Solar System Archives

January 11, 2022January 12, 2022 by Matt Williams

Rings in the Early Solar System Kept our Planet From Becoming a Super-Earth

A protosolar disk is the disk of material around a young stellar object that isn't yet a star. It's called a protoplanetary disk once the star has formed and begun fusion. Planetesimals are the building blocks of planets and are present in both stages of a disk's evolution. Image Credit: NASA/JPL

To date, a total of 4,884 extrasolar planets have been confirmed in 3,659 systems, with another 8,414 additional candidates awaiting confirmation. In the course of studying these new worlds, astronomers have noted something very interesting about the “rocky” planets. Since Earth is rocky and the only known planet where life can exist, astronomers are naturally curious about this particular type of planet. Interestingly, most of the rocky planets discovered so far have been many times the size and mass of Earth.

Of the 1,702 rocky planets confirmed to date, the majority (1,516) have been “Super-Earths,” while only 186 have been similar in size and mass to Earth. This raises the question: is Earth an outlier, or do we not have enough data yet to determine how common “Earth-like” planets are. According to new research by an international team led by Rice University, it may all have to do with protoplanetary rings of dust and gas in an early solar system.

November 23, 2021November 23, 2021 by Evan Gough

Here are Hubble’s 2021 Photos of the Outer Solar System

The NASA/ESA Hubble Space Telescope has completed its annual grand tour of the outer Solar System for 2021. This is the realm of the giant planets — Jupiter, Saturn, Uranus, and Neptune — extending as far as 30 times the distance between Earth and the Sun. Unlike the rocky terrestrial planets like Earth and Mars that huddle close to the Sun’s warmth, these far-flung worlds are mostly composed of chilly gaseous soups of hydrogen, helium, ammonia, and methane around a packed, intensely hot, compact core. Note: The planets are not shown to scale in this image. Credit: NASA, ESA, A. Simon (Goddard Space Flight Center), and M.H. Wong (University of California, Berkeley) and the OPAL team

If we had to rely solely on spacecraft to learn about the outer planets, we wouldn’t be making great progress. It takes a massive effort to get a spacecraft to the outer Solar System. But thanks to the Hubble Space Telescope, we can keep tabs on the gas giants without leaving Earth’s orbit.

October 27, 2021October 27, 2021 by Evan Gough

Researchers Use Ancient Literature to Track 3,000 Years of Auroras

EIELSON AIR FORCE BASE, Alaska -- The Aurora Borealis, or Northern Lights, shines above Bear Lake here Jan. 18. The lights are the result of solar particles colliding with gases in Earth's atmosphere. Early Eskimos and Indians believed different legends about the Northern Lights, such as they were the souls of animals dancing in the sky or the souls of fallen enemies trying to rise again. (U.S. Air Force photo by Senior Airman Joshua Strang)

Auroral activity on Earth varies over time. As the magnetic poles drift, auroras can appear at different latitudes around the globe. Solar activity also affects them, with powerful solar storms pushing the auroras further into mid-latitudes.

In an effort to better understand how auroras move around, how they’ll move in the future, and when powerful solar storms might pose a threat, a team of researchers have tracked auroral activity for the last 3,000 years.

October 27, 2021October 27, 2021 by Evan Gough

This is How You Get Moons. An Earth-Sized World Just got Pummeled by Something Huge.

An MIT-led team has discovered evidence of a giant impact in the nearby HD 17255 star system, in which an Earth-sized terrestrial planet and a smaller impactor likely collided at least 200,000 years ago, stripping off part of one planet’s atmosphere. Credits:Image: Mark A. Garlick

Titanic collisions are the norm in young solar systems. Earth’s Moon was the result of one of those collisions when the protoplanet Theia collided with Earth some 4.5 billion years ago. The collision, or series of collisions, created a swirling mass of ejecta that eventually coalesced into the Moon. It’s called the Giant Impact Hypothesis.

Astronomers think that collisions of this sort are a common part of planet formation in young solar systems, where things haven’t settled down into predictability. But seeing any of these collisions around other stars has proved difficult.

October 22, 2021October 22, 2021 by Evan Gough

The Early Solar System Had a Gap Where the Asteroid Belt is Today

An MIT study suggests that a mysterious gap existed within the solar system’s protoplanetary disk around 4.567 billion years ago, and likely shaped the composition of the solar system’s planets. This image shows an artist’s interpretation of a protoplanetary disk. Image Credit: National Science Foundation, A. Khan

Wind the cosmic clock back a few billion years and our Solar System looked much different than it does today. About 4.5 billion years ago, the young Sun shone much like it does now, though it was a little smaller. Instead of being surrounded by planets, it was ensconced in a swirling disk of gas and dust. That disk is called a protoplanetary disk and it’s where the planets eventually formed.

There was a conspicuous gap in the early Solar System’s protoplanetary disk, between where Mars and Jupiter are now, and where the modern-day asteroid belt sits. What exactly caused the gap is a mystery, but astronomers think it’s a sign of the processes that governed planet formation.

October 14, 2021October 14, 2021 by Evan Gough

Why Visit Just one Moon When you Could Explore Them all?

Illustration of Jupiter and the Galilean satellites. Credit: NASA

The Solar System’s moons are intriguing objects for exploration. Especially moons like Europa and Enceladus. Their subsurface oceans make them primary targets in the search for life.

But why not send one spacecraft to visit several moons? NASA’s about to launch its Lucy mission which will visit 8 separate asteroids. Could the same be done for a mission to multiple moons?

For a spacecraft to do that, it would have to do a little dance with the notorious three-body problem, which makes a stubborn partner. A new study presents a possible way to do that.

October 13, 2021October 13, 2021 by Nancy Atkinson

Images of 42 of the Biggest Asteroids in the Solar System

This image depicts 42 of the largest objects in the asteroid belt, located between Mars and Jupiter. Most of them are larger than 100 kilometres, with the two biggest asteroids being Ceres and Vesta, which are around 940 and 520 kilometres in diameter, and the two smallest ones being Urania and Ausonia, each only about 90 kilometres. The images of the asteroids have been captured with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument on ESO’s Very Large Telescope.

A huge team of astronomers have combined forces to use the European Southern Observatory’s Very Large Telescope (ESO’s VLT) to provide the sharpest view ever of 42 of the largest objects in the asteroid belt, located between Mars and Jupiter.

Fittingly, the collection of images was released on the 42nd anniversary of the publication of “The Hitchhiker’s Guide to the Galaxy” by Douglas Adams. In the book, the number 42 is the answer to the “Ultimate Question of Life, the Universe, and Everything.” These 42 images represent some of the sharpest views ever of these objects — which might contribute to answering these ultimate questions!

Plus, there’s a great poster of the asteroids, too:

October 12, 2021October 12, 2021 by Evan Gough

Greenland’s Ice Sheet is Similar in Many Ways to the Solar System’s Icy Worlds and Can Teach Us How to Search for Life

Floating ice at the calving front of Greenland's Kangerdlugssuaq glacier, photographed in 2011 during Operation IceBridge (Credit: NASA/Michael Studinger)

Many regions on Earth are temperate, nutrient-rich, stable environments where life seems to thrive effortlessly. But not all of Earth. Some parts, like Greenland’s ice sheet, are inhospitable.

In our nascent search for life elsewhere in the Solar System, it stands to reason that we’ll be looking at worlds that are marginal and inhospitable. Icy worlds like Jupiter’s moon Europa and Saturn’s moon Enceladus are our most likely targets. These frozen worlds have warm oceans under layers of ice.

What can Greenland’s cryo-ecosystems tell us about searching for life on icy bodies like Europa and Enceladus?

September 30, 2021September 30, 2021 by Evan Gough

BepiColombo Meets Mercury for the First Time on October 1

New research suggests that Mercury is still contracting and shrinking. Credits: NASA/JHUAPL/Carnegie Institution of Washington/USGS/Arizona State University

BepiColombo made a quick visit to Venus in August and is on to its next rendezvous. On October 1st it’ll perform a flyby of Mercury, the spacecraft’s eventual destination. This visit is just a little flirtation—one of six—ahead of its eventual orbital link-up with Mercury in late 2025.

The quick visit will yield some scientific results, though, and they’ll be just a taste of what’s ahead in BepiColumbo’s one-year mission to Mercury.

September 28, 2021September 28, 2021 by Evan Gough

The Early Solar System was Messier and More Violent Than Previously Believed

This artwork shows a rocky planet being bombarded by comets. Image credit: NASA/JPL-Caltech

Our conventional models of planet formation may have to be updated, according to a pair of new papers.

Accretion is the keyword in current planet formation theory. The idea is that the planets formed out of the solar nebula, the material left over after the Sun formed. They did this through accretion, where small particles accumulate into more massive objects. These massive boulder-sized objects, called planetesimals, continued to merge together into larger entities, sometimes through collisions. Eventually, through repeated mergers and collisions, the inner Solar System was populated by four rocky planets.

But the new research suggests that the collisions played out much differently than thought and that objects collided with each other several times, in a series of hit and runs, before merging. This research fills some stubborn holes in our current understanding.