Wednesday, July 18, 2012
Begins the summer, the longest season of the year
The start of summer is marked by the position of the Earth from the Sun.
The astronomical summer, the longest season of the year with 93 days and fifteen hours.
Summer astronomical longest season of the year with 93 days and fifteen hours, will officially start on Thursday at 09.01 hours of the morning hours between the mainland and phenomena that may consider include "meteor showers" delta Aquarius and the Presides.
The beginning of summer, like the other stations, is marked by the position of the Earth from the Sun In the case of summer, occurs when the Sun reaches its northernmost position, ie when it reaches its maximum declination north and for several days at noon maximum height does not change.
Therefore, this circumstance is also called "Solstice" (Quiet Sun) summer, remember the National Astronomical Observatory.
On July 21, the longest day
On Thursday June 21 is officially the longest day of the year, fifteen hours and three minutes long, compared with shorter (21 December), with only nine hours and seventeen minutes.
You might think that the longest day of the year is also the day when the sun rises earlier and sets later but it is not, that is because the Earth's orbit around the Sun is not circular but elliptical and that the axis of the planet is inclined in a direction which has nothing to do with the axis of said ellipse.
This is the reason that makes a sundial and a conventional (based on a fictitious Sun) are misaligned.
The greatest distance between Earth and the Sun
At this time there is also the maximum annual withdrawal from the Earth to the Sun that, on this occasion will be the 5th of July, when the distance between them is just over 152 million kilometers, more than five million in early January, chanson solar distance marks its annual minimum.
From the astronomical point of view, the skies of summer solstice will be dominated by the presence of Mars and Saturn, two planets during this season will go closer to each other to achieve, on 17 August, a minimum distance of about three degrees (six times the diameter of the moon).
These two planets will be visible as evening constellations, while Venus and Jupiter will be the morning.
And like every year, the event will star this time meteor showers, the Aquarius of the delta, whose maximum is observed on 30 July, and the Presides, which occur on 12 August this year look better than the past. Summer ends on September 22 when it begins this fall.
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