Tylers Green Middle School are celebrating their 50th Anniversary this year by holding a Science Week to study the technological advances made over the last half a century. Wycombe Astronomical Society were invited to participate and we provided our contribution with a short lecture from Sandy Giles to the whole school on the Apollo 11 Lunar landing in 1969. Sandy also went round to the individual year groups fielding questions about astronomy from the children. “I was rather nervous about the questions, but fortunately the teachers had vetted them first. There was a refreshing simplicity to some of them which nevertheless required careful answers – for example why does the Moon sometimes change colour.” The school are entering their budgeting phase for next year and the purchase of a telescope is now actively being pursued.
Actually, we have already heard quite a bit of what Colin Stuart had to say before – specifically from Libby Jackson in March last year. Nevertheless it was helpful to revisit the problems we face in sending humans to Mars. This was a well-delivered and well-illustrated presentation, and drawing upon relevant information from other scientific endeavours, such as the Antarctic Concordia Research Station, and space missions such as Voyager, the Mars rovers Opportunity and Curiosity, and the International Space Station.
Getting off our own planet remains a big deal, though the cost of lifting one kilogram has fallen from $20,000 to $3,000 since the launch of Falcon Heavy by SpaceX. The physiological problems facing astronauts remain a formidable problem; for example osteoporosis through weightlessness and DNA damage from solar coronal mass ejections. Much is made of the psychological effects on astronauts being so far from Earth and Mars; but surely this is over-stated? – did not early explorers like Columbus experience exactly the same challenges on their voyages across the Atlantic? – and at that time they didn’t know whether they were halfway there or indeed if there was “another side” at all!
Colin gave us some insight to what it will be like living on Mars. For example where would humans colonise first? Noctis Labyrinthus might be suitable, being equatorial in location (good for power generation) and providing natural shelter (in sub-surface tunnels). Astronauts will have to grow their own food, too – there have been early efforts at this in the International Space Station, and now by the Chinese on the far side of the Moon.
So when is all this going to happen? It could be as early as the 2020’s or 2030’s. More realistically, Colin speculated, the 2050’s – well in time, then, for the Transit of Earth which will be seen from Mars in 2084 – dust storms permitting!
A New Year and a New topic for WAS – Practical Spectroscopy! And who better than Lee Sproats of David Hinds/Baader UK to guide us through it?
Was there some nervousness about this? – some thoughts that this was not quite for us? Well, it might have started that way, but as Lee talked us through the construction and operation of the DADOS Slit Spectrograph, he gradually drew us in and members were actively participating and understanding how the instrument worked and was used. Plans to go outside and actually capture a spectrum were thwarted by the weather (and it was bloomin’ freezing out there anyway!!) so we contented ourselves with viewing the spectra generated by the lights in the Hall and the Neon Calibration Lamp. Lee finally demonstrated the rudiments of the BASS software for processing spectra.
Assuming the weather cooperates, we now have the opportunity as a society to try this instrument out – Lee has kindly lent WAS the DADOS instrument he demonstrated for the next month. Neil Hawkins has it and he can be contacted to borrow it.
To measure distance these days you need, not a ruler, but a clock! For the metre is the length of the path travelled by light in vacuum during a time interval of 1/299792458th of a second.
The metric system was originally conceived as a system of measurement derivable from unchanging phenomena; but technical limitations necessitated the use of artefacts (the prototype metre and prototype kilogram for example) when the metric system was first introduced in France in 1799.
But in the same way that has been done for the metre, from 20th May 2019 the kilogram, ampere, kelvin, and mole will be defined by setting exact numerical values for the Planck constant (h), the elementary electric charge (e), the Boltzmann constant (k), and the Avogadro constant (NA), respectively.
The November lecture from our Vice President Prof Bob Lambourne, focussed on the history of the determination of the speed of light, such that now it is deemed to be a fixed value – a constant in the same way as the Planck or Boltmann constants.
Galileo in 1638 started it, coming up with a value of about 200,000 km/s, but admitting it was actually too fast to measure. Then through the work of Bradley, Huygens and Newton in the 18th Century; Fresnel, Fizeau, Foucault, Michelson and Morley in the 19th Century to arrive at estimates closer to 300,000 km/s; culminating in the theories of Lorentz and Einstein in the 20th Century. Along the way, the notion of the “ether” was invented and discarded, and Einstein’s Theory of Relativity showed how to relate measurements made by observers in a specified state of relative motion. Whilst “c” does represent the speed of light, its real significance is that it is the fundamental constant in all space-time physics.
Not strictly a lecture about astronomy, this was a welcome revision of this corner of the history of science. The Society wishes Bob a happy retirement from his post at the Open University and we are extremely pleased that he will continue to be our Vice President and wants to come back and give us more lectures!
Continuing his monthly series of chats with Mick Lewis of Wycombe Sound Radio, WAS’s Sandy Giles this month was talking about the use of his new ZWO video camera for taking lunar images. He also fielded a question from a listener recently back from a trip to South America, why could she see more stars in the southern hemisphere that she sees at home – likely because there was less light pollution and atmospheric disturbance. Sandy also discussed the end of one space mission (the Kepler Space Telescope) and the beginning of another (the BepiColombo mission to Mercury).
You can listen to show here: http://listenagain.wycombesound.org.uk/index.php/shows/Afternoons/ and click on, Afternoons_Tuesday 13 November 2018.
Sandy’s next interview will be at 2:00 pm on Tuesday 11th December (106.6 FM).