How can we see supernova remnant G1.9+0.3? If it is estimated to be about 25,000 light years away and now NASA says that it is about 140 years old, how can we even observe it? Wouldn't it still appear as a star to us for the next 24,860 years or so?
1 Answer
Jun 3, 2016
The supernova has been visible for 140 years.
Explanation:
Although the star is some 25,000 light years away. When it went supernova, the light reached the Earth around 1868.
So, the star exploded some 25,000 years ago. What NASA is saying is that we have been observing the supernova for 140 years. All of the light having been travelling for 25,000 years to reach us.
