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Predicting Eclipses: How Does the Saros Cycle Work?

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A sequence of images from the April 15th 2014 ‘Tax Day’ total lunar eclipse. Image credit and copyright: Kenneth Brandon

Boy, how about that total solar eclipse last Friday? And there’s more in store, as most of North America will be treated to yet another total lunar eclipse on the morning of April 4th. This eclipse is member three of four of a quartet of lunar eclipses, known as a tetrad. [click to continue…]

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Asteroid 2014 YB35 will safely pass Earth at 4.5 million km on Friday, March 27. (Composite image by J. Major showing asteroid Lutetia imaged by ESA's Rosetta, Earth and Moon imaged by NASA's Galileo, and the Milky Way imaged by ESO and Serge Brunier.)

Asteroid 2014 YB35 will safely pass Earth at 4.5 million km on the morning of Friday, March 27. (Composite image by J. Major showing asteroid Lutetia imaged by ESA’s Rosetta, Earth and Moon imaged by NASA’s Galileo, and the Milky Way imaged by ESO and Serge Brunier.)

There are ways to report on occasional close approaches by near-Earth objects (NEOs) that convey the respectful awareness of their presences and the fact that our planet shares its neighborhood with many other objects, large and small… and that sometimes their paths around the Sun bring them unnervingly close to our own.

Then there’s just straight-up over-sensationalism intended to drum up page views by scaring the heck out of people, regardless of facts.

Apparently this is what’s happened regarding the upcoming close approach by NEO 2014 YB35. An asteroid of considerable (but definitely not unprecedented) size – estimated 440-990 meters in diameter, or around a third of a mile across – YB35 will pass by Earth on Friday, March 27, coming as close as 11.7 times the distance between Earth and the Moon at 06:20 UTC.

11.7 lunar distances. That’s 4.5 million kilometers, or almost 2.8 million miles. Cosmically close, sure, but far from “skimming”…and certainly with no danger of an impact or any of the nasty effects that would be a result thereof. None. Zero. Zilch. NASA isn’t concerned, and you shouldn’t be either.

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Is the Universe Finite or Infinite?


Two possiblities exist: either the Universe is finite and has a size, or it’s infinite and goes on forever. Both possibilities have mind-bending implications.
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Using 19th Century Technology to Time Travel to the Stars

This image of a spiral galaxy, taken on a glass photographic plate, is one in a series of photos taken over decades. From the Harvard Plate collection.  Image courtesy American Museum of Natural History.

This image of a spiral galaxy, taken on a glass photographic plate, is one in a series of photos taken over decades. From the Harvard Plate collection. Image courtesy American Museum of Natural History.

In the late 19th century, astronomers developed the technique of capturing telescopic images of stars and galaxies on glass photographic plates. This allowed them to study the night sky in detail. Over 500,000 glass plate images taken from 1885 to 1992 are part of the Plate Stacks Collection of the Harvard-Smithsonian Center for Astrophysics (CfA), and is is the largest of its kind in the world.

“The images captured on these plates remain incredibly valuable to science, representing a century of data on stars and galaxies that can never be replaced,” writes astronomer Michael Shara, who is Curator in the Department of Astrophysics at the American Museum of Natural History in New York City, who discussed the plates and their significance in a new episode of AMNH’s video series, “Shelf Life.”

These plates provide a chance to travel back in time, to see how stars and galaxies appeared over the past 130 years, allowing astronomers to do what’s called “time domain astronomy”: studying the changes and variability of objects over time. These include stars, galaxies, and jets from stars or galactic nuclei.
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Help ULA name America’s next rocket to space. Credit: ULA

Help ULA name America’s next rocket to space. Credit: ULA
Voting Details below
Watch ULA’s March 25 Delta Launch Live – details below
Update 3/26: 2 new names have been added to the voting list – Zeus and Vulcan !

United Launch Alliance (ULA) is asking the public for your help in naming their new American made rocket, now under development that “represents the future of space”- and will replace the firms current historic lines of Atlas and Delta rocket families that began launching back near the dawn of the space age.

Eagle, Freedom or GalaxyOne – those are the names to choose from for the next two weeks, from now until April 6.

UPDATE 3/26: 2 new names have been added to the voting list – Zeus and Vulcan !
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Turning Stars Into Art

Short time exposure of the star Sirius with the camera attached to a small telescope. I tapped the tube to make the star bounce around, recording the star's rapid color changes as it twinkled. All photos by the author

Color Crazy. Short time exposure of the star Sirius photographed through a small telescope. I tapped the tube to make the star bounce around, recording the star’s continuous and rapid color changes as it twinkled.  Refraction of the star’s light by our turbulent atmosphere breaks it up into every color of the spectrum. Credit: Bob King

We all have cameras, and the sky’s an easy target, so why not have a little fun? Ever since I got my first camera at age 12 I wanted to shoot time exposures of the night sky. That and a tripod are all you need. Presented here for your enjoyment are a few oddball and yet oddly informative images of stars and planets.  Take the word “art” loosely!  [click to continue…]

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The solar eclipse on Friday, March 20, 2015, photographed at 14,000 meters. Credit and copyright: Guillaume Cannat.

The solar eclipse on Friday, March 20, 2015, photographed at 14,000 meters. Credit and copyright: Guillaume Cannat.

What does a solar eclipse look like from a fast-flying Falcon 7X jet at 14,000 meters (48,000 feet)? French journalist Guillaume Cannat described the Sun as looking black and “ruffled.”

Cannat was part of a group accompanying professional and amateur astronomers on board three Dassault Falcon 7X executive jets that flew in the narrow zone where totality of the eclipse could be observed, from southern Greenland to the geographic North Pole. Traveling through the stratosphere provided the unique opportunity to watch the total eclipse without atmospheric turbulence — which improved the view and the ride. And flying at speeds near Mach .9 also “lengthened” the view of the eclipse to over a minute.

Cannat described the view of totality:
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As It Turns Out, We Really Are All Starstuff

Hubble image of the Crab Nebula supernova remnant captured with the Wide Field and Planetary Camera 2. Credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)

Hubble image of the Crab Nebula supernova remnant captured with the Wide Field and Planetary Camera 2. Credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)

“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars,” Carl Sagan famously said in his 1980 series Cosmos. “We are made of starstuff.”

And even today, observations with NASA’s airborne SOFIA observatory are supporting this statement. Measurements taken of the dusty leftovers from an ancient supernova located near the center our galaxy – aka SNR Sagittarius A East – show enough “starstuff” to build our entire planet many thousands of times over.

“Our observations reveal a particular cloud produced by a supernova explosion 10,000 years ago contains enough dust to make 7,000 Earths,” said research leader Ryan Lau of Cornell University in Ithaca, New York – the same school, by the way, where Carl Sagan taught astronomy and space science.

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At the turn of the 20th Century, Einstein’s theory of relativity stunned the physics world, but the experimental evidence needed to be found. And so, in 1919, another respected astronomer, Arthur Eddington, observed the deflection of stars by the gravity of the Sun during a solar eclipse. Here’s the story of that famous experiment.
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You’ve had a busy day wandering around a faraway part of our solar system. It’s time to put your head down for a nap. Where do you place it? According to Erik Seedhouse in his book “Bigelow Aerospace: Colonizing Space One Module at a Time“, you easily slip into a space module, doff your all-purpose space suit and enjoy the pleasures of a safe secure environment. Know of a better way to get over that stressful day?
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