Thursday, June 20, 2013

Summer solstice 2013 (June solstice)

In less than a half an hour, the earth will pass through the point of June solstice -- summer solstice in the northern hemisphere. This means that the earth will pass through the point at which its north pole points most directly at the sun in its annual orbit.  Earth will cross this point at 10:04 pm Pacific time (here in California in the US) on 20 June -- although it will already be 21 June in most of the rest of the world, including the east coast of North America.

Above is a video showing the earth orbiting around the sun with its axial tilt.  Note that the axis always remains pointed in the same direction as the earth orbits the sun.  In previous posts, I have used the "earth-ship metaphor" to help visualize this concept.  You can imagine the poles of the earth as being the prow and the stern of an old-time sailing ship, and as the ship circles the sun, the prow and stern remain pointing in the same direction, so that at the summer solstice the prow points towards the sun as the ship sweeps by, and at winter solstice the stern points towards the sun as the ship sweeps by.

If the north pole is the prow of the ship (blatant northern-hemisphere centrism here), then the prow will sweep by the sun and point at it (or as towards it as it ever points during the year) at 10:04 Pacific time tonight.

Below is a video of a talk by physicist Nassim Haramein explaining that because the sun is actually streaking through space rather than staying in place, the traditional image of a stationary sun with circular static orbits around it is not correct.*  In fact, the orbits of the earth and other planets around the speeding sun are vorticular, as shown in the video.  This important fact is discussed in this previous post as well.  However, it does not make the earth-ship metaphor incorrect -- it just makes it more exciting!

* If you are wondering why all the background stars still look the same if the sun (and the planets that follow it) streaks through space billions of miles each year, the reason is simple -- those background stars are incredibly far away!  How far away?  Take a look at this recent blog post, and be sure to watch both of the videos in that post.