Apr 18

NASA – Dying Supergiant Stars Implicated in Hours-long Gamma-Ray Bursts

Three unusually long-lasting stellar explosions discovered by NASA’s Swift satellite represent a previously unrecognized class of gamma-ray bursts (GRBs). Two international teams of astronomers studying these events conclude that they likely arose from the catastrophic death of supergiant stars hundreds of times larger than the sun.

GRB 111209A exploded on Dec. 9, 2011. The blast produced high energy emission for an astonishing seven hours, earning a record as the longest-duration GRB ever observed.

GRB 111209A exploded on Dec. 9, 2011. The blast produced high-energy emission for an astonishing seven hours, earning a record as the longest-duration GRB ever observed. This false-color image shows the event as captured by the X-ray Telescope aboard NASA’s Swift satellite. Credit: NASA/Swift/B. Gendre (ASDC/INAF-OAR/ARTEMIS)

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The astronomers discussed their findings Tuesday at the 2013 Huntsville Gamma-ray Burst Symposium in Nashville, Tenn., a meeting sponsored in part by the University of Alabama at Huntsville and NASA’s Swift and Fermi Gamma-ray Space Telescope missions.

GRBs are the most luminous and mysterious explosions in the universe. The blasts emit surges of gamma rays — the most powerful form of light — as well as X-rays, and they produce afterglows that can be observed at optical and radio energies. Swift, Fermi and other spacecraft detect an average of about one GRB each day.

via NASA – Dying Supergiant Stars Implicated in Hours-long Gamma-Ray Bursts.

Apr 17

NASA – The Long and Storied Path to Human Asteroid Exploration

This June 1978 artist's concept shows an asteroid retrieval mission.

This artist’s concept from 1978 shows an asteroid retrieval mission. (NASA)View larger image

Within NASA’s new FY2014 budget proposal lies a project known as the Asteroid Retrieval and Utilization Mission. This project would be the first to capture a small near-Earth asteroid and safely redirect it to a lunar orbit so that astronauts can visit and explore it. Such a mission would expand scientific knowledge of the origins of both humanity and the universe.

The goal of asteroid retrieval is not a new endeavor for NASA. In fact, the idea dates to the earliest days of the agency. In a 1964 document that looked at “long range future mission planning,” NASA expressed an early aspiration to visit asteroids through unmanned probes by the end of the 1970s. NASA did indeed send a probe through the asteroid belt early in that decade – Pioneer 10 safely traversed the Belt on its way to Jupiter in 1972. By 1969, according to a “Five Year Plan” laid out by the Office of Manned Space Flight, NASA was already looking at plans to send crewed missions to asteroids. However, at the time, the then-latest technology was insufficient to pursue this goal. NASA

via NASA – The Long and Storied Path to Human Asteroid Exploration.

Apr 17

NASA – NASA’s Wind Mission Encounters ‘SLAMS’ Waves

Earth is surrounded by a giant magnetic bubble called the magnetosphere. As it travels through space, a complex system of charged particles from the sun and magnetic structures piles up in front of it.

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Earth is surrounded by a giant magnetic bubble called the magnetosphere. As it travels through space, a complex system of charged particles from the sun and magnetic structures piles up in front of it. Scientists wish to better understand this area in front of the bow shock, known as the foreshock, as it can help explain how energy from the rest of space makes its way past this boundary into the magnetosphere. Credit: Credit: NASA/GSFC

As Earth moves around the sun, it travels surrounded by a giant bubble created by its own magnetic fields, called the magnetosphere. As the magnetosphere plows through space, it sets up a standing bow wave or bow shock, much like that in front of a moving ship. Just in front of this bow wave lies a complex, turbulent system called the foreshock. Conditions in the foreshock change in response to solar particles streaming in from the sun, moving magnetic fields and a host of waves, some fast, some slow, sweeping through the region.

To tease out what happens at that boundary of the magnetosphere and to better understand how radiation and energy from the sun can cross it and move closer to Earth, NASA launches spacecraft into this region to observe the changing conditions. From 1998 to 2002, NASA’s Wind spacecraft traveled through this foreshock region in front of Earth 17 times, providing new information about the physics there.

via NASA – NASA’s Wind Mission Encounters ‘SLAMS’ Waves.