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Evolving galaxies shed gas and fireballs

...astronomers studying the Coma Cluster of galaxies have discovered that galactic collisions are powerful enough to strip a galaxy of its gas and fling star-forming fireballs out into space...

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Small asteroid burns up in Earth’s atmosphere

...according to predictions, three metre wide asteroid 2008TC3 exploded in the Earth’s atmosphere at 0246 UT above northern Sudan on Tuesday...

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Cloudy weather on failed star twins

...A team of astronomers using one of the Keck telescopes on Mauna Kea has found evidence for cloudy weather on two failed stars...

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Video archive

STS-120 day 2 highlights

Flight Day 2 of Discovery's mission focused on heat shield inspections. This movie shows the day's highlights.


STS-120 day 1 highlights

The highlights from shuttle Discovery's launch day are packaged into this movie.


STS-118: Highlights

The STS-118 crew, including Barbara Morgan, narrates its mission highlights film and answers questions in this post-flight presentation.

 Full presentation
 Mission film

STS-120: Rollout to pad

Space shuttle Discovery rolls out of the Vehicle Assembly Building and travels to launch pad 39A for its STS-120 mission.


Dawn leaves Earth

NASA's Dawn space probe launches aboard a Delta 2-Heavy rocket from Cape Canaveral to explore two worlds in the asteroid belt.

 Full coverage

Dawn: Launch preview

These briefings preview the launch and science objectives of NASA's Dawn asteroid orbiter.

 Launch | Science

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MESSENGER reveals more of Mercury’s secrets

Posted: October 08, 2008

The MESSENGER spacecraft successfully completed its second flyby of the innermost planet yesterday, unveiling another 30 percent of the planet’s surface in over 1,200 high resolution photos.

In January, MESSENGER revealed 20 percent of the planet’s surface that Mariner 10 had missed in 1974 and 1975, and the latest flyby completes the first global view of Mercury.

“The MESSENGER team is extremely pleased by the superb performance of the spacecraft and the payload,” says MESSENGER Principal Investigator Sean Solomon of the Carnegie Institution of Washington. “We are now on the correct trajectory for eventual insertion into orbit around Mercury, and all of our instruments returned data as planned from the side of the planet opposite to the one we viewed during our first flyby. When these data have been digested and compared, we will have a global perspective of Mercury for the first time.”

Here are some of the very first images returned to Earth:

The wide angle camera took this image of the planet about 90 minutes after closest approach. The image reveals an extensive ray system of bright white material emanating from a relatively young impact crater in the north of the planet and extending to regions south of the crater known as Kuiper, the bright crater in the centre of the image, that was previously identified in Mariner 10 images. The rays appear brighter than their surrounds since they represent fresh material thrown out from the crater that has yet to be degraded by Mercury’s environment. Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.

This is the highest resolution colour image ever acquired of any portion of Mercury’s surface and overlaps with data obtained by MESSENGER’s Mercury Atmospheric and Surface Composition Spectrometer and Mercury Laser Altimeter instruments, the first time that three instruments have gathered data of the same area of Mercury. The largest impact crater at the top of the image measures 133 kilometres in diameter and is flooded with smooth material, similar to the comparably large crater to the left of the image. Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.

The Narrow Angle Camera captured this image as MESSENGER swooped past the surface at an altitude of 17,100 kilometres. The foreground features at the right of the image are near the terminator - the boundary between day and night side of the planet - casting long shadows across the surface. Two very long cross-cutting scarps are visible in this region, and the easternmost scarp also cuts through a crater, showing that it formed after the impact that created the crater. Other neighboring impact craters, such as in the upper left of this image, appear to be filled with smooth plains material. Analysis of data from the first flyby suggests that the planet’s plains material is a result of volcanic activity. Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.

The MESSENGER team has only had a few hours to examine the features unveiled in this new set of images, and more images from the flyby are still streaming back to Earth. Collectively, these images, and the measurements made by the other MESSENGER instruments, will soon provide a global perspective for understanding the formation and geologic history of the innermost planet.

For more information about the flyby go to NASA's MESSENGER homepage and stay tuned to for more news updates.