this post was submitted on 24 Dec 2025
22 points (100.0% liked)

Space

1999 readers
105 users here now

A community to discuss space & astronomy through a STEM lens

Rules

  1. Be respectful and inclusive. This means no harassment, hate speech, or trolling.
  2. Engage in constructive discussions by discussing in good faith.
  3. Foster a continuous learning environment.

Also keep in mind, mander.xyz's rules on politics

Please keep politics to a minimum. When science is the focus, intersection with politics may be tolerated as long as the discussion is constructive and science remains the focus. As a general rule, political content posted directly to the instance’s local communities is discouraged and may be removed. You can of course engage in political discussions in non-local communities.

Related Communities

🔭 Science

🚀 Engineering

🌌 Art and Photography

Other Cool Links

founded 3 years ago
MODERATORS
ZafiraHUN@mander.xyz
otter@lemmy.ca
Bitswap@lemmy.world
otter@mander.xyz
22
Earth’s radio bubble marks how far our signals have traveled (earthsky.org)
submitted 8 hours ago by cm0002@mander.xyz to c/space@mander.xyz
2 comments fedilink hide all child comments
 

The first intentional radio broadcast is credited to Reginald Aubrey Fessenden on December 24, 1906. Fessenden transmitted voice and music (a short speech, a violin performance of O Holy Night, and a Bible reading). Prior to this, radio signals were mostly Morse code. This was the first known broadcast meant to be heard by a general audience as sound. And it’s said that ship radio operators in the Atlantic, who heard it, were astonished to hear music and speech over their receivers!

And now, more than a century later, the radio waves that transmitted Fessenden’s broadcast – and many more radio waves since then – are still traveling outward into our Milky Way galaxy. But just how far have our radio waves reached? Radio waves are part of the electromagnetic spectrum, so they travel at the speed of light. And it’s been 119 years since that first radio broadcast.

So the radius of Earth’s radio bubble is 119 light-years, or a sphere with a diameter of 238 light-years across.

you are viewing a single comment's thread
view the rest of the comments
[–] Thorry@feddit.org 5 points 6 hours ago (1 children)

Please note that the inverse square law applies here, so with distance it becomes much harder to detect those signals over other noise. Not impossible exactly, but exceedingly hard the further you go. There is some practical limit to where the signal to noise ratio becomes such that it's impossible to extract any meaningful information.

[–] xia 2 points 4 hours ago

Other "noise"? Maybe it's a cacophony of signals, and we fit right in!?