Life ‘not as we know it’ possible on Saturn’s moon Titan

F3.large

States of acrylonitrile. (A) Azotosome. Interlocking nitrogen and hydrogen atoms reinforce the structure. (B) Solid. Adjacent nitrogen atoms create some unfavorable repulsion. (C) Micelle. Adjacent nitrogen atoms make this highly unfavorable. (D) Azotosome vesicle of diameter 90 Å, the size of a small virus particle.

Liquid water is a requirement for life on Earth. But in other, much colder worlds, life might exist beyond the bounds of water-based chemistry.

Taking a simultaneously imaginative and rigidly scientific view, Cornell chemical engineers and astronomers offer a template for life that could thrive in a harsh, cold world – specifically Titan, the giant moon of Saturn. A planetary body awash with seas not of water, but of liquid methane, Titan could harbor methane-based, oxygen-free cells that metabolize, reproduce and do everything life on Earth does.

Their theorized cell membrane, composed of small organic nitrogen compounds and capable of functioning in liquid methane temperatures of 292 degrees below zero, is published in Science Advances, Feb. 27. The work is led by chemical molecular dynamics expert Paulette Clancy, the Samuel W. and Diane M. Bodman Professor of Chemical and Biomolecular Engineering, with first author James Stevenson, a graduate student in chemical engineering. The paper’s co-author is Jonathan Lunine, the David C. Duncan Professor in the Physical Sciences in the College of Arts and Sciences’ Department of Astronomy.

Membrane alternatives in worlds without oxygen: Creation of an azotosome“, , ,

Lunine is an expert on Saturn’s moons and an interdisciplinary scientist on the Cassini-Huygens mission that discovered methane-ethane seas on Titan. Intrigued by the possibilities of methane-based life on Titan, and armed with a grant from the Templeton Foundation to study non-aqueous life, Lunine sought assistance about a year ago from Cornell faculty with expertise in chemical modeling. Clancy, who had never met Lunine, offered to help. Continue reading Life ‘not as we know it’ possible on Saturn’s moon Titan

Link

A Detector to Track Antineutrinos

B. R. Safdi and B. Suerfu, Phys. Rev. Lett. (2015) Slicing and dicing. In a proposed detector design, an antineutrino (green track) triggers inverse beta decay in a target layer, creating a neutron (yellow) and a positron (purple) that generate signals in adjacent capture layers. Connecting the dots makes it possible to deduce the antineutrino’s trajectory.

B. R. Safdi and B. Suerfu, Phys. Rev. Lett. (2015)
Slicing and dicing. In a proposed detector design, an antineutrino (green track) triggers inverse beta decay in a target layer, creating a neutron (yellow) and a positron (purple) that generate signals in adjacent capture layers. Connecting the dots makes it possible to deduce the antineutrino’s trajectory.

A proposed detector for low-energy antineutrinos would reveal the particles’ trajectories, potentially allowing more detailed studies of Earth’s radioactivity and of nuclear reactors….
… Read more at http://physics.aps.org/articles/v8/15

Aside

Particle Weighing in the Early Universe

Constraint on a Varying Proton-Electron Mass Ratio 1.5 Billion Years after the Big Bang
J. Bagdonaite, W. Ubachs, M. T. Murphy, and J. B. Whitmore

Certain models predict that the dark energy that accelerates the Universe’s expansion is a field that evolves over cosmological times. This could mean that certain fundamental quantities related to forces and masses were different long ago. However, a new analysis of the spectrum from a very distant quasar finds no evidence of deviation in molecular lines produced 12 billion years ago, thus implying no change in the mass ratio of the proton to the electron.

One possible explanation for dark energy is that it comes from an all-pervasive scalar field, similar to the Higgs field. Such a field would likely interact with other particles, and these interactions could influence fundamental quantities, causing them to change as the scalar field evolves over time. To check for such evolution, scientists often study distant astrophysical bodies, whose light was emitted billions of years ago.

For the proton-electron mass ratio, astronomers look for unexpected shifts in the wavelengths at which molecules absorb light. Most molecules can only be seen in relatively nearby objects, but the hydrogen molecule (H2) is abundant enough to be observed at great distances. Wim Ubachs of VU University Amsterdam, the Netherlands, and his colleagues analyzed the spectrum of a very distant quasar (J1443+2724) and identified H2 absorption lines from a galaxy in front of the quasar. This absorption signal was etched into the spectrum when the Universe was just 1.5 billion years old. The lines showed no shift (beyond the normal redshift) compared to values measured on Earth, allowing the authors to place an upper bound of a few parts per million on a varying proton-electron mass ratio. The results imply that a dark energy scalar field—if it exists—has evolved very little over 90% the age of the Universe.
Read more at http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.114.071301

85 Years after Pluto’s Discovery, NASA’s New Horizons Spots Small Moons Orbiting Pluto

The moons Nix and Hydra are visible in a series of images taken by the New Horizons spacecraft. Image Credit: NASA/Johns Hopkins APL/Southwest Research Institute

The moons Nix and Hydra are visible in a series of images taken by the New Horizons spacecraft.
Image Credit: NASA/Johns Hopkins APL/Southwest Research Institute

Exactly 85 years after Clyde Tombaugh’s historic discovery of Pluto, the NASA spacecraft set to encounter the icy planet this summer is providing its first views of the small moons orbiting Pluto.

The moons Nix and Hydra are visible in a series of images taken by the New Horizons spacecraft from Jan. 27-Feb. 8, at distances ranging from about 125 million to 115 million miles (201 million to 186 million kilometers). The long-exposure images offer New Horizons’ best view yet of these two small moons circling Pluto which Tombaugh discovered at Lowell Observatory in Flagstaff, Arizona, on Feb. 18, 1930.

“Professor Tombaugh’s discovery of Pluto was far ahead its time, heralding the discovery of the Kuiper Belt and a new class of planet,” says Alan Stern, New Horizons principal investigator from Southwest Research Institute, Boulder, Colorado. “The New Horizons team salutes his historic accomplishment.”

Assembled into a seven-frame movie, the new images provide the spacecraft’s first extended look at Hydra (identified by a yellow diamond ) and its first-ever view of Nix (orange diamond). The right-hand image set has been specially processed to make the small moons easier to see. “It’s thrilling to watch the details of the Pluto system emerge as we close the distance to the spacecraft’s July 14 encounter,” says New Horizons science team member John Spencer, also from Southwest Research Institute. “This first good view of Nix and Hydra marks another major milestone, and a perfect way to celebrate the anniversary of Pluto’s discovery.”

nh_lorri_4x4

Assembled into a seven-frame movie, the new images provide the spacecraft’s first extended look at Hydra (identified by a yellow diamond ) and its first-ever view of Nix (orange diamond). Image Credit: NASA/Johns Hopkins APL/Southwest Research Institute

These are the first of a series of long-exposure images that will continue through early March, with the purpose of refining the team’s knowledge of the moons’ orbits. Each frame is a combination of five 10-second images, taken with New Horizons’ Long-Range Reconnaissance Imager (LORRI) using a special mode that combines pixels to increase sensitivity at the expense of resolution. At left, Nix and Hydra are just visible against the glare of Pluto and its large moon Charon, and the dense field of background stars. The bright and dark streak extending to the right of Pluto is an artifact of the camera electronics, resulting from the overexposure of Pluto and Charon. As can be seen in the movie, the spacecraft and camera were rotated in some of the images to change the direction of this streak, in order to prevent it from obscuring the two moons.

The right-hand images have been processed to remove most of Pluto and Charon’s glare, and most of the background stars. The processing leaves blotchy and streaky artifacts in the images, and also leaves a few other residual bright spots that are not real features, but makes Nix and Hydra much easier to see. Celestial north is inclined 28 degrees clockwise from the “up” direction in these images.

Nix and Hydra were discovered by New Horizons team members in Hubble Space Telescope images taken in 2005. Hydra, Pluto’s outermost known moon, orbits Pluto every 38 days at a distance of approximately 40,200 miles (64,700 km), while Nix orbits every 25 days at a distance of 30,260 miles (48,700 km). Each moon is probably between 25-95 miles (approximately 40- 150 kilometers) in diameter, but scientists won’t know their sizes more precisely until New Horizons obtains close-up pictures of both of them in July. Pluto’s two other small moons, Styx and Kerberos, are still smaller and too faint to be seen by New Horizons at its current range to Pluto; they will become visible in the months to come.

The Johns Hopkins University Applied Physics Laboratory manages the New Horizons mission for NASA’s Science Mission Directorate in Washington. Alan Stern, of the Southwest Research Institute (SwRI), headquartered in San Antonio, is the principal investigator and leads the mission. SwRI leads the science team, payload operations, and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. APL designed, built and operates the spacecraft.

Read more at www.nasa.gov