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Ancient volcanism aligned with dinosaur extinction, says study

A new geological timeline from Princeton University researchers shows that a series of massive eruptions 66 million years ago in a primeval volcanic range in western India known as the Deccan Traps played a role in the extinction event that claimed Earth's non-avian dinosaurs, and challenges the dominant theory that a meteorite impact was the sole cause of the extinction. Pictured above are the Deccan Traps near Mahabaleshwar, India. Image courtesy of Gerta Keller, Department of Geosciences

The primeval volcanic range known as the Deccan Traps near Mahabaleshwar, India. Image courtesy of Gerta Keller, Princeton Department of Geosciences

Massive eruptions 66 million years ago in India played a role in dinosaur extinction, say researchers, a challenge to the theory that a meteorite impact was the sole cause.

Star of the week: Mirfak is Perseus’ brightest star

Brightest-Star-algol

Mirfak (Alpha Persei) ranks as the brightest star in the constellation Perseus, which represents a Hero in ancient skylore, but whose shape might remind you of someone dancing. Dancing Perseus also contains the sky’s most celebrated eclipsing binary star, Algol, sometimes called the Demon Star. Algol wins notoriety for its wild swings in brightness, which recur with clock-like precision. However, Mirfak is the easier of the two stars to find, and can serve as your guide star to Algol. Follow the links below to learn more about Mirfak, Perseus’ brightest star.

Lifeform of the week: Mistletoe

Image Credit: Nova

Image Credit: Nova

The quaint holiday decoration you invited into your home and hung over your doorways is a vicious parasite that leeches nutrients from innocent host trees. It is riddled with cytotoxins and is pollinated via bird crap. Merry Christmas.

Was the Christmas Star real?

What was the Christmas Star? Scientist Bradley Schaefer has some new things to say on this week’s EarthSky 22. Photo by Russell Croman

The Star of Bethlehem, or Christmas Star, is mentioned in the Bible. It’s said to have led the three wise men to Bethlehem. But was the Christmas Star a real object in the sky? Or was it just a symbol?

See it! Comet Lovejoy now low in northern skies

View larger. | Comet Lovejoy on December 20, 2014 by Denis Crute in Parkes, NSW, Australia.

Comet Lovejoy on December 20 by Denis Crute in Parkes, NSW, Australia. This comet is low in Northern Hemisphere skies now and will be well placed for viewing by January, 2015. Thank you, Denis!

Skywatchers with binoculars and telescopes in the Southern Hemisphere have been watching Comet C/2014 Q2 Lovejoy – or Comet Q2 as many are calling it. It’s brightening, and people at southerly Northern Hemisphere locations are capturing cool shots of the comet already! In January, 2015, it’ll be high in Northern Hemisphere skies.

Young moon and Venus near horizon after sunset December 22

If you miss the extremely thin and tenuous moon after sunset on December 22, keep in mind that a more substantial lunar crescent will light up the early evening sky after sunset on December 23 and 24. The green line depicts the ecliptic - Earth's orbital plane projected onto the dome of sky.

Look for the extremely thin crescent moon and Venus shortly after sunset on December 22. A more substantial lunar crescent will light up the early evening sky after sunset on December 23 and 24. Watch for the moon near Mars! The green line depicts the ecliptic, or sun’s path across our sky.

Tonight – as soon as the sky begins to darken after sunset – look west for a very slim crescent moon and the brightest planet Venus. Although the moon and the planet Venus rank as the brightest and second-brightest orbs of nighttime, respectively, it’ll take a big effort to spot these two brilliant beauties after sunset on December 22, 2014. You’ll need an unobstructed horizon in the sunset direction. Binoculars will be helpful!

Happy December solstice, everyone

View larger. | This is a a solargraph, created by a simple pinhole camera (made of a beer can!) between June 21 and December 20, 2012. The camera was fixed to a single spot for the entire exposure time, and it continuously recorded the sun’s path as a glowing trail burned into the photosensitive paper inside of it. The breaks and gaps between the lines are caused by clouds. Created by Attila Kalman in Littlehampton, UK.

On the December solstice solstice, we celebrate the (unofficial) first day of winter in the Northern Hemisphere and first day of summer in the Southern Hemisphere. Unofficial? Yes. Winter and summer start at the solstices by tradition, not official decree. Yet these solstices bring very real occurrences to our sky, which you can witness for yourself.

Watching solstices and equinoxes from space

How sunlight falls on Earth’s surface during the solstices and equinoxes, as seen from geosynchronous orbit.

Venus over Saronikos Gulf, Greece

Venus over the Saronikos Gulf, Greece, by Nikolaos Pantazis.  Thank you, Nikolaos!

Venus over the Saronikos Gulf, Greece, by Nikolaos Pantazis. Photo taken December 18, 2014. Thank you, Nikolaos!

The waxing crescent moon will be moving up past Venus in the first few days of this new week. Watch for them exceedingly low in the west after sunset.

Where does noon come only once a year, on the December solstice?

sunrise_pho_2008265

Yes, at the Earth’s South Pole, high noon comes only once a year, on the December summer solstice. Yet, it’s midnight at the other end of the world – at the Earth’s North Pole – where midnight only comes once a year, on the December winter solstice.