WHAT is the saddest piece of music ever composed? A survey carried out by The Why Factor (World Service, Saturday) suggested that the answer was Samuel Barber's Adagio. And the saddest instrument in the world? The Armenian duduk, a woodwind instrument that imbues music with a melodious wail. The programme did not explore the effect of setting Barber's Adagio for a choir of duduk, perhaps because the result would breach the BBC's psychological health-and-safety protocol.

That we do not switch off when sad music is broadcast - quite the opposite: we often seek it out - was the "Why?" at the heart of Helena Merriman's programme. Indeed, music in a minor key has become more popular over the past 40 years.

Crying does not have the cathartic effect that we think it has. The answer, a group of researchers in Ohio suggests, may involve a hormone, prolactin, which is released with crying, but also when nursing mothers produce milk. That can be only part of any answer, however: otherwise, performances of the Barber, or Tchaikovsky's Pathétique Symphony, or pretty much anything by Morrissey, would be messy affairs.

A large constituency within university music faculties is now exercised by these questions of music psychology; in the past, scholars of music would be earnestly discussing musica mundana - the music of the spheres. In a neat reversion to tradition, The Sound of Space (Radio 4, Friday) gave us an inkling of what the spheres sound like.

By translating and transposing radio waves and radiation pulses into audible sound, the scientists in Dr Lucie Green's programme presented us with hisses, rhythmic crackles, and tone clusters that might easily find a place within techno or electro-acoustic music.

Particularly evocative is the sound made by "the singing comet" (its real name is Churyumov-Gerasimenko 67P), as recorded on the Rosetta mission: a virtuoso toccata of pitches, created by oscillations in the magnetic field of the comet. Similarly powerful was a recording of the Cassini spacecraft as it passed through the rings of Saturn, and was bombarded with tiny particles, while its landing on Titan, one of Saturn's moons, is surely the chart-topping track of the galaxy.

What The Sound of Space provided was a "Best of . . ." album, extracted from the trillions of gigabytes of information extracted from the computers that we have flung out into space. But Dr Daniel Levitin, the author of a new book about how the brain organises information, thinks that we are all assailed by information overload; and, in discussion with Matthew Sweet on Free Thinking (Radio 3, Wednesday of last week), made the striking claim that we now have to cope daily with five times more information than we did in 1986 - the equivalent of 175 average newspapers. He argues for greater value being placed on uni-tasking and day-dreaming.

How he manages to quantify this inflation in information, Dr Levitin did not explain. We could, I suppose, read his book, but that would involve coping with more information than most of us could endure.