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 11
Explanation: Dwarf planet Ceres is the largest object in the Solar System’s main asteroid belt with a diameter of about 950 kilometers. Exploring Ceres from orbit since March, the Dawn spacecraft’s camera has revealed about 130 or so mysterious bright spots, mostly associated with impact craters scattered around the small world’s otherwise dark surface. The brightest one is near the center of the 90 kilometer wide Occator Crater, seen in this dramatic false color view combining near-infrared and visible light image data. A study now finds the bright spot’s reflected light properties are probably most consistent with a type of magnesium sulfate called hexahydrite. Of course, magnesium sulfate is also known to Earth dwellers as epsom salt. Haze reported inside Occator also suggests the salty material could be left over as a mix of salt and water-ice sublimates on the surface. Since impacts would have exposed the material, Ceres’ numerous and widely scattered bright spots may indicate the presence of a subsurface shell of ice-salt mix. In mid-December, Dawn will begin taking observations from its closest Ceres mapping orbit.
Geminid meteors this weekend
Tonight, look for meteors! The 2015 Geminid meteor shower will be building towards its peak over this weekend. The peak comes Sunday night – the night of December 13, 2015 – but Friday and Saturday nights are good times to watch, too. Just know that the best viewing hours are typically in the wee hours after midnight, no matter where you are on Earth. In the Northern Hemisphere, this meteor shower often rates as one of the best – if not the best – shower of the year on a dark, moonless night. The shower’s zenithal hourly rate – maximum number of meteors seen – is up to 120/hour now, after some good displays in recent years. The moon turns new on December 11, 2015, guaranteeing dark skies for this year’s Geminid meteor shower.
For the Southern Hemisphere. At temperate latitudes in the Southern Hemisphere, the meteor count will tend to be lower. The Geminids do favor the Northern Hemisphere, where the radiant is higher in the sky. However, this shower is also visible from the tropical and subtropical parts of the Southern Hemisphere. Watch for it this weekend!
If you’re not one to stay up late, watch during the evening hours. Although the meteors are few and far between at early-to-mid evening, you might – if you’re really lucky – catch an earthgrazer – a slow-moving and long-lasting meteor that shoots horizontally across the sky.
At northerly latitudes, the shower radiant point – near the bright star Castor in the constellation Gemini – stays out from early evening until dawn. When the radiant point is near the horizon, the number of meteors that you see are few. The radiant climbs highest up around 2 a.m. and that’s why you see the highest numbers of Geminid meteors around that time.
How many meteors will I see? The Geminids are a consistent and prolific shower. You’ll see the most meteors in a dark sky, unspoiled by light pollution. Meteors often come in spurts and are interspersed by lulls, so give yourself at least an hour of observing time. Simply sprawl out on a reclining lawn chair, look upward and enjoy the show. Often, in the wee hours after midnight, you can see 50 or more meteors per hour.
Why are they called the Geminids? The Geminid meteors are named for the constellation Gemini the Twins, because the radiant point of this shower lies in front Gemini, closely aligning with the bright star Castor. If you trace all the Geminid meteors backward, they all appear to originated from this constellation.
But you don’t need to know the constellation Gemini to see the meteor shower. The Geminid meteors will streak across all parts of the heavens from late night until dawn.
Where do the meteors come from? Although meteors are sometimes called ‘shooting stars,’ they have nothing to do with stars. Instead, they are strictly a solar system phenomenon. Around this time every year, our planet Earth crosses the orbital path of a mysterious object called 3200 Phaethon, which might be an asteroid or a burnt-out comet orbiting our sun. Debris from this object burns up in the Earth’s upper atmosphere to give us the annual Geminid meteor shower. The moderately fast Geminids slice through the Earth’s atmosphere at some 35 kilometers – or 22 miles – per second.
Bottom line: Find a dark sky to watch a seasonal attraction, the Geminid shower. It peaks on the night of December 13, 2015 (morning of December 14), but the nights before and after will be good as well. With no moon to ruin the show, 2015 promises to be a great year for the Geminids. Some are predicting it might be the best shower of the year!
The Words of Confucius
When we see persons of worth, we should think of equaling them; when we see persons of a contrary character, we should turn inwards and examine ourselves.
Your Daily Influences
December 11, 2015
Four of Swords Reversed
Activity begins again. Success will be realized. Move with caution and wisdom as your guides.
Thurisaz reversed often represents your inability to come to terms with repressed issues. It is a warning that if you do not purge past demons they may return to harm you. This Rune is also indicative of a time when you should not act on impulse.
Aries the Ram
This aspect of your life will be strongly influenced by a person who is selfish, quick-tempered, impulsive, impatient, foolhardy and a bit of a daredevil. Be careful this person keeps your best interest at heart and not their own. This person is probably someone you already know. Do not allow yourself to get caught up in their impulsiveness.
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 Daily Charm for Today
There is a good vibration surrounding this aspect. It feels better than it has in quite some time. Maintain your faith in your deity of choice and this good vibration will remain. Waiver from your faith and this good vibration will dissipate.
This Etruscan talisman – a tusk carved in basalt, and elaborately mounted in gold filigree work – was worn as a protector from danger and evil influences. The charm was supposed to attract good fortune and success. The Tusk represented one of the horns of the Crescent Moon, which was a symbol of the Egyptian goddess Isis, who, in the course of time, became the most universal and powerful of all the goddesses. The Estrucans, Greeks and Romans had great faith in the reputed virtues of amulets, a belief which was greatly influenced by the Egyptians.
Your Daily Tile
December 11, 2015
The Unicorn tile indicates a clear vision of the future and the ability to see people for who the really are. In rare cases the Unicorn tile may suggest a person with psychic powers.
Your Animal Spirit for Today
December 11, 2015
Otter represents one of the most playful feminine energies on earth—and she has swum over into your reading to bring a message of joyful play. If life has been difficult or challenges overwhelming, relax a little—Otter is here to remind you that play is just as important as work—and NOT competitive play, but rather the kind you loved as a child. Hopscotch anyone?