When a space particle (meteoroid) enters the Earth's atmosphere, it often burns up and leaves behind a trail of ionized matter. This trail acts as a mirror for radio waves. We’re picking up signals from the GRAVES military radar in France. This radar operates at a frequency of 143.050 MHz, but its signals don’t reach us directly, since the radar is about 1,100 km from Kraków and, due to the curvature of Earth, lies below the horizon for us. However, meteor trails high above the Earth’s surface reflect these signals, making them travel straight to our antennas in Kraków.

 

Why specifically radio waves? With the naked eye, we can see only the brightest meteors at night. Our antennas 'see' more—they detect even micrometeors that are invisible to the human eye. And they do this around the clock!

We’ve recently started streaming the signal from our visualization-focused station on YouTube. Here, you can spot the radio ‘peaks’ that indicate passing space particles: https://youtube.com/@RadioMeteorHunting/live

 

Look for signals around 143.050 MHz; you'll hear a ‘ping’. There are also plenty of signals reflected from passing satellites—and maybe even space debris? They form diagonal lines and slowly change frequency.

Radio observations of this kind have been a tradition at our Observatory for seven years now. Although we had to change our signal source and ‘retune’ to France after analog TV was shut down in the East, radio echoes from meteors are once again within our range.