Using both archival and recent spectrographic data taken by the Hubble Space Telescope, scientists have discovered water vapor in the atmosphere of Jupiter’s moon Ganymede.

IMAGE: This image presents Jupiter’s moon Ganymede as seen by the NASA/ESA Hubble Space Telescope in 1996. Located over 600 million kilometers away, Hubble can follow changes on the moon and reveal other characteristics at ultraviolet and near-infrared wavelengths. Astronomers have now used archival datasets from Hubble to reveal the first evidence for water vapor in the atmosphere of Jupiter’s moon Ganymede, the result of the thermal escape of water vapor from the moon’s icy surface. CREDIT: ESA/Hubble, NASA, J. Spencer

Sometimes, science is about pretty images. And sometimes, it’s really not. When it comes to examining Hubble Space Telescope images of objects within our solar system, they leave a bit to be desired, especially when it comes to smaller objects, like moons. But Hubble isn’t just about pretty pictures, either.

Onboard Hubble are several spectrographs — instruments that split light into individual wavelengths. One such instrument is the Space Telescope Imaging Spectrograph, which works in wavelengths ranging from near-infrared all the way to ultraviolet. Back in 1998, this instrument took the first ultraviolet pictures of Jupiter’s largest moon Ganymede, and…


Using ALMA, scientists detected a circumplanetary disk around exoplanet PDS 70c, which is a Jupiter-like planet orbiting a star about 400 light-years away.

IMAGE: This image, taken with the Atacama Large Millimeter/submillimeter Array (ALMA), in which ESO is a partner, shows wide (left) and close-up (right) views of the moon-forming disc surrounding PDS 70c, a young Jupiter-like planet nearly 400 light-years away. The close-up view shows PDS 70c and its circumplanetary disc centre-front, with the larger circumstellar ring-like disc taking up most of the right-hand side of the image. The star PDS 70 is at the centre of the wide-view image on the left. CREDIT: ALMA (ESO/NAOJ/NRAO)/Benisty et al.

New observations published in The Astrophysical Journal Letters show that there is a potential exomoon forming around an exoplanet. And we have images!

Using the Atacama Large Millimeter/submillimeter Array (ALMA), scientists detected a circumplanetary disk around exoplanet PDS 70c, which is a Jupiter-like planet orbiting a star about 400 light-years away. This disk surrounds the planet, similar to how protoplanetary disks surround a star, and it’s full of dust that could be turned into a moon. An…


In three new papers, scientists analyzed data from NASA’s InSight lander to reveal the structure of Mars and its crust, lithosphere, mantle, and core.

IMAGE: Artist’s impression of the internal structure of Mars. CREDIT: IPGP / David Ducros

It has been an exciting week in the world of space science, with some revolutionary stories being published. Let’s look at the results from three separate papers released this week in the journal Science on the structure of Mars. The teams involved analyzed data from NASA’s InSight lander. Remember how we told you about how InSight’s seismometer detected hundreds of marsquakes? …


NASA’s Juno spacecraft has observed the interaction of particles from Io’s volcanoes with Jupiter’s massive magnetic field, causing radio transmissions.

IMAGE: This is a representation of the Jupiter-Io system and interaction. The blue cloud is the Io plasma torus, which is a region of higher concentration of ions and electrons located at Io’s orbit. This conceptual image shows the radio emission pattern from Jupiter. The multi-colored lines represent the magnetic field lines that link Io’s orbit with Jupiter’s atmosphere. The radio waves emerge from the source which is located at the line of force in the magnetic field and propagate along the walls of a hollow cone (grey area). Juno receives the signal only when Jupiter’s rotation sweeps that cone over the spacecraft, in the same way a lighthouse beacon shines briefly upon a ship at sea. Juno’s orbit is represented by the white line crossing the cone. CREDIT: NASA/GSFC/Jay Friedlander

By now, most of my audience likely knows that my favorite moon is Io, the closest in of Jupiter’s four Galilean moons. Io is an incredibly volcanic body, constantly being squeezed by the gravitational forces of both Jupiter and two of the other Galilean moons. The squeezing heats up Io’s interior, which then provides the power to generate multiple volcanic eruptions all over the small moon. Images of lava fountains have been captured by the Galileo, Voyager, and New Horizons


Four new teenage planets were found orbiting two separate but related stars in data collected by the TESS spacecraft, adding to the theory of planetary formation.

IMAGE: Short-period planets, or those with orbits shorter than one day, are rare. Potential lava world TOI 1807 b, illustrated here, is the youngest example yet discovered. CREDIT: NASA’s Goddard Space Flight Center/Chris Smith (KBRwyle)

At first glance, this story was interesting because more exoplanets were found, but we’ve been announcing new exoplanets almost steadily for the last decade-plus. Digging a little deeper, this story involves a new paper published in The Astronomical Journal about four new exoplanets that were found orbiting a pair of stars. …


From small meteorites to huge impact craters to tiny diamonds, scientists study rocks of all kinds and gain information about the formation and evolution of our solar system.

IMAGE: The Carina nebula, where newborn stars are irradiated by intense ultraviolet light from nearby massive stars — possibly similar to the environment which birthed our solar system — is pictured over a fragment of Acfer 094. (Carina nebula image: NASA; ESA; N. Smith ,University of California, Berkeley; and The Hubble Heritage Team (STScI/AURA). Acfer 094 image: Ryan Ogliore CREDIT: Ryan Ogliore, Washington University in St. Louis

There is one planet we can observe in detail: our own Earth. And sometimes we are lucky enough to find rocks from elsewhere here that we can analyze and use to learn about our solar system’s history. Understanding that history can help us understand not only our own solar system but exoplanetary systems as well. …


New research helps understand the effects of constant impact gardening on the surface of Jupiter’s moon Europa and how that may affect the search for life.

IMAGE: This image taken by NASA’s Galileo spacecraft in the late 1990s shows Europa’s ice shell, marked by fractures and impact craters, and it evokes a sense of mystery about what lies within it and beneath that shell. The color variations on the surface show that there’s communication between the surface and subsurface, the nature of which is a subject of intense study. This paper helps us to understand the effects of constant surface bombardment on materials that may be available for study at the surface. CREDIT: NASA/JPL-Caltech/SETI Institute

While Enceladus is on the radar for possible life, there are currently no missions planned to go to the tiny world. However, another icy moon, larger and just as interesting, Europa, is on the mission schedule with the Europa Clipper.

New research published in Nature Astronomy examines the results of “impact gardening” on the surface of Europa. For tens of millions of years, small impacts have churned the icy surface down to an average…


A new analysis of MARSIS data from ESA’s Mars Express is processed using an alternative technique from a previous study and reveals that a bright reflection seem under Mars’ south pole may not be liquid water.

IMAGE: Examples of radar slice images of the Martian south polar region from Mars Express and the Mars Reconnaissance Orbiter. CREDIT: NASA/ESA/JPL- Caltech/University of Rome/Washington University in St. Louis

We talk a lot about water on Mars in the planetary science community. It’s an important topic. With plans underway to send humans to the red planet, scientists and engineers are concerned about how to provide the necessary resources for a prolonged mission. …


Three stories take a look at the struggles of finding extraterrestrial life as well as life on Earth.

IMAGE: An artistic representation of the potentially habitable planet Kepler 422-b (left), compared with Earth (right). CREDIT: Ph03nix1986 / Wikimedia Commons

Everything we study about our planet, our solar system, and even exoplanets seems to come back to one big question: Are we alone? It’s a huge question, really. Perseverance is looking for evidence that Mars had life. Phosphine was in the news last year because it could have been a biological marker for Venus. Europa Clipper is in the works, with teams meeting this week to discuss the instruments and science objectives, one of which is to look for molecular signs of…


A trans-Neptunian object has been found and confirmed using data from the Dark Energy Survey, and at the end of this decade, it will make its way almost to Saturn’s orbit.

IMAGE: Computer generated orbital path of 2014 UN271 on 2030–09–28 00:00 UTC. CREDIT: NASA JPL/Solar System Dynamics

This story is one that is just beginning, really. In an article first reported in New Scientist and rapidly being picked up everywhere else, a trans-Neptunian object has been found and confirmed using data from the Dark Energy Survey. The object, called 2014 UN271, was captured in data from 2014, 2016 and 2018, and is either a minor planet or a large comet, somewhere between 100 and 370 kilometers…

Beth Johnson

Planetary scientist, podcast host. Communication specialist for SETI Institute and Planetary Science Institute. Journalist on the Weekly Space Hangout.

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