Thursday, November 23, 2017

Dark Matter and Dark Energy: Do They Really Exist?

This set of images shows the distribution of the dark matter, obtained from a numerical simulation, at a redshift z~2, or when the Universe was about 3 billion years old. Credit: The Virgo Consortium/Alexandre Amblard/ESA

For close on a century, researchers have hypothesized that the universe contains more matter than can be directly observed, known as "dark matter". They have also posited the existence of a "dark energy" that is more powerful than gravitational attraction. These two hypotheses, it has been argued, account for the movement of stars in galaxies and for the accelerating expansion of the universe respectively.

Lightning, with a Chance of Antimatter

A Kyoto University-based team has unraveled the mystery of gamma-ray emission cascades caused by lightning strikes. Credit: Kyoto University/Teruaki Enoto

A storm system approaches: the sky darkens, and the low rumble of thunder echoes from the horizon. Then without warning... Flash! Crash! -- lightning has struck. This scene, while familiar to anyone and repeated constantly across the planet, is not without a feeling of mystery. But now that mystery has deepened, with the discovery that lightning can result in matter-antimatter annihilation.

Wednesday, November 22, 2017

Unexpected Atmospheric Vortex Behavior on Saturn’s Moon Titan

Titan’s winter polar vortex imaged by the Cassini Spacecraft’s ISS camera. The vortex is now in deep winter and can only be seen because the polar clouds within the vortex extend high above Titan’s surface into the sunlight. The vortex was extremely cold from 2012-2015 giving rise to unusual nitrile ice clouds. NASA/JPL-Caltech/Space Science Institute/Jason Major

A new study, led by a University of Bristol earth scientist, has shown that recently reported unexpected behavior on Titan, the largest moon of Saturn, is due to its unique atmospheric chemistry.

Moon’s Crust Underwent Resurfacing After Forming from Magma Ocean

Credit: The University of Texas at Austin/Jackson School of Geosciences

The Earth’s Moon had a rough start in life. Formed from a chunk of the Earth that was lopped off during a planetary collision, it spent its early years covered by a roiling global ocean of molten magma before cooling and forming the serene surface we know today.

Uncovering the Origins of Galaxies' Halos

Eleven dwarf galaxies and two star-containing halos were identified in the outer region of the nearby Whale Galaxy. (Credit: Tohoku University/NAOJ)

Using the Subaru Telescope atop Maunakea, researchers have identified 11 dwarf galaxies and two star-containing halos in the outer region of a large spiral galaxy 25 million light-years away from Earth. The findings, published in The Astrophysical Journal, provide new insight into how these 'tidal stellar streams' form around galaxies.

Tuesday, November 21, 2017

Long March 6 Launches a Trio of Jilin-1 Earth-Observing Satellites Into Orbit

Long March 6 launches trio of Jilin-1 satellites on November 21. Credit: Xinhua

A Long March 6 rocket took to the skies for the second time in history on Tuesday, November 21, carrying three Jilin-1 satellites designed for Earth observation purposes. Liftoff took place at 4:50 GMT (11:50 p.m. EST on Monday) from the Launch Complex 16 at the Taiyuan Satellite Launch Center (TSLC) in China’s Shanxi Province.

NASA Telescope Studies Quirky Comet 45P

Comet 45P/Honda-Mrkos-Pajdušáková is captured using a telescope on December 22 from Farm Tivoli in Namibia, Africa. Credits: Gerald Rhemann

When comet 45P zipped past Earth early in 2017, researchers observing from NASA’s Infrared Telescope Facility, or IRTF, in Hawai’i gave the long-time trekker a thorough astronomical checkup. The results help fill in crucial details about ices in Jupiter-family comets and reveal that quirky 45P doesn’t quite match any comet studied so far.