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May 22, 2009 | 7
New research may shed light on the stellar explosions used as cosmic mileposts.
Type Ia supernovae, known as "standard candles" in astronomy, have consistent properties that make them good markers of distance when peering at galaxies across the universe. In fact, studies of this kind of exploding star a decade ago produced one of the most significant scientific discoveries in recent history: that the universe is expanding at an accelerating rate, thanks to the influence of so-called dark energy.
In a paper set to be published in Astronomy & Astrophysics, members of a consortium known as the Nearby Supernova Factory present a new way to ascertain type Ia supernovae's relative distance quickly and accurately, thereby increasing their usefulness as markers. Whereas past approaches painstakingly tracked the light output from the explosion over time, the new method can be used to measure a supernova's luminosity, and hence distance, much more quickly, and with a level of accuracy the study's authors say surpasses the traditional approach.
May 14, 2009
The European Space Agency (ESA) successfully launched two spacecraft this morning that should shed light on some of the big questions in astronomy and cosmology, from the origins of the universe to the formation of stars and planets.
ESA's Planck and Herschel lifted off on board an Ariane 5 rocket at 9:12 Eastern Daylight Time from the European Spaceport in French Guiana.
Less than 40 minutes later the two spacecraft radioed back to an ESA antenna in Australia to confirm that they had separated from the launcher as planned. (The video below shows an animation of Planck's separation.) They are on separate trajectories to loop around a point 930,000 miles (1.5 million kilometers) from Earth, well beyond the moon. To lend a sense of scale, ESA has a video showing Herschel's planned trajectory and orbit.
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