Thursday, September 27, 2012

Hubble Catches Glowing Gas and Dark Dust in a Side-On Spiral

The NASA/ESA Hubble Space Telescope has produced a sharp image of NGC 4634, a spiral galaxy seen exactly side-on. Its disk is slightly warped by ongoing interactions with a nearby galaxy, and it is crisscrossed by clearly defined dust lanes and bright nebulae.

NGC 4634, which lies around 70 million light-years from Earth in the constellation of Coma Berenices, is one of a pair of interacting galaxies. Its neighbor, NGC 4633, lies just outside the upper right corner of the frame, and is visible in wide-field views of the galaxy. While it may be out of sight, it is not out of mind: its subtle effects on NGC 4634 are easy to see to a well-trained eye.

Gravitational interactions pull the neat spiral forms of galaxies out of shape as they get closer to each other, and the disruption to gas clouds triggers vigorous episodes of star formation. While this galaxy’s spiral pattern is not directly visible thanks to our side-on perspective, its disk is slightly warped, and there is clear evidence of star formation.

Along the full length of the galaxy, and scattered around parts of its halo, are bright pink nebulae. Similar to the Orion Nebula in the Milky Way, these are clouds of gas that are gradually coalescing into stars. The powerful radiation from the stars excites the gas and makes it light up, much like a fluorescent sign. The large number of these star formation regions is a telltale sign of gravitational interaction.

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Monday, September 10, 2012

NASA Mars Rover Curiosity Begins Arm-Work Phase

Before completing its final flight on the back of a 747 on September 20 the Space Shuttle Endeavour will visit the Bay Area, flying low over NASA Ames Research Center and possibly other area landmarks such as the Golden Gate Bridge. Endeavour will begin its multi-day cross-country journey by taking off near dawn on September 17 from Kennedy Space Center in Florida. The final stop of Endeavour’s tour will be Los Angeles International Airport, 12 miles way from its new museum home at the California Science Center.

Although the exact timing and path of the ferry flight will depend on weather conditions and operational constraints, the piggybacked duo are scheduled to conduct low-level flyovers of several locations along the planned flight path. These include the Kennedy Space Center Visitor Complex, Cape Canaveral Air Force Station and Patrick Air Force Base, in and around the Florida spaceport; NASA's Stennis Space Center in Mississippi and the agency's Michoud Assembly Facility in New Orleans; Houston, Clear Lake and Galveston, near NASA's Johnson Space Center; White Sands Test Facility near Las Cruces, N.M.; NASA's Dryden Flight Research Center at Edwards Air Force Base, Ames Research Center at Moffett Field, and various landmarks in multiple California cities. Social media users are encouraged by NASA to share their Endeavour sightings using the hashtags #spottheshuttle and #OV105, Endeavour’s orbiter vehicle designation.

After arriving at LAX, the shuttle will be removed from its 747 carrier aircraft and spend a few weeks in a United Airlines hanger being prepared for transportation and display. Endeavour then will travel through Inglewood and Los Angeles city streets on a 12-mile journey from the airport to the science center, arriving in the evening on Oct. 13. Beginning Oct. 30, the shuttle will be on display in the California Science Center's Samuel Oschin Space Shuttle Endeavour Display Pavilion.

Monday, September 03, 2012

NASA's IceBridge Seeking New View of Changing Sea Ice

This year scientists working on NASA's Operation IceBridge, a multi-year airborne science mission to study changing ice conditions at both poles, debuted a new data product with the potential to improve Arctic sea ice forecasts.

Using new data processing techniques, IceBridge scientists were able to release an experimental quick look product before the end of the 2012 Arctic campaign. The main challenge faced when producing data for seasonal forecasts is the time needed to crunch the numbers, something that has in the past taken IceBridge scientists more than six months to do after the data was collected in the spring. This is too late to use for Arctic sea ice forecasts of the annual seasonal minimum, which takes place in September.

The new product could potentially be used in seasonal sea ice forecasts in the future. "The community is excited about it," said IceBridge science team co-lead Jackie Richter-Menge of the U.S. Army Corps of Engineers Cold Regions Research Laboratory, Hanover, N.H. "We're hoping to build on this season's momentum and interest."

Scientists have been keeping an eye on Arctic sea ice in recent years because it is changing and they want to understand what those changes might mean. Arctic sea ice grows and recedes in a seasonal pattern, with a maximum coverage in March and a minimum in September. These high and low points vary from year to year, but there is a clear trend toward smaller minimums that mean more open water in the Arctic each summer and fall. This decrease in ice is already affecting ocean and terrestrial life in the Arctic, accelerating warming in the region and leading to economic and social changes.

"Sea ice is a sensitive indicator of a changing climate," said NASA researcher Nathan Kurtz at NASA's Goddard Space Flight Center, Greenbelt, Md. It can also act as a feedback to warming in the Arctic. Because ice is much lighter in color than ocean water it has a higher albedo, meaning it reflects more sunlight than water. "A loss of sea ice can cause the Earth as a whole to warm," Kurtz said. The loss of sea ice has also been linked to shifts in weather patterns and distribution of nutrients in the ocean.