Astronomers Discover Most Distant Quasar
Published June 30, 2011
Artist’s impression showing how quasar ULAS J1120+0641 may have looked 770 million years after the Big Bang.
Image Credit: ESO/M. Kornmesser
Based on their findings, the light from the quasar took nearly thirteen billion years to reach us, presenting a view of the quasar from less than 800 million years after the Big Bang.
“This quasar is a vital probe of the early Universe. It is a very rare object that will help us to understand how supermassive black holes grew a few hundred million years after the Big Bang,” says Stephen Warren, leader of the research team.
What make quasars interesting to astronomers is that they are extremely bright, yet distant galaxies, believed to possess “supermassive” black holes in their galactic centers. The brightness of quasars make them ideal “beacons” to help understand the era in which the first stars and galaxies were formed.
There have been other, more distant objects found in our universe, but the second most-distant quasar was seen as it was almost 900 million years after the Big Bang. Objects this distant are seen in infra-red due to their light being stretched, or “red shifted” (ULAS J1120+0641 is at redshift 7.1) by the expansion of the Universe. To search for objects like ULAS J1120+0641, the astronomers searched through the Infrared Deep Sky Survey database, based on data acquired from the United Kingdom Infrared Telescope in Hawaii.
“It took us five years to find this object,” explains Bram Venemans, one of the authors of the study. “We were looking for a quasar with redshift higher than 6.5. Finding one that is this far away, at a redshift higher than 7, was an exciting surprise. By peering deep into the reionisation era, this quasar provides a unique opportunity to explore a 100-million-year window in the history of the cosmos that was previously out of reach.”
Tycho Thursday: ASU Releases Stunning Tycho Crater Imagery
Published June 30, 2011
Oblique view of summit area of Tycho crater central peak. The boulder in the background is 120 meters wide, and the image is about 1200 meters wide. Image Credit: NASA/GSFC/Arizona State University
Click for larger view.
From the press release:
“We planned the image because it would dramatically show the geologic relations from a more human perspective. Drama we got!†says Mark Robinson, a professor in the School of Earth and Space Exploration at ASU. “When I first saw the reconstructed image all I could think was what it would be like to be on the first mission to Tycho. Imagine coming in for a landing within this geologic wonderland! When can we go?â€
Robinson also adds at the LROC Blog: “Tycho’s features are so steep and sharp because the crater is young by lunar standards, only about 110 million years old. Over time, micrometeorites, and not so micro meteorites, will grind and erode these steep slopes into smooth mountains.“
Named after 16th century Danish astronomer Tycho Brahe, the crater is very popular with amateur astronomers. The crater’s popularity is due, in part, to its visibility when the Moon is full and because it is surrounded by a distinctive dark halo and radiating bright rays. Measuring roughly 80km in diameter, Tycho is located in the southern highlands at 43.37°S, 348.68°E. The summit of the central peak is 2km above the crater floor and the crater floor is about 4.7km below the rim.
Earth’s Core
Published June 29, 2011Having more or less minored in Geology, this XKCD Cartoon gave me quite a laugh!
If you don’t already view XKCD on a regular basis, be sure to visit at: http://www.xkcd.com
Neutron Star “Bites” Companion Star
Published June 28, 2011
An artist's impression of XMM-Newton. Credits: ESA-C. Carreau
ESA’s XMM-Newton space observatory has observed a faint star flare up to almost 10,000 times it’s normal brightness in the X-ray portion of the electromagnetic spectrum. The outburst is speculated to be a result of the star attempting to “eat” a clump of matter expelled from its blue super-giant companion star. The source of the outburst is a neutron star about 10 km in diameter. Neutron stars are extremely dense “core” remnants of large stars. Given their small size and extreme density, neutron stars generate very strong gravitational fields.“This was a huge bullet of gas that the star shot out, and it hit the neutron star allowing us to see it,†said team leader Enrico Bozzo, ISDC Data Centre for Astrophysics, University of Geneva, Switzerland.
Lasting for about four hours, the flare and X-ray emissions came from the gas in the clump as it was heated to millions of degrees as it was pulled into the neutron star’s intense gravity field. Despite the neutron star’s immense gravity field, the clump of matter was so large only a small amount actually hit the neutron star and had the star not been in the way, the clump would have most likely disappeared into space. XMM-Newton detected the flare during a planned 12.5-hour observation of the system, only by catalog number IGR J18410-0535. Interestingly enough, the research team was not immediately aware of the discovery.
Artist's impression of a neutron star partially devouring a massive clump of matter. Image Credit: ESA/AOES Medialab
Nearly two weeks after the observations, Bozzo and his team received the data and realized XMM-Newton was not only pointed in the right direction for the observation of the flare, but their observations had also captured the entire duration of the flare, from beginning to end.“I don’t know if there is any way to measure luck, but we were extremely lucky,†said Bozzo, who estimates that flares of this magnitude can be expected a few times a year at most for the IGR J18410-0535 star system.
The research team was able to use the duration of the flare to estimate the size of the clump at about 16 million km across (about 100 billion times the volume of the Moon). Despite the incredible volume of the clump, using estimates made from the flare’s brightness, the clump was only about 1/1000th of our moon’s mass. The process of a star expelling matter into space is commonly referred to as “stellar wind” and in the case of this blue super-giant its stellar wind is expelled in a clumpy manner.
“This remarkable result highlights XMM-Newton’s unique capabilities,†adds Norbert Schartel, XMM-Newton Project Scientist. “Its observations indicate that these flares can be linked to the neutron star attempting to ingest a giant clump of matter.â€
Source: European Space Agency Press Release
MSL Arrives at KSC
Published June 28, 2011
Curiosity, the Mars Science Laboratory mission's rover, along with the mission's descent stage, arrived at NASA's Kennedy Space Center, Fla., on June 22, 2011, aboard a U.S. Air Force C-17 transport plane. Image credit: NASA
“The design and building part of the mission is nearly behind us now,” said JPL’s David Gruel, who has managed Mars Science Laboratory assembly, test and launch operations since 2007. “We’re getting to final checkouts before sending the rover on its way to Mars.”
About twice the length and over five times the weight of previous Mars rovers, Curiosity’s ten science instruments include two for ingesting and analyzing Martian soil samples. The “prime” mission is scheduled for one Martian year (almost two Earth years) during which time, researchers will use the rover’s tools to study whether the landing region has had environmental conditions favorable for supporting microbial life and favorable for preserving clues about whether life existed. For more information about the mission, visit: http://www.nasa.gov/msl.
To follow the mission on Facebook and Twitter, visit: http://www.facebook.com/marscuriosity or http://www.twitter.com/marscuriosity.
Source:NASA / MSL Press Release
Earth Flyby of Asteroid 2011 MD on Monday
Published June 26, 2011Tomorrow, around 9:30 AM EDT, near-Earth asteroid 2011 MD will pass less than 8,000 miles above Earth’s surface.
2011 MD was discovered by the LINEAR near-Earth object discovery team observing from Socorro, New Mexico. Â While the asteroid does come fairly close to Earth, it is estimated to be 5-20 meters in diameter and there is no chance of the object hitting Earth’s surface.
Even if 2011 MD were to enter Earth’s atmosphere, due to its small size it would simply burn up in our atmosphere and have no impact on Earth’s surface . Below is a diagram that shows the asteroid’s trajectory as viewed from the Sun, showing 2011 MD’s close approach, which researchers say will be over the Atlantic Ocean and could be bright enough to see with a medium-to-large size telescope.
If you’d like to learn more about 2011 MD and other near-Earth objects, visit http://neo.jpl.nasa.gov.
Trajectory of 2011 MD from the general direction of the Sun. Image credit: NASA/JPL-Caltech
Source:NASA/JPL NEO Press Release