Chandra is the unsung hero of space telescopes. Far better known is the Hubble Space Telescope, which is rightly famous for the spectacular images it has produced. But Hubble was only ever intended to be one arm of a four-pronged approach to astronomical observations, another of which is provided by Chandra. Whereas Hubble produces images … Continue reading Chandra: the Universe as seen in X-rays
Why believe in the Big Bang?
It is often said that the reason why we “know” the Big Bang took place is because the Universe is expanding and if time were played backwards then everything would have started from the same point at the same moment in time. That moment, when everything started moving apart, is what we call the Big … Continue reading Why believe in the Big Bang?
Astronomy and Cosmology
It would be fair to say that whereas astronomy is an observational science, cosmology uses those observations to model the Universe. With this distinction in mind, there are a number of forthcoming events and publications that I think are worth highlighting. First and foremost is next week’s (April 8th) total solar eclipse, which will be … Continue reading Astronomy and Cosmology
The Hertzsprung-Russell diagram
It is obvious that the stars in the night sky differ from one another; some look brighter, some appear larger and some have different colours. One of the earliest ideas was that all stars are the same but they look different because they are at different stages of development: it’s as simple as the fact … Continue reading The Hertzsprung-Russell diagram
Balloon on the Moon
Imagine that you could take a helium-filled balloon to the moon. If you stood on the lunar surface, holding the ribbon tied to the bottom of the balloon, what would you expect to happen when it was released? We'll assume that the balloon doesn't burst and I'll give you four possible outcomes; The balloon rises … Continue reading Balloon on the Moon
Star Count 2023
Looking up at the stars is awe-inspiring experience but light pollution from the ground greatly reduces the number of stars that can be seen. Even a single neighbouring security light that is either permanently on or frequently activated by people or animals can ruin the night sky for others. There is an annual event that … Continue reading Star Count 2023
Standard Form
Every GCSE physics paper normally has at least one question with a mark for the correct interpretation or expression of numbers in standard form. This is a basic skill that is taught as part of GCSE mathematics courses but it holds a great deal of power for scientific calculations that is rarely mentioned at this … Continue reading Standard Form
More than meets the eye
Optical illusions aren't part of the school science curriculum - but they should be. We tend to believe what we see, and a lot of what we know about science is based on visual observations, but we aren't normally taught to question the evidence of our own eyes. One of the classic puzzles of astronomy, … Continue reading More than meets the eye
Congratulations
The results are in and, overall, the AQA Trilogy course has been very successful. I have heard of some great individual results and I've been delighted to shake hands with some of you. I also know there have been some slight disappointments but that is the way things are: we live and learn (please never … Continue reading Congratulations
Energy Budget
It is well known that darker surfaces heat up faster than lighter surfaces and reach a higher maximum temperature. But why? When the maximum temperature is achieved, there is a state of thermal equilibrium that is is due to a balance between the rates at which (new) energy is being absorbed and (previously) stored energy … Continue reading Energy Budget
Mr Tarrant's physbang 'blog 