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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: Supercharging the Hubble
4 November 2011 12:43 pm
An international team of astronomers has turbocharged the Hubble Space Telescope, enabling it to observe a brightly glowing disc of matter that is being sucked into its galaxy's central black hole. Such discs, known as quasar accretion disks, are typically about 100 billion kilometers across, and most lay billions of light-years away. So how was Hubble able to observe it? Through a technique called gravitational microlensing in which the light from a background object is bent by gravity around a foreground object. If scientists can line up a quasar almost exactly behind a much closer galaxy, they are able to see not one quasar but two or four magnified images of the same quasar—a gravitational lens. (In the image above the more distant quasar HE 1104-1805 is seen as the two larger images on either side of the smaller yet closer lens galaxy [WKK93] G.) The stars in that lens galaxy then act like ultra-high resolution telescopes (see the NASA video). The level of detail involved is equivalent to being able to study individual grains of sand on the surface of the moon while standing on Earth. This enabled the astronomers to measure the diameter of the accretion disc and plot its various temperatures, providing a new experimental confirmation of how quasars work.
See more ScienceShots.