Viewing a single comment thread. View all comments

doubletaxed88 t1_jb6s8sh wrote

Reply to comment by mac4281 in James Webb Telescope captures the same galaxy at three different points in time in a single mind-boggling image by mirzavadoodulbaig

No, it is one image. The objects are behind another supermassive object which causes gravitational lensing, and you see it three times. Because of the extra distance it has to travel as the light bends, you are seeing the objects in different moments in time.

Edit: I forgot to mention there is also something called time dilation with gravity, and the more you have it the slower time travels, so the images that are lensed with the most gravity arrive later in time.

48

Chichachachi t1_jb72447 wrote

But why is it saying one was 320 days later and the other is 1000 days later? If it is just one image, how would we be able to know the time dilation to the precision of days of time difference? But also, James Webb was placed at the Lagrange point less than a year ago, so I guess we DO know the difference that light travelled to the degree of days.

The supernova event is 3.2 billion light years away. But we can actually tell that one lens delayed the light from one image by 320 days and the other by 1000 days. Incredible.

3

doubletaxed88 t1_jb786ol wrote

Because they can see the various stages of the supernova in the three images, and supernovas are fairly well understood from a timing and energy mass ejection standpoint.

14

pmMeAllofIt t1_jb7iskw wrote

It's one image, with the Supernova's galaxy appearing in it 3 times, at 3 different moments in time. The duration was estimated using scans from Hubble last year. Believing it to be a type Ia supernova (which all have the same luminosity) allowed them to plug the numbers and figure out the precise "prescription" of the lens that galaxy in the foreground is creating. JWST confirmed it's a type Ia supernova, which means their numbers are accurate.
 Lensing is pretty well understood and they have amazing software to help them out.

9

doubletaxed88 t1_jb814uh wrote

How much of the night sky is lensed? Is there any estimates of how much you see is duplicates, or is it a rare occurance?

3

daggada t1_jbabe9o wrote

I think for that to really come into play, you need to be looking pretty far. Like it's not something you'll really see in the stars you see at night with your eyes in our local galaxy.

But sure, looking into deep intergalactic space, which requires a decent telescope, it's probably not all that uncommon. Take a look at some of Webbs early pics, you'll see lots of warped and stretched images which I believe are examples of that phenomenon as well. And those are just in small patches of space.

1

doubletaxed88 t1_jb78den wrote

So the cool thing is as they watch this over the next three years, they will see the same image develop of three objects to two.

7