Planet 9 is Running out of Places to Hide

Illustration of the hypothetical Planet 9. Credit: R. Hurt/IPAC, Caltech

We have a pretty good idea of what lurks within our solar system. We know there isn’t a Mars-sized planet orbiting between Jupiter and Saturn, nor a brown dwarf nemesis heading our way. Anything large and fairly close to the Sun would be easily spotted. But we can’t rule out a smaller, more distant world, such as the hypothetical Planet 9 (or Planet 10 if you want to throw down over Pluto). The odds against such a planet existing are fairly high, and a recent study finds it even less likely.

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These Ancient Microbes Give a Glimpse of What Extraterrestrial Life Might Look Like

Rhodopsins are ancient proteins evolved by some of Earth's first life forms. They turned sunlight into energy without photosynthesis. Image Credit: Sohail Wasif/University of California, Riverside.

Will we discover simple life somewhere? Maybe on Enceladus or Europa in our Solar System, or further away on an exoplanet? As we get more proficient at exploring our Solar System and studying exoplanets, the prospect of finding some simple life is moving out of the creative realm of science fiction and into concrete mission planning.

As the hopeful day of discovery draws nearer, it’s a good time to ask: what might this potential life look like?

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JWST Also Looked Inside the Solar System, at Jupiter and its Moons

Jupiter, center, and its moon Europa, left, are seen through the James Webb Space Telescope’s NIRCam instrument 2.12 micron filter. Credits: NASA, ESA, CSA, and B. Holler and J. Stansberry (STScI)

After the ‘big reveal’ earlier this week of the James Webb Space Telescope’s first full color images and spectra of the universe, the science team has now released data from closer to home. One stunning shot includes Jupiter and its moons, and there are also data from several asteroids. These latest data are actually just engineering images, designed to test JWST’s ability to track solar system targets, as well as test out how the team can produce images from the data. The quality and detail in these test images have excited the mission scientists.

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A Swarm of Swimming Robots to Search for Life Under the Ice on Europa

An artist’s interpretation of liquid water on the surface of the Europa pooling beneath chaos terrain. Credit: : NASA/JPL-Caltech

When Galileo pointed his telescope at Jupiter 400 years ago, he saw three blobs of light around the giant planet, which he at first thought were fixed stars. He kept looking, and eventually, he spotted a fourth blob and noticed the blobs were moving. Galileo’s discovery of objects orbiting something other than Earth—which we call the Galilean moons in his honour—struck a blow to the Ptolemaic (geocentric) worldview of the time.

Galileo couldn’t have foreseen the age of space exploration that we’re living in now. Fast forward 400 years, and here we are. We know the Earth doesn’t occupy any central point. We’ve discovered thousands of other planets, and many of them will have their own moons. Galileo would be amazed at this.

What would he think about robotic missions to explore one of the blobs of light he spotted?

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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.

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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!

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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.

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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.

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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.

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Pluto’s Orbit is Surprisingly Close to an Unstable Zone

According to a new study, the idea that Pluto is not a planet is unsupported in scientific literature. Credit: NASA

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 14th, 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.

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