA/ESA Hubble Space Telescope image features the dwarf galaxy IC 776. This swirling collection of new and old stars is located in the constellation Virgo, in the Virgo galaxy cluster, 100 million light-years from Earth. Although IC 776 is a dwarf galaxy, it’s also classified as a SAB-type or ‘weakly barred’ spiral. This highly detailed Hubble view demonstrates that complexity. IC 776 has a ragged, disturbed disc that appears to spiral around the core with arcs of star-forming regions.
The image is from an observation program dedicated to the study of dwarf galaxies in the Virgo cluster that is searching for the visible light emissions from sources of X-rays in these galaxies. X-rays are often emitted by accretion discs, where material that is drawn into a compact object by gravity crashes together and forms a hot, glowing disc. The compact object can be a white dwarf or neutron star in a binary pair that is stealing material from its companion star, or it can be the supermassive black hole at the heart of a galaxy devouring material around it. Dwarf galaxies like IC 776, traveling through the Virgo cluster, experience pressure from intergalactic gas that is similar to the pressure you feel from air hitting your face when you ride a bicycle. This intergalactic gas pressure can both stimulate star formation and feed the central black hole in a galaxy. As more material swirls down toward the black hole, it creates an energetic accretion disc, hot enough to emit X-rays.
While Hubble is not able to see X-rays, it can coordinate with X-ray telescopes such as NASA’s Chandra X-Ray Observatory, revealing the sources of this radiation in high resolution using visible light. Dwarf galaxies are very important to our understanding of cosmology and the evolution of galaxies. As with many areas of astronomy, the ability to examine these galaxies across the electromagnetic spectrum is critical to their study.
Text Credit: European Space Agency (ESA)
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Never mind little green men: life on other planets might be purple
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