Solar System Archives

July 10, 2022July 10, 2022 by Carolyn Collins Petersen

When did the Sun Blow Away the Solar Nebula?

Young stars have a disk of gas and dust around them called a protoplanetary disk. Credit: NASA/JPL-Caltech

The story of our solar system’s origin is pretty well known. It goes like this: the Sun began as a protostar in its “solar nebula” over 4.5 billion years ago. Over the course of several million years, the planets emerged from this nebula and it dissipated away. Of course, the devil is in the details. For example, exactly how long did the protoplanetary disk that gave birth to the planets last? A recent paper submitted to the Journal of Geophysical Research takes a closer look at the planetary birth crèche. In particular, it shows how the magnetism of meteorites helps tell the story.

July 6, 2022July 6, 2022 by Matt Williams

It Would Take About 100 Billion Years for Another Star to Pass Close Enough to Make the Solar System Unstable

A lovely artistic look at our Solar System that's definitely not to scale. Image Credit: NASA

In 1687, Sir Isaac Newton published his magnum opus, Philosophiæ Naturalis Principia Mathematica, which effectively synthesized his theories on motion, velocity, and universal gravitation. In terms of the latter, Newton offered a means for calculating the force of gravity and predicting the orbits of the planets. Since then, astronomers have discovered that the Solar System is merely one small point of light that orbits the center of the Milky Way Galaxy. On occasion, other stars will pass close to the Solar System, which can cause a dramatic shakeup that can kick objects out of their orbits.

These “stellar flybys” are common and play an important role in the long-term evolution of planetary systems. As a result, the long-term stability of the Solar System has been the subject of scientific investigation for centuries. According to a new study by a team of Canadian astrophysicists, residents of the Solar System may rest easy. After conducting a series of simulations, they determined that a star will not pass by and perturb our Solar System for another 100 billion years. Beyond that, the possibilities are somewhat frightening!

June 17, 2022June 17, 2022 by Evan Gough

This is What the Metal Asteroid Psyche Might Look Like

Asteroid Psyche's varied surface suggests a dynamic history, which could include metallic eruptions, asteroid-shaking impacts, and a lost rocky mantle. Image Credit: Screenshot courtesy of NASA

If you wanted to do a forensic study of the Solar System, you might head for the main asteroid belt between Mars and Jupiter. That’s where you can find ancient rocks from the Solar System’s early days. Out there in the cold vacuum of space, far from the Sun, asteroids are largely untouched by space weathering. Space scientists sometimes refer to asteroids—and their meteorite fragments that fall to Earth—as time capsules because of the evidence they hold.

The asteroid Psyche is especially interesting, and NASA is sending a mission to investigate the unusual chunk of rock. In advance of that mission, a team of researchers combined observations of Psyche from an array of telescopes and constructed a map of the asteroid’s surface.

June 3, 2022June 3, 2022 by Evan Gough

The Early Solar System was Total Mayhem

An artist's illustration of a chaotic young solar system. Image Credit: Tobias Stierli, flaeck / PlanetS

There’s no question that young solar systems are chaotic places. Cascading collisions defined our young Solar System as rocks, boulders, and planetesimals repeatedly collided. A new study based on chunks of asteroids that crashed into Earth puts a timeline to some of that chaos.

May 16, 2022May 16, 2022 by Andy Tomaswick

Did a 5th Giant Planet Mess up the Orbits of Jupiter, Saturn, Uranus and Neptune?

The solar system’s current planetary orbits seem stable, but that’s only because the planets have settled into them over billions of years. The early solar system was a much different place than that seen today, and for almost 20 years, scientists thought they had a good handle on how it got that way. But more recently, data had started pointing to some flaws in that understanding – especially about how the giant planets in the outer solar system got where they are today. Now an international team of astrophysicists thinks they have a better understanding of that process, and they believe it could help solve a long-standing argument about the early solar system.

April 20, 2022April 25, 2022 by Matt Williams

Pluto’s Orbit is Surprisingly Close to an Unstable Zone

New Horizons view of Pluto — The heart-shaped region of Pluto's surface was formed at least in part by a cataclysmic "splat," scientists say. (Credit: NASA / JHUAPL / SwRI)

In 1930, astronomer Clyde Tombaugh discovered the fabled “Ninth Planet” (or “Planet X”) while working at the Lowell Observatory in Flagstaff, Arizona. The existence of this body had been predicted previously based on perturbations in the orbit of Uranus and Neptune. After receiving more than 1,000 suggestions from around the world, and a debate among the Observatory’s staff, this newfound object was named Pluto – which was proposed by a young schoolgirl from Oxford (Venetia Burney).

Since that time, Pluto has been the subject of considerable study, a naming controversy, and was visited for the first time on July 14^th, 2015, by the New Horizons mission. One thing that has been clear from the beginning is the nature of Pluto’s orbit, which is highly eccentric and inclined. According to new research, Pluto’s orbit is relatively stable over longer timescales but is subject to chaotic perturbance and changes over shorter timescales.

March 11, 2022March 11, 2022 by Evan Gough

The Sun is Slowly Tearing This Comet Apart

A fine sungrazer nears its doom as seen via SOHOs LASCO C2 camera. Image credit: NASA/ESA/SOHO/NRLSungrazers

Using ground-based and space-based observations, a team of researchers has been monitoring a difficult-to-see comet carefully. It’s called Comet 323P/SOHO, and it was discovered over 20 years ago in 1999. But it’s difficult to observe due to its proximity to the Sun.

They’ve found that the Sun is slowly tearing the comet to pieces.

February 27, 2022February 13, 2023 by Matt Williams

Laser-Powered Sails Would be Great for Exploring the Solar System too

Swarm of laser-sail spacecraft leaving the solar system. Credit: Adrian Mann

Between the exponential growth of the commercial space industry (aka. NewSpace) and missions planned for the Moon in this decade, it’s generally agreed that we are living in the “Space Age 2.0.” Even more ambitious are the proposals to send crewed missions to Mars in the next decade, which would see astronauts traveling beyond the Earth-Moon system for the first time. The challenge this represents has inspired many innovative new ideas for spacecraft, life-support systems, and propulsion.

In particular, missions planners and engineers are investigating Directed Energy (DE) propulsion, where laser arrays are used to accelerate light sails to relativistic speeds (a fraction of the speed of light). In a recent study, a team from UCLA explained how a fleet of tiny probes with light sails could be used to explore the Solar System. These probes would rely on a low-power laser array, thereby being more cost-effective than similar concepts but would be much faster than conventional rockets.

January 20, 2022January 20, 2022 by Evan Gough

The Moon’s Crust was Formed From a Frozen Slushy Magma

Magma ocean and first rocky crust on the Moon. Image Credit: NASA/Goddard Space Flight Center

Scientists’ detailed study of the Moon dates back to the Apollo missions when astronauts brought rock samples from the lunar surface back to Earth for analysis. Apollo 11 gathered samples from the lunar highland regions, the pale areas on the Moon’s surface easily seen from Earth. The highlands are made of a relatively light rock called anorthosite, which formed early in the history of the Moon, between 4.3 and 4.5 billion years ago.

There’s some mystery involved in the anorthosite formation on the Moon. The age of the anorthosite highlands doesn’t match how long it took for the Moon’s magma ocean to cool. But scientists behind a new study think they’ve solved that mystery.

January 20, 2022January 20, 2022 by Evan Gough

Even Tiny Mimas Seems to Have an Internal Ocean of Liquid Water

Mimas, as imaged by NASA's Cassini spacecraft and processed by @kevinmgill

Data from the Cassini mission keeps fuelling discoveries. The latest discovery is that Saturn’s tiny moon Mimas may have an internal ocean. If it does, the moon joins a growing list of natural satellites in our Solar System that may harbour liquid water under their surfaces.