Archive

Archive for February 20, 2013

Sweeping The Dust From A Cosmic Lobster

February 20, 2013 Leave a comment

Credit: ESO/VVV Survey/D. Minniti. Acknowledgement: Ignacio Toledo

Credit: ESO/VVV Survey/D. Minniti. Acknowledgement: Ignacio Toledo

A new image from ESO’s VISTA telescope captures a celestial landscape of glowing clouds of gas and tendrils of dust surrounding hot young stars. This infrared view reveals the stellar nursery known as NGC 6357 in a surprising new light. It was taken as part of a VISTA survey that is currently scanning the Milky Way in a bid to map our galaxy’s structure and explain how it formed.

Located around 8000 light-years away in the constellation of Scorpius (The Scorpion), NGC 6357 — sometimes nicknamed the Lobster Nebula due to its appearance in visible-light images — is a region filled with vast clouds of gas and tendrils of dark dust. These clouds are forming stars, including massive hot stars which glow a brilliant blue-white in visible light.

This image uses infrared data from ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA) at the Paranal Observatory in Chile. It is just a small part of a huge survey called VISTA Variables in the Vía Láctea (VVV) that is imaging the central parts of the Galaxy. The new picture presents a drastically different view to that seen in visible-light images.

Full Story: http://www.eso.org/public/news/eso1309/

3-D Observations Of The Outflow From An Active Galactic Nucleus

February 20, 2013 Leave a comment

An artist's rendition of the central region of the quasar. Credit: Shinshu University and the National Astronomical Observatory of Japan

An artist’s rendition of the central region of the quasar. Credit: Shinshu University and the National Astronomical Observatory of Japan

A Japanese team of astronomers, led by Toru Misawa (Shinshu University), has used the Subaru Telescope to observe a distant gravitationally-lensed quasar and probed an active galactic nucleus in its central region. Looking through multiple sight lines, the astronomers obtained a 3-D view of the quasar and discovered complex small structures inside outflows from the galactic nucleus. These outflows will spread widely and eventually affect the evolution of the host galaxy.

Quasars are bright central regions of some distant galaxies. Their luminosities are often hundreds of times greater than those of their host galaxies (Note 2). Scientists believe that their light source is a very bright gaseous disk surrounding a supermassive black hole at the center of the galaxy. Gas streams called “outflows” move outward from the disk (Figure 1) and have a substantial influence on surrounding interstellar/intergalactic regions. However, because quasars at large distances look like mere stars, their internal structures are not easy to investigate.

The current team used the large light-gathering power of the 8.2 m Subaru Telescope mounted with its high-resolution spectrograph HDS (High Dispersion Spectrograph) to observe the quasar SDSS J1029+2623 and examine its structure. This quasar is ~10 billion light years distant from Earth toward the constellation Leo, and a massive cluster of galaxies, ~5 billion light years away, lies between the quasar and Earth. Because astronomical objects are usually very distant, they are difficult to study from different angles. Nevertheless, gravitational lensing opens up this possibility.

Full Story: http://naoj.org/Pressrelease/2013/02/18/index.html

Water On The Moon: It’s Been There All Along

February 20, 2013 Leave a comment

Traces of water have been detected within the crystalline structure of mineral samples from the lunar highland upper crust obtained during the Apollo missions, according to a University of Michigan researcher and his colleagues.

The lunar highlands are thought to represent the original crust, crystallized from a magma ocean on a mostly molten early moon. The new findings indicate that the early moon was wet and that water there was not substantially lost during the moon’s formation.

The results seem to contradict the predominant lunar formation theory — that the moon was formed from debris generated during a giant impact between Earth and another planetary body, approximately the size of Mars, according to U-M’s Youxue Zhang and his colleagues.

“Because these are some of the oldest rocks from the moon, the water is inferred to have been in the moon when it formed,” Zhang said. “That is somewhat difficult to explain with the current popular moon-formation model, in which the moon formed by collecting the hot ejecta as the result of a super-giant impact of a martian-size body with the proto-Earth.

Full Story: http://www.ns.umich.edu/new/releases/21208-water-on-the-moon-it-s-been-there-all-along

Ed Lu’s Message: Our Cosmic Challenge

February 20, 2013 Leave a comment

The B612 Foundation believes we should find threatening asteroids before they find us. Today’s meteor explosion over Chelyabinsk is a wake-up call that the Earth orbits the Sun in a shooting gallery of asteroids, and that these asteroids sometimes hit the Earth. Later today, a separate and larger asteroid, 2012 DA14, narrowly missed the Earth passing beneath the orbits of our communications satellites. We have the technology to deflect asteroids, but we cannot do anything about the objects we don’t know exist. To date, less than 1% of asteroids larger than the one that leveled Tunguska in 1908 have been tracked. The B612 Foundation Sentinel Space Telescope, to be launched in 2018, will provide a comprehensive map of the locations and trajectories of threatening asteroids and will give humanity the decades of warning needed to prevent asteroid impacts with existing technology. By the end of its planned lifetime, Sentinel will have discovered well over 90% of the asteroids that could destroy entire regions of Earth on impact (those larger than 350ft in diameter) and more than 50% of the currently unknown DA14-like near-Earth asteroids.

Full Story: http://b612foundation.org/ed-lus-message-our-cosmic-challenge/

ATLAS: The Asteroid Terrestrial-Impact Last Alert System

February 20, 2013 Leave a comment

In the realm of potential planetary disasters, asteroids are among the ones to fear—like the meteorite that hit Russia today, they can inflict serious damage on Earth.

With the aid of a $5-million grant from NASA, a University of Hawaii team of astronomers is developing ATLAS, a system to identify dangerous asteroids before their final plunge to Earth. The team is on track to build and operate an asteroid detection system that will patrol the visible sky twice a night looking for faint objects moving through space.

ATLAS (Asteroid Terrestrial-Impact Last Alert System) will operate up to 8 small telescopes, each fitted with cameras of up to 100 megapixels, on mounts housed at one or two locations in the Hawaiian Islands. Astronomers expect the system to be fully operational by the end of 2015.

Full Story: http://www.ifa.hawaii.edu/info/press-releases/ATLAS/

California Scientists Propose System To Vaporize Asteroids That Threaten Earth

February 20, 2013 Leave a comment

An asteroid roughly half as large as a football field –– and with energy equal to a large hydrogen bomb –– recently buzzed by Earth at close range. Someday, a threat of that size could be eliminated within an hour under a proposed system just unveiled by two California scientists. The same system could destroy asteroids 10 times larger than that known as 2012 DA14 in about a year, with evaporation starting at a distance as far away as the Sun.

UC Santa Barbara physicist and professor Philip M. Lubin, and Gary B. Hughes, a researcher and professor from California Polytechnic State University, San Luis Obispo, conceived DE-STAR, or Directed Energy Solar Targeting of Asteroids an exploRation, as a realistic means of mitigating potential threats posed to the Earth by asteroids and comets.

Described as a “directed energy orbital defense system,” DE-STAR is designed to harness some of the power of the sun and convert it into a massive phased array of laser beams that can destroy, or evaporate, asteroids posing a potential threat to Earth.

Full Story: http://www.ia.ucsb.edu/pa/display.aspx?pkey=2943

Novel Approach In Hunt For Cosmic Particle Accelerator

February 20, 2013 Leave a comment

A composite image of the supernova remnant SN 1006. Credit: X-ray: NASA/CXC/Rutgers/G.Cassam-Chenaï, J.Hughes et al.; Radio: NRAO/AUI/NSF/GBT/VLA/Dyer, Maddalena & Cornwell; Optical: Middlebury College/F. Winkler, NOAO/AURA/NSF/CTIO Schmidt & DSS

A composite image of the supernova remnant SN 1006. Credit: X-ray: NASA/CXC/Rutgers/G.Cassam-Chenaï, J.Hughes et al.; Radio: NRAO/AUI/NSF/GBT/VLA/Dyer, Maddalena & Cornwell; Optical: Middlebury College/F. Winkler, NOAO/AURA/NSF/CTIO Schmidt & DSS

A team of astronomers led by Sladjana Nikolić from the Max Planck Institute for Astronomy has observed the supernova remnant SN 1006, probing in unprecedented detail the region where the gas ejected during the supernova meets the surrounding interstellar matter. Such remnants have long been thought to be the source of cosmic ray particles hitting Earth. The observations show, for the first time, the presence of “seed particles”, possible precursors of such cosmic rays. The novel approach used by the astronomers promises further insights as to how supernovae remnants act as cosmic particle accelerators. The results will be published on February 14, 2013 in the journal Science.

When Victor Hess first discovered cosmic ray particles hitting Earth almost exactly a hundred years ago, he had little notion about their origin. Since then, ever more sensitive observations of these particles have turned up a number of sources. Among them are supernova remnants – cosmic blast waves launched by stellar explosions; expanding gas shells flung into space when certain stars end their lives in a supernova.

Where such a blast wave meets the surrounding interstellar medium, there is an abrupt change in density and temperature: a shock front similar to the sonic boom produced by an aircraft going supersonic. This expanding, high-velocity shock front is a natural candidate for a cosmic particle accelerator. Now, for the first time, astronomers have found observational evidence of accelerated protons in these shock regions. While these are not the sought-for high-energy cosmic rays themselves, they could be the necessary “seed particles”, which the go on to interact with the shock to reach the extremely high energies required and fly off into space as cosmic ray particles.

Full Story: http://www.mpia.de/Public/menu_q2e.php?Aktuelles/PR/2013/PR130214/PR_130214_en.html
Also: http://www.eso.org/public/news/eso1308/