Talk:G299.2-2.9

4500 years old contradiction?
The lead says the remnant is 4500 years old and that it is 16,000 light years away. If that were literally true, we would not be able to see it for another 11,500 years, no? Nicolas Perrault (talk) 02:48, 29 April 2024 (UTC)


 * You are correct. I was jarred by the same time inconsistency. Your calculations are correct, given the figures in this article. They're wrong. 173.21.38.106 (talk) 03:47, 29 April 2024 (UTC)
 * The supernova could have happened 4,500 years ago from our perspective, and the object be 16,000 light years away. That just means that the actual supernova event occurred approximately 20,500 years ago. 132.160.77.184 (talk) 03:55, 29 April 2024 (UTC)
 * Perhaps the values are transposed 75.115.129.168 (talk) 13:19, 29 April 2024 (UTC)
 * The ref says the age is 4500 years:
 * "Because it is older than most supernova remnants caused by these explosions, at an age of about 4500 years, G299.2-2.9 provides astronomers with an excellent opportunity to study how these objects evolve over time."
 * https://chandra.harvard.edu/blog/taxonomy/term/5?page=7
 * Johnjbarton (talk) 17:43, 29 April 2024 (UTC)
 * We can only meaningfully talk about a distant object's apparent age based on what we see now. See One-way_speed_of_light. Holy (talk) 23:43, 29 April 2024 (UTC)
 * Then shouldn't we specify that it is ~20500 years old or so and then say it first appeared roughly 4500 years ago? Joecompan (talk) 00:14, 30 April 2024 (UTC)
 * No. We should say what the ref says. The ref says that analysis based on the radius of the remnant shell gives an age of 4500 years. That is the age of the shell blast wave structure.
 * The age of the nova is irrelevant. Astronomers will look around for other nova remnants and collect a bunch of these with different ages, then compare the structure they observe to nova explosion models. Over the history of the universe the explosion model does not change, so the date of the nova does not matter.
 * To reiterate, 20,500 years is not relevant to anything. Johnjbarton (talk) 00:33, 30 April 2024 (UTC)
 * I reworded the intro again, is this better? Johnjbarton (talk) 02:32, 30 April 2024 (UTC)
 * That's really good, thanks! It was fine as it was, but you've really improved it. Holy (talk) 03:13, 30 April 2024 (UTC)

Did you know nomination

 * Also, I forgot to add ALT1, what about "...that the supernova remnant G299.2-2.9 is the result of a natural thermonuclear explosion?" ( ͡°( ͡° ͜ʖ( ͡° ͜ʖ ͡°)ʖ ͡°)͡°) (talk) 16:48, 21 March 2024 (UTC)