To The Core, Part I

We know today that the Milky Way is a big place and that we start each and every exploration trip from a pretty normal, some might say underwhelming spot on the galactic disc. But that was not always so. Back in the 20th century scientists based their cosmology models around only one galaxy in the entire universe and the firm belief that Sol was located in the very center. So far, so good. “Barbaric times” you might want to say. Looking back now, 1,300 years later, we allow ourselves to be that arrogant, but we forget the fact that science never was nor will ever be a static thing. Science can only develop as far as we can see and think.

It is because of this that the first ‘real’ waypoint for the Distant Worlds Expedition couldn’t have been selected at a more ideal point. After leaving Pallaeni, the flotilla assembled at the planetary nebula named Shapley 1, dubbed the Fine Ring Nebula. And it was that guy Harlow Shapley back in circa 1930 AD who through tireless observation and calculation deduced that the Milky Way had to be much bigger than it was thought back in the day. He also found out that Sol was located at that ‘underwhelming’ spot mentioned earlier. Needless to say, he had a hard time and a Great Debate about the fuss he created: Shapley hadn’t scratched at a pillar of the ‘written-in-stone’ cosmology model. No, he just kicked it over.

Now, you might say “Why is Shapley 1 so ideal as a first waypoint?” and I would answer “Because from here we venture forth to show that the galaxy is a bigger place.” Once again, we were at the threshold to commit ourselves to opening our eyes to the universe and to bring home a new idea of its vastness and beauty.

Back then, I couldn’t think of a better and more symbolic place to start this endeavor…

A couple of days later and after a thorough survey of the area, the flotilla left the Fine Ring  and began its trek towards the next waypoint, the mighty Lagoon Nebula, also known as Messier 8. What lay before us were some 1,000 light years and the approach towards the Sagittarius Gap. I could have taken the direct road, speeding towards the Lagoon, but I decided to take a detour and poke around some of the deep sky objects that lay, well, not exactly along the way, but in the exploration corridor the fleet was going to take anyway.

I always wanted to see and travel to the Northern Jewel Box (NGC 6231). It is dubbed the V945 Scorpii Cluster by explorers and it is magnificent to behold even from afar. The cluster is very young and is thought to have formed directly from material from the Lagoon. Despite its age (or lack thereof) several massive stars must have collapsed already, leaving behind the occasional black hole or neutron star.

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While heading towards NGC 6231, I also paid my tribute to the bipolar planetary nebula of NGC 6302, dubbed the Bug Nebula. It was allegedly formed after a massive star had collapsed into a Wolf-Rayet object, shedding most of its mass into interstellar space. The WR’s strong magnetic fields then acted as a containment for the ejected material and that – simply speaking – is why we see the nebula in its bipolar ‘hourglass’ shape. Like I said, go there and write a postcard to your loved ones.

Another deep sky object of note is the Red Spider Nebula (NGC 6537). It is some thousand light years away from the Bug Nebula, but hey, no rush! The Spider is a worthy sight. Contrary to the Bug Nebula the Spider does not seem to have a central star. There are theories about a White Dwarf or a cool Neutron star but so far nothing was found. What the nebula has in common with the Bug Nebula (and in fact with many planetary nebulae) is its bipolar structure. The central star blew off much of its outer shells and the magnetic fields or maybe the gravitational influence of a massive binary star has forced the stellar ejecta into its peculiar form. It’s nice to behold and absolutely interesting for studying plasma physics.

Finally, and formally a day late, I reached the H II region of the Lagoon Nebula. The entire complex is much bigger than the nebula itself, spanning several hundred light years in every direction and consequently there are more things to explore than just the nebula. Two of these are open clusters of NGC 6531 and NGC 6530. Both are relatively young and dense and still undergo expansion and the surroundings are still rich enough to continue star formation for quite some time. One red giant’s collapse here, one supernova blast there and you have enough shockwaves ploughing through the area and igniting hot dust cloud cores for the next generation of stars.

Speaking of stars: Of the brighter stars in those clusters there is one that has acted as a veritable beacon system in the past, a cornerstone of coreward expeditions and a magnet to cosmic explorers, tourists and – lately – pirates: The bright supergiant of Thor’s Eye. It has been labelled ‘Eye of the Beholder’, ‘Lagoon’s Jewel’ and also the ‘Maw of the Abyss’. Melodramatic for sure and everybody who has visited this system sure has different feelings about it!
I am somewhat biased towards the Eye. It is an O-type star of more than 16 solar radii alright, but it does not have any celestials except a gas giant and a black hole. Yes, okay, a black hole but with FSD technology and ultra-resolution imaging systems it’s not that these are elusive stellar rarities anymore. Maybe I am a bit callous here but I can’t understand the hype about the system. However, word spread fast that the expedition flotilla was going to move through.

It was here that a wing of several pirates from god-knows-where waylaid unsuspecting explorers of the Distant Worlds Expedition not long ago. Casualties were light but rumours of these attacks spread faster than the speed of light in the scientific community, leading to an increase in the local travel advisory rating (which is generally a bad thing for unarmed exploration vessels).

However, there is another star system I would like to point out and that is LKHA 115. It is also embedded in the NGC 6530 cluster, but it has a total of three black holes, two of which are in close orbit around each other. The total mass of those three is a bit lower than that of the single one of Thor’s Eye, granted, but the system is much more dynamical. If you have a graviton suite hooked up with your discovery scanner you might be able to pick up some gravitational waves from the two orbiting black holes. Good luck!

Now, the Lagoon Nebula is a very interesting region, because it is embedded in a much larger cloud of gas and dust in which, until recently, star formation took place. The result of this star formation is the open cluster NGC 6530, which lies directly at the Lagoon’s doorstep. It may have worked like this: Parts of the original bigger dust cloud must have collapsed, forming the young NGC 6530 cluster with its bright, hot stars. The solar winds of these new-born stars ‘burned away’ the remnants of the surrounding dust cloud of the complex. What is left is the star cluster on one side and the nebula we see today as the Lagoon Nebula on the other side. So the nebula is basically that part of the original cloud that did not collapse and commence star formation. That is why the Lagoon and NGC 6530 lie so close together: They are made of the same matter from the same cosmic cloud and thus the ‘Lagoon Complex’ bears great similarity to older star forming regions like the Orion Complex or the Carina Complex. The ‘Lagoon’ is just younger, an astronomical infant, so to say.

Leaving the Lagoon behind, the Distant Worlds flotilla set course for the next important waypoint, the Omega Nebula. As it happened, the Omega Nebula also was on my short list of ‘things to visit’ so I couldn’t wait getting there and have a decent meet-up with some of my exploration pals.

And where the Lagoon Nebula was already an eye catcher, the Omega Nebula would sure leave its own mark. It’s already visible from the Lagoon, a distant and darker hue of gas against the plane of the Milky Way. You will also see the bright, young stellar cluster of NGC 6618, which was born out of parts of the nebula in the not-so-distant past.

The Omega Nebula is thought to hold some 800 times the mass of Sol. That is no biggie for a nebula, mind you, but those parts of the Omega Complex that we don’t see hold some additional 30,000 solar masses and that gives you an idea about how much stuff there is. In fact, it makes the complex one of the most massive ones on our side of the galaxy; and it also gives you an idea about the complexity of those interstellar gas clouds. In fact, the complex is nearly identical in its makeup when compared to the Orion Complex in our immediate neighbourhood. We just see it at a different angle from Sol.

The area around the nebula is a so-called H II region, much like the Lagoon. It’s a region dominated by ionized atomic gas. This ionization comes from the nearby cluster of massive, young stars, namely NGC 6618. Their radiation is so intense that it tears atoms apart and makes the surrounding gas heat up and ‘shine’. So when we see the Omega Nebula, we only see an illuminated hotspot within a much bigger cloud of gas and dust. Again, it gives you an idea about the size of these interstellar cloud monsters.

When talking about the young star cluster of NGC 6618 we are talking about a former part of the Omega Complex that somehow collapsed and gave birth to a multitude of protostars (both T Tauri and Herbig Ae/Be stars) and young main sequence stars, including a few O  types. They should now be in the process of using up the remains of the cloud core’s gases and eventually drift away. For the interested explorer, there are quite a few spectacular objects to be surveyed here. The most massive stars seem to have collapsed already so there are quite a few neutron stars and black holes hidden in the cluster. Especially the stars of the PW2010 survey seem to hold most of them and they are awesome to behold and sometimes quite hazardous to navigate.Scanning down all of the NGC’s stars would obviously take a huge amount of time and would warrant an entire expedition in its own right, so I made a mental note on coming back at a later time. It’s not like those stars are going anywhere soon, their expansion rate is estimated to be merely 12km per second.

With all these impressions it was really hard to hit up the navigation computer and set a new course further coreward. But DW Command finally gave the green signal and after three days in the Omega region we eventually set sail towards the next few waypoints ahead.

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