Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 06/06/2016 19:50:02

Title: How long would it take to see an event that happens 1000 light years away through a telescope?
Post by: thedoc on 06/06/2016 19:50:02

Susanne Beck asked the Naked Scientists:
   Love your podcast (http://www.thenakedscientists.com/HTML/podcasts/)!!  At 50 I feel I am an idiot asking this, but here goes.  Suppose you had a great telescope and see a particular planet a little less than 1000 light years away, called William the Conqueror because the distance shows how that planet looked, real time, during his reign.  Now suppose 500 years later, Henry VIII, a fat gas giant with six moons, decapitates and bullies it's way into Billy's "solar" system, like a late coming Jupiter to our Earth.  If your telescope was trained on William, would you not be able to see Henry's existence until 2500, 1000 years after it appeared in William's 1000 light years away area?
What do you think?

Title: Re: How long would it take to see an event that happens 1000 light years away through a telescope?
Post by: alancalverd on 07/06/2016 00:14:45

Too many negatives, but yes.

Title: Re: How long would it take to see an event that happens 1000 light years away through a telescope?
Post by: Bill S on 08/06/2016 00:42:35

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FyL8XRqY.png&hash=45429f1d3863bfa670670498c45b582f)

This is a simplified form of a chart of cosmic times and distances.  It can be created, in varying degrees of complication, on line at: http://www.einsteins-theory-of-relativity-4engineers.com/TabCosmo7.html. 

It can help with working out times and distances in an expanding universe.