Solar System Archives

February 18, 2024February 18, 2024 by Brian Koberlein

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.

February 17, 2024February 17, 2024 by Laurence Tognetti

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?

February 14, 2024February 14, 2024 by Brian Koberlein

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.

January 24, 2024January 24, 2024 by Evan Gough

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.

January 11, 2024January 11, 2024 by Evan Gough

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.

January 9, 2024January 10, 2024 by Evan Gough

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?

December 14, 2023December 14, 2023 by Matt Williams

Voyager 1 Has Another Problem With its Computer System

For more than 46 years, the Voyager 1 probe has been traveling through space. On August 25th, 2012, it became the first spacecraft to cross the heliopause and enter interstellar space. Since then, mission controllers have maintained contact with the probe as part of an extended mission, which will last until the probe’s radioisotopic thermoelectric generators (RTGs) finally run out. Unfortunately, the Voyager 1 probe has been showing its age and signs of wear and tear, which is unavoidable when you’re the farthest spacecraft from Earth.

This includes issues with some of the probe’s subsystems, which have been a bit buggy lately. For instance, engineers at NASA recently announced that they were working to resolve an error with the probe’s flight data system (FDS). This system consists of three onboard computers responsible for communicating with another of Voyager 1’s subsystems, known as the telemetry modulation unit (TMU). As a result, while the spacecraft can receive and execute commands sent from Earth, it cannot send any science or engineering data back.

December 4, 2023December 4, 2023 by Nancy Atkinson

NASA's Interstellar Mapping Probe Prepares for a 2025 Launch

IMAP will study the protective magnetic bubble that surrounds our solar system, called the heliosphere, and the particle acceleration that occurs across it. Credits: NASA/Princeton/Johns Hopkins APL/Josh Diaz

Engineers at NASA have completed an important milestone in developing the Interstellar Mapping and Acceleration Probe (IMAP) spacecraft. It’s now moving from development and design to the assembly, testing, and integration phase, targeting a launch in late Spring 2025. After launch, the spacecraft will fly to the Earth-Sun L1 Lagrange Point and analyze how the Sun’s solar wind interacts with charged particles originating from outside the Solar System.

IMAP will follow up on discoveries and insights from the two Voyager spacecraft and the Interstellar Boundary Explorer (IBEX) and will help investigate two of the most important overarching issues in heliophysics: the energization of charged particles from the Sun and the interaction of the solar wind at its boundary with interstellar space.

November 29, 2023November 29, 2023 by Evan Gough

It Doesn’t Take Much to Get Tilted Planets

Earth's axial tilt (or obliquity) and its relation to the rotation axis and plane of orbit. Credit: Wikipedia Commons

Chinese and Indian astronomers were the first to measure Earth’s axial tilt accurately, and they did it about 3,000 years ago. Their measurements were remarkably accurate: in 1120 BC, Chinese astronomers pegged the Earth’s axial tilt at 24 degrees. Now we know that all of the planets in the Solar System, with the exception of Mercury, have some tilt.

While astronomers have puzzled over why our Solar System’s planets are tilted, it turns out it’s rather normal.

November 24, 2023November 24, 2023 by Evan Gough

What Would Happen to Earth if a Rogue Star Came Too Close?

The speeding rogue star Kappa Cassiopeiae sets up a glowing bow shock in this Spitzer image (NASA/JPL-Caltech)

Stars are gravitationally fastened to their galaxies and move in concert with their surroundings. But sometimes, something breaks the bond. If a star gets too close to a supermassive black hole, for example, the black hole can expel it out into space as a rogue star.

What would happen to Earth if one of these stellar interlopers got too close?