| Status: | Active, open to new members |
| Leader: | |
| When: | Monthly on Monday afternoons 4th week of the Month |
The Pillars of Creation
6,500 Light years from Earth. We'll never be able to visit, but here we can learn about the Pillars, and the science behind the Astronomy.
Earthrise
The most iconic image of our home - ever.
July 1969 The first manned landing on the moon
Our Science & Astronomy Group meets at the house of Ray Lawrence on the fourth Monday of each month, 2-4pm. If you would like to learn more about the Group, or would like to join us, contact Ray by clicking on the Link above.
A Happy New Year to the Science of Astronomy Group. For our January meeting the group learned (!!) - well, Ray endeavoured teach us - about the various methods used to determine the mass of celestial bodies such as planets, stars and galaxies. Although it is difficult to physically to directly measure these objects it is possible to assess their mass by the way they move and the effect they have on nearby objects.
Unfortunately the group was unable to meet together in February, but already here we are in March and this month the group were able to learn about Cosmology, which deals with investigating the Universe on the very largest scale. We looked at the Big Bang theory of how the universe started 13.8 billion years ago, although we still have not the faintest idea or theorey of of what, (or Who!), existed before the Big Bang. We also looked at the possible scenarios of how the Universe will end, fortunately we will not be here to witness that event!
So for our April meeting it was time to learn about how the brightness of stars are categorised and how the system developed from a scale of 1 (brightest) to 6 (faintest) as ranked by Greek Astronomer Hipparchus around 129BCE who could only observe the Apparent Magnitude of the star, ie how bright it appears from Earth without considering its distance from us. With ever improving observation methods and measurement systems and the observation that a magnitude 1 star shines around 100 times as bright as a magnitude 6 star, a logarithmic scale of
brightness emerged where any difference of 5 magnitudes corresponds to star brightness changing by a
factor of 100. This resulted in the brightest stars like our sun, the planets and Sirius being given negative apparent brightnesses to make the scale work, the Sun being categorised at less than -25 and some very faint stars only visible by telescope being categorised at +25 plus.
Astronomers can now measure the true brightness of a celestial object, defined as its Absolute Magnitude when viewed at a standard distance of 10-parsec (32.6 light years). At a distance of 10 parsecs, Absolute and Apparent magnitude are equal and the difference between the two values can now be used to determine the distance to a star from Earth. Mind expanding stuff! We were very grateful Ray didn’t get into the maths.
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