Henrietta was never allowed to follow her own lines of study but was remembered as 'possessing the best mind at the observatory' and later 'the most brilliant woman at Harvard'. She had been considered for the 1926 Nobel Prize for physics but unknown to her nominee, she had died 4 years earlier from cancer and did not live to see Hubble's amazing discovery using her work. A crater on the moon is named after her, in honour of the deaf men and women who have worked as astronomers and she has her own nominated Asteroid - 5383 Leavitt.
Tuesday, 27 September 2016
Henrietta Swann Leavitt (1868 - 1921) made one the great astronomical discoveries of the 20th Century. Her work enabled the existence of galaxies to be proved and astronomers realise the scale of our Universe.
Henrietta graduated from Radcliffe College, USA leaving her with a passion for astronomy, but a long illness had left her deaf. She recovered to work at Harvard College Observatory. With no chance of actual theoretical work (only open to men) she still rose to become head of photographic photometry.
Stars which changed in brightness were of particular interest to astronomers. By comparing the astronomer's photographic plates, Henrietta catalogued 2,400 of these stars. It was a huge painstaking manual effort comparing star fields on thousands of photographic plates to find ones that 'blinked'. In 1908 she observed a type of star, called a Cephied Variable, had a link between blinks and luminosity. By timing the period she could calculate overall brightness. Henrietta had discovered a powerful tool for astronomers - the standard candle.
The known brightness of a star indicates its distance. In a similar way that the dimmer a street light is, the further away it is likely to be. If a Cepheid with a blink of 5 days was fainter than another Cepheid with a blink of 5 days it was further away. The scale of the universe could now be measured by using these 'standard candle' stars. In 1923 after finding a Cepheid Variable (V1) in the Andromeda 'spiral nebula' (M31) Edwin Hubble made the astonishing discovery that it was a separate galaxy; 2 million light years away. The first indication of the true scale of the universe.
Monday, 19 September 2016
Keisha has worked on many sites across the UK.She enjoys taking projects from start to finish, and this helps her to see derelict sites turn into new residential/commercial properties which have economic benefits to society. In 2012, Keisha became a Chartered Environmentalist. See how Keisha got on at a SATRO Business Game!
"I started working for SATRO on 5 September and was thrusted into active duty on 9 September volunteering at the SATRO Business Game at Heathside School. The day involved working with Year 11 students who work in teams to run their own profit-making business for the day. It was a brilliant day with all ten teams keenly taking part in running their businesses. I found the structure of the game gave students an accurate awareness of how businesses are run; from training for employees to dealing with strikes! The feedback from the students on the day was also positive; “I learnt how people in a company have to work together and the various roles they have to take. It helped me to make my future career path clearer to me”.
This wasn’t my first time volunteering at a SATRO event, as it was something I did regularly when I was working as an Environmental Engineer, however it was my first Business Games and my first event representing SATRO and it was a great introduction into the brilliant work done by SATRO. The day was wonderfully finished off by seeing one of my teams winning the overall competition by making the most profit! I’d like to think it was because of my insight, support and knowledge……but I’m sure it was more as a result of their teamwork and commitment to do well!"
Thursday, 15 September 2016
Yesterday, a group of 10 Year 8 students attended a Numeracy Day at Sandown Racecourse. It was a lovely sunny day and throughout, the students were able to set mathematical skills and knowledge into context through their application in daily working life.
The students were given a workbook at the beginning of the day which was filled with exercises including a range of calculations based on what happens at a racecourse on the day of a race. After a run down on the days schedule, we all headed down to the weighing room for a behind-the-scenes appreciation of working in the weighing room. The students also got to see the jockeys changing rooms and sit in the sauna which is used for the jockeys to sweat ... to lose body weight!
The day was filled with plenty of maths exercises, including seeing the horses come out of the horse vans and looking at the Length, Width and Height of the van and trying to guess how many horses can fit in! The students also got to go on the race track and learn about a furlong which is a measure of distance in imperial units.
Also, we were very fortunate to watch the first race at 2:05pm. This included 7 horses as 3 dropped out.
These Numeracy Days are part of BHE&ST's Racing to School Programme. If you are interested in booking a similar event for a group of your own students then please email - email@example.com
Monday, 12 September 2016
"About 2,200 years ago an unknown genius in ancient Greece built a mechanical computer" - Guest Blog by John Faulkner
About 2,200 years ago an unknown genius in ancient Greece built a mechanical computer. It calculated and displayed astronomical events. The device had a level of engineering skill 1,500 years ahead of its time.
In 1900 Greek sponge divers, blown off course by a storm, took their chances in deep water. They were off the island of Antekythera and instead found a Roman shipwreck from 85BC, loaded with Greek artefacts. The haul contained curious wood and bronze fragments. About the size of a roof tile, the largest piece had gear wheels visible. Archaeologists were baffled but with modern scanning techniques and rigorous science, over a period of about 60 years of painstaking work, the puzzle has been solved.
The Antekythera Mechanism Research Project, set up by Cardiff University in 2000, used CT scans (microfocus X Ray Computer Tomography) to produce 3D structural images and advanced photography (polynomial texture mapping) to search for markings. This revealed hidden gears, lines, text and markings on the fragments. They confirmed the ancient Greeks had arranged precision gears so accurately the device could model the motion of astronomical objects far into the future. It was operated by handle and individual pointers on the front face, driven by 30 intermeshed gears, indicated the astronomical position of the sun, moon and planets. On the rear face is the ancient Greek calendar with pointers to predict lunar eclipses, solar eclipses and the Olympic games dates between their four games venues.
To predict lunar position and phase is very complicated. The moon shifts position, speed and angle on it's elliptical orbit of the earth. Also a year is 365.25 days so to make any daily calendar work regular corrections are needed. This complexity means a complete lunar cycle, where the moon ends up at the same phase and position in the sky, takes about 19 years. This is called the Metatonic cycle. However an even more accurate 76 year cycle, discovered and used by the Greeks, called the Callipic cycle confirms an astonishing level of technical and scientific skill.
Thought to be invented in the middle ages the mechanism had differential (variable speed) gears yet the calendar start date was 205BC.
The first scientist to reconstruct a machine is Dr Michael Wright previously of the Science Museum here are the workings of his model: https://m.youtube.com/watch?v=MqhuAnySPZ0
The maker is unknown but are there clues? There are several philosophers possibly involved and such a complex device would have evolved over time. Archimedes (287 - 212BC) as an engineer used gears and the astronomy is based on theories of Hipparchus(190 - 120BC). An intriguing clue about a mechanism can be found in a surviving letter. Hipparchus is thought to have founded a school on Rhodes. One of his students Posidonius, who knew the Roman diarist Cicaro, later ran the school. In 79BC, Cicero mentions, in one of his letters a device “recently constructed by our friend Posidonius, which at each revolution reproduces the same motions of the sun, the moon, and the five planets that take place in the heavens every day and night.”
The Antekythera Mechanism was lost for 2000 years. Bronze was very valuable to the Roman military and melted much down, so other devices may have been destroyed. However, the technology was not lost and appeared later in the Arabian geared Islamic Astrolabe and then in Europe in the first clocks, leading to our modern geared machines. Yes, the ancestor of the gearbox in your car could well be a 2200 year old computer!
and here is a Lego version!.....
- John Faulkner
Wednesday, 7 September 2016
The STEM placement students are sending us weekly blogs all about their experience in the world of work!
Work experience is great and it provides students with many benefits whilst gaining skills and helping choose the right future career path for pupils. Having work experience on a Curriculum Vitae will make a person stand out to employers as they will notice they have motivation and a real passion for work. It will also help to boost a students confidence in themselves!
See how Caitlin got on at her Extended Work Placement!
Week one -
"It’s the end of my first week at Surrey satellites, and I’m already having an amazing time. The week began with me being rather lost at Guildford train station, before spotting the minibus which takes me directly to Tycho house. The receptionist was lovely and guided me through the signing in process which I would have to complete every morning.
Once I had received my work experience card, Andy was called down to meet me. He was very welcoming and gave me a tour of both the office (Tycho) and lab (Kepler) buildings. I was told what codes I needed to get into each building, where to go and who to ask for technical help, and most importantly, where to go for lunch! From there, I was taken to IT to receive a laptop for me to work on at my time at Surrey Satellites. I was given a laptop rather than a desktop as many of my experiments involved moving buildings or staying outside for prolonged periods of time. The rest of the week mainly consisted of research into what ADS-B actually was, and different computer programs to find and record ADS-B signals.
I also got a chance to learn how to solder professionally which I’d never done before! I can’t wait for next week!"
Week two -
"My second week at SSTL went really well, and I’m amazed by how much I’ve learnt. I was given an ‘RTL-SDR dongle’ by a colleague (a device which is tuned to 1090Mhz, ADS-B frequency) and I’ve managed to get it working, with some help from IT! I’ve been using programs such as SDR# and DUMP1090 to convert the received signals into aircraft data, and RTL1090 to plot the data into a live map showing where aircraft are in the nearby area.
My next goal is to increase the range of the antenna, either by building a new antenna myself, or perhaps by using a LNA to boost the signal. I’ve also been calculating the range the antenna should receive by using some tricky calculations involving antenna gain, using measurements I hadn’t heard of before I came here! I found that my antenna should receive a lot more signals than it currently is, but this lack of signal may be down to the large buildings and trees nearby that are blocking the signal. I’m looking forward to building things next week!"
Week three -
"It’s the end of another week, and there has been a small amount of improvement! After a lot of research, I discovered that an antenna design worth trying would be a ‘coaxial collinear antenna’. A study online described the calculations for the proportions of the antenna in detail which was just what I needed! Next, I headed down to the lab and put on all of the necessary gear. It’s taken some time to get used to, but now putting on all of the electrostatic protection and clean room clothes feels like second nature.
I spent a day in the lab building my antenna out of coaxial cable and SMA connectors, before taking it out to test. To my surprise, it worked quite well, though somewhere my measurements weren’t perfect as the antenna was slightly out of tune. It worked wonderfully at 900-1000Mhz, but not at that magic 1090Mhz that I was looking for! We still tested it in the ‘R2D2 building’ – named as such because of its shape – and my signal strength and range has increased slightly. Next week I hope to make another antenna with what I’ve learned!"
Week four -
"I can’t believe my time at SSTL has come to an end already, it feels as if I only started yesterday! In my final week, I managed to significantly improve my antenna design, so much so that I’m now receiving signals from as far as Scotland! This time, I decided to create a helical antenna with a copper baseplate. This antenna would be much more predictable as the calculations were simpler and it could easily be adjusted. The antenna expert very kindly helped me with my design by showing me how to 3D print with solidworks. The 3D print would have a groove carved into the outside of a cylinder, to make the angle of the wire more accurate than I could by hand.
The print took over 25 hours, but in the end made my antenna so much more solid and stable. When we tested the antenna on an RF analyser in an anechoic chamber, we found that the antenna had a huge gain at 1090Mhz, which was exactly what I wanted! As expected, the antenna worked really well, so well in fact that the computer program couldn’t handle the amount of data that we were discovering!
There are so many more things I’d like to try but unfortunately my time here has come to an end. I said my goodbyes and gave out presents and cards on my last day and yet I didn’t feel like it was enough after everything that everyone had done for me. Hopefully I’ll get to work with some of these people again!"