Space Calendar November 1 – November 7 2011

Space related activities and anniversaries for November 1 – November 7 2011. Fetched live every week from NASA JPL

If you want the complete list going more than a year ahead then see the Space Calendar at NASA JPL.

Astronomers Pin Down Galaxy Collision Rate

Astronomers Pin Down Galaxy Collision Rate

A new analysis of Hubble surveys, combined with simulations of galaxy interactions, reveals that the merger rate of galaxies over the last 8 billion to 9 billion years falls between the previous estimates.

The galaxy merger rate is one of the fundamental measures of galaxy evolution, yielding clues to how galaxies bulked up over time through encounters with other galaxies. And yet, a huge discrepancy exists over how often galaxies coalesced in the past. Earlier measurements of galaxies in deep-field surveys made by NASA’s Hubble Space Telescope generated a broad range of results: anywhere from 5 percent to 25 percent of the galaxies were merging.

The new study, led by Jennifer Lotz of the Space Telescope Science Institute in Baltimore, Md., analyzed galaxy interactions at different distances, allowing the astronomers to compare mergers over time. Lotz’s team found that galaxies gained quite a bit of mass through collisions with other galaxies. Large galaxies merged with each other on average once over the past 9 billion years. Small galaxies were coalescing with large galaxies more frequently. In one of the first measurements of smashups between dwarf and massive galaxies in the distant universe, Lotz’s team found these mergers happened three times more often than encounters between two hefty galaxies.

[SOURCE: hubblesite.org]

Map of Titan – April 2011

Map of Titan - April 2011

This global digital map of Saturn’s moon Titan was created using images taken by the Cassini spacecraft’s imaging science subsystem (ISS). The images were taken using a filter centered at 938 nanometers, allowing researchers to examine variations in albedo (or inherent brightness) variations across the surface of Titan. Because of the scattering of light by Titan’s dense atmosphere, no topographic shading is visible in these images. The map is an equidistant projection and has a scale of 2.5 miles (4 kilometers) per pixel. Actual resolution varies greatly across the map, with the best coverage (close to the map scale) along the equator near the center of the map at 180 degrees west longitude and near the left and right edges at 0 and 360 degrees west longitude. The worst coverage is on the leading hemisphere (particularly around 120 degrees west longitude) and in some northern latitudes. Coverage in the northern polar region continues to improve as the north pole comes out of shadow after Titan’s northern vernal equinox in August 2009. Large dark areas, now known to be liquid-hydrocarbon-filled lakes, have been documented at high latitudes (see Maps of Titan – January 2009). This map is an update to the version released in February 2009 (see Map of Titan – February 2009). Data from the last two years, including the most recent data in the map from April 2011, have improved coverage in the southern trailing hemisphere and over portions of the north polar region. The mean radius of Titan used for projection of this map is 1,600 miles (2,575 kilometers). Titan is assumed to be spherical until a control network — or model of the moon’s shape based on multiple images tied together at defined points on the surface — is created at some point in the future. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov or http://www.nasa.gov/cassini . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL-Caltech/Space Science Institute

[SOURCE: saturn.jpl.nasa.gov]

NASA Telescopes Help Solve Ancient Supernova Mystery

NASA Telescopes Help Solve Ancient Supernova Mystery

PASADENA, Calif. — A mystery that began nearly 2,000 years ago, when Chinese astronomers witnessed what would turn out to be an exploding star in the sky, has been solved. New infrared observations from NASA’s Spitzer Space Telescope and Wide-field Infrared Survey Explorer, or WISE, reveal how the first supernova ever recorded occurred and how its shattered remains ultimately spread out to great distances.

The findings show that the stellar explosion took place in a hollowed-out cavity, allowing material expelled by the star to travel much faster and farther than it would have otherwise.

“This supernova remnant got really big, really fast,” said Brian J. Williams, an astronomer at North Carolina State University in Raleigh. Williams is lead author of a new study detailing the findings online in the Astrophysical Journal. “It’s two to three times bigger than we would expect for a supernova that was witnessed exploding nearly 2,000 years ago. Now, we’ve been able to finally pinpoint the cause.”

[SOURCE: spitzer.caltech.edu]

In, Around, Beyond Rings

In, Around, Beyond Rings

A quartet of Saturn’s moons, from tiny to huge, surround and are embedded within the planet’s rings in this Cassini composition. Saturn’s largest moon, Titan, is in the background of the image, and the moon’s north polar hood is clearly visible. See Haze Layers on Titan to learn more about that feature on Titan (3,200 miles, or 5,150 kilometers across). Next, the wispy terrain on the trailing hemisphere of Dione (698 miles, or 1,123 kilometers across) can be seen on that moon which appears just above the rings at the center of the image. See Dione’s Icy Wisps and Highest Resolution View of Dione to learn more about Dione’s wisps. Saturn’s small moon Pandora (50 miles, or 81 kilometers across) orbits beyond the rings on the right of the image. Finally, Pan (17 miles, or 28 kilometers across) can be seen in the Encke Gap of the A ring on the left of the image. This view looks toward the northern, sunlit side of the rings from just above the ringplane. The image was taken in visible blue light with the Cassini spacecraft narrow-angle camera on Sept. 17, 2011. The view was obtained at a distance of approximately 1.3 million miles (2.1 million kilometers) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 27 degrees. Image scale is 8 miles (13 kilometers) per pixel on Dione. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov or http://www.nasa.gov/cassini . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL-Caltech/Space Science Institute

[SOURCE: saturn.jpl.nasa.gov]

Space Calendar October 26 – 0 2011

Space related activities and anniversaries for October 26 – 0 2011. Fetched live every week from NASA JPL

If you want the complete list going more than a year ahead then see the Space Calendar at NASA JPL.

Enceladus Flyby E-15 (Raw Image #8)

Enceladus Flyby E-15 (Raw Image #8)

This raw, unprocessed image of Saturn’s moon Enceladus were taken on Oct. 19, 2011. As the spacecraft passed Enceladus, its infrared instruments, cameras and other instruments monitored activity on the moon, in particular the famed jets erupting from the moon’s south pole. The orbiter flew within about 765 miles (1,230 kilometers) of Enceladus’ surface. This image has not been validated or calibrated. A validated/calibrated image will be archived with the NASA Planetary Data System in 2012. For more information on raw images check out our Frequently Asked Questions section. Credit: NASA/JPL-Caltech/Space Science Institute

[SOURCE: saturn.jpl.nasa.gov]

Enceladus Flyby E-15 (Raw Image #9)

Enceladus Flyby E-15 (Raw Image #9)

This raw, unprocessed image of Saturn’s moon Enceladus were taken on Oct. 19, 2011. As the spacecraft passed Enceladus, its infrared instruments, cameras and other instruments monitored activity on the moon, in particular the famed jets erupting from the moon’s south pole. The orbiter flew within about 765 miles (1,230 kilometers) of Enceladus’ surface. This image has not been validated or calibrated. A validated/calibrated image will be archived with the NASA Planetary Data System in 2012. For more information on raw images check out our Frequently Asked Questions section. Credit: NASA/JPL-Caltech/Space Science Institute

[SOURCE: saturn.jpl.nasa.gov]

NASA’s Spitzer Detects Comet Storm in Nearby Solar System

NASA's Spitzer Detects Comet Storm in Nearby Solar System

PASADENA, Calif. — NASA’s Spitzer Space Telescope has detected signs of icy bodies raining down in an alien solar system. The downpour resembles our own solar system several billion years ago during a period known as the “Late Heavy Bombardment,” which may have brought water and other life-forming ingredients to Earth.

During this epoch, comets and other frosty objects that were flung from the outer solar system pummeled the inner planets. The barrage scarred our moon and produced large amounts of dust.

Now Spitzer has spotted a band of dust around a nearby bright star in the northern sky called Eta Corvi that strongly matches the contents of an obliterated giant comet. This dust is located close enough to Eta Corvi that Earth-like worlds could exist, suggesting a collision took place between a planet and one or more comets. The Eta Corvi system is approximately one billion years old, which researchers think is about the right age for such a hailstorm.

[SOURCE: spitzer.caltech.edu]

Dark Matter Mystery Deepens

Dark Matter Mystery Deepens

Like all galaxies, our Milky Way is home to a strange substance called dark matter. Dark matter is invisible, betraying its presence only through its gravitational pull. Without dark matter holding them together, our galaxy’s speedy stars would fly off in all directions. The nature of dark matter is a mystery — a mystery that a new study has only deepened.

“After completing this study, we know less about dark matter than we did before,” said lead author Matt Walker, a Hubble Fellow at the Harvard-Smithsonian Center for Astrophysics.

The standard cosmological model describes a universe dominated by dark energy and dark matter. Most astronomers assume that dark matter consists of “cold” (i.e. slow-moving) exotic particles that clump together gravitationally. Over time these dark matter clumps grow and attract normal matter, forming the galaxies we see today.

[SOURCE: www.cfa.harward.edu]