Summer officially begins June 20
Thursday, June 14, 2012
Spring has sprung, fall has fell, summer is here -- and boy is it hot.
Well, not exactly poetic, but the version that rhymes is not suitable for family newspapers.
Actually summer will be here next week on June 20, at 5:09 p.m. MDT to be exact, when the sun reaches its most northern point from our view. The event is called the summer solstice.
The word solstice is Latin for "Sun stands still." Not that the sun stops moving, it just means that, measured against the location and direction of sunrise and sunset on the horizon, the sun appears to not be moving either north or south, hence, standing still.
This effect is due to Earth's 231⁄2-degree axial tilt to its orbital plane. It is at this time that the northern hemisphere is leaning, or pointing, toward the Sun thus getting more direct sunlight.
The summer solstice (or as it is referred to by some ancient cultures mid-summer day) is also traditionally the longest day of the year.
That is only true if you live on the equator. Living here as we do in southwest Nebraska and northwest Kansas, we are almost exactly 40 degrees north of the equator so the "longest day" is not on the day summer begins.
For us the longest day last for about nine days, from June 17 to June 25, when the sun is above the horizon for 15 hours for each of those days.
If you lived near the Arctic Circle you would really have a long day as during this time the Sun never sets from their point of view. Thus giving rise to the name, "The Midnight Sun."
Conversely, at the south pole the Sun never rises and they have several days of complete, continuing darkness.
Another strange oddity is many people think the reason it is hot in the summer is because Earth is close to the sun. However, such is not the case. During the northern summer is when Earth is at its farthest distance from the sun. It is during our winter season when Earth is closest to the Sun.
Now for some "old" business. Attempts to view the recent transit of Venus were a washout, at least from here in Colorado. The sky was partly cloudy for most of the day, and was particularly cloudy just at the time the transit started.
Any attempts to view it directly were impossible, except for a short 10-minute period about 20 minutes before sunset when a small clearing of clouds occurred.
However, it was what we astronomers call a "Sucker Hole." That is just a short opening in the cloud cover that gives you enough time to get your equipment ready for viewing just in time for the clouds to close up again.
I ended up watching the transit from my computer as presented by the various locations showing it live and online. Not the same as being there, but close enough.
SKY WATCH: New moon, June 19. We are getting two more planets in our viewing sky this week. After having crossed the face of the sun, Venus returns as a morning object joining giant Jupiter this week. Look in the east on the morning of June 15 about 45-minutes before sunrise when a very, very thin crescent moon joins Venus and Jupiter. They will be very close to the horizon, binoculars will be of help. The planetary pair will be rising higher as the month progresses. Another planet, Mercury will join the evening crew of Mars and Saturn tonight. The tiny planet will form a triangle in the east with the stars Pollux and Castor in Gemini just above it.
NEXT WEEK: More astronomical blathering.