Answer:
Physicists have built devices to move me very fast. My last seven letters can be commonly found in newspapers magazines and journals.
I have a gown but I'm not a priest; I have a crown but I'm not a king.
I give people a huge fright but at the end I'm sweet. I normally celebrate at night when there's less heat.
Fatherless and motherless. I was born without sin. Roared when I came into the world, but I never spoke again. What am I?
I can be driven but have no wheels. I can be sliced but still remains whole
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.