Researchers Develop way to Control Speed of Light, Send it Backward
That’s the headline at phys.org, who Should Know Better. But that site is not as well-regulated as you might think from the impressive title. Phys.org is to physics as Business Insider is to business — poorly moderated group blogs around a supposed focus of interest.
I’ll cut to the chase. A comment illuminated the problem with the post.
Comment author: antialias_physorg
“*Sigh* this is group velocity. Not velocity of individual photons.
It’s like passing a laserpointer accross the face of the moon.
Can the bright spot on the moon APPEAR to move faster than light? Yes.
Does anything in this setup (including information transmission) move faster than light? No.
Speed of light limits aren’t broken, here. It’s achieved with a (very clever) modulation of the beam characteristics with the magnetic and electric fields not at right angles to the direction of propagation but canted sharply forwards/aft.”
That comment is (taken with similar comments further down) the only thing of value on the page. Perhaps the author of the article, “University of Central Florida” could have titled and written the post differently, in a manner which reflects the story being reported upon with more , um, honesty. But this was not done, the article stands or falls as written, and it falls in an atrocious fashion.
The last line of the comment shows its author to be a man of my stripe:
“(Full paper is linked in the article, BTW…so all you nutjobs could have saved your time and just read it before posting your ludicrous comments)”