Where would we be without axial tilt?

The world would be a more boring place: we’d have no seasons, no spring and summer, no dead of winter, no dog days of summer, and no Yule celebrations.

New views of Saturn!

Phil Plait has pictures and explanations of a large-scale image of Saturn taken by Cassini, along with a link to the full-size version: Saturn: incredible mosaic of the ringed wonder.

Saturn occluding the Sun

Meteorite strikes southeast Russia

Phil Plait of Bad Astronomy has a roundup of links for the meteor strike this morning just east of the Ural Mountains: Huge Meteor Blazes Across the Sky: Windows Shatter.

Neil DeGrasse Tyson puts Bill O’Reilly in his place

This is the source of a beautiful quote that I’ve seen going around the Web. Astrophysicist Neil DeGrasse Tyson explains what should be obvious, that science explains a lot of things that we thought were divine and we do know what causes tides.

NASA’s Grail gravity twins enter moon orbits

Two satellites are going to map the mass profile of the moon.

The first satellite, Grail-A, achieved orbit on Saturday, December 31: “Together, the satellites will make measurements that are expected to give scientists remarkable new insights into the internal structure of the Moon. This new data should clarify ideas about the Moon’s formation and resolve many mysteries, such as why its near and far sides look so different.”

NASA's Grail satellites circling Luna

The second satellite, Grail-B, entered orbit on Sunday, January 1.The two satellites will note tiny differences between the distance between them, caused by variation in gravity as they pass over the surface of the moon. This will enable scientists to calculate variations in the density of the moon’s crust.  This is the first time two satellites have been placed around Luna.

Correlating their distances

You can read more at NASA.

Stone Age astronomy in Ireland

The Imax documentary “Solar Max” calls it “the oldest room in the world, older than the pyramids.” An ancient room in County Sligo, Ireland, in a mound called Newgrange, is lit up by the rising sun of winter solstice. This ancient alignment was noticed only in 1967.

Since this very special alignment shines the sun’s rays across a bowl, I wonder if anyone has filled the bowl with water at winter solstice to observe the effects.

New image of a distant globular cluster

Globular cluster NGC 7006

Phil Plait has the goods on one of the most distant globular clusters in our galaxy. It’s so far away that it might be a scrap of another galaxy, left over from a pass by another galaxy. Scientist have been tracking it for forty years and now have an idea of its orbit around galactic centre. It is 135,000 light years away and will almost triple that at the farthest curve of its long orbit. It is receding at 380 km/s or 250 mi./s—that’s fast. Read about it, and find much bigger images, in “Lonely sentinel of the galaxy“

The darkest planet

Astronomers using the Kepler telescope have detected the darkest known planet. It has a faint, reddish glow. Its surface temperature is about 1800 degrees C., which makes it too hot to form methane clouds that would reflect more light. Its chemistry is partially known. It is

…a Jupiter-sized exoplanet some 750 light-years away that is so black that it reflects just one percent of the light that reaches it. TrES-2b is so black that it’s darker than coal, or any other planet or moon that we’ve yet discovered. It’s less reflective than black acrylic paint….. TrES-2b’s atmosphere is made up of things like vaporized sodium, potassium, and titanium oxide–things that actually compound the problem by absorbing heat. But even these don’t fully explain the planet’s extreme blackness, which is still puzzling astronomers. There’s some kind of strange chemistry going on out there that even Kepler can’t see.