Audio signals from a Marconi antenna: a big 'T' 11m high with 30m long top hat.

The audio streaming server is provided by Paul Nicholson at abelian.org.

'[T]he idea of listening to natural radio signals - those that are not emitted by a man standing somewhere, or a radio speaker or a modem - leaves us a little disorientated. Today, when we talk about radio signals, we mean the TV, radio, mobile phones, remote controls, or other communication systems linked to something technological..

We must be careful not to forget that most of the advanced knowledge we have today about the universe comes from observations done with radio telescopes, and not with observations in an optical field.

[O]ur planet is a radio signal source, mainly at low frequencies: every one of us has, at one time, listened to crackly radio noises on the medium wave during a storm! Different natural phenomena such as Auroras, earthquakes and storms create radio signals and these signals can be studied with very simple and cheap devices. The particular sound of these signals makes them unique and very fascinating.

It seems like scientific research by the individual belongs to the past or that it is possible only in hyper-technological environments; thankfully this is not true! '

From introduction to RADIO NATURE: The reception and study of naturally originating radio signals by Renato Romero

Radio Atmospheric

About 100 lightning strokes per second are generated all over the world excited by thunderstorms located mainly in the continental areas at low and middle latitudes.[15][16] In order to monitor the thunderstorm activity, sferics are the appropriate means..

A lightning channel with all its branches and its electric currents behaves like a huge antenna system from which electromagnetic waves of all frequencies are radiated. Beyond a distance where luminosity is visible and thunder can be heard (typically about 10 km), these electromagnetic impulses are the only sources of direct information about thunderstorm activity on the ground. Transients electric currents during return strokes (R strokes) or intracloud strokes (K strokes) are the main sources for the generation of impulse-type electromagnetic radiation known as sferics (sometimes called atmospherics).[1] While this impulsive radiation dominates at frequencies less than about 100 kHz, (loosely called long waves), a continuous noise component becomes increasingly important at higher frequencies.[2][3] The longwave electromagnetic propagation of sferics takes place within the Earth-ionosphere waveguide between the Earth's surface and the ionospheric D- and E- layers. Whistlers generated by lightning strokes can propagate into the magnetosphere along the geomagnetic lines of force.[4][5] Finally, upper atmospheric lightning or sprites, that occur at mesospheric altitudes, are short-lived electric breakdown phenomena, probably generated by giant lightning events on the ground.

http://en.wikipedia.org/wiki/Radio_atmospheric

Whistlers

A whistler is a very low frequency or VLF electromagnetic (radio) wave generated by lightning.[1] Frequencies of terrestrial whistlers are 1 kHz to 30 kHz, with a maximum amplitude usually at 3 kHz to 5 kHz. Although they are electromagnetic waves, they occur at audio frequencies, and can be converted to audio using a suitable receiver. They are produced by lightning strokes (mostly intracloud and return-path) where the impulse travels along the Earth's magnetic field lines from one hemisphere to the other. They undergo dispersion of several kHz due to the slower velocity of the lower frequencies through the plasma environments of the ionosphere and magnetosphere. Thus they are perceived as a descending tone which can last for a few seconds. The study of whistlers categorizes them into Pure Note, Diffuse, 2-Hop, and Echo Train types.

Whistlers were probably heard as early as 1886 on long telephone lines, but the clearest early description was by Barkhausen in 1919. In 1953, Storey showed that whistlers originate from lightning discharges.[1]

http://en.wikipedia.org/wiki/Whistler_%28radio%29

Dawn Chorus (electromagnetic)

The electromagnetic dawn chorus is a phenomenon that occurs most often at or shortly after dawn local time. With the proper radio equipment, dawn chorus can be converted to sounds that resemble birds' dawn chorus (by coincidence).

http://en.wikipedia.org/wiki/Dawn_chorus_(electromagnetic)

"Cluster One", an instrumental, is the opening track on Pink Floyd's 1994 album, The Division Bell.

The noise which opens the track caused some confusion among fans in 1994, who were unsure, on playing the album for the first time, whether or not their copy was faulty, as the noise lasts for nearly 1 minute before any music begins. According to an interview with Andy Jackson, recording engineer for the album, this noise is electromagnetic noise from the solar wind.[3] More precisely, this sound is a very low frequency record of dawn chorus[4] and sferics,[5] radio events respectively due to solar wind interference with Earth's magnetosphere, and lightning strikes radio emissions interfering with Ionosphere; this sound is often mistaken for Earth's crust shifting and cracking.[6][7][8]

http://en.wikipedia.org/wiki/Cluster_One

Solar wind

The solar wind is a stream of plasma released from the upper atmosphere of the Sun. It consists of mostly electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in density, temperature, and speed over time and over solar longitude. These particles can escape the Sun's gravity because of their high energy, from the high temperature of the corona and magnetic, electrical and electromagnetic phenomena in it.

The solar wind flows outward supersonically to great distances, filling a region known as the heliosphere, an enormous bubble-like volume surrounded by the interstellar medium. Other related phenomena include the aurora (northern and southern lights), the plasma tails of comets that always point away from the Sun, and geomagnetic storms that can change the direction of magnetic field lines and create strong currents in power grids on Earth..

As the solar wind approaches a planet that has a well-developed magnetic field (such as Earth, Jupiter and Saturn), the particles are deflected by the Lorentz force. This region, known as the magnetosphere, causes the particles to travel around the planet rather than bombarding the atmosphere or surface. The magnetosphere is roughly shaped like a hemisphere on the side facing the Sun, then is drawn out in a long wake on the opposite side.

The solar wind is responsible for the overall shape of Earth's magnetosphere, and fluctuations in its speed, density, direction, and entrained magnetic field strongly affect Earth's local space environment. For example, the levels of ionizing radiation and radio interference can vary by factors of hundreds to thousands; and the shape and location of the magnetopause and bow shock wave upstream of it can change by several Earth radii, exposing geosynchronous satellites to the direct solar wind. These phenomena are collectively called space weather.

From the European Space Agency’s Cluster mission, a new study has taken place that proposes it is easier for the solar wind to infiltrate the magnetosphere than previously believed. A group of scientists directly observed the existence of certain waves in the solar wind that were not expected. A recent publication in the Journal of Geophysical Research shows that these waves enable incoming charged particles of solar wind to breach the magnetopause. This suggests that the magnetic bubble forms more as a filter than a continuous barrier. This latest discovery occurred through the distinctive arrangement of the four identical Cluster spacecraft, which fly in a strictly controlled configuration through near-Earth space. As they sweep from the magnetosphere into interplanetary space and back again, the fleet provides exceptional three-dimensional insights on the processes that connect the sun to Earth.

The team of scientists was able to characterize variances in formation of the interplanetary magnetic field (IMF) largely influenced by Kelvin-Helmholtz waves (which occur upon the interface of two fluids) as a result of differences in thickness and numerous other characteristics of the boundary layer. Experts believe that this was the first occasion that the appearance of Kelvin-Helmholtz waves at the magnetopause has been displayed at high latitude dawnward orientation of the IMF.

http://en.wikipedia.org/wiki/Solar_wind#Magnetospheres