Caltech Researchers Find Evidence of a Real Ninth Planet

Caltech press release

Caltech researchers have found evidence of a giant planet tracing a bizarre, highly elongated orbit in the outer solar system. The object, which the researchers have nicknamed Planet Nine, has a mass about 10 times that of Earth and orbits about 20 times farther from the sun on average than does Neptune (which orbits the sun at an average distance of 2.8 billion miles). In fact, it would take this new planet between 10,000 and 20,000 years to make just one full orbit around the sun.

Planet 9 Artist's Concept
This artistic rendering shows the distant view from Planet Nine back towards the sun. The planet is thought to be gaseous, similar to Uranus and Neptune. Hypothetical lightning lights up the night side. Credit: Caltech/R. Hurt (IPAC)
The researchers, Konstantin Batygin and Mike Brown, discovered the planet’s existence through mathematical modeling and computer simulations but have not yet observed the object directly.

“This would be a real ninth planet,” says Brown, the Richard and Barbara Rosenberg Professor of Planetary Astronomy. “There have only been two true planets discovered since ancient times, and this would be a third. It’s a pretty substantial chunk of our solar system that’s still out there to be found, which is pretty exciting.”

Brown notes that the putative ninth planet—at 5,000 times the mass of Pluto—is sufficiently large that there should be no debate about whether it is a true planet. Unlike the class of smaller objects now known as dwarf planets, Planet Nine gravitationally dominates its neighborhood of the solar system. In fact, it dominates a region larger than any of the other known planets—a fact that Brown says makes it “the most planet-y of the planets in the whole solar system.”

Batygin and Brown describe their work in the current issue of the Astronomical Journal and show how Planet Nine helps explain a number of mysterious features of the field of icy objects and debris beyond Neptune known as the Kuiper Belt.

“Although we were initially quite skeptical that this planet could exist, as we continued to investigate its orbit and what it would mean for the outer solar system, we become increasingly convinced that it is out there,” says Batygin, an assistant professor of planetary science. “For the first time in over 150 years, there is solid evidence that the solar system’s planetary census is incomplete.”

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NASA and Caltech Astronomers Find Potential Energy Supply For Life on Europa

W. M. Keck Observatory press release

Observations of Europa from the W. M. Keck Observatory help NASA and California Institute of Technology (Caltech) astronomers go one step further in demonstrating life may be possible in the ocean of one of Jupiter’s moons. In addition to the known existence of water, a paper published today shows hydrogen peroxide is abundant across much of the surface of the smallest of the Galilean Moons. The paper argues that if the peroxide on the surface of Europa mixes into the ocean below, it could be an important energy supply for simple forms of life. The paper was published online in the Astrophysical Journal Letters.

(On March 14, a separate paper was published by the same team in Astronomical Journal, demonstrating the salty ocean of Europa makes its way through the frozen surface, introducing the possibility the ocean is habitable. Click here for that news release.)

“Life as we know it needs liquid water, elements like carbon, nitrogen, phosphorus and sulfur, and it needs some form of chemical or light energy to get the business of life done,” said Kevin Hand, the paper’s lead author, based at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “Europa has the liquid water and elements, and we think that compounds like peroxide might be an important part of the energy requirement. The availability of oxidants like peroxide on Earth was a critical part of the rise of complex, multicellular life.”

Europa
This color composite view combines violet, green, and infrared images of Jupiter’s intriguing moon, Europa, image credit NASA/JPL/University of Arizona

The scientists think hydrogen peroxide is an important factor for the habitability of the global liquid water ocean under Europa’s icy crust because hydrogen peroxide decays to oxygen when mixed into liquid water. “At Europa, abundant compounds like peroxide could help to satisfy the chemical energy requirement needed for life within the ocean, if the peroxide is mixed into the ocean,” said Hand.

Co-author Mike Brown of Caltech in Pasadena, analyzed data collected from the Near-Infrared Echelle Spectrograph (NIRSPEC) and OH Suppressing Infra-Red Imaging Spectrograph (OSIRIS) instruments on the mighty Keck II telescope on Mauna Kea, Hawaii, over four nights in September 2011. The highest concentration of peroxide found was on the side of Europa that always leads in its orbit around Jupiter, with a peroxide abundance of 0.12 percent relative to water. (This is roughly 20 times more diluted than the hydrogen peroxide mixture available at drug stores.) The concentration of peroxide in Europa’s ice then drops off to nearly zero on the hemisphere of Europa that faces backward in its orbit.

Hydrogen peroxide was first detected on Europa by NASA’s Galileo mission, which explored the Jupiter system from 1995 to 2003, but Galileo observations were of a limited region. The data from Keck Observatory shows that peroxide is widespread across much of the surface of Europa, and the highest concentrations are reached in regions where Europa’s ice is nearly pure water with very little sulfur contamination. The peroxide is created by the intense radiation processing of Europa’s surface ice that comes from the moon’s location within Jupiter’s strong magnetic field.

“The Galileo measurements gave us tantalizing hints of what might be happening all over the surface of Europa, and we’ve now been able to quantify that with our Keck telescope observations,” Brown said. “What we still don’t know is how the surface and the ocean mix, which would provide a mechanism for any life to use the peroxide.”

Neptune and Triton

Mike Brown did more than give a lecture while in Hawai’i. He just finished a four day observing run using Keck 2 with AO and OSIRIS, as well as gathering data with NIRSPEC. The target? Among other things Mike and his team observed Neptune and the large moon Triton. Triton is thought to be a captured KBO (Kuiper Belt Object). These objects, including well known Pluto, and lesser known, but just as large objects like Eris, Haumea, Makemake and Quaoar, are Mike’s area of expertise.

It is always nice to see a system I help maintain operating well and producing images like this…

Triton and Neptune
A Keck AO / OSIRIS photo of Neptune and the large moon Triton, credit Mike Brown/CalTech