Writing: Input Wanted Effects of Gamma-Ray Burst on Solar System

[Strato Incendus]

Whether I actually let a gamma-ray burst hit the solar system in my sci-fi story or not, at least the looming threat of this event will shape the plot in major ways. Therefore, I need to accurately predict the effects of such an event on not only Earth itself, but also the rest of the solar system — to the extent that I depict it as colonised within my setting.

Starting with the sun itself:

Specifically, I was wondering if the sun being hit by a gamma-ray burst would make solar flares more likely. Both kind of rely on magnetic fields, after all. However, as far as I understand it, a gamma-ray burst merely maintains its “shape” over thousands of light-years, whereas the magnetic fields that created it only surround the star from which it originated, rather than accompanying the burst on its journey.

There’s also the question what the mere exposure to the sheer energy levels contained in a GRB would do to the sun.

The reason I’m asking this particular question is that I kind of need both the GRB and a solar flare to coincide at one point in my story, so that my interstellar ship both a) loses contact with Earth, due to technology being damaged on a massive scale and b) the ship crew has a reason to assume there might be few to no survivors left on Earth.

This would be the “dual armageddon” scenario some forum users have warned me against in the past — but it wouldn’t technically be a dual armageddon if both events are connected.

Thoughts? Am I just grasping at straws here?

 

[stefan r]

The Sun’s surface is at an extreme energy level. The corona even more so. Of course gamma rays or other radiation would effect any surface. The magnitude of those effects are trivial compared to what it does to cold objects.

The story line might make more sense if it is a supernova shock wave and a coronal mass ejection. People on Earth know that the shock wave is coming. This will push the solar wind down close to the Sun exposing Earth and cis-lunar space to Galactic wind. They send up magnetic field generators to slightly deflect the supernova material headed straight at Earth. They also plan to utilize turbulent ions to amplify additional magnetic fields and electrical gradients. The stations are flying toward the supernova source but need to be lined up correctly. “Correctly” is not exactly “straight” because both the solar wind and the supernova shock have to be accounted for. With this setup the CME can spoil the project. The magnets might still have some effect on the flow of particles but Earth is not in that shadow. The deflected ions just make it worse.

I am not good at magnetism. Deflecting high velocity particles by a few degrees or, better, less than a degree takes much less effort than stoping or reflecting the particles. The further away your deflector the smaller an angle it needs to make. With the magnetic field generators riding the solar wind out into the Kuiper belt the outermost units interact with the shock wave first. The unexpected CME leaves the Sun’s surface later.

 

[Strato Incendus]

Thanks a lot for your reply!

Indeed, the star I have in mind, WR 104, will likely create a hypernova when the stars it’s comprised of collide. This star system however is so far away that the nova itself will not be a threat to Earth (and will obviously also move more slowly than the gamma-ray burst, which travels at the speed of light). As long as I stick to established stars, I’m stuck with the problem (which is of course a good thing IRL) that there are no stars in sufficiently close proximity to Earth which could even go supernova one day to begin with.

Could your scenario also play out with the combination of a gamma-ray burst and a coronal mass ejection, rather than solar flare? I must admit I often think of solar flare vs. coronal mass ejection as very similar, while being all the more aware of the differences between supernovae and gamma-ray bursts.

 

[Strato Incendus]

I'm reviving this thread since I just stumbled across this video:


Interestingly, they also claim here that power supply and communication on Earth would break down, much like from a solar flare - which is something I had asked about previously in this thread. And the loss of communication with Earth is crucial for my plot.

What do you think? Do the claims in the video make sense to you? If so, I might not have to postulate a "dual armageddon" of a solar flare following the gamma-ray burst after all - I might get by with just making the gamma-ray burst itself go off at a plot-convenient time, just like the writing principle of Chekhov's Gun suggested to me all along.


I was thinking about making my ship crew notice the GRB directly as it hits Earth. But it would of course be even more dramatic if even the ship gets partially hit by it, and has to take certain measures to protect the crew. Somebody here pointed out to me previously how there isn't really a sharp boundary along the edges of the GRB's cone. And with the ship only being 10 to 12 light-years away from Earth, they would probably still be partially affected.

However, this may become a plot hole in combination with the time messages from Earth need to travel (at light speed) before they reach the ship - as the crew derive the possible extinction of humanity in the solar system from the fact that no further messages from home have reached the ship ever since.

• If the ship crew merely observes the gamma-ray burst "from the side" as it hits the solar system, they'd be observing light that took 10 to 12 years to get to them on the ship. Meaning, the GRB actually already hit Earth 10 to 12 years ago (say, in 2465). The messages from Earth would consequently cease shortly after the crew have observed this 10- to 12-year-old light of the GRB.
• If however the ship itself is still in part in the area of effect of the GRB, this would imply the GRB hit in the current year (2475). Messages from Earth should therefore continue to reach the ship for another 10 to 12 years ship time before they cease.

Unless of course the GRB hits Earth in 2465, passes onwards through and beyond the Sol system, then hits the interstellar ship near Teegarden's Star 10 years later in 2475. That would be ideal for the order of events in my story.

To make this feasible, though, I'd need a 3D model of the three relevant stars in relation to each other: WR104 (source of the GRB in the Sagittarius constellation), Sol, and Teegarden's Star (in the constellation of Aries). Does anyone have an idea where I could simulate this for myself?
I don't think Universe Sandbox 2 will work here... And 100,000 stars doesn't feel helpful for answering this question, either.

As far as I can tell, Teegarden's Star lies pretty much diagonally across from WR104, with the Sol system in the middle in between them. At least judging by this map.
(Teegarden's Star is immediately above the yellow lettering "Aur Cloud", slightly to the left).
This map shows a bird's-eye / "top"-down view of the galaxy. The galactic centre, as far as I know, should be to the right side of this top-down map; WR104 should be much further along in the direction of the bottom right corner of the map (from Proxima Centauri onwards).
For added context, here is a map for the vertical dimensions.

(PS: I'd also have to describe the colour of the jets as they're enveloping the ship and being recorded by the outboard cameras; obviously, the gamma rays themselves are invisible to the human eye, but the jets, moving at almost light-speed themselves, should be visible, right?)

 

[Strato Incendus]

Since I understand my story and setting have reached a "critical mass of complexity" - too much context information I could ask any human forum user to process quickly enough - I've consulted ChatGPT.

I just thought some of you might be interested in the results? :D Of course, no guarantee for accuracy of any of this, since it comes from an AI.
But currently, it's the best answer I have, so I'm inclined to go with this one.

I'd also have to describe the colour of the jets as they're enveloping the ship

In summary, a GRB itself would not have a "color" as humans perceive it, but the interaction of gamma rays with the surrounding environment might produce visible effects, likely appearing as a bright, brief flash dominated by blue or white light

It also stated that a lot of the ship's equipment may obviously be damaged by the GRB, too - including the outboard cameras - so the crew might not be able to observe this for long. However, this blue-white flash would be my go-to visual cue for the reader.

To make this feasible, though, I'd need a 3D model of the three relevant stars in relation to each other: WR104 (source of the GRB in the Sagittarius constellation), Sol, and Teegarden's Star (in the constellation of Aries)

Considering the spatial positions of WR 104, Earth, and Teegarden's Star, the described trajectory of a gamma-ray burst passing through Earth's solar system and then reaching a spaceship near Teegarden's Star 10 years later is implausible. The lack of collinearity between these objects means that a GRB from WR 104 would not sequentially intersect both Earth's solar system and a location near Teegarden's Star.

Since that was what I had feared, I then asked ChatGPT whether the increasing width of the gamma-ray burst the further it travels might be enough to affect both Earth and Teegarden's Star. I'm including the formulas ChatGPT used for its calculation.

Beam Divergence and Width at a Distance

Angular Beam Width:
Let’s assume a beam width of 10 degrees (a typical, moderate value).
Beam Diameter at Earth’s Distance from WR 104: At 8,000 light-years:
D=2×(8,000)×tan⁡(5°)≈1,400 light-years.
This is the diameter of the beam when it reaches Earth's solar system.

Beam Diameter at Teegarden’s Star’s Distance (8,010 light-years):
After traveling an additional 10 light-years:
D=2×(8,010)×tan⁡(5°)≈1,402 light-years.

The increase in the beam's width over the extra 10 light-years is negligible because the GRB has already traveled a vast distance, and the beam has nearly reached its maximum divergence.
Separation Between Earth and Teegarden’s Star: The distance between Earth and Teegarden’s Star is only 12.5 light-years. This is minuscule compared to the GRB’s beam diameter at 8,000 light-years (~1,400 light-years).

Next, with Teegarden's Star not exactly on the opposite side of WR 104 compared to Earth, I asked how much longer the GRB would take to affect it, by referencing galactic longitude and latitude. Here, ChatGPT said several millennia, which led me to conclude I was asking the wrong question. Instead, I focused on the GRB's width again, ending up with this:

The gamma-ray burst from WR 104 does not need to travel any additional distance beyond the solar system to affect Teegarden’s Star, as the GRB’s width already encompasses both the solar system and Teegarden’s Star when it reaches Earth. The immense width of the GRB (~1,000 light-years) at Earth ensures that both locations are affected simultaneously.

This fits the objection another user had a while ago: Fleeing to a star as close as Teegarden's probably isn't going to protect anyone if Earth is in the line of fire of a GRB.

Somebody here pointed out to me previously how there isn't really a sharp boundary along the edges of the GRB's cone.

But of course, I can engineer the GRB to give Teegarden's Star plot armour. ;) So I asked ChatGPT to do just that:

Step 1: Geometry of the Problem
The gamma-ray burst’s coverage at Earth’s distance forms a circular area with a radius of 700 light-years. The center of this circle (the GRB's axis) must be offset slightly to include Earth but exclude Teegarden's Star.

The offset distance between Earth and the GRB’s center is therefore:

Offset = GRB Radius−Distance from Earth to Teegarden’s Star; Offset = 700 − 12.5 = 687.5light-years

Step 2: Angle of the GRB’s Axis
The angle θ between the GRB’s axis and the line from WR 104 to Earth can be calculated using basic trigonometry. The sine of this angle is given by:

sin⁡(θ) = Offset / Distance to Earth
The distance from WR 104 to Earth is approximately 8,400 light-years, so:

sin⁡(θ) = 687.5 / 8,400 ≈ 0.08185
Using the arcsine function to find the angle:

θ = arcsin⁡(0.08185) ≈ 4.69°


The axis of WR 104’s gamma-ray burst would need to be tilted at an angle of approximately 4.69° away from Earth’s direct line of sight so that Earth is on the outer edge of the GRB’s width and the burst barely misses Teegarden’s Star. This precise alignment would allow the GRB to affect Earth while sparing Teegarden’s Star.

A spaceship located 2.5 light-years from Teegarden’s Star and 10 light-years from Earth would likely not be affected by the gamma-ray burst. Since the GRB’s edge passes through Earth and misses Teegarden’s Star by design, the spaceship’s position outside this narrow overlap region ensures its safety.

This gives me Plot Outcome Option 1 (GRB angle 4.69°): The ship observes Earth being hit by the gamma-ray burst from 10 light-years away, meaning the GRB happened 10 years ago (in 2465, ship time is 2475). This also means the ship stops receiving any communication signals from Earth immediately after having observed the burst, assuming it has destroyed the communication infrastructure as assumed in the video from the previous post: Starting in 2465, Earth could no longer send any messages to the ship, so there's nothing to receive for a ship 10 light-years away in 2475.

However, of course it makes for better drama if the ship is almost hit by the GRB itself. ;) So I asked ChatGPT to adjust the angle accordingly without affecting Teegarden's Star.

Offset = R(GRB)− D(Earth-Ship); Offset = 700 − 10 = 690 light-years
[. . .]
sin⁡(θ) = 690 / 8,400 ≈ 0.08214; θ = arcsin(0.08214) ≈ 4.71°
[. . .]
To ensure the spaceship is affected by the GRB while Teegarden’s Star is not, the axis of WR 104’s gamma-ray burst would need to be tilted approximately 4.71° relative to Earth’s direct line of sight. This adjustment shifts the GRB’s center closer to the spaceship, placing it inside the affected region while excluding Teegarden’s Star.

This gives me Plot Outcome Option 2 (GRB angle 4.71°): The ship and Earth are being hit by the gamma-ray burst simultaneously in 2475. The ship now continues to receive messages from Earth for roughly the next 10 years, as those messages were sent in between 2465 and 2475. Thus, the crew could not infer humanity's possible extinction on Earth from the absence of messages from the Sol system; rather, they would have to assume this possibility based on the fact that they themselves were still hit by the gamma-ray burst, and that the GRB is wide enough to engulf the Sol system, too.

Given that the ship has spherical water tanks with a diameter of 1 km on both ends, these should provide ample shielding against the GRB. The problem is the sides of the ship, as the GRB with its massive width will most likely engulf it completely, rather than just "hitting" it from behind (in which case it would "hit" the fore sphere of the ship, as it has already turned around to brake).



TL;DR: If ChatGPT's suggestions are accurate (which is indeed a big "If"), I have two plot outcomes to choose from:
Plot Outcome Option 1 (GRB angle 4.69°): The ship observes Earth being hit by the gamma-ray burst from 10 light-years away, meaning the GRB happened 10 years ago. The ship itself is spared.
or
Plot Outcome Option 2 (GRB angle 4.71°): The ship and Earth are being hit by the gamma-ray burst simultaneously in 2475.

Which one would you prefer? Which would you consider "more realistic" in comparison?

(The actual angle of WR 104 towards Earth is currently assumed to be much larger, between 30 and 40°. But I handwave that away by postulating a new and improved telescope in the future, capable of depicting WR 104 more clearly, showing that not only is the angle much smaller, but the two stars are already much closer to collision than we thought in the 21st century, thereby placing the GRB much closer in the future.)

(I've also asked ChatGPT about how far underground you'd have to go to be safe from the GRB on Earth, Mars, the moon etc., but I'll save that for later. )