is a supernova that we view today actual an event in the past?

Yes. In fact, everything that we view is from the past. The closer the object is, the less time interval has past. The view of the moon from the Earth's surface is about 3 seconds old by the time we see it.

We hope that any supernovae we see happened in the distant past. If we see a supernova 8 min and 20 seconds in the past, the earth will have only seconds before it is consumed.

Yes. It takes light time to travel to our eyes, so everything we see is an event in the past. Generally it's just a few milliseconds, but in the case of a supernova that happens, say, 20,000 light years away, we see the light 20,000 years later.

Yes... We see any object when the light reflected back or emitted from an object....

And light also tajes time to reach to the viewer's eyes..... So any supernova that u re viewing is the past event.... And is the case relativity..........

Yes, as the light that gets in our eyes are actually released from the stars and supernovae many years ago, as the distance between us and the stars is COLOSSAL and light takes years to travel that distance.

FUN FACT - The light we see coming from the sun is actually 8 mins 20 secs from the past!!