Answer:
Physicists have built devices to move me very fast. My last seven letters can be commonly found in newspapers magazines and journals.
I don't live within a house, nor do I live without. Most will use me when they come in, and again when they go out. What am I?
The warmer I am the fresher I am.
My first is in riddle but not in little. My second is in think but not in brink. My third is in thyme but not in time. My fourth is in mother but not in brother. My last is in time but no t in climb.
When young I am sweet in the sun. When middle-aged I make you gay. When old I am valued more than ever.
If itβs information you seek, come and see me. If itβs pairs of letters you need, I have consecutively three. What am I?