The Search for Exomoons is On

An artist's conception of a potentially-habitable exomoon. It seems reasonable that exoplanets have exomoons, and now we're going to look for them. Credit: NASA

Moons are the norm in our Solar System. The International Astronomical Union recognizes 288 planetary moons, and more keep being discovered. Saturn has a whopping 146 moons. Every planet except Mercury and Venus has moons, and their lack of moons is attributed to their small size and proximity to the Sun.

It seems reasonable that there are moons around exoplanets in other Solar Systems, and now we’re going to start looking for them with the James Webb Space Telescope.

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A Stellar Flyby Jumbled Up the Outer Solar System

This is a screenshot from a supercomputer simulation. It shows how an ancient stellar flyby shaped the Solar System. Among other things, the flyby can explain the Solar System's population of irregular moons. Image Credit: Forschungszentrum Jülich

An ancient passerby may have visited the Sun and inadvertently helped shape the Solar System into what it is today. It happened billions of years ago when a stellar drifter came to within 110 astronomical units (AU) of our Sun. The effects were long-lasting and we can see evidence of the visitor’s fleeting encounter throughout the Solar System.

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Comparing Two Proposed NASA Missions to Jupiter’s Moon Io

Juno captured this image of Io during Perijove 57. Data from Juno's JIRAM instrument is helping researchers understand how tidal heating shapes the moon's volcanic activity. Image Credit: NASA / SWRI / MSSS / Jason Perry © cc nc sa

Thanks to NASA’s Juno mission to the Jupiter system, we’re getting our best looks ever at the gas giant’s volcanic moon Io. Even as Juno provides our best views of the moon, it also deepens our existing questions. Only a dedicated mission to Io can answer those questions, and there are two proposed missions.

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If We Want To Find Life-Supporting Worlds, We Should Focus on Small Planets With Large Moons

A rocky planet with a large moon may have good potential to host life, given that the Moon controls essential aspects for life on Earth, including the length of the day, ocean tides, and stable climate. Image Credit: University of Rochester photo illustration by Michael Osadciw featuring Unsplash photography from Brad Fickeisen, Jaanus Jagomagi, and Engin Akyurt

There’s no perfect way of doing anything, including searching for exoplanets. Every planet-hunting method has some type of bias. We’ve found most exoplanets using the transit method, which is biased toward larger planets. Larger planets closer to their stars block more light, meaning we detect large planets transiting in front of their stars more readily than we detect small ones.

That’s a problem because some research says that life-supporting planets are more likely to be small, like Earth. It’s all because of moons and streaming instability.

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How Mars’ Moon Phobos Captures Our Imaginations

This is a colourized version of a black and white image captured by the ESA's Mars Express in 2010. Andrea Luck, a skilled image processor from Glasgow, improved the original image. Image Credit: ESA/DLR/FUBerlin/AndreaLuck CC BY. Original Image: https://www.planetary.org/space-images/20130714_phobosnd_img

For a small, lumpy chunk of rock that barely reflects any light, Mars’ Moon Phobos draws a lot of attention. Maybe because it’s one of only two moons to orbit the planet, and its origins are unclear. But some of the attention is probably because we have such great images of it.

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Are Titan's Dunes Made of Comet Dust?

Two different dune fields on Titan: Belet and Fensal, as imaged by Cassini’s radar. It also shows two similar dune fields on Earth in Rub Al Khali, Saudi Arabia. CREDIT NASA/JPL–Caltech/ASI/ESA and USGS/ESA
Two different dune fields on Titan: Belet and Fensal, as imaged by Cassini’s radar. It also shows two similar dune fields on Earth in Rub Al Khali, Saudi Arabia. Credit: NASA/JPL–Caltech/ASI/ESA and USGS/ESA

A new theory suggests that Titan’s majestic dune fields may have come from outer space. Researchers had always assumed that the sand making up Titan’s dunes was locally made, through erosion or condensed from atmospheric hydrocarbons. But researchers from the University of Colorado want to know: Could it have come from comets?

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Did An Ancient Icy Impactor Create the Martian Moons?

A composite image of Mars and its two moons, Phobos (foreground) and Deimos (background). Credit: NASA/JPL/University of Arizona

The Martian moons Phobos and Deimos are oddballs. While other Solar System moons are round, Mars’ moons are misshapen and lumpy like potatoes. They’re more like asteroids or other small bodies than moons.

Because of their odd shapes and unusual compositions, scientists are still puzzling over their origins.

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A Single Grain of Ice Could Hold Evidence of Life on Europa and Enceladus

The Cassini spacecraft captured this image of cryovolcanic plumes erupting from Enceladus' ice-capped ocean. Image Credit: NASA/JPL/CalTech

The Solar System’s icy ocean moons are primary targets in our search for life. Missions to Europa and Enceladus will explore these moons from orbit, improving our understanding of them and their potential to support life. Both worlds emit plumes of water from their internal oceans, and the spacecraft sent to both worlds will examine those plumes and even sample them.

New research suggests that evidence of life in the moons’ oceans could be present in just a single grain of ice, and our spacecraft can detect it.

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Europe Has Big Plans for Saturn’s Moon Enceladus

A false-colour image of the plumes erupting from Enceladus. Image Credit: NASA/ESA
A false-colour image of the plumes erupting from Enceladus. Image Credit: NASA/ESA

Saturn’s moon, Enceladus, is a gleaming beacon that captivates our intellectual curiosity. Its clean, icy surface makes it one of the most reflective objects in the entire Solar System. But it’s what’s below that ice that really gets scientists excited.

Under its icy shell is an ocean of warm, salty water, and the ESA says investigating the moon should be a top priority.

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What Can We Learn Flying Through the Plumes at Enceladus?

The Cassini spacecraft captured this image of cryovolcanic plumes erupting from Enceladus' ice-capped ocean. Image Credit: NASA/JPL/CalTech

In the next decade, space agencies will expand the search for extraterrestrial life beyond Mars, where all of our astrobiology efforts are currently focused. This includes the ESA’s JUpiter ICy moon’s Explorer (JUICE) and NASA’s Europa Clipper, which will fly past Europa and Ganymede repeatedly to study their surfaces and interiors. There’s also NASA’s proposed Dragonfly mission that will fly to Titan and study its atmosphere, methane lakes, and the rich organic chemistry happening on its surface. But perhaps the most compelling destination is Enceladus and the lovely plumes emanating from its southern polar region.

Since the Cassini mission got a close-up look at these plumes, scientists have been aching to send a robotic mission there to sample them – which appear to have all the ingredients for life in them. This is not as easy as it sounds, and there’s no indication flying through plumes will yield intact samples. In a recent paper, researchers from the University of Kent examined how the velocity of a passing spacecraft (and the resulting shock of impact) could significantly affect its ability to sample water and ice within the plumes.

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