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Everyday science

Milky Way blues, detecting alien megastructures, solar mission goes to the movies

04 May 2018 Matin Durrani

If you fancy some soothing jazz over the weekend, why not check out Milky Way Blues by astronomer Mark Heyer from the University of Massachusetts Amherst, which is being featured all month on the Astronomy Sound of the Month website. The culmination of a 25-year idea for Heyer, it’s not any ordinary jazz composition, but is instead based on the motion of the gas between stars in the Milky Way, as measured by radio telescopes.

The frequency of every note in the music depends on the speed of the gas, with gas that’s moving toward us being the high notes (faster speeds being higher notes) and gas going away from us being the low notes (faster speeds now meaning lower notes). Heyer has in fact mapped the data onto a “pentatonic minor blues scale”, which has five notes in an octave instead of the usual seven, and in a minor key, apparently because when he heard the bass notes “it sounded jazzy and blue”.

Different instruments are used for each note depending on the phase of gas it originated from: wood blocks and piano for molecular gas, a saxophone for ionized gas and acoustic bass for atomic gas. Meanwhile, the intensity of the emission from the gas is proportional to the length of the note (strong emissions meaning long notes). In essence, you can now hear how gas in the Milky Way rotates around the centre of our galaxy. You can read the full story here.

Alien megastructures

A Dyson sphere is a hypothetical structure that would surround a star in order to deliver vast amounts of energy to an alien civilization. Named after the physicist Freeman Dyson, who pointed out in 1960 that the energy needs of an advanced civilization could become so large that they would encase a star within a sphere to capture most of the energy it emitted. Some energy would escape, and in “Dyson spheres, the ultimate alien megastructures, are missing from the galaxy“, Ethan Siegel explains how we could detect these colossal solar panels and asks why we have not seen any so far.

If you want  to build a Dyson sphere, or a solar probe, you better make sure that it can withstand the blast of radiation that comes out of the Sun. Physicists working on NASA’s upcoming Parker Solar Probe have come up with a low-cost way of testing the robustness of the mission’s Faraday cup – which will catch charged particles. The have used bulbs from an IMAX projector to deliver a whopping 10 kW of light onto the Faraday cup. Find out more by watching the above video.

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