How else can you explain the Helium?

Normally when you talk about half-lives, you are talking about radioactive elements that break down into other elements at some point. You also have some gases like Helium that are so light that they escape the atmosphere easily. Helium in fact is mainly created during the decay of Uranium and Thorium. As our technology improves, our satellites are getting more sensitive and are gathering massive amounts of data constantly. The data available to normal scientists was mind-boggling, but there was another set of data that most people were never aware of.

Spy satellites and data-gathering devices were in use for obvious reasons but more than twice as many dark launches were made and the bleeding edge of what is possible was constantly improving and replacing older less sensitive versions. This was generating even more data but the number of people authorized to know about it, much less work with it was even smaller. I happened to be given some data to put through our systems and spit out the latest reports when I noticed that there was too much Helium over the Southwest US. Even with all of the known or suspected deposits of radioactive elements, the constant stream from hundreds of sources was increasing, year over year.

I went back through all of the records and put together a report on the rise of Helium coming from this area since the 1960s. It was almost as if we had hundreds of massive nuclear power plants or thousands of normal size nuclear plants somewhere underground in this region and the rate was increasing. I ran the numbers through another program to estimate the industrial capacity that those figures could represent and put everything into a report for my supervisor.

I thought I would hear something right away, but it took almost a month before I was called into a meeting. On the boards around the room, I saw highlights from my report and lots of other conclusions and reports. I couldn't help but notice the words Neutrino SHIELDING!?!?! written on another board with a whole bunch of math I didn't recognize and I majored in math. In walks my supervisor with around a dozen people who were giving off scientist vibes when he looks me straight in the eyes and says: "What would you do if you needed to hide your neutrino signature from a technologically advancing civilization?"

I think for a few moments and then reply: "I would try to stack layers of superconductor, graphene, and black phosphorus into disks that I could spin up to warp space and reflect the neutrinos back at their source. You would need to surround the whole thing in a series of them but it should be possible. It should improve your efficiency by several orders of magnitude as well, letting you build much more compact reactors."

"Where do we have you working right now?" The oldest scientist asks.

"Data Analysis." is my reply

"Not anymore!" He says excitedly as the group all start talking at once.

"We have to get the minutes of this meeting to home office immediately. This young man just gave us the obvious answer to that neutrinos aren't unblockable and a possible route to do so. I have no idea if that idea will work, but warping space to hide neutrinos is a brilliant idea if we can get it to work." He says then stands signaling the meeting had come to an end.

"Walk with me as I show you to your new work area. We are going to have to get your clearance bumped up a bit, but I think you are going to enjoy working with the future tech today. That plume of gas that you found by the way they can't hide their activity but it isn't aliens if that is what you were thinking. Americans that volunteered to live underground for at least a century were placed around the US in deep underground bunkers. Since the 1960s we have worried about an attack that we couldn't prevent. There were too many potential vectors and not enough ways to protect everyone so we put colonies down in case we got wiped out. They were to continue to develop as they are able and apparently the ones that you detected, have been doing quite well. Now, explain why you think that odd disk would warp space."

The rest is history, if you have the clearance.