A new study was just published today that is the culmination of a long period of research into quantum entanglement by physicists from MIT, the University of Vienna, the University of California at San Diego, Harvey Mudd College, and the Austrian Academy of Sciences, which uses ancient quasars to help confirm what Einstein once referred to as "spooky action at a distance."
As MIT News reports, this research gives a great deal of support for the idea that two particles can be linked to one another regardless of how far away they may be from each other with regard to both time and space, which is something that goes against everything we know about classical physics.
To illustrate how very strange the notion of quantum entanglement is when it comes to classical physics, picture in your mind two particles that sit across the universe from each other.
By using the theory of quantum mechanics, the only way that these two particles could be legitimately entangled would be if they shared physical properties in a manner which made it so that if you were to measure one of the particles it would immediately "convey information about any future measurement outcome of the other particle."