Why is the day so short?

We are coming up to the winter solstice on December 21st when it will be the shortest day of the year. At this time of year we can watch the sun rise above the horizon on our way to school and see sunset in the afternoon at school. By the time we leave school it is dark.
Why is the day so short in winter and so long in summer?

This is because the earth tilts on its axis. If you live in the northern hemisphere it is winter, the days are short and it is colder, because we are tilted away from the sun.

This diagram is not to scale. The sun is much, much bigger and much,much further away!

When there is a lot of activity on the sun a solar wind is created and particles fly across space towards earth. The particles are drawn in to the earth at its magnetic poles. This creates the aurora borealis or 'northern lights'. When this happens we can see the lights if we look towards the north.

We are lucky to have a dark night sky which is mostly unaffected by light pollution. Since we also have more hours of darkness we are more likely to get a good view of the lights which are sometimes called 'The Merry Dancers' in Orkney. The closer to the north  pole you live the better the view you get! Here is a video of the aurora borealis from the north of Norway.


 
 
Of course the best view is from space.
 


 
Have you seen 'The Merry Dancers'?
 

35 comments:

  1. I think that is interesting but why does it happen?
    I bett the Northern lights look nice. I never new about that it is colder because we are tilted away from the sun. I realy like that post.

    stephanie

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    1. I'm glad you enjoyed that post Stephanie. It is a fascinating subject. I hope I explained why the northern lights occur clearly. Why is the earth tilted on its axis? That is a whole other question!

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  2. I have never seen the Northern lights but my granny says they are caused by storms on the sun, which throws out particles that hit the earth at the north pole causing the bright known as the northern
    lights. My granny told me that the southern lights are known as the Aurora Australias. Often you see the northern lights on frosty calm nights or when most people are sleeping ( I loved the videos and the space one was awesome) I wonder how many people have seen them? Laura

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    1. You are lucky to have an expert granny Laura. I like your comment very much and you finish with a question - fantastic!
      I have seen the northern lights this year. In fact, a few weeks ago. I drove out of town towards Shapinsay to get away from the streetlights. I knew this was happening because of a website called aurora watch. Since it takes a while for the particles to arrive here from storms on the sun we can predict when they will happen. If it is not too cloudy you will see the aurora and probably lots of stars too.

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  3. Lovely footage of the Northern lights. I wonder how many of you have ever seen them? Often they only appear on clear frosty nights and often while most people are asleep. They can be very bright and colourful but sometimes they are not so noticeable. I haven't seen them this year yet but I'll keep watching for them and if I see them I'll let you know.Caroline(Laura's mum)

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  4. It is amazing that its getting darker but less time to play outdoors. The northen lights are brilliant but i've never seen them before. I wonder when the northen lights come out? What colour are the northen lights? (Tommy)

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    1. Good question Tommy. The northern lights are usually green or pink but they can be lots of different colours.
      I have only seen green lights. Do you think we should get a link to the aurora watch website so that we know when to look for them?
      We are quite good at having thriving indoor sports in the winter in Orkney,perhaps because it would be difficult to carry on outdoors!

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  5. I have never seen the Northern lights before but they look very beautiful. Wideford Hill is just a bit up from my house it is quite a popular place for seeing the Northern lights so I might go up there when there is a clear sky and maybe i will see them. It is weird how the day gets longer and shorter. The people that lived in Skara Brae went to sleep when it got dark so that would probably be about 4 o'clock that they would go to sleep! Imagine what time it would be in Summer. I found a website for Skara Brae here is the link http://www.orkneyjar.com .
    I wonder how many times a year there are Northern lights in Orkney?


    Maddie

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    1. You are lucky to be near such a good viewing place!

      The nights must have seemed very long in winter for the people who lived at Skara Brae. I wonder what they thought caused that? They might have celebrated when the days started to become longer again,maybe round about the time we celebrate Christmas.What do you think they did during the winter? Perhaps they told stories and played games!

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  6. Watching the Northern lights from space is so beautiful.I have never seen them, though I want to.I wonder why it is called the Aurora Borealis?

    Alia

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  7. I agree with you Alia, the space video is amazing!
    Aurora was the Roman Goddess of the dawn and Boreas was the God of the North Wind so, when the French scientist Pierre Gassendi was naming the lights in 1621, he put the two together and made up a new name.
    Good question!

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  8. It's quite intresting that the sky can go green cuased by bad weather! Iv'e never seen the merry dancers have you? I wonder if you could see the merry dancers in Sweden and Russia because there very north?

    Jack p5

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    1. Only if the bad weather is on the sun Jack! I am sure you would be able to see the Merry Dancers in Sweden and the north of Russia, and I am sure the people who live there will have their own local names for the northern lights too. The ancient Swedish name for aurora is sillblixt (herring flash)because they thought it looked like silvery fish swimming in the sky.

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  9. They are really awesome.

    Why is there so many colours?

    elin sinclair p5

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    1. Elin, I'm sure we'd need a scientist to explain why there are so many colours, but I agree with you they are awesome!

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  10. I think the Aurora Boreas is so pretty.I love all the colours that they come in.In the video it looked like the earth was in a green and pink bubble.I would love to see them as I have never seen them before.I wonder when they were first seen?I also wondeer why Pierre Gassendi choose that name?


    Emma

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    1. Emma, the aurora is beautiful, I agree. I suppose the idea that the lights looked light dawn breaking but were moving around as if they were being blown by the north wind made the name appealing. We will never really know for certain. What would you have called them?

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  11. Wow I wonder how long it lasts for?
    I would love to see them.
    These posts keep on geting more and more intresting.
    Have you ever seen the Northen lights?


    (From Caitlin)

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  12. I am learning more and more about the northern lights myself! I have seen the northern lights in Orkney, it was so cold that eventually I had to go back inside so I have no idea how long they lasted for that night. I think it will depend on how fierce the storm on the sun was and how long the night is and how clear the sky is. I suppose it must be different every time. I know that some years there is very little solar activity and so hardly any northern lights occur.

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  13. I saw the merry dancers when I was driving home the other night with mum, they were ahead of us above Rousey.
    Shannon Pasotti (P5)

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    1. Lucky you Shannon!It would have been nice and dark out on the West Mainland away form the lights of the town.
      Were the lights greenish in colour? Did you see them moving?

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  14. I have seen the Northern lights in Sanday at night we are so lucky to see the Northern lights people in London probably couldn't see them.

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  15. This is such an interesting post and I have really enjoyed reading your comments. Who needs wikipedia when you've got Ms Mackay? I was very blessed to see the Merry Dancers in all of their splendour last week in Tankerness. As it is very dark here at night, we get a brilliant view of them. They were very green last week and quite spectacular. I just had a look at the Aurora Watch website and it says there is no activity tonight which is a shame as it is lovely and clear. I will definitely be keeping an eye on that site. I noticed that you can get free messages from it sent to your phone to let you know when you are likely to see them.
    Well done to all of the people who have posted 'quality' comments.

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  16. I have seen the Northern lights many of times. Me and my dad always go up to Wideford Hill if we see activity in the sky. A couple of months ago I saw them in my back garden and there was a moonbow as well. I wonder if that's why some people can see them near their house and some can't?

    Erin P5

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    1. Erin, you are very lucky to have seen the northern lights so frequently. I wonder if some people who live in the town don't notice them becasue of the light pollution from our street lighting? How excellent to have seen a lunar rainbow - that is very special. You are quite a sky watcher. Do you know some of the star constellations too?

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  17. Since everyone is really getting into this project and leaving lots of comments, I thought maybe you'd like to look at John Vetterlein the Rousay astronomer photos of the Northern Lights, if you go to www.spanglefish.com/northern skies and follow the link on the right hand side, you will see pictures taken in Rousay a few days ago of the merry dancers. Hope this is of some interest.Caroline(Laura's mum)

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    1. Thank you for the excellent link Caroline!

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  18. I think they look amazing and I would love to see them especially from space. It is amazing that these particles can make such beutiful colours and effects that can be seen from earth and space. Cameron

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  19. Do you think it will be possible to go on trips to see the northern lights from space in the future? That would be amazing!

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  20. It's really interesting how the Northern Lights look from space.I wonder if I could see one some day? Are most of them green?


    Aidan P5

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  21. Wow the Northen lighs are beautiful,I wonder who called them the Northern lights or merry dancers?

    Keira p5

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  22. When the sun sets on Winter Solstice its last rays shine through the entrance to Maes Howe.

    This means Maes Howe must have been built facing that way because of the Solstice.

    How did the people who built Maes Howe know which way to build the entrance to catch the last rays of sun on Winter Solstice?


    Joe P5

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  23. Good question Joe! You have added new information to our thread of comments! The winter solstice must have been an important moment in ancient times. I think there is a web cam set up to record the light flooding in. There are some pictures from past years here: http://www.charles-tait.co.uk/library/archaeology/orkney/maeshowesolstice/index.htm
    Have you been there?

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  24. I see it is some time since any entries appeared on your page with reference to astronomical topics. We though that in addition to the “merry dancers” you would like to see some of the images we took here on Rousay of Comet PanSTARRS. Please go to the following link: http://www.spanglefish.com/northernskies/index.asp?pageid=468807

    There is the prospect of another bright comet towards the end of 2013. We shall update information on the general comet page at:

    http://www.spanglefish.com/northernskies/index.asp?pageid=386198

    Best wishes to you all from Rousay Observatory.

    John Vetterlein

    June 11th 2013

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    1. Thank you Mr Vetterlein, we will look at that link. I think quite a few of us had no idea there was an observatory on Rousay. We are pleased that you came across our blog post.

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