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Last Post 10/20/2010 8:22 AM by  Emilia Kilpua
learning about the Sun
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10/20/2010 1:34 AM

    Greetings from Romania!

    We are an enthusiastic group of students from 6th grade in Tudor Vianu National High School of Computer Science, Bucharest, Romania. We are really honored to take part in this marvelous project. We would like to ask several questions about Sun:

    1. What do you think is the most interesting phenomenon that occurs on the sun?

    2. How can the Sun emit heat for millions of years?

    Thank you very much for this opportunity.

    Tags: heat, phenomena

    Emilia Kilpua



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    10/20/2010 8:22 AM
    Hi! There are so many interesting phenomena taking place at the Sun that it is difficult to choose the most interesting one! Compared to the other stars in our universe we have good measurements of the Sun, but still many phenomena on the Sun are not well understood as we cannot go directly to the Sun and make measurements. All our knowledge comes from the remote sensing observations. One very interesting questions is how cyclic changes in the solar activity are generated. It would be really important to be able to predict how solar activity varies in the long run. Before it was believed that the gravitational collapse is the source of Sun’s energy. The scientist Lord Kelvin argued that this mechanism can generate energy only for few tens of millions years although geologist had provided evidence that the Earth is much older. At the beginning of 20th century the understanding of the atomic physics allowed British astrophysicists Arthur Eddington to propose that solar energy is generated by nuclear fusion where two hydrogen atoms are combined to create helium. How long the Sun can shine depends on the amount of the fuel available and the consumption rate. About 75% of solar material is hydrogen so there is plenty of fuel available. Astronomers have estimated that the Sun can still shine about seven billion years. The massive starts consume their energy faster than less massive stars.


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