Stories from the stores

Category: Physics

The Northern Lights head south

August 6th, 2010 | by | art, astronomy, physics

Aug
06

In recent days, the aurora borealis, better known as the Northern Lights, have been visible at more southerly latitudes than usual thanks to solar storm activity.

If you tried to have a look but were scuppered by the weather, or like us at the Science Museum you’re just too far south, enjoy these images of the aurora from our picture library instead.

The aurora and icebergs in the Arctic, as depicted in the Illustrated London News, 1849 (Science Museum).

This 19th century magic lantern slide shows the aurora (Science Museum).

The Northern Lights over Iceland, 2005 (Jamie Cooper / Science & Society).

Of course, if you’re far south enough, you’ll be looking for the Southern Lights instead. The aurora australis is particularly elusive, as there’s a lot less inhabited landmass at high southern latitudes than in the north. It’s also been putting on a more widespread lightshow in recent days. But it would be hard to beat this view…

A time exposure of the Southern Lights, as seen from the Space Shuttle Endeavour, 1994 (NASA / Science & Society).

No Comments »

From Planck to pigeon poo

July 5th, 2010 | by | astronomy, physics, quirky, space

Jul
05

The European Space Agency has just released the first all-sky map from the Planck satellite. The centre of the map is dominated by purple swirls from the dust around our Galaxy, but Planck’s main business is to look closely at the blobby structures visible in the map’s outer regions. These ’blobs’ show temperature fluctuations in the Cosmic Microwave Background (CMB), the remnant radiation from the Big Bang. Irregularities in the CMB became the seeds of today’s galaxies.

Planck's all sky survey (ESA, HFI and LFI consortia)

The fluctuations in the background radiation were first mapped by NASA’s COBE satellite, launched in 1989. An instrument on board also measured the CMB’s spectrum. FIRAS’s moving mirrors created interference patterns in a radiation beam, enabling the precise spectrum to be reconstructed. To the delight of scientists, the results perfectly matched the predictions of Big Bang theory.

This prototype mirror mechanism for the FIRAS instrument is on display in Cosmos & Culture (Science Museum).

The FIRAS prototype is on loan to us from the kind folks at the Smithsonian Institution’s National Air and Space Museum in Washington DC.  NASM’s display about the 1964 discovery of the microwave background features one of my favourite objects in any museum, anywhere. Arno Penzias and Robert Wilson initially thought that an annoying background hiss from their radio antenna was caused by pigeon droppings, and used this trap to try and capture the pesky critters. It turned out they’d accidentally found what other scientists had been looking for – the Big Bang’s echo.

No Comments »

Over the rainbow

June 14th, 2010 | by | physics, weather

Jun
14

Recently, I was lucky enough to visit the mighty Victoria Falls. As I stood at the falls’ edge drenched in spray, I spotted double rainbows formed by sunlight being refracted through the water droplets.

A rainbow, with a fainter secondary companion above, at Victoria Falls. (Alison Boyle)

One of the first people to explain how rainbows form was the Persian mathematician Kamal al-Din al-Farisi, who was born around 1260. Using a glass sphere filled with water to represent a raindrop, he showed that sunlight is bent as it enters the drop, reflects off the back of the drop, and is bent again on its way out. If rays are reflected twice inside the drop, a secondary rainbow is formed with the colours reversed. Here’s a more detailed explanation. Around the same time Theorodic of Freiberg performed a similar experiment. The two were not in contact, but both had been influenced by Ibn al-Haytham‘s Book of Optics. You can find out more about al-Farisi and al-Haytham in the 1001 Inventions exhibition.

Rainbows have fascinated people for centuries, as this illustration from 1535 shows. (Science Museum)

Isaac Newton explained that the rainbow’s colours arise as a result of white light being split into its constituent colours. Many people will have childhood memories of making a Newton colour wheel with a disc of cardboard and a pencil. Here’s a late 19th century version.

A 19th century demonstration apparatus. (Science Museum)

As our understanding of the nature of light has continued to change, so has our understanding of the rainbow. For a detailed account of how people have portrayed rainbows in science and beyond, check out Raymond Lee and Alastair Fraser’s The Rainbow Bridge: Rainbows in Art, Myth and Science.

2 Comments »

Science on the telly

June 1st, 2010 | by | events, exhibitions, physics

Jun
01

The Science Museum is formally over 100 years old.

The Science Museum's permanent building under construction, 1916 (Science Museum / Science & Society)

Over the century since 1909, it has had to compete with more and more media getting-in on the business of popular science.

A hundred years ago, popular science publishing was already a big scene, as Peter Bowler shows in his enlightening new book, Science for All.

Radio came along in the 1930s, and soon featured science. But our biggest competitor really got into its stride in the 1950s, when television began to get seriously interested, long before even Tomorrow’s World .

BBC producers had heated arguments about whether to treat science in highly-crafted documentaries, or as topical live programmes in the studio or out in the scientists’ labs.

Very often, the same subjects have been treated in books, radio, television and the Museum. Sometimes the same people crop up on television, in Museum displays, and also behind the scenes. One example is Lawrence Bragg, the distinguished physicist.

Bragg served on the BBC’s General Advisory Council, where he worked hard to promote the cause of science broadcasts. He was also on the Science Museum’s Advisory Council in the ’60s. His Royal Institution Lectures were the first to be broadcast live in 1959. There is a rare opportunity to see him in action, in Before Horizon, a special showing at BFI Southbank on Monday 7th June. Why not make a day of it and spend the afternoon at the Science Museum?

Our displays include at the X-ray spectrometer used by Lawrence and his father William in our Making the Modern World gallery.

No Comments »

Older Posts
Newer Posts