Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2015 December 25
A Dust Devil on Mars
Image Credit: HiRISE, MRO, LPL (U. Arizona), NASA Explanation: It was late in the northern martian spring when the HiRISE camera onboard the Mars Reconnaissance Orbiter spied this local denizen. Tracking across the flat, dust-covered Amazonis Planitia in 2012, the core of this whirling dust devil is about 140 meters in diameter. Lofting dust into the thin martian atmosphere, its plume reaches about 20 kilometers above the surface. Common to this region of Mars, dust devils occur as the surface is heated by the Sun, generating warm, rising air currents that begin to rotate. Tangential wind speeds of up to 110 kilometers per hour are reported for dust devils in other HiRISE images.
First full moon on Christmas since 1977
This month, the December full moon falls on Friday, December 25, 2015. For Earth’s Western Hemisphere, it’s the first full moon on Christmas Day since 1977.*
We won’t have another full moon on a Christmas Day until 2034.
A 19-year cycle of the moon is the reason. Amazingly, the moon’s phases recur on (or near) the same calendar dates every 19 years. This cycle – known as the Metonic cycle – happens because 235 returns to full moon almost exactly equal 19 years.
So, in other words, the phases of the moon realign (or nearly realign) with the same calendar dates every 19 years. We just missed a full moon on Christmas 19 years ago; instead, the full moon fell on Christmas Eve. It was December 24, 1996 at 20:41 Universal Time, or UT.
But two Metonic cycles ago – 38 years (or 2 X 19 years) – the full moon fell on Christmas Day. That full moon happened on December 25, 1977 at 12:49 UT.
Astronomically speaking, the moon is only full for an instant – at the moment that it’s 180o opposite the sun in ecliptic longitude.
This month, that happens on December 25, 2015 at 11:11 UT. At United States time zones, that translates to 6:11 a.m. EST, 5:11 a.m. CST, 4:11 a.m. MST or 3:11 a.m. PST.
Although the moon turns full at the same instant worldwide, the clock reads differently by timezone. On a worldwide scale, the full moon actually comes at all hours around the clock. See the worldwide map below. The full moon takes place before sunrise December 25 in North America, noon in Europe and Africa and after sunset December 25 in eastern Asia, Australia and New Zealand.
Moon cycles are not commensurate with the calendar, which is based upon the seasons – not the lunar cycle. Therefore, one year from now, the December 2016 full moon will not fall on December 25.
In any year, the phases of the moon take place about 11 days earlier than in the previous year. For instance, the December 2016 full moon will happen on December 14, 2016, and the December 2017 full moon will fall on December 3, 2017.
The moon will look plenty full tonight as it lights up the nighttime from dusk till dawn. Look for the full-looking moon to rise opposite of the setting sun at early evening. The moon will shine highest up for the night around midnight and then will sink low into the western sky as dawn colors the sky.
*Note: For most of the world’s Eastern Hemisphere (Asia, Indonesia, Australia and New Zealand), the last Christmas full moon happened in 1996. In 1996, the full moon occurred on December 24 at 20:41 Universal Time … December 25 in those places.
Bottom line: The December 25, 2015 full moon is the Western Hemisphere’s first full moon on Christmas Day since 1977. We won’t have another full moon on a Christmas Day until 2034. A 19-year cycle of the moon – called the Metonic Cycle – is the reason.
About the Author
The Words of Confucius
Silence is a true friend who never betrays.
Your Daily Influences
December 25, 2015
The Devil Reversed
The reversed Devil signifies a spiritual rebirth, freedom from the preoccupation with the secular and the overcoming of pride and selfishness.
Berkano reversed may foretell family problems and dissatisfaction. Your life path my not be clear to you at this time. Be careful to protect that which is yours.
The tortoise represents the dome of the sky, the universe. It tells you to take slow, deliberate steps and you can achieve everything you desire.
Your Daily Influences represent events and challenges the current day will present for you. They may represent opportunities you should be ready to seize. Or they may forewarn you of problems you may be able to avoid or lessen. Generally it is best to use them as tips to help you manage your day and nothing more.
Your Ancient Symbol Card for Today
The Crow is the trusted messenger that alerts its allies to both danger and opportunity. Although they may appear playful and too opportunistic to be trusted, Crows are in fact powerful and trustworthy. The Crow sees and hears all. When The Crow reports it is best to listen as their news is always important and presented accurately.
Today’s Witches Rune
Keywords: Love, relationships.
Meanings: The Rings is the rune of love and when it is the leading stone, it is a positive answer to your question. It is very much a rune of relationship and can indicate engagement, marriage or a new/renewed relationship. It can also indicate the need for a fresh approach to an existing relationship.
Your Crowley Thoth Tarot Card for Today
Adjustment denotes an inner power, mastery of will and development of inner might. Through mastering one’s emotions and learning from both success and failure the person Adjustment represents has reached a place where they are influential without applying physical force, able to weather the roughest of storms, and not likely to abandon the less fortunate. Adjustment also denotes a large capacity for forgiveness and compassion. Adjustment is not as much about winning as it is about achieving balance, overcoming hardship, and using well crafted persuasion to gain allies. Adjustment suggests the need and ability to make our decisions based on objective perceptions of events, and good or bad, accepting responsibility for our actions.
Your Daily I Ching Hexagram
December 25th, 2015
Do not be forceful or start fights of any kind. Find compromises. Stay calm and do not think with your emotions. Seek allies.
Line One of Your Hexagram is a 6:
State your case to the public and not in the courts.
Line Two of Your Hexagram is a 9:
Do not fight battles you cannot win.
Line Three of Your Hexagram is a 6:
Begin your own enterprise. Abandon failing relationships.
Line Four of Your Hexagram is a 9:
Avoid conflict with the irrational and taunting.
Line Five of Your Hexagram is a 9:
Express your point of view and expect positive feedback.
Line Six of Your Hexagram is a 9:
You will have setbacks in the short-term. Be patient.