This is the other search for life: not planets, but radio signals. If another civilization is broadcasting, a telescope would catch a thin, steady tone from their star.
The hard part is Earth's own noise — phones, satellites, radar. So telescopes use a trick called the cadence test:
Point AT the star (an ON panel), then away (an OFF panel), over and over.
A real signal from that star shows up in the ON panels only.
Earth interference leaks into all the panels — that's how you catch it.
You'll read "waterfall" plots — time runs left→right, radio frequency top→bottom, brighter = stronger. Call each one: signal from the stars, interference, or nothing.
The Search — Signal Lab
You're shown a waterfall — radio brightness across frequency (top→bottom) and time (left→right), stacked in the telescope's ON-OFF-ON cadence. A signal from the star appears in the ON panels only; Earth's interference shows up in the OFF panels too. Your call: a candidate worth a human's follow-up, interference, or a quiet sky.
Observation #1
Warm-up
time →frequency ↓ · brighter = stronger
Is this a signal from the star, interference, or nothing?
A real signal sits in the ON panels only. Interference is in the OFF panels too.
Your measured performance
Observations reviewed
0
Accuracy vs. known truth
—
Candidates flagged
0 / 0
Stars ruled out
0 / 0
Current streak
0
📡 Signal Hunter — 8/10 correct on real reads
Why ruling stars out is real science: in 60 years, every SETI candidate has turned out to be interference or nature — and each careful "no" makes the map of the quiet sky more complete. In the live project, each waterfall is shown to many people; the crowd's agreement — checked against known-answer cards like these — is what flags a signal for a professional to examine. Open the Field Guide →