Perseverance Sees Phobos, Deimos and Mercury Passing in Front of the Sun

NASA's Perseverance Mars rover used its Mastcam-Z camera to capture the silhouette of Phobos, the larger of Mars' pair of moons, as it passed in front of the Sun on Feb. 8, 2024, the 1,056th Martian day, or sol, of the mission. Image Credit: NASA/JPL-Caltech/ASU/MSSS/SSI

NASA’s Perseverance rover is busy exploring the Martian surface and collecting samples for eventual return to Earth. But the rover recently took some time to gaze upward and observe the heavens. Using Mastcam-Z, the rover’s primary science camera, Perseverance captured Phobos, Deimos, and Mercury as they transited in front of the Sun.

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New Moons Found at Uranus and Neptune

The discovery image of the new Uranian moon S/2023 U1 using the Magellan telescope on November 4, 2023. Uranus is just off the field of view in the upper left, as seen by the increased scattered light. S/2023 U1 is the faint point of light in the center of the image with the yellow arrow. The trails are from background stars. Credit: Scott Sheppard.

Astronomers have found three new moons orbiting our Solar System’s ice giants. One is orbiting Uranus, and two are orbiting Neptune. It took hard work to find them, including dozens of time exposures by some of our most powerful telescopes over several years. All three are captured objects, and there are likely more moons around both planets waiting to be discovered.

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A Star Passed Through the Oort Cloud Less Than 500,000 Years Ago. It Wasn’t the Only One.

Stars travel throughout the Galaxy. It's inevitable that some will pass near the Sun and perhaps even through our Oort Cloud, with interesting consequences. Credit: NASA/ESA/STScI.
Stars travel throughout the Galaxy. It's inevitable that some will pass near the Sun and perhaps even through our Oort Cloud, with interesting consequences. Credit: NASA/ESA/STScI.

As stars in the Milky Way move through space, some of them have an unexpected effect on the Solar System. Over time, one comes closer to the Sun during its orbit in the galaxy. Some of them actually get within a light-year of our star and pass through the Oort Cloud. Such close flybys can affect the orbits of the outer planets and send cometary nuclei on a long inward rush to the Sun.

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A New Space Telescope will Map the Universe and Help Protect the Earth from Asteroids

This artist's illustration shows NASA's SPHEREx observatory in orbit. The mission will launch in 2025. Image Credit: By NASA/JPL - https://www.jpl.nasa.gov/missions/spherex, Public Domain, https://commons.wikimedia.org/w/index.php?curid=143819030

Can we secure our place in the Solar System? Not in any absolute sense because nature can be very unpredictable. But we can make the effort to safeguard our civilization by cataloguing potentially dangerous asteroids. An upcoming space telescope will help.

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Even Eris and Makemake Could Have Geothermal Activity

Illustration of the icy dwarf planets Eris and Makemake. Credit: Southwest Research Institute

Whether or not you agree that Pluto isn’t a planet, in many ways, Pluto is quite different from the classical planets. It’s smaller than the Moon, has an elliptical orbit that brings it closer to the Sun than Neptune at times, and is part of a collection of icy bodies on the edge of our solar system. It was also thought to be a cold dead world until the flyby of New Horizons proved otherwise. The plucky little spacecraft showed us that Pluto was geologically active, with a thin atmosphere and mountains that rise above icy plains. Geologically, Pluto is more similar to Earth than the Moon, a fact that has led some to reconsider Pluto’s designation as a dwarf planet.

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There’s One Last Place Planet 9 Could Be Hiding

Artist's illustration of Planet Nine with the Sun and orbit of Neptune (ring) in the distance. (Credit: ESO/Tomruen/nagualdesign)

 A recently submitted study to The Astronomical Journal continues to search for the elusive Planet Nine (also called Planet X), which is a hypothetical planet that potentially orbits in the outer reaches of the solar system and well beyond the orbit of the dwarf planet, Pluto. The goal of this study was to narrow down the possible locations of Planet Nine and holds the potential to help researchers better understand the makeup of our solar system, along with its formation and evolutionary processes. So, what was the motivation behind this study regarding narrowing down the location of a potential Planet Nine?

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Passing Stars Changed the Orbits of Planets in the Solar System

Scholz’s Star seen from Earth 70,000 years ago. Credit: José A. Peñas/SINC

The orbit of Earth around the Sun is always changing. It doesn’t change significantly from year to year, but over time the gravitational tugs of the Moon and other planets cause Earth’s orbit to vary. This migration affects Earth’s climate. For example, the gradual shift of Earth’s orbit and the changing tilt of Earth’s axis leads to the Milankovitch climate cycles. So if you want to understand paleoclimate or the shift of Earth’s climate across geologic time, it helps to know what Earth’s orbit was in the distant past.

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Exploring the Solar System with Swarms of Microprobes

Schematic of components for the proposed femtoscale solar sail. The pressure of solar radiation against the sail will provide propulsion for the spacecraft, while cell phone-based and MEMS technologies will enable navigation, communication and image capture. (Image courtesy of Alexander Alvara)

It’s satisfying to sit back and take stock of all the places in the Solar System that we’ve explored. The Moon came first, then over the following decades, we’ve sent spacecraft to Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and even distant Pluto. We’ve also explored some of the asteroid belt’s inhabitants and even several comets.

That’s an impressive list, but it’s still dwarfed by the number of objects we haven’t visited. Could swarms of microprobes help us expand our reach? New research shows that tiny, solar sail microprobes could complete a round trip to asteroid Bennu faster than OSIRIS-REx did.

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Planetesimals Are Buffeted by Wind in their Nebula, Throwing Debris into Space

This artist's illustration shows planetisimals around a young star. New research shows that planetesimals are blasted by headwind, losing debris into space. Image Credit: NASA/JPL

Before planets form around a young star, the protosolar disk is populated with innumerable planetesimals. Over time, these planetesimals combine to form planets, and the core accretion theory explains how that happens. But before there are planets, the disk full of planetesimals is a messy place.

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Three Iron Rings Around A Star Show Where Planets are Forming

Observations with the European Southern Observatory's (ESO) Very Large Telescope Interferometer (VLTI) found various silicate compounds and potentially iron, substances we also find in large amounts in the solar system's rocky planets. Credit: Jenry

Researchers using the ESO’s Very Large Telescope Interferometer (VLTI) have found three iron rings around a young star about 500 light-years away. The rings indicate that planets are forming. What can these rings tell us about how Earth and the other planets in our Solar System formed?

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