2026 May 07 - Supernova in a Sideways Spiral

Greetings and welcome to the Astronomy Picture of the Day podcast. Today's picture is titled Supernova in a Sideways Spiral. So, what do we see here? Well, here we see an image showing us a spiral galaxy. Now spiral galaxies, if we look at them from above or below, we see the great spiral structure swirling around from the center. However, spiral galaxies are very flattened, a very thin disk. So, if we see them sideways, we see just that thin disk of the galaxy. Now, this is actually a video clip that we're going to play and it is showing a supernova explosion that occurred in this distant galaxy. Now, this was discovered this year and this is Supernova 2006 KID and that is how supernovae are named. It's the year in which they're discovered and then the letters of the alphabet afterwards and as we go through the alphabet once a second and then a third letter is added and that allows us to count the now thousands of supernovae that we find every single year. You can see how far we are through the alphabet and here it is only May. Now, let's go ahead and watch the video and let this play and we can then see the galaxy here. We're not seeing the supernova yet. We are seeing various trails going across the image and those are caused by satellites that happen to come through the same field of view. And if we keep an eye on this, we'll then see the supernova appearing marked there with the red arrow that shows the location of a star that appeared that was not there before. Now, a supernova is an exploded star and in this case this is what is known as a type 2 supernova. A type 2 supernova occurs at the end of the life of a massive star which builds up an iron core, becomes unstable, and then explodes. And that star can, in many cases, outshine the entire galaxy for a period of time. Now, the supernova that we see here does not look quite that bright. It's because we're looking at a disc galaxy which has a lot of dust in it, so the location of this star is important. Were it on the near side of the galaxy where we could see it easily, it would be significantly brighter. But if it's towards the middle or the far side, that dust dims the light making even a supernova explosion very hard to see. Now, there are many prominent supernovae that have occurred in history. We know of the supernova of 1054, now seen as the Crab Nebula, and the brightest supernova seen a few decades before that, supernova 1006, and that was reported to be brighter than the planet Venus and could be visible during the day. So, you get an idea of how bright these supernovae can actually be to seen during the day. Whereas no stars and no planets can be seen during the day, here we could see another star appearing. And you can see why these were very interesting and often recorded by people thousands of years ago when a new star appeared in the sky. Now, in terms of recent supernovae, there's been a lot of them, but not within our galaxy. Now, in a typical spiral galaxy, a supernova will occur about once every hundred years or so. However, it has to be in the right location for you to see it. Supernovae are going off in our galaxy all the time, but we can't see them if they're on the other side of the galaxy or hidden behind areas with a lot of dust. They'll go off, but even a supernova will not be visible through that much material. The last supernova that occurred in our galaxy that we were able to detect visually would be the supernova that occurred in the early 1600s, less than a decade before the development of the telescope. So, in our own galaxy, we have not been able to study a supernova close within the time that we have had telescopes. One will occur eventually, but when that will be is a very good question. So, that was our picture of the day, titled Supernova in a Sideway Spiral. We'll be back again tomorrow for the next picture, previewed to be Open Star Cluster. So, we'll see what that is about tomorrow, and until then, have a great day, everyone, and I will see you in class.