My friend and gifted mathematical physicist David McAnally died suddenly last week. I attended David’s funeral today. It’s hard to believe that he’s gone. It hadn’t ever crossed my mind that this shy, gentle man, who loved mathematics and physics would pass on so soon. David was 44.
For the last couple of months David had been teaching me a crash course on general relativity. He’d gone through the material but decided to give me one more lecture - scheduled for last Tuesday afternoon. Unfortunately, he passed away unexpectedly that morning.
I sat in that empty lecture room last week, reminiscing and trying to get my head around this awful thing.
The ESA reports on this spectacular lensed quasar image obtained by the Hubble space telescope. This is the first time a 5 times lensed object has been discovered.
Gravitational lensing results in an odd number of images - but some images are very weakly magnified and difficult to see, especially if the image is close to the lensing object. In this case the geometry is quite good and the fifth image is discernable from the lensing object. The five images of the distant quasar are marked by blue circles.
Also shown are three lensed images of a background galaxy, marked by red circles, and a distant supernova marked by the yellow circle.
Full story:European Space Agency
Some papers on gravitational lensing from the arXiv and elsewhere