If Hycean Worlds Really Exist, What are Their Oceans Like?

Artist's impression of possible hycean world K2-18 b. Credit: NASA, ESA, CSA, Joseph Olmsted (STScI)

Astronomers have been on the hunt for a new kind of exoplanet in recent years – one especially suited for habitability. They’re called hycean worlds, and they’re characterized by vast liquid water oceans and thick hydrogen-rich atmospheres. The name was coined in 2021 by Cambridge astronomer Nikku Madhusudhan, whose team got a close-up look at one possible hycean world, K2-18b, using the James Webb Space Telescope in 2023. In a newly accepted paper this January, Madhusudhan and coauthor Frances Rigby examined what the internal structure of hycean planets might look like, and what that means for the possibility of finding life within.

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Solar Eclipses Provide a Rare Way to Study Cloud Formation

Types of solar eclipses. Credits (left to right): Hinode/XRT, NASA/Aubrey Gemignani, NASA/Noah Moran.

April 8’s North American solar eclipse is just around the corner, and it has astronomy fans and weather aficionados alike preparing for an incredible show. But it’s not just fun and games. Eclipses are rare opportunities for scientists to study phenomena that only come around once in a while.

Last week, a team of meteorological experts from the Netherlands released a paper describing how eclipses can disrupt the formation of certain types of clouds. Their findings have implications for futuristic geoengineering schemes that propose to artificially block sunlight to combat climate change.

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China's Chang'e-8 Mission Will Try to Make Bricks on the Moon

Artist's impression of Chang'e-8. Credit: CNSA.

The China National Space Administration (CNSA) has put out a call for international and industry partners to contribute science payloads to its Chang’e-8 lunar lander, set for launch to the Moon in 2028. The mission, which will involve a lander, a rover, and a utility robot, will be China’s first attempt at in-situ resource utilization on the Moon, using lunar regolith to produce brick-like building materials.

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Two Giant Structures Have Been Found Billions of Light-Years Away

Artistic impression of the Giant Arc and the Big Ring on the sky. Background image credit: Stellarium.

The early universe, according to the Standard Model of Cosmology, ought to be a fairly homogenous place, with little structure or arrangement. In 2021, however, astronomers discovered a large pattern of galaxies forming a giant arc 3.3 billion light years across. Now, a second large-scale pattern has emerged. This time, it’s an enormous circle of galaxies, nicknamed the Big Ring. Together, the Giant Arc and the Big Ring present a challenge to the Standard Model, and may send cosmologists back to the drawing board.

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Young Stars in the Outskirts of Galaxies Finally Have an Explanation

Star formation is well understood when it happens in the populous centers of galaxies. From our vantage point on Earth, within the Milky Way, we see it happening all around us. But when newborn stars are birthed in the empty outskirts of galactic space, it requires a new kind of explanation. At the 243rd meeting of the American Astronomical Association yesterday, astronomers announced that they have observed, for the first time, the unique molecular clouds that give rise to star formation near the remote edges of galaxies.

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Iron Snow Could Explain the Magnetic Fields at Worlds Like Ganymede

Iron snow in the core of Ganymede. Credits: Image by Ludovic Huguet and map texture from NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Jupiter’s largest moon, Ganymede, features a surprisingly strong magnetic field for its size. Tidal effects from Jupiter continually stretch and squeeze the moon, keeping its core warm and driving the magnetic field. But the exact geological processes occurring within the core are not fully understood. Now, a new experimental study has put one of the leading models of core dynamics to the test: the formation of crystalized ‘iron snow’.

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Ouch. Canadarm2 Took a Direct Hit From a Micrometeorite

Canadarm with a micrometeorite impact: ESA/NASA-A.Mogensen.

Living in space comes with risks. For astronauts on the International Space Station (ISS), those risks occasionally make themselves intrusively apparent.

Earlier this month, European Space Agency astronaut Andreas Mogensen snapped a photo of the Canadarm2, in which damage from a micrometeorite impact is clearly visible.

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Weather in the Solar System Can Teach Us About Weather on Exoplanets

Image credit: Envato.

The way astronomers study planets in our own solar system is surprisingly similar to the way they study exoplanets, despite the latter being orders of magnitude more distant. The key is spectroscopy – examining the wavelengths of light that reach a telescope from a planet’s atmosphere. Different molecules allow different wavelengths to pass through, creating unique patterns in the spectrum and giving scientists clues about the composition of an atmosphere.

Of course, for planets nearby, we can get more details by visiting them – but this is expensive and difficult – we haven’t visited Uranus since Voyager 2 in 1986, for example, so for all intents and purposes, studying Uranus today is done the same way as studying an exoplanet: with a telescope.

A recent review of planetary atmospheres, in our solar system and elsewhere, reveals the incredible complexity and diversity of weather in our solar system, and what we might expect to find around other stars – but also what we don’t yet understand about our near neighbours: there’s plenty of unknowns.

So let’s take a weather-watcher’s tour of the solar system:

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OSIRIS-REx Failed to Deploy its Drogue Chute Properly. Now NASA has Figured out Why

A training model of the OSIRIS-REx sample return capsule, August 30, 2023. Credit: NASA/Keegan Barber.
A training model of the OSIRIS-REx sample return capsule, August 30, 2023. Credit: NASA/Keegan Barber.

On September 24, 2023, NASA’s OSIRIS-REx mission returned a precious sample of rocky material from asteroid Bennu to Earth. The capsule landed safely under its main parachute, but it arrived more than a minute early. The cause: a small drogue parachute, designed to slow the spacecraft down prior to the main chute’s deployment, failed to open. After an investigation into the mishap, NASA believes they have determined the cause of the (happily non-catastrophic) failure.

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Dimorphos is Probably a Piece of Didymos

NASA/Johns Hopkins APL.

Last September, NASA purposefully smashed a spacecraft into Dimorphos, a 160m-wide space rock orbiting a larger asteroid named Didymos. The goal of the mission, called DART (the Double Asteroid Redirection Test), was to demonstrate humanity’s ability to redirect hazardous asteroids away from Earth. That part of the mission was a success above and beyond all expectations. But now scientists are also learning more about the origins of the two asteroids. A study conducted in the wake of the DART impact found that Dimorphos is made from the same material as Didymos, and that the pair of asteroids likely originated from a single body.

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