I attended an astronomy lecture the other night, and had a piece of awareness drop in a very unexpected way while listening to the speaker.
She was discussing results from NASA's Spitzer Space Telescope that were possible due to the use of infrared sensors. She gave a short primer on the discovery of infrared light before hurrying on to her more pertinent data... and while I was interested throughout her lecture, I confess that I was taken with the idea of infrared and began drawing parallels to our relationships with the departed.

First, I will share an abbreviated history of infrared.

Sir Frederick William Herschel (1738-1822) discovered infrared by accident. 

He had noticed that when he held his prism to the light that the rainbow spectrum seemed to have different heat related to color. He devised a clever experiment to investigate his hypothesis. 

He directed sunlight through his prism to create the rainbow spectrum and then measured the temperature of each color by using thermometers with blackened bulbs (to better absorb heat) and, for each color of the spectrum, placed one bulb in a visible color while the other two were placed beyond the spectrum as control samples. He noticed that all of the colors had temperatures and that the temperatures of the colors increased from the violet to the red part of the spectrum. Then he accidentally measured the temperature just beyond the red portion of the spectrum in a region where no sunlight was visible. To his surprise, he found that this region had the highest temperature of all.He called this infrared because the prefix infra means below.

Herschel's experiment led to the discovery of infrared light, AND it was the first time that someone showed that there were forms of light that we cannot see with our eyes. We now know that there are diverse types of light that we cannot see and that the visible colors are only a very small part of the entire range of light which we call the electromagnetic spectrum. 

It makes it possible to see things like this:
The picture on the left is a normal telescope's image. On the right is what infrared can divulge. 
It made me think a lot about our beloved departed and their apparent absence in our lives. Perhaps, they could present in ways not detectable to us. Perhaps it merely takes a altered viewpoint to become aware of them. 

I wish I had a telescope that revealed what lies beyond the veil...