20th April 1902: Marie and Pierre Curie prove the existence of radium

Marie and Pierre Curie proved the existence of the new element radium when they chemically isolated one-tenth of a gram of pure radium chloride.

Marie and Pierre Curie were both pioneering scientists in their own right, but as a research partnership they are most famous for their work on radioactivity. Inspired by the work of the French physicist Henri Becquerel who had been the first person to discover radioactivity, the Curies’ work won them the 1903 Nobel Prize in Physics which they shared with Becquerel himself.

Marie had been born and raised in Poland but, since women were not permitted to attend university there, she moved to France to take up a place to study at the Sorbonne in Paris. Having secured degrees in both physical sciences and mathematics by 1894 she married Pierre, an established physicist, whom she had met through a mutual friend. Marie subsequently began to pursue a Ph.D. for which she studied the recently-discovered rays emitted by uranium.

Having coined the term radioactivity to describe the radiation she observed, Curie focused on the minerals pitchblende and torbernite in her search for materials that emitted more radiation than uranium itself. Inspired by his wife’s discovery that the element thorium was radioactive, Pierre dropped his own research in 1898 to work with her. In July they published a joint paper announcing the existence of an element they named polonium, and in December they did the same for radium.

To unequivocally prove their existence, the Curies sought to isolate them from pitchblende. Having processed tons of the mineral, they eventually obtained one-tenth of a gram of radium chloride on 20 April 1902, for which they shared the 1903 Nobel Prize in Physics.

13th April 1970: Explosion causes crisis on board Apollo 13

Late on the 13th April 1970, the spacecraft Apollo 13 was rocked by an explosion from one of its oxygen tanks. The resulting emergency led to the calm announcement by the crew of, “Houston we’ve had a problem”. However, most people misquote the phrase as “Houston we have a problem” after the award winning 1995 film changed the tense. The movie also placed the words in the mouth of Commander Jim Lovell, where in fact it was Command Module Pilot Jack Swigert who first reported the issue.

The explosion occurred after a routine procedure to stop gasses settling in their tanks. An investigation by NASA has since found that a spark from an exposed wire in the oxygen tank caused a fire, leading to an expansion of gasses that eventually blew apart the tank. The explosion ripped off the side of the Service Module, vented oxygen into space, and left the crew stricken in a damaged craft.

Rather than landing on the moon, the mission’s focus was now to bring the crew safely home. Improvisation was key, with the crew forced to turn their landing unit into a lifeboat to ferry them back to Earth before transferring back to the Command Module for reentry. Fortunately the heat shield had not been damaged, and the crew splashed down safely on April 17th.

22nd March 1895: The Lumière brothers stage their first film screening in Paris

Put on for an audience of 200 invited attendees at the “Society for the Development of the National Industry”, the reaction to the moving black-and-white pictures caught the brothers by surprise. They had attended the conference to share Louis’ recent work on colour photography and only showed the 45-second film La Sortie des Usines Lumière (Workers Leaving the Lumière Factory), as a novelty after Louis’ lecture.

The machine used to project the film had been patented by the brothers the previous month. Their father owned a photographic materials factory in Lyon and told his sons about the Edison kinetoscope that he had seen in Paris in 1894. Inspired by their father’s enthusiasm they invented the Cinématographe which combined a camera, developer and projector into a single unit. Its drive mechanism was based on the “presser foot” used in sewing machines, and used a clawed gear to engage with perforations in the side of a roll of film. As the gear rotated, individual frames moved in front of the lens to capture the moving image at a rate of 12 frames every second. The same mechanism could later be used to project the captured images.

The positive reception to the first film screening led the brothers to refine their invention and, on 28 December 1895, they staged their first public show at the Grand Café in Paris. Within less than a decade, however, the brothers withdrew from the motion picture industry and instead turned their attention to the development of colour photography, a technology that they went on to dominate for a number of years with their Autochrome process.

4th March 1890: The Forth Bridge in Scotland opened by the future King Edward VII

The Forth Railway Bridge stretches almost 2.5km across the Firth of Forth, a large estuary area to west of Edinburgh. The bridge, which features two main spans of over 500m each, continues to operate as vital rail link between Fife and the Lothians.

The Forth Bridge was designed by the English engineers Sir John Fowler and Sir Benjamin Baker using the cantilever principle in which a central span is supported by the tension and compression of supporting arms that are only anchored at one end.

Before construction even began on the bridge in 1882, the contractor Sir William Arrol & Co. landscaped the shores on each side. They then constructed buildings such as workshops, as well as huts and houses to accommodate the more than 4,500 workers who worked on the bridge. Of these, 73 are known to have died in work-related accidents.

The bridge was finally completed in December 1889 and was tested the following month to ensure that it operated properly under load. Satisfied that the bridge was safe, the chairmen of the various railway companies involved in funding the £3.2 million construction travelled over it several times on 24 February. A week later the future King Edward VII formally opened the bridge and secured the last of 6.5 million rivets.

The bridge continues to carry more than 200 trains a day, and is an important symbol of Scotland. Thanks to the development of a new coating, it is also no longer necessary to continuously paint the bridge, a task that takes 10 years to complete.

2nd March 1791: Frenchman Claude Chappe sends the first message by semaphore machine

Chappe was born into a wealthy family in 1763 and originally trained as a member of the church. However, the turmoil of the French Revolution meant that he was unable to continue in his position and he returned home to focus on science. Working with his brothers, Chappe began to experiment with optical telegraph designs.

Chappe was not the first person to attempt to create a system of long-distance communication. The English scientist Robert Hooke had presented a proposal a century earlier, but his idea was never implemented. Consequently the Chappe brothers were the first to successfully transmit a message when they demonstrated their system on 2 March 1791, covering more than 16km from Brûlon to Parcé.

Using what became known as the Synchronized System, Chappe was able to transmit the phrase ‘If you succeed, you will soon bask in glory’ in just four minutes. Two pendulum clocks had their faces modified with a series of symbols and, after being synchronised, were placed in the two locations alongside a telescope that pointed to the other. The transmitting station used black and white panels to alert the receiver to when the second hand of the clock was passing over the appropriate symbol, which they then recorded. The string of symbols, when decoded, produced the message.

Chappe soon abandoned synchronised clocks in favour of mechanical arms to portray the different symbols. When mounted on top of a tower, the arms could be seen through a telescope and their alignment either recorded or relayed onwards. A 230km semaphore line of these towers between Paris and Lille was installed in 1792.

23rd February 1455: Gutenberg Bible published (traditional date)

On the 23rd February 1455, tradition dictates that Johannes Gutenberg published his printed Bible – the first book to be produced with moveable type in the West. Although there is no definitive evidence for this publication date, numerous secondary sources state it and therefore it is accepted by most people.

Gutenberg was not the first person in the world to use moveable type, and nor was the Bible his first foray into printing with it. He didn’t even produce that many copies, with estimates ranging from 160 to 185 Bibles of which only twenty-three complete copies survive. However, the process with which Gutenberg printed his Bible revolutionised the production of books and is viewed by many as crucial to the developments that followed in the Renaissance and the Reformation.

The earliest examples of moveable type – the use of individual components that can be ordered to produce a printed document – date back to China’s Northern Song Dynasty at the turn of the last millennium, but the enormous number of characters in scripts based on the Chinese writing system made the system unwieldly. Gutenberg therefore benefited from the much smaller number of characters in the Latin alphabet, but also invented a reliable way to cast large numbers of individual metal letters using a device called the hand mould. Furthermore, he developed an oil-based ink that was optimised for metal-type printing onto paper.

With 1,286 pages a complete copy of the Gutenberg Bible is now estimated to be worth up to $35 million dollars, but the value of the printing press itself is immeasurable. Gutenberg’s creation was responsible for an intellectual revolution.

16th February 1937: Organic chemist Wallace Carothers is awarded a patent for nylon

The DuPont company’s organic chemist Wallace Carothers received a patent for linear condensation polymers, the basis of the material better known as nylon.

Carothers joined DuPont from Harvard University, where he had taught organic chemistry. He was initially reluctant to move due to concerns that his history of depression would be a problem in an industrial setting, but DuPont executive Hamilton Bradshaw persuaded him otherwise and he took up his role in February 1928.

Having thrown himself into researching the structure and synthesis of polymers, Carothers and his team were responsible for creating the first synthetic replacement for rubber which was later named neoprene. Their laboratory, which was nicknamed “Purity Hall”, then began to focus on producing synthetic fibres that could be used in place of silk as this was becoming harder to source due to declining relations with Japan following the Great Depression.

On 28 February 1935 Carothers produced a fibre initially referred to as polyamide 6-6 as its components had six carbon atoms. Although the manufacturing process was complicated, DuPont were excited by the new material’s strength and elasticity and ordered the laboratory to press ahead with their research. However, plagued by depression, Carothers committed suicide in a hotel room in April 1937 by drinking potassium cyanide dissolved in lemon juice.

DuPont continued to refine the manufacturing process and revealed women’s stockings made of nylon, as it became known, at the 1939 New York World’s Fair. By the time the first pairs were made commercially available in 1940, the company had invested $27 million into the development of a material that is now found in everything from guitar strings to medical implants.

14th February 1990: Voyager 1 creates the ‘Pale Blue Dot’ image of Earth

Pale Blue Dot, the most distant photograph ever taken of Earth, was created by the Voyager 1 space probe.

Voyager 1 was launched in September 1977 to study the outer Solar System including flybys of Jupiter and Saturn. Having completed the mission for which it had been created in November 1980, the spacecraft was allowed to continue its flight and leave the Solar System.

Carl Sagan, the astronomer and author, was a member of the Voyager imaging team and suggested that Voyager 1 should take a last photograph of Earth before the cameras were deactivated to allow their power to be used for the flight into interstellar space. NASA scientists were concerned that such a photograph, in which the Earth would be relatively close to the sun, could permanently damage Voyager 1’s Imaging Science Subsystem. They consequently held off turning the cameras around until 14 February 1990, by which time the spacecraft was approximately 6 billion kilometres from Earth.

Known as the Family Portrait series of images, Voyager 1 transmitted 60 frames back to Earth where NASA stitched them together to create a mosaic of the Solar System. Three of the images, each taken with a different colour filter, were combined to produce the Pale Blue Dot image, in which the tiny dot of Earth fills less than 1 pixel of the 640,000 pixels that make up the rest of the frame.

Barely visible within the vastness of space, Sagan reflected on the ‘pale blue dot’ at a public lecture at Cornell University and later wrote about it in his book that drew its name from the image.

‘Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.’

9th February 1969: First test flight of Boeing 747 ‘Jumbo Jet’

On the 9th February 1969, the first test flight of the Boeing 747 ‘Jumbo Jet’ took place. The 747 went on to hold the record for the largest passenger capacity for 37 years before being surpassed by the Airbus A380.

The 1960s saw an enormous increase in the use of air transportation. However, existing planes such as the Boeing 707 were relatively small. The first person to approach Boeing with the idea of developing a larger passenger aircraft was Juan Trippe, president of Pan Am, but the company had already produced initial large airframe designs for a failed bid to build a cargo plane for the United States Air Force.

By 1966 the design was still far from complete but, in April, Pan Am committed to buying twenty-five 747s. Boeing agreed to deliver the first one by the end of 1969. However a suitable engine still hadn’t been created, and the company didn’t even own a facility large enough to assemble the completed aircraft.

These issues were eventually overcome to allow the first test flight to take place on the 9th February 1969, piloted by Jack Waddell with co-pilot Brien Wygle and flight engineer Jess Wallick. The plane, named the City of Everett, left the Paine Field near Everett in Washington State – about 30 miles north of Seattle – and performed a number of tests before landing again at 12.50pm. Over 1,000 more test flights were conducted before the plane was certified by the Federal Aviation Authority on the 30th December. The first passenger flight took place on the 22nd January 1970, on Pan Am’s New York to London route.

5th February 1924: The BBC ‘pips’ first broadcast to mark the time

On the 5th February 1924 the BBC ‘pips’ were broadcast for the first time. Five short pips signal the five seconds leading up to the hour, with a slightly longer pip marking the start of the new hour. Although now largely inaccurate as a result of the inherent delay in the encoding, transmission, and decoding of digital radio broadcasts, the pips are still a part of many BBC radio programmes.

The BBC successfully broadcast the chimes of Big Ben for the first time at New Year 1924. This led the Astronomer Royal at the time, Sir Frank Watson Dyson, to suggest that time signals could be broadcast more regularly. Having convinced BBC boss John Reith, the Royal Greenwich Observatory fitted the pendula of two mechanical clocks with electrical contacts that sent a signal to the BBC every second.

The equipment that generated the pips moved from Greenwich in 1939, but the pips are still known officially as the Greenwich Time Signal. The name was even kept after the Greenwich Time Service stopped transmitting the pips in 1990. Since then, the national BBC stations have generated the pips themselves using an atomic clock in the basement of Broadcasting House.

Due to their use as a time signal, the BBC doesn’t allow programmes to broadcast the six pip sequence for any other reason, and used to strongly discourage broadcasters from ‘crashing the pips’ – that is playing any other sound at the same time. Although this rule is now less rigorously enforced on most stations, some Radio 4 listeners still wait with baited breath to hear a presenter accidentally talk over them.

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