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.
2016 March 18
Explanation: A familiar, zigzag, W pattern in northern constellation Cassiopeia is traced by five bright stars in this colorful and broad mosaic. Stretching about 15 degrees across rich starfields, the celestial scene includes dark clouds, bright nebulae, and star clusters along the Milky Way. In yellow-orange hues Cassiopeia’s alpha star Shedar is a standout though. The yellowish giant star is cooler than the Sun, over 40 times the solar diameter, and so luminous it shines brightly in Earth’s night from 230 light-years away. A massive, rapidly rotating star at the center of the W, bright Gamma Cas is about 550 light-years distant. Bluish Gamma Cas is much hotter than the Sun. Its intense, invisible ultraviolet radiation ionizes hydrogen atoms in nearby interstellar clouds to produce visible red H-alpha emission as the atoms recombine with electrons. Of course, night skygazers in the Alpha Centauri star system would also see the recognizable outline traced by Cassiopeia’s bright stars. But from their perspective a mere 4.3 light-years away they would see our Sun as a sixth bright star in Cassiopeia, extending the zigzag pattern just beyond the left edge of this frame.
Small asteroid detected 4 days after passing as close as satellites
On March 15, astronomers detected an asteroid that had passed closest to Earth on March 11, sweeping in at about the distance of our geostationary satellites.
On March 15, 2016, astronomers detected a space rock – now designated as asteroid 2016 EF195 – using the PanSTARRS 1 telescope at Hawaii. Surprisingly, as they analyzed its trajectory, they realized it had been closest to Earth on March 11 at 03:52 UT (March 10 at 10:52 pm ET). This means the asteroid’s closest approach occurred 4 to 5 days before it was seen. Moreover, they realized that asteroid 2016 EF195 flyby had passed at about 23,900 miles (38,463 km) from the surface of our planet, or about 0.1 the Earth-moon distance.
For comparison, TV and other communications satellites orbit Earth at 22,300 miles.
Asteroid 2016 EF195 has a size between 16 to 49 meters (52 to 161). That means this space rock has an average size about twice as big as the asteroid that penetrated the skies over Chelyabinsk, Russia in February, 2013, breaking windows in six Russian cities and causing some 1,500 people to seek treatment for injuries, mostly from flying glass.
The stealth space rock is travelling at 22,369 miles per hour (36,000 km/h).
The newly found asteroid also belongs to the Apollo type asteroids, a class of space rocks that sometimes pass close to Earth.
There have also been some small asteroids passing closer to Earth than the moon’s distance during this past month.
On March 10, 2016, small asteroid 2016 EN157 passed at 0.82 lunar distances. While on March 8, small asteroid 2016 EV28, with a size between 3 to 12 meters passed at 0.41 lunar distances.
It must be clarified that asteroids like 2016 EF195 are too small to cause an extinction level event, so we were never at any significant risk from this particular asteroid.
Bigger asteroids are easier to detect. However, even a small asteroid would produce an impressive meteor if it enters our atmosphere.
Can a Chelyabinsk type event repeat? Yes, clearly it can.
In any event, asteroid asteroid 2016 EF195 – passing so closely, unseen – is a reminder of the importance of supporting asteroid detection programs.
Various space agencies are already working towards earlier asteroid detections, but adequate funding is always required.
Bottom line: On March 15, astronomers detected an asteroid – now labeled 2016 EF195 – that had passed closest to Earth on March 11. It passed at about 23,900 miles (38,463 km) from the surface of our planet, or about 0.1 the Earth-moon distance. That’s about the distance of some satellites.
Eddie Irizarry of the Sociedad de Astronomía del Caribe (Astronomical Society of the Caribbean) has been a NASA Solar System Ambassador since 2004. He loves public outreach and has published multiple astronomy articles for EarthSky, as well as for newspapers in Puerto Rico. He has also offered dozens of conferences related to asteroids and comets at the Arecibo Observatory.
Article published on EarthSky
Moon and Cancer on March 18
Tonight – March 18, 2016 – the bright waxing gibbous moon shines in front of Cancer the Crab, the faintest constellation of the Zodiac. Although the moon pinpoints Cancer’s place in the sky on this night, the moonlit glare will make Cancer virtually impossible to see.
However, you shouldn’t have much trouble spotting the planet Jupiter as darkness falls. This dazzling world lights up the eastern sky at nightfall and early evening. Look closely and you might even see Regulus, the brightest star in the constellation Leo, between the moon and Jupiter.
As the Earth spins beneath the heavens throughout the night, going from west to east, the moon, Regulus and Jupiter will appear to move westward across the sky. The moon and Cancer will set in the west in the wee hours before sunrise March 19.
Once the moon leaves the evening sky in late March, use the planet Jupiter and the star Regulus to star-hop to the constellation Cancer, as displayed on the sky chart above.
Bottom line: The bright waxing gibbous moon shines in front of Cancer the Crab, the faintest constellation of the Zodiac, on March 18, 2016.
Bruce McClure is the chief writer for the popular EarthSky Tonight pages. Since joining EarthSky in 2004, he has written thousands of astronomy articles, enjoyed here by millions. He also writes, gives planetarium shows and hosts a wide assortment of public astronomy programs in and around his home in upstate New York. If you ask an astronomy question on our site, it’s likely to be Bruce that answers it. His love for the heavens has taken him to Lake Titicaca in Bolivia, and he has sailed the North Atlantic, earning his celestial navigation certificate through the School of Ocean Sailing and Navigation. Bruce is also a sundial aficionado. He says his number one passion – besides his wife Alice – is stargazing.
Article published on EarthSky
The Wisdom of Buddha
To be idle is a short road to death and to be diligent is a way of life; foolish people are idle, wise people are diligent.
Your Daily Influences
March 18, 2016
Nine of Pentacles
Material wealth enjoyed alone. Knowledge of the workings of those things in your best interest. Love of home and garden.
This may be a period of loneliness and stagnation you must fight through. This may not be a good time for you to take chances or indulge in any form of gambling.
You are distracted from this aspect by other areas of your life you feel are more pressing. This aspect is suffering from this lack of attention. You must ask yourself how much more you can let it suffer before you give it due attention.
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 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 Etruscans, Greeks and romans had great faith in the reputed virtues of amulets, a belief which was greatly influenced by the Egyptians.
The Four Courses
The Four Courses reading presents possible paths for the querent to take to reach a more complete state of being. While all paths may offer a degree of fulfillment, usually one will be more fruitful than the others. The trick of course, is to pick the one that will bring most beneficial results.
Your Current State
Your spiritual and physical self may be out-of-balance at this time. While the journey may be arduous at times, the opportunity for you to bring these two important aspects of your being into a harmonious state is before you.
Your are in a place where can discover new aspects about you and the world you live in. Open up your spirit to new ways of seeing things and act based upon the new knowledge you will soon gain.
New friendships and opportunities will soon be yours. It is possible you will meet a new love, or the love you already have will deepen. However you must be open to change and have the courage to act.
Remember that you will reap what you sow. Do not allow yourself to become greedy or totally absorbed in yourself. To do so will leave you isolated and unhappy.
That which has confused you will soon become clear. Your ability to think lucidly is at or near its zenith. Solutions to lingering problems will soon be obvious to you.
Your Daily Domino
March 18, 2016
Now is the time for you to pursue new ventures. If you share your goals and ambitions with a partner, your partnership is extremely potent at the moment. Regardless of how wild some opportunities may seem, at least explore there potential before passing on them.