Thursday, May 26, 2016

Life on Ceres? Mysterious Changes in the Bright Spots Still Baffle Scientists

The bright central spots near the center of Occator Crater are shown in enhanced color in this view from NASA's Dawn spacecraft. Such views can be used to highlight subtle color differences on Ceres. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI/LPI

Bright spots on the dwarf planet Ceres continue to puzzle researchers. When recently a team of astronomers led by Paolo Molaro of the Trieste Astronomical Observatory in Italy, conducted observations of these features, they found out something unexpected. The scientists were surprised to detect that the spots brighten during the day and also show other variations. This variability still remains a mystery.

Number of Habitable Planets Could Be Limited by Stifling Atmospheres

Artist's impression of an exoplanet system. Image: NASA

New research has revealed that fewer than predicted planets may be capable of harboring life because their atmospheres keep them too hot. When looking for planets that could harbor life, scientists look for planets in the ‘habitable zones’ around their stars – at the right distance from the stars to allow water to exist in liquid form. Traditionally, this search has focused on looking for planets orbiting stars like our Sun, in a similar way to Earth.

Scientists Discover Evidence of Ice Age at Martian North Pole

Climatic cycles of ice and dust build the Martian polar caps, season by season, year by year, and periodically whittle down their size when the climate changes. This image is a simulated 3-D perspective view, created from image data taken by the THEMIS instrument on NASA's Mars Odyssey spacecraft. Credits: NASA/JPL/Arizona State University, R. Luk

Using radar data collected by NASA’s Mars Reconnaissance Orbiter, a Southwest Research Institute-led team found evidence of an ice age recorded in the polar deposits of Mars. Ice ages on Mars are driven by processes similar to those responsible for ice ages on Earth, that is, long-term cyclical changes in the planet’s orbit and tilt, which affect the amount of solar radiation it receives at each latitude.

Close Encounters of a Tidal Kind Could Lead to Cracks on Icy Moons

NASA's New Horizons captured this high-resolution enhanced color view of Pluto's moon Charon, showing the crack on the icy moon. It was taken just before closest approach on July 14, 2015. The image combines blue, red and infrared images and the colors are processed to best highlight the variation of surface properties across Charon. Credit: NASA

A new model developed by University of Rochester researchers could offer a new explanation as to how cracks on icy moons, such as Pluto’s Charon, formed. Until now, it was thought that the cracks were the result of geodynamical processes, such as plate tectonics, but the models run by Alice Quillen and her collaborators suggest that a close encounter with another body might have been the cause.

Supermassive Black Holes in 'Red Geyser' Galaxies Cause Galactic Warming

An artist’s rendition of the galaxies Akira (right) and Tetsuo (left) in action. Akira’s gravity pulls Tetsuo’s gas into its central supermassive black hole, fueling winds that have the power to heat Akira’s gas. Because of the action of the black hole winds, Tetsuo’s donated gas is rendered inert, preventing a new cycle of star formation in Akira. (Credit: Kavli IPMU)

Scientists have uncovered a new class of galaxies with supermassive black hole winds that are energetic enough to suppress future star formation. Devoid of fresh young stars, red and dead galaxies make up a large fraction of galaxies in our nearby universe, but a mystery that has plagued astronomers for years has been how these systems remain inactive despite having all of the ingredients needed to form stars. Now, an international team of researchers have used optical imaging spectroscopy from the Sloan Digital Sky Survey-IV Mapping Nearby Galaxies at Apache Point Observatory (SDSS-IV MaNGA) to catch a supermassive black hole in the act of heating gas within its host galaxy, leading to the prevention of star formation.

Footprints of Baby Planets in a Gas Disk

HCO+ gas (blue) and dust (red) distributions in the disk around HL Tauri. The ellipses show the locations of the gaps (radii of 30 and 70 au). Credit: ALMA (ESO/NAOJ/NRAO), Yen et al.

A new analysis of the ALMA data for a young star HL Tauri provides yet more firm evidence of baby planets around the star. Researchers uncovered two gaps in the gas disk around HL Tauri. The locations of these gaps in the gas match the locations of gaps in the dust found in the ALMA high resolution image taken in 2014. This discovery supports the idea that planets form in much shorter timescales than previously thought and prompts a reconsideration of alternative planet formation scenarios.

A Young Mammoth Cluster of Galaxies Sighted in the Early Universe

The newly discovered protocluster of galaxies located in the Bootes field of the NOAO Deep Wide-field Survey. Green circles identify the confirmed cluster members. Density contours (white lines) emphasize the concentration of member galaxies toward the center of the image. The patch of sky shown is roughly 20 arcminutes x 17 arcminutes in size. The cluster galaxies are typically very faint, about 10 million times fainter than the faintest stars visible to the naked eye on a dark night. The inset images highlight two example members that glow in the Ly-alpha line of atomic hydrogen. The protocluster is massive, with its core weighing as much as a quadrillion suns. The protocluster is likely to evolve, over 12 billion years, into a system much like the nearby Coma cluster of galaxies, shown in the image below. Credit: Dr. Rui Xue, Purdue University.

Astronomers have uncovered evidence for a vast collection of young galaxies 12 billion light years away. The newly discovered “proto-cluster” of galaxies, observed when the universe was only 1.7 billion years old (12% of its present age), is one of the most massive structures known at that distance. The discovery, made using telescopes at Kitt Peak National Observatory in Arizona and the W. M. Keck Observatory on Mauna Kea, has been reported in the Astrophysical Journal.