The Planetary Society Blog 20 Oct 2017, 22:19 UTC Three years ago, on October 19, 2014, comet C/2013 A1 Siding Spring passed within 138,000 kilometers of Mars. No fewer than seven active Mars spacecraft pointed instruments at the cometary visitor, which was thought to be on its first trip in toward the Sun from the Oort Cloud. The newly arrived MAVEN got to do some amazing science even before their mission was to start, watching a cometary coma collide with the Martian atmosphere. Apart from MAVEN, the most anticipated data set was from Mars Reconnaissance Orbiter’s HiRISE camera. As the largest telescope ever sent beyond the Moon, it stood to capture well-resolved views of the comet’s nucleus.
Scientific American 20 Oct 2017, 14:30 UTC Juno probe discovers surprising activity in the giant planet’s interior -- Read more on ScientificAmerican.com
Starts With A Bang! 20 Oct 2017, 14:27 UTC “O. Hahn and F. Strassmann have discovered a new type of nuclear reaction, the splitting into two smaller nuclei of the nuclei of uranium and thorium under neutron bombardment. Thus they demonstrated the production of nuclei of barium, lanthanum, strontium, yttrium, and, more recently, of xenon and caesium. It can be shown by simple considerations that this type of nuclear reaction may be described in an essentially classical way like the fission of a liquid drop, and that the fission products must fly apart with kinetic energies of the order of hundred million electron-volts each.” -Lise Meitner Now that we’ve observed merging neutron stars for the first time, in many different wavelengths of light as well as in gravitational waves, we’ve got a whole new world of data to work with. We’ve independently confirmed that gravitational waves are real and that we can, in fact, pinpoint their locations on the sky. We’ve demonstrated that merging neutron stars create short gamma ray bursts, and shown that the origin of the majority of elements heavier than the first row of transition metals comes primarily from neutron star-neutron star mergers. This color-coded periodic table groups elements by how they were produced in the ...
SPACE.com 20 Oct 2017, 10:40 UTC Autumn brings longer and darker nights for skywatchers, as well as a bonus: an upswing in meteors, the bright and transitory trails of tiny particles that burn up as they plunge into Earth's atmosphere at tremendous speed. Between late September and early January every year, Earth's orbit carries us through a series of debris fields left by passing comets, producing meteor showers for skywatchers to enjoy. It all kicks off this weekend with the peak of the Orionid meteor shower.
ESO Blog 20 Oct 2017, 10:00 UTC Have you heard the game-changing news? For the first time ever, astronomers have observed the visible counterpart of a gravitational wave source. Gravitational waves were detected passing by Earth on 17 August, and telescopes around the world leapt into action to locate their source — spearheaded by ESO’s fleet of telescopes in Chile. Together, this global collaborative effort observed both gravitational waves and light from the same event, indicating that the source was the merger of two neutron stars. The drop-of-a-hat observing campaign involved dozens of scientists across the globe, and we asked two of them what it was really like to experience such a historic discovery first-hand. Here, we talk to Stephen Smartt (Queen’s University Belfast, UK) and Stefano Covino (INAF–Osservatorio Astronomico di Brera, Italy).
Sky and Telescope 20 Oct 2017, 08:58 UTC This week, the big W of Cassiopeia stands almost on end high in the northeast. Below it, binoculars will show the Double Cluster of Perseus. Friday, October 20 • The modest Orionid meteor shower continues in the early-morning hours for the next couple of nights. The apparent radiant point of the shower is near Orion's Club, low in the east after midnight and high in the south by the beginning of dawn. The morning sky is free of moonlight. See Orionid Meteors Max Out Sunday Morning. • Look for Capella sparkling low in the northeast after dinnertime this week. Then find the little Pleiades cluster to its right by about three fists at arm's length. They rise higher as evening grows late, harbingers of the cold months to come. Upper right of Capella, and upper left of the Pleiades, the stars of Perseus stand astride the Milky Way. To the upper left of Perseus, the Milky Way runs through Cassiopeia. Saturday, October 21 • After dark, spot the W of Cassiopeia high in the northeast. It's standing almost on end. The third segment of the W, counting down from the top, points almost straight down. Extend that segment twice as ...
Space Fellowship 20 Oct 2017, 08:11 UTC The beautiful Trifid Nebula is a cosmic study in contrasts. Also known as M20, it lies about 5,000 light-years away toward the nebula rich constellation Sagittarius. A star forming region in the plane of our galaxy, the Trifid does illustrate three different types of astronomical nebulae; red emission nebulae dominated by light from hydrogen atoms, blue reflection nebulae produced by dust reflecting starlight, and dark nebulae where dense dust clouds appear in silhouette. But the red emission region roughly separated into three parts by obscuring dust lanes is what lends the Trifid its popular name. Pillars and jets sculpted by newborn stars, below and left of the emission nebula’s center, appear in famous Hubble Space Telescope close-up images of the region. The Trifid Nebula is about 40 light-years across. Just too faint to be seen by the unaided eye, it almost covers the area of the Moon in planet Earth’s sky.