
In grade 5, for a science project, I created a model of the solar system and wrote a blurb on each planet, the sun and the asteroid belt (regrettably no comets). This experience kept me thinking about space. It wasn’t until after my teen years that I thought about the solar system in more detail. I took a course on astronomy at the local university and vowed to buy a telescope. I didn’t have enough money then, and became distracted by other things. It wasn’t until 2004 that I showed my then ‘new’ husband some pictures from
Photon Echoes. This piqued his interest and we invested in a small telescope. Viewing was not ideal in London, England; however, we could view Saturn and this justified the purchase 10-fold.
Now we are in Vancouver, Canada and the viewing is much better, we now have 3 telescopes: solar, refractor and catadioptric – thanks largely to my husband.
I feel it is a shame if someone does not have a basic understanding of where the earth sits, so here are some crude remarks on astronomy:
>Stars are fixed (constellations), they appear to move as though the earth is encased in a rotating cylinder. This illusion is due to: the earth revolves on an axis, orbits the sun and stars are very far away. So, constellations at different times of the year either appear in the daytime or at night, without super telescopes viewing is best in the dark.
>People in the northern and southern hemispheres see different parts of space. >Ancient astronomers noticed that some bodies move around the sky, they called these the wanderers i.e. the word planet is derived from Greek for ‘wanderers’.
>Retrograde motion took some time to figure out. This is when a planet appears to go back on itself i.e. opposite way of its usual path. What is happening is that the planets are orbiting the sun in an ellipse.
>Johannes Kepler was an amazing person. His discoveries shaped our understanding and opened our minds to conceive what space is. No small feat. Suggested reading is Arthur Koestler’s The Sleepwalkers. Kepler's laws of planetary motion:
1. The orbit of every planet is an ellipse with the sun at one of the foci. An ellipse is characterized by its two focal points. Thus, Kepler rejected the ancient Aristotelian, Ptolemaic, and Copernican belief in circular motion.
2. A line joining a planet and the sun sweeps out equal areas during equal intervals of time as the planet travels along its orbit. This means that the planet travels faster while close to the sun and slows down when it is farther from the sun. With his law, Kepler rejected the Aristotelian astronomical theory that planets have uniform speed.
3. The squares of the orbital periods of planets are directly proportional to the cubes of the semi-major axes (the "half-length" of the ellipse) of their orbits. This means not only that larger orbits have longer periods, but also that the speed of a planet in a larger orbit is lower than in a smaller orbit. Source for the laws:
http://en.wikipedia.org/wiki/Kepler%27s_laws_of_planetary_motion >Aristarchus of Samos (310 BC – c. 230 BC) first postulated a heliocentric model of the solar system (opposed to geocentric). For many interesting, albeit wrong reasons, his theory was squashed until 1514 when this concept had an audience again via Copernicus. >We see the planets because light from the sun is reflected. Due to their proximity, planets may appear brighter than stars.
>The sun rotates on its axis about once every 27 days, it rotates counter-clockwise as seen from the northern hemisphere.
>Finally, we only see one side of the moon due to: the moon rotates on its axis once a month, it orbits around the earth once a month and the earth also rotates on an axis every 24 hrs and orbits the sun once a year. All this motion produces this phenomenon. Plenty of times I’ve held an orange and cherry trying to replicate the process.
Top image: Johannes Kepler, 1610