We have a few different likely sources, but especially one that is overlooked.

SPOILERS FOR SEASON 1



1. The Red Eye

The second episode, Gem Glow, features the Red Eye. While it is destructive, it seems to cause harm secondarily because of its gravity. It’s not actively shooting lasers, for example. We can assume because it is an eye that it’s main purpose is to transmit visual data. It even has an iris aperture like a camera (or your actual biological iris), which is used to focus light.

The Red Eye could have transmitted video back to Homeworld of the Crystal Gems. But what did it see that would make Homeworld want to send someone to investigate in person (Peridot and Jasper) now? The Homeworld knows Rose Quartz is protecting Earth and has been, what’s new? Does it see Steven and understand what that means? Jasper in The Return thinks Steven is just Rose Quartz shapeshifted into a human child and doesn’t comprehend his hybrid nature, so we can assume the Eye seeing Steven alone doesn’t tell Homeworld this fact either. And why would Homeworld care about that anyway?

An aside; The Red Eye might be one of many automated scouting machines circulating in Gem space. It might be a self-assembling robot called a Von Neumann probe, which can operate independently and replicate more Eyes to explore vast distances.

We don’t know how Gem long distance data transmissions works (the wailing stone in The Message shows they can send long distance messages at least) so we can’t be sure if what the Eye saw was transmitted. Perhaps it was not, because it was destroyed.

2. Lapis Lazuli tells Homeworld some news.

The next chance Homeworld got to hear that something was changing on Earth was Lapis Lazuli returning to Homeworld.

Because of Jasper’s interest in Rose Quartz, perhaps Lapis getting healed and released by Steven was the instigating fact that sent the investigation team? But Homeworld knew Rose Quartz was still located on Earth. Nothing in Lapis’s report would tell them anything new had happened, except possibly that Rose Quartz was releasing Gems from confinement. Lapis’s surprise that Steven freed her despite being a Crystal Gem hints that this isn’t standard Crystal Gem behavior (as she’s known it, anyway).

But there’s another instance of data transmission that coincides with a likely important change from the millenia of status quo on Earth, but it’s easy to miss.

3. The Pyramid Temple Transmission.

In Serious Steven, the Crystal Gems mission takes them to a historical Gem battlefield (that they return to in Rose’s Scabbard). There lies an imposing pyramid.

Why are they visiting the pyramid now?

They probably only recently found this key to enter it.

What happens when they remove the Gem powering the pyramid?

It dissolves in an explosion of light.

But after that, there’s a few short frames of the temple emitting light directly into the sky above.

If that’s not a deliberate transmission of data that was programmed to be sent out upon the release of the Gem from the pyramid, what else could it be?

This release of a Gem from its holding state is likely the change in status quo that gets Homeworld’s attention. Especially when we think we know the important, powerful Gem it is. White Diamond.

Peridot is sent out to check on and restart the Kindergarten, a Gem site that mass assembles Gems, likely Gem soldiers. If White Diamond, a leader in the original battle for Earth, is now freed, and Homeworld wants to start up their soldier-generating site on Earth, it looks like a new battle is being planned.



It’s time to get serious,

The Oracle of Delmarva,