Galaxy Cores

[Counciler]

((Note: I'm not sure whether to post this in the SW section or the SLAM Section, or neither. So please excuse me if it is in the wrong place.))

I was reading about how dangerous the Deep Core of Star Wars is supposed to be. I have seen various sources state things regarding the close proximity of the stars causes dangerous hyperspace travel and radiation and such.

Well, I wonder if there is any evidence so far to say that our Milky Way core is a dangerous place. Can our X-Ray, Infrared, and Visible Light images tell us anything about how dangerous the Core might be? Aside from the theorized "Supermassive Black Hole", just how much threat could closely packed stars pose to future travelers?

[dragon]

Well the stars being that close is going to put out a lot of radiation that is going to overlap. So we'll have areas of dense radiation patterns. Also the number of stars in the core and the giant black hole is going to have some interesting gravitational interactions. There's most likely more but all I can thing of for now.

[dragon]

Here you go.

Galactic core outbursts are the most energetic phenomenon taking place in the universe. The active, quasar-like core of spiral galaxy PG 0052+251 (Figure 1-a), for example, is seen to radiate 7 times as much energy as comes from all of the galaxy's stars. Most of this is emitted in the form of high energy cosmic ray electrons accompanied by electromagnetic radiation ranging from radio wave frequencies on up to X ray and gamma ray frequencies.

snip

Galactic superwaves are a recent discovery. During the early 60's astronomers began to realize that the massive object that forms the core of our Galaxy (the Milky Way), periodically becomes active.(9) The cores of all spiral galaxies cycle through a similar phase. During its active period, our galactic core spews out a fierce quasar-like barrages of cosmic rays, with a total energy output equal to hundreds of thousands of supernova explosions.(10, 11) In some galaxies these active emissions have been observed to equal the energy from billions of supernova explosions.

Until recently, astronomers believed these eruptions were very infrequent, occurring every 10 to 100 million years.(10) They also believed the interstellar magnetic fields, in the Galactic nucleus, would trap the emitted particles in spiral orbits causing them to reach the Earth very slowly.(12) For these reasons, many did not believe that Galactic core explosions posed any immediate threat to the Earth.

However, in 1983 Paul LaViolette presented evidence to the scientific community indicating that:(2 - 4)

Galactic core explosions actually occur about every 13,000 - 26,000 years for major outbursts and more frequently for lesser events.


The emitted cosmic rays escape from the core virtually unimpeded. As they travel radially outward through the Galaxy, they form a spherical shell that advances at a velocity approaching the speed of light.
Astronomical discoveries subsequently confirmed aspects of Dr. LaViolette's hypothesis. In 1985, astronomers discovered that Cygnus X-3, an energetic celestial source of cosmic rays, which is about the same distance from Earth as the Galactic Center (25,000 light years), is showering Earth with particles, traveling at close to the speed of light, moving in essentially straight paths.(13) Later, scientists found the Earth is impacted, at sporadic intervals, with cosmic rays emitted from the X-ray pulsar Hercules X-1 (about 12,000 light years distant).(14, 15) The intervening interstellar medium has so little effect on these particles, that their pulsation period of 1.2357 seconds, is constant to within 300 microseconds.

These findings are reason to be gravely concerned about the effects of a Galactic core explosion because they imply that the cosmic rays generated can impact our planet, virtually without warning, preceded only by the wave-flash from the initial explosion.(1, 2, 6) Astronomical observations show the last major Galactic core explosion occurred as recently as 10,000 to 15,000 years ago.(16, 17) Data obtained from polar ice core samples show evidence of this cosmic ray event as well as other cosmic ray intensity peaks from earlier times (Figure 2).(1, 18)

link

[Counciler]

Here you go.

Galactic core outbursts are the most energetic phenomenon taking place in the universe. The active, quasar-like core of spiral galaxy PG 0052+251 (Figure 1-a), for example, is seen to radiate 7 times as much energy as comes from all of the galaxy's stars. Most of this is emitted in the form of high energy cosmic ray electrons accompanied by electromagnetic radiation ranging from radio wave frequencies on up to X ray and gamma ray frequencies.

snip

Galactic superwaves are a recent discovery. During the early 60's astronomers began to realize that the massive object that forms the core of our Galaxy (the Milky Way), periodically becomes active.(9) The cores of all spiral galaxies cycle through a similar phase. During its active period, our galactic core spews out a fierce quasar-like barrages of cosmic rays, with a total energy output equal to hundreds of thousands of supernova explosions.(10, 11) In some galaxies these active emissions have been observed to equal the energy from billions of supernova explosions.

Until recently, astronomers believed these eruptions were very infrequent, occurring every 10 to 100 million years.(10) They also believed the interstellar magnetic fields, in the Galactic nucleus, would trap the emitted particles in spiral orbits causing them to reach the Earth very slowly.(12) For these reasons, many did not believe that Galactic core explosions posed any immediate threat to the Earth.

However, in 1983 Paul LaViolette presented evidence to the scientific community indicating that:(2 - 4)

Galactic core explosions actually occur about every 13,000 - 26,000 years for major outbursts and more frequently for lesser events.


The emitted cosmic rays escape from the core virtually unimpeded. As they travel radially outward through the Galaxy, they form a spherical shell that advances at a velocity approaching the speed of light.
Astronomical discoveries subsequently confirmed aspects of Dr. LaViolette's hypothesis. In 1985, astronomers discovered that Cygnus X-3, an energetic celestial source of cosmic rays, which is about the same distance from Earth as the Galactic Center (25,000 light years), is showering Earth with particles, traveling at close to the speed of light, moving in essentially straight paths.(13) Later, scientists found the Earth is impacted, at sporadic intervals, with cosmic rays emitted from the X-ray pulsar Hercules X-1 (about 12,000 light years distant).(14, 15) The intervening interstellar medium has so little effect on these particles, that their pulsation period of 1.2357 seconds, is constant to within 300 microseconds.

These findings are reason to be gravely concerned about the effects of a Galactic core explosion because they imply that the cosmic rays generated can impact our planet, virtually without warning, preceded only by the wave-flash from the initial explosion.(1, 2, 6) Astronomical observations show the last major Galactic core explosion occurred as recently as 10,000 to 15,000 years ago.(16, 17) Data obtained from polar ice core samples show evidence of this cosmic ray event as well as other cosmic ray intensity peaks from earlier times (Figure 2).(1, 18)

link

Wow... thats exactly the kind of stuff I was looking for! Though it's sort of unnerving to know that the core of our galaxy could just pop like a nuke at random intervals. Even if it doesn't hit Earth, thats kinda scary.

I haven't had much sleep, and will read it over again after a nap later on today. From what I can tell, it's saying that every now and then (on a galactic time scale) a galaxy's core just sorta emits these massive waves of radiation and energy? Would that mean that the only planetary or pseudo-planetary bodies you would find would be burnt to a crisp between the blasts from radiation and annihilated during the eruptions? So much for a real life"Byss".

[drachefly]

If it happens every few tens of thousands of years, then it can't be cataclysmic on the level of a major extinction event.

Hmm. I wonder if that's what causes pole flips?

[Junghalli]

If it happens every few tens of thousands of years, then it can't be cataclysmic on the level of a major extinction event.

But a planet in the deep core of the galaxy would be getting much higher doses of that radiation than Earth, what with the inverse square law and all. I'll leave it to someone more knowledgeable in the subject to try to figure out what effect it would have on the lifeforms there.

The deep core would also be subject to periodic starbursts, and therefore have periods where a lot of supernovae would be happening pretty close together (on cosmic timescales). Those supernovae are also going to flood their immediate cosmic regions with radiation, which will have detrimental effects on nearby Earthlike planets.

There's also the factor that the galactic nucleus has lots more old, metal-poor Population II stars than the spiral arms. That means it'll probably have a lot less big terrestrial planets (like Earth).

Altogether, it does sound like a rather hostile place.

http://en.wikipedia.org/wiki/Galactic_Center

[drachefly]

I was responding to the idea that it's scary.

Also, the idea that popping like a nuke is sort of amusing considering how much stupendously more enormous than a nuke the smallest of these events is.