A stochasticly updated blog about interesting topics in Physics & Astronomy
Last Thursday, I talked about stars, and how big they were, and also very briefly the different types that exist. Today, I’m going to talk about something else I also mentioned last week – how a star is made. The first stage of a star is where it is using hydrogen as its main fuel source – the Main Sequence Stars. So, it would be natural to assume that whatever forms a star is predominantly hydrogen. And what astronomers found when they went looking for places in the Galaxy that had a lot of hydrogen was something truly spectacular – they found star factories.
A star factory is simple a massive cloud of hydrogen. Again, scale here is something that is going to cause trouble – when I say massive this time, I mean even bigger than any of the stars we were talking about last week. Remember NML Cygni, the star that a radius of 1 billion km? The star factory which I’m going to talk about here – the Pillars of Creation – are 3 columns of hydrogen gas, with the highest column having a height of 37,840,000,000,000 km (that’s the same as four light years, which is the distance light, which travels at the fastest known speed in the Universe, would cover in 4 years). That distance really is unthinkable. Now, a single cloud of hydrogen won’t just produce a single star. Infact, the hydrogen cloud will collapse into different segments, each segment forming its own smaller segments, until finally the segments are just small enough to produce a single star – see the gif below for a better idea of this. As you can see, as time goes on, the large cloud splits into 4 smaller ones, which again split into 4 smaller-er ones when they get small enough. In reality, this happens many, many times in the hydrogen clouds, and you get an entire region of new stars!
Of course, the time scales for this to happen are massive. It can take millions of years for these clouds to collapse into stars, and even then, they all won’t collapse at once. You might get a particularly large part of the cloud to form into a giant hydrogen star (and as we learned last week) this star could go through its entire life and go pop before another, smaller section of the cloud has formed a small, orange star.
Now, the title of this blog is “The Pillars of Creation”. I haven’t said much on them yet other than they are one of these star forming regions. So what’s so spectacular about them? I mean, they aren’t even that big in comparison to other star forming regions (as I said, the Pillars largest column has a height of 4 lightyears – a normal star forming region can be as big as 100 lightyears (which is waaaay too many 0’s to type in kilometers)). Well, what’s special about them is in the image below. Look at that picture and tell me it’s not truly beautiful.
So there you go. We now know that stars are born out of large Hydrogen clouds that produce many, many stars over millions and millions of years. And using the fact that if we see blue stars, we know stellar birth happened in the region recently, astronomers and astrophysicists have been able to locate hundreds of these star factories. But luckily, the story with the Pillars isn’t over yet. Above, you see a picture of 3 massive pillars of hydrogen, in a picture taken by the Hubble Space Telescope in 1996. The Pillars are still observable with large telescopes today. Now, what if I told you that these pillars more than likely don’t exist anymore, and all we’re seeing is what they looked like 6,500 lightyears ago? Yeah, just so you know, things are going to get a bit weirder from here on out.
Before I talk anymore about the pillars, I need to clarify something – when we look at objects in space, we never actually see them as they are right now. We see them as they were when the light we see left the object. Bit of a confusing notion, so let’s take an example. The Sun emits light (and quite a lot of it). Light travels at the fastest speed in the Universe, and nothing (at least, yet) can travel faster than it. It travels at 30,000,000 meters per second (approximately). The distance from the Sun to the Earth is 149,600,000,000 m. So, it takes about 8 minutes for light to travel from the Sun to us (this distance is referred to as 8 light-minutes). This means we see the Sun as it was 8 minutes ago, not as it actually is. Strange, right?
Now, back to the Pillars. The Pillars are 6,500 lightyears away from us, which means it takes 6,500 years for the light to travel from them to us. Hence, we see them as they were 6,500 years ago. Great. It’s kind of like seeing into the past really. So, why am I saying they don’t exist anymore? Well, astrophysicists currently think that one of the stars in the image above actually went supernova (ie blew up with a hell of a lot of energy) around 6,000 years ago. The supernova would have sent out incredibly powerful winds, and quite literally blew the 3 pillars away. But do you see the problem? We see the pillars as they were 6,500 years ago. The supernova happened (we think) around 6,000 years ago. This means some time within the next 500 years ago, we should see this destruction happen, and it will truly be a beautiful sight for the astronomers of the time.
A final point I’d like to add here. The pillars are actually part of a much larger star forming region, known as the Eagle Nebula. If you’d like to find out more, go here and follow the image tour on the Hubble Space Telescopes site. It really is worth it. Also, below is a picture of another star forming region, much like the pillars. This region, called the “Mystic Mountain”, is 3 lightyears tall, and has some new, bright massive stars very close to its surface.
If you liked this post, please comment, ask questions or fact-check (I get things wrong very often to be honest) below. Also, sign up to the email portion of the site on the right to get notifications of new posts. Finally, Thursday blog will be the start of a series about how the Universe is out to get us. Part 1 will be all about our friend, the Sun.