from The Open University
Alternatively you can skip the navigation by pressing 'Enter'.
The Met: Policing London: Episode FourThursday, 2nd July 2015 00:10 - BBC OneThis episode of OU/BBC's The Met: Policing London looks at tackling the city's crime after dark - from... Read more: The Met: Policing London: Episode Four
The Met: Policing London: Episode FourThursday, 2nd July 2015 01:00 - BBC One
The Bottom Line: Summer 2015: The Bottom Line - Burger BattlesThursday, 2nd July 2015 20:30 - BBC Radio 4
The Bank: Love and MoneyThursday, 2nd July 2015 23:20 - BBC Two
The Bank: Love and MoneyAvailable until Sunday, 2nd August 2015 00:50The second episode of The Bank looks at love in relation to money - with everything from engagements, marriage,... Read more: The Bank: Love and Money
The Met: Policing London: Episode FourAvailable until Monday, 6th July 2015 22:00
Thinking Allowed: Factory music and volunteering post-recessionAvailable for over a year
Thinking Allowed: White working class boys and French thoughtAvailable for over a year
Video and Transcript - ItalianAs part of an international project to get our International Year of Light animation... Watch now: Video and Transcript - Italian
Take the photographic memory testCan you capture scenes just by looking at them? Find out with our photographic memory test. Launch now: Take the photographic memory test
Start writing fictionHave you always wanted to write, but never quite had the courage to start? This free course,... Try: Start writing fiction now
What is strategic human resource management?This free course, What is strategic human resource management?, is about the interplay between... Try: What is strategic human resource management? now
The sun dominates our lives by defining our day, but how much do you know and...
The sun dominates our lives by defining our day, but how much do you know and understand about it? This unit will help you to explore the workings of the brightest star in our universe looking at its structure and the main processes taking place within it. You will also examine the phenomena of sun spots.
At the end of this unit you should:
- know about the electromagnetic spectrum and how it is used to infer properties of sources of radiation;
- know about the range of sizes, distances and motions of objects in the Universe and how they can be measured;
- know about the structure of, and the main processes operating in, the Sun;
- comprehend concepts lying well outside everyday experience, including those that involve very large and very small distances, times, temperatures and energies, and those that are non-intuitive;
- develop the skill of being able to receive and respond to a variety of information sources including textual, numerical, graphical and visual material.
Study this free course
Enrol to access the full course, get recognition for the skills you learn, track your progress and on completion gain a statement of participation to demonstrate your learning to others. Make your learning visible!
For astronomers, the Sun is fascinating because it is our nearest star. By studying the Sun, they can gain an insight into the workings of the other millions of stars that are visible in the night sky. Learning that the Sun is a star can be a little surprising. After all, the Sun is a brightly glowing, yellow object – so bright that it is dangerous to look at it directly, and so hot that we can feel its radiation warming the whole Earth. Stars, on the other hand, are mere silvery pinpoints of light that are visible only against the darkness of the night sky and with no discernible heating effect on Earth. How can they possibly be the same sort of object? The key to the answer lies in their distances.
In astronomical terms, the Sun is relatively close, being only about 150 million kilometres (93 million miles) from Earth. The stars that are visible at night are much further away: the nearest is about 40 million million kilometres from Earth, and most are much more distant than that. Imagine looking at a glowing light bulb first from very close up and then from a much greater distance. Close up, you would see the shape of the bulb but, from far away, it would be just a point of light.
This unit is from our archive and is an adapted extract from Introducing astronomy (S194) which is no longer taught by The Open University. If you want to study formally with us, you may wish to explore other courses we offer in.
The Open University is conducting a survey investigating how people use the free educational content on our OpenLearn website. The aim is to provide a better free learning experience for everyone. So if you’re a regular user of OpenLearn and have 10 minutes to spare, we’d be delighted if you could take part and tell us what you think. Please note this will take you out of OpenLearn, we suggest you open this in a new tab by right clicking on the link and choosing open in a new tab.
This is an extract from an Open University course which is no longer available to new students. If you found this interesting you could explore more free Physics and Astronomy courses or view the range of currently available OU Physics and Astronomy courses.
Copyright & revisions
Originally published: Monday, 6th June 2011
- Creative-Commons: The Open University is proud to release this free course under a Creative Commons licence. However, any third-party materials featured within it are used with permission and are not ours to give away. These materials are not subject to the Creative Commons licence. See terms and conditions. Full details can be found in the Acknowledgements section.
- This site has Copy Reuse Tracking enabled - see our FAQs for more information.
If you enjoyed this, why not follow a feed to find out when we have new things like it? Choose an RSS feed from the list below. (Don't know what to do with RSS feeds?)
Remember, you can also make your own, personal feed by combining tags from around OpenLearn.
- Latest OpenLearn pages
- Latest pages from OpenLearn - Physics and Astronomy
- Latest pages tagged - sun
- Latest pages tagged - universe
- Latest pages tagged - astronomy
- Latest pages tagged - memory-work
- Latest pages tagged - Fermanagh
- Latest pages tagged - listing
- Latest pages tagged - economic decline
- Latest pages tagged - wavelength
- Latest pages tagged - radiation
- Latest comments on this page