Solar System Archives

January 2, 2025January 2, 2025 by Matt Williams

NASA Scientists Discover “Dark Comets” Come in Two Populations.

An artist's concept of a dark comet floating in space. Courtesy Nicole Smith.

On October 19th, 2017, the Panoramic Survey Telescope and Rapid Response System-1 (Pan-STARRS-1) in Hawaii announced the first-ever detection of an interstellar object, named 1I/2017 U1 ‘Oumuamua (the Hawaiin word for “scout”). This object created no shortage of confusion since it appeared as an asteroid but behaved like a comet (based on the way it accelerated out of the Solar System). Since then, scientists have noticed a lot of other objects that behave the same way, known as “dark comets.”

These objects are defined as “small bodies with no detected coma that have significant nongravitational accelerations explainable by outgassing of volatiles,” much like ‘Oumuamua. In a recent NASA-supported study, a team of researchers identified seven more of these objects in the Solar System, doubling the number of known dark comets. Even more important, the researchers were able to discern two distinct populations. They consist of larger objects that reside in the outer Solar System and smaller ones in the inner Solar System.

December 18, 2024December 18, 2024 by Matt Williams

New Research Suggests Io Doesn’t Have a Shallow Ocean of Magma

NASA’s Galileo spacecraft captured this image of a volcanic eruption on Io in 1997. Image Credit:NASA, NASA-JPL, DLR

Jupiter’s moon Io is the most volcanically active body in the Solar System, with roughly 400 active volcanoes regularly ejecting magma into space. This activity arises from Io’s eccentric orbit around Jupiter, which produces incredibly powerful tidal interactions in the interior. In addition to powering Io’s volcanism, this tidal energy is believed to support a global subsurface magma ocean. However, the extent and depth of this ocean remains the subject of debate, with some supporting the idea of a shallow magma ocean while others believe Io has a more rigid, mostly solid interior.

In a recent NASA-supported study, an international team of researchers combined data from multiple missions to measure Io’s tidal deformation. According to their findings, Io does not possess a magma ocean and likely has a mostly solid mantle. Their findings further suggest that tidal forces do not necessarily lead to global magma oceans on moons or planetary bodies. This could have implications for the study of exoplanets that experience tidal heating, including Super-Earths and exomoons similar to Io that orbit massive gas giants.

December 10, 2024December 10, 2024 by Mark Thompson

An Interstellar Visitor Helped Shape the Orbits of the Planets.

This artist’s impression illustrates an interstellar object rapidly approaching our Solar System. The object, ejected from its home planetary system long ago, traveled through interstellar space for billions of years before briefly passing through our cosmic neighborhood. Rubin Observatory will reveal many of these previously unknown interstellar visitors. Alt-Text: An artist’s impression of a small, rocky interstellar object hurtling from the upper right toward the inner Solar System. The orbits of the four inner planets (Mercury, Venus, Earth, Mars) are fully visible, drawn as teal concentric circles around the bright ball of the Sun at the center. We see the orbits from a slightly elevated angle, so that the circular paths appear oval. The black background is sprinkled with points of starlight. The interstellar object looks like an elongated potato above the Sun, streaming toward the Sun from the upper right, with a short tail of gas and dust trailing behind.

The orbits of the planets around the Sun have been the source for many a scientific debate. Their current orbital properties are well understood but the planetary orbits have evolved and changed since the formation of the Solar System. Planetary migrations have been the most prominent idea of recent decades suggesting that planetary interactions caused the young planets to migrate inwards or outwards from their original positions. Now a new theory suggests 2-50 Jupiter mass object passing through the Solar System could be the cause.

December 3, 2024December 3, 2024 by David Dickinson

Catch Jupiter at Opposition 2024 This Coming Weekend

Now is the time to catch Jupiter at its best.

The King of the Planets rules the winter night skies. Early December gives sky watchers a good reason to brave the cold, as Jupiter shines at its best. Look for the regal planet rising in the east at sunset, while the Sun sets to the west.

October 28, 2024October 28, 2024 by Mark Thompson

Astronauts Could Take an Asteroid Ferry from Earth to Mars

This idea really is quite a fascinating one. Currently a trip to Mars would require large amounts of air, water and other resources to sustain human life but would also expose travellers to harmful levels of radiation. A wonderful solution has been proposed in a new paper recently published by researchers from Ukraine. They propose that asteroids which already travel relatively close by Earth, Mars and even Venus already could be used to hop between the planets. They are already making the journey anyway and so perhaps the cosmos already provides the solution to interplanetary travel.

October 22, 2024October 22, 2024 by Matt Williams

New Research Reveals Provides Insight into Mysterious Features on Airless Worlds

Artist's rendition of the Dawn mission on approach to the protoplanet Ceres. Credit: NASA/JPL

Between 2011 and 2018, NASA’s Dawn mission conducted extended observations of Ceres and Vesta, the largest bodies in the Main Asteroid Belt. The mission’s purpose was to address questions about the formation of the Solar System since asteroids are leftover material from the process, which began roughly 4.5 billion years ago. Ceres and Vesta were chosen because Ceres is largely composed of ice, while Vesta is largely composed of rock. During the years it orbited these bodies, Dawn revealed several interesting features on their surfaces.

This included mysterious flow features similar to those observed on other airless bodies like Jupiter’s moon Europa. In a recent study, Michael J. Poston, a researcher from the Southwest Research Institute (SWRI), recently collaborated with a team at NASA’s Jet Propulsion Laboratory to attempt to explain the presence of these features. In the paper detailing their findings, they outlined how post-impact conditions could temporarily produce liquid brines that flow along the surface, creating curved gullies and depositing debris fans along the impact craters’ walls.

October 17, 2024October 19, 2024 by Matt Williams

Establishing a New Habitability Metric for Future Astrobiology Surveys

An illustration of the variations among the more than 5,000 known exoplanets discovered since the 1990s. Could their stars' metallicity play a role in making them habitable to life? Credit: NASA/JPL-Caltech

The search for exoplanets has grown immensely in recent decades thanks to next-generation observatories and instruments. The current census is 5,766 confirmed exoplanets in 4,310 systems, with thousands more awaiting confirmation. With so many planets available for study, exoplanet studies and astrobiology are transitioning from the discovery process to characterization. Essentially, this means that astronomers are reaching the point where they can directly image exoplanets and determine the chemical composition of their atmospheres.

As always, the ultimate goal is to find terrestrial (rocky) exoplanets that are “habitable,” meaning they could support life. However, our notions of habitability have been primarily focused on comparisons to modern-day Earth (i.e., “Earth-like“), which has come to be challenged in recent years. In a recent study, a team of astrobiologists considered how Earth has changed over time, giving rise to different biosignatures. Their findings could inform future exoplanet searches using next-generation telescopes like the Habitable Worlds Observatory (HWO), destined for space by the 2040s.

October 15, 2024October 15, 2024 by Matt Williams

China Releases its First Roadmap for Space Science and Exploration Through 2050.

China has released its first national plan for space 2024 and 2050. Credit: CFP

China’s space program has advanced considerably since the turn of the century. In addition to developing heavy-launch vehicles like the Long March 5 and building a modular space station in orbit, China has also embarked on an ambitious program of lunar exploration (Chang’e) – which has launched six robotic missions to explore the Moon’s surface since 2007. These missions are paving the way for crewed missions to the Moon by 2030 and creating a permanent habitat around the Moon’s southern polar region – the International Lunar Research Station (ILRS).

They also plan to send crewed missions to Mars by 2033, which will culminate in the creation of a permanent base there too. Earlier today, the Chinese Academy of Sciences (CAS), the China National Space Administration (CNSA), and the China Manned Space Agency (CMSE) jointly released the country’s first long-term scheme for space science and exploration. Titled “National Medium—and Long-Term Development Plan for Space Science (2024-2050),” this plan elaborated on the basic principles, development goals, and roadmap for the country’s space science and exploration through 2050.

October 12, 2024October 14, 2024 by Matt Williams

A Possible Exomoon Could be Volcanic, like Jupiter’s Moon Io

New NASA-led research suggests a sodium cloud seen around the exoplanet WASP-49 b might be created by a volcanic moon, which is depicted in this artist’s concept. Jupiter’s fiery moon Io produces a similar cloud. Credit: NASA/JPL-Caltech

In 2012, astronomers detected a gas giant transiting in front of WASP-49A, a G-type star located about 635 light-years from Earth. The data obtained by the WASP survey indicated that this exoplanet (WASP-49 b) is a gas giant roughly the same size as Jupiter and 37% as massive. In 2017, WASP-49 b was found to have an extensive cloud of sodium, which was confounding to scientists. Further observations in 2019 using the Hubble Space Telescope detected the presence of other minerals, including magnesium and iron, which appeared to be magnetically bound to the gas giant.

WASP-49 b and its star are predominantly composed of hydrogen and helium, with only trace amounts of sodium – not enough to account for this cloud. In addition, there was no indication of how this sodium cloud was ejected into space. In our Solar System, gas emissions from Jupiter’s volcanic moon Io create a similar phenomenon. In a recent study, an international team led by scientists from NASA’s Jet Propulsion Laboratory found potential evidence of a rocky, volcanic moon orbiting WASP-49 b. While not yet confirmed, the presence of a volcanic exomoon around this gas giant could explain the presence of this sodium cloud.

October 6, 2024October 6, 2024 by Matt Williams

Primordial Holes Could be Hiding in Planets, Asteroids, and Here on Earth

An artistic take on primordial black holes. Credit: NASA’s Goddard Space Flight Center

Small primordial black holes (PBHs) are one of the hot topics in astronomy and cosmology today. These hypothetical black holes are believed to have formed soon after the Big Bang, resulting from pockets of subatomic matter so dense that they underwent gravitational collapse. At present, PBHs are considered a candidate for dark matter, a possible source of primordial gravitational waves, and a resolution to various problems in physics. However, no definitive PBH candidate has been observed so far, leading to proposals for how we may find these miniature black holes.

Recent research has suggested that main-sequence neutron and dwarf stars might contain small PBHs in their interiors that are slowly consuming their gas supply. In a recent study, a team of physicists extended this idea to include a new avenue for potentially detecting PBHs. Basically, we could search inside objects like planets and asteroids or employ large plates or slabs of metal to detect PBHs for signs of their passage. By detecting the microchannels these bodies would leave, scientists could finally confirm the existence of PBHs and shed light on some of the greatest mysteries in cosmology today.