Can You Look At the Same Object at Two Different Points in Time?

They say it all has to do with a galaxy cluster and a cosmic lens

Transcript

00:00When looking deep into space, we're actually peering back in time at light that was produced

00:08possibly millions of years ago.

00:10But back in 1979, astronomers noticed a pair of supermassive black holes at the center

00:15of two gas-filled galaxies, also known as quasars.

00:18But it turned out those two quasars were actually the same object, with one of the images delayed

00:23by something out in space.

00:24Recently, a team of astronomers from the University of Valencia discovered the same thing happening

00:29again.

00:30Over the course of 14 years, they clocked a 6.73 year delay between the two images of

00:34the same quasar.

00:36Experts say that the nearby cluster of galaxies is the culprit, creating a sort of cosmic

00:40gravitational lens that distorts the light that passes through it.

00:44That lens changed the light's path, forcing it to seemingly slow down and producing multiple

00:48images of the same object in space at different points in time.

00:51In the case of this newer quasar, four images, with the researchers writing, since the trajectory

00:56followed by the light rays to form each image is different, we observe them at different

01:00instants of time.

01:01In this case, we have to wait 6.73 years for the signal we observed in the first image

01:06to be reproduced in the fourth one.