Listening to Jupiter, The Sun & The Milky Way
24-hr Spectrogram of the sky from 17 Mhz to 31 Mhz
Jimmy Newland https://jimmynewland.com
The Sun and Jupiter at long wavelengths
In the 1950’s, researchers discovered that Jupiter and the Sun have strong radio emission. Outbursts from the Sun and Jupiter as charged particles rush around their magnetic fields give off characteristic radio signals. There is a radio quiet (ish) region around 20.1 Mhz where signals can be received from the Sun and Jupiter so it is possible to observe these outbursts and listen to them.
Between amatuer bands
The useful band for monitoring the Sun and Jupiter is centered on 20.1 Mhz and falls into a zone of the radio spectrum not used by amateurs. (Side note: 15m band is open to technicians license, while 17m is not.)
There is plenty of earthly and extraterrestrial interference in this band but also lots of room to hear the Sun,Jupiter, and the milky way.
Radio JOVE Receiver and Antenna
A group of dedicated scientists, enthusiasts, and HAMs have maintained a program called Radio JOVE. They have lots of projects and a simple (ish) radio receiver and antenna setup. This isn’t a HAM rig and doesn’t transmit - only receive.
Radio JOVE Antenna - simple but crucial
The signals from the Sun, Jupiter, & galaxy are rather weak and require a good antenna, good filtering, and good conditions.
A dual dipole antenna means more gain but a narrower beam width.
The conductor should be elevated and electrically isolated. PVC Masts!
Jupiter in radio - L-Bursts
As electrons are accelerated along the Jovian magnetic field lines, the radio emission vary over short and long time scales. L bursts are thought to be modulation introduced into Jupiter emissions by the solar wind. They sound like waves crashing. Listen here.
Above: radio spectrogram of an L Burst
Right: time sequence (strip chart) of an L Burst
Jupiter in radio - S Bursts
S-bursts change rapidly over their short lifetime and sound super spooky when slowed down! Listen to a sample at normal speed. Listen to a sample slowed down. These are likely the result of lightning in the Jovian atmosphere.
Above: radio spectrogram of an S Burst
Right: time sequence (strip chart) of an S Burst
Listening to the Sun
The sun is a good radio emitter in the 20.1 MHz band. Top right: a solar burst seen in a spectrogram. Bottom right, Earth’s ionosphere is strongly affected by solar bursts as the galactic background and terrestrial HF propagation show strong attenuation due to a solar flare. Below, a strip chart graph of a “shark fin” shaped burst. Listen here.
Listening to the Milky Way
Karl Jansky first detected the galaxy in the 20.1 MHz band in 1931. The galactic background (GB) is generated by electrons accelerated to relativistic speeds by the galactic magnetic field. Top right: the galactic core transiting a radio telescope. The brightening in the spectrogram centered on 1000 UTC represents a roughly 3 dB increase in the galactic background. Bottom right: strip chart of GB. Listen to the GB here.
Replica of original Jansky array at Green Bank Observatory
Radio Jove Livestream & Cassiopeia A from Greenbank
Livestream of Radio JOVE via K4LED https://www.youtube.com/watch?v=Iwnz0zcyPW0
Cassiopeia A Supernova Remnant at 1420 MHz - characteristic of cold, neutral hydrogen gas taken by author using 20 m telescope at Greenbank Observatory via SkyNet. https://www.gb.nrao.edu/20m/idlinks/27938.htm
References