Expert: Jayendra Upadhye - 9/25/2009

Question
QUESTION: Dear Sir:
        The Hubble has viewed points in space that they say are from 13.5 billion  light years ago.  Is there anyway of knowing what is happening right now at those locations or do we have to wait that same numbers of years to know what was happening in 2009, thus getting 13.5 billion light years-old information?  In other words, is it that what is happening now in those distant places forever unknowable?  thank you.

ANSWER: Hi,
Yes Gary, we are forever cutoff from them.
regards
jayen

---------- FOLLOW-UP ----------

QUESTION:    Thank you for your response.  I have read that it takes light 7 minutes to arrive from our sun--so, what we see right now is what was happening 7 minutes ago.  Is that correct?  If the sun suddenly blew up, would it be 7 minutes before we saw this, our last mortal vision as we are burnt to a crisp?  Would the Hubble telescope, if pointed in that direction, view this explosion at the exact same time(7 minutes later)?  Thank you.

Answer
Hi,
Yes and No.
Yes because in a "day to day" sense, hubble and us would see the events roughly 8 minutes after the actual conflagration had happened on the sun.
No because strictly speaking, depending on whether the Hubble was "sunward" or "on the nightside, it would see the conflagration a little before or after us. The difference being a few microseconds.

Another interesting thing is I doubt the flash from the conflagration would burn us immediately.
After the main flash, the exploding gaseous contents would proceed outwards at a few 1000s of km/sec, substantially slowly as compared to C.

These would burn us by direct heat transfer, when they reached 1 astronomic unit from the sun.

And even before we started burning, would come the terrible sound of the blast (trapped in the escaping gas as accoustic waves)!
It would still our hearts by its amplitude and severity!

The Aroras woul have become visible at the tropics due to the severe influx of charged particles from the van allen belts.
And in the last few moments, Atmospheric Nitrogen would combine with Ozone to form brown Nitrous Oxide, which would extinguish all life on earth.

This is what is supposed to have happened just after life began in the earth, when the first great dying is supoosed to have been triggered by a blast from a wolf rayet star near by in the galaxy. (A gamma ray burst).

regards
Jayen