"A Map of the Galaxy" Topic

Ours to be specific:

picture

The map is realistic, other than that I have divided it into arbitrary "sectors", and proclaimed it the Terran Empire.

Now, for any astronomers out there, suppose I wanted to run a realistic (assuming that such things as FTL travel were realistic) campaign set in our own galaxy. What would conditions be like in the various "sectors"? I am assuming that radiation would get pretty intense in the galactic center, and so have marked it impassable. I am also guessing that stars would be more abundant in the areas near the center.

Are my guesses right or wrong? Also, what other "terrain" features would the galaxy likely have?

Regards

Intense radiation near the core, thanks to our local galactic black hole. Interstellar dust and gas of varying density, but on quite a local scale. Increasing density towards the core, of course. Most other hazards would be on the 10-100 lightyear scale, as aforementioned density variations, black holes, supernovae etc.

Dark energy/matter? Could be all over the place, in between the arms, we don't know what it does really.

Then of course there's your handwavium, whatever hyperspace barriers you have.

Pardon me for asking but I'm not from around here Where's Earth on the map?

Where it says "Sonne" on the map, ie the Lokaler (local) arm. Behind us is the Perseus arm and towards the core is Sagittarius.

Sonne= German for, I believe, Sun, or Sol.

@Lampyridae

Thanks for the info. Are you an astronomer? Couple of questions: What are the orange, pink and light blue blobs on the map? I assume that orange=nebula and light blue=dust cloud, though I am not quite sure what the difference is. Also, what are the pink blobs?

Thanks for any help.

Thank you! The map is very good.

Glad you liked it. Of course, I can't take credit (except for the Terran Empire stuff ), and I got it so long ago, I don't remember the web site.

Further to Lampyridae's comment, you might want to read Larry Niven's "At the Core" with respect to this

Thanks!

For an interesting take on "terrain effects" of moving outward from the galactic core, read Vernor Vinge's A Fire Upon the Deep and A Deepness in the Sky. His premise is entirely speculative (and largely fanciful), but it makes for a neat concept, and the books are terrific.

Read them, and they are good, though they definitely are science fantasy.

Take this as you like, just an amateur here.

The core is not impassible. Just because you have a supermass BH there does not mean anything is that different from anywhere else. If the event horizon is crossed or the gravitational effects of the hole being there cause something else to shift its movement, then things would change for you or if your star lost its magnetosphere you'd fry, but otherwise living near a star there wouldn't be much different. I mean we are talking about a supermassive black hole that is about the size of Mercury's orbit around the sun, some 44-46 million kilometers. The number of stars and the excited gas clouds would probably mean you wouldn't have very dark nights, depending on where you are. The acretion disk around our helpful black hole would be a bad place, but anywhere else would be pretty normal.

X-Rays would be a threat unless the black hole is "sleeping" and not feeding. Spikes in radiation apparently come off in massive waves. The last one occurred 300 years ago for our galaxy and likely was caused by the death of a very large star, probably in the O-B-A class area going nova and expelling gaseous energy in to the area, which got pulled into the black hole, which gave off the wave energy, exciting the gas clouds in the area temperarily.

The radiation would be largely handled by your star's solar flux – it is what lessens the amount of cosmic radiation attempting to fry us right now. Our own magnetic fields and atmosphere do a lot, but the Sun certainly helps.

If your ship had FTL and ability to navigate complicated grav wells, then I don't see much hurting you.

The radiation would be largely handled by your star's solar flux – it is what lessens the amount of cosmic radiation attempting to fry us right now. Our own magnetic fields and atmosphere do a lot, but the Sun certainly helps.

Low-energy cosmic rays, yes, but not high-energy particles which would be largely undeflected by magnetic fields or stellar flux. The X-ray and gamma flux would also be bad, an atmosphere would not protect you enough. It wouldn't stop a ship with handwavium radiation shields, but even passing through the galactic arms are thought to be too hazardous for habitable planets. Then there's the gravity of those other stars; a constant hail of comets and asteroids through the system.

In terms of stars, the galactic centre is very interesting in a "My God, it's full of stars!" way. The parsec around Sag A (our local galactic black hole) has *thousands* of main sequence stars in stable orbits, as well as young stars. Stars are formed on a regular basis (500 million years) around the galactic core, around 400 lightyears, in spontaneous "starbursts" which boil up into chains of massive supernovae. So any complex life would be pretty much cooked, perhaps up to a thousand parsecs from the core, on top of everything else.