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"I want to know why the universe exist, why there is something greater than nothing."

Steven Hawking

Scientist, Space Lover

Shadow Rise on the Inside Passage

At sunset look east not west. As Earth's dark shadow rises from the eastern horizon, faint and subtle colors will appear opposite the setting Sun. This beautiful evening sea and skyscape records the reflective scene from a cruise on the well-traveled Alaskan Inside Passage in the Pacific Northwest. Along the horizon the fading sunset gives way to the pinkish anti-twilight arch, more poetically known as the Belt of Venus. Often overlooked at sunset in favor of the brighter western horizon, the lovely arch is tinted by filtered sunlight backscattered in the dense atmosphere, hugging the planet's rising blue-grey shadow.

Analemma over the Callanish Stones

If you went outside at the same time every day and took a picture that included the Sun, how would the Sun's position change? A more visual answer to that question is an analemma, a composite image taken from the same spot at the same time over the course of a year. The featured analemma was composed from images taken every few days at noon near the village of Callanish in the Outer Hebrides in Scotland, UK. In the foreground are the Callanish Stones, a stone circle built around 2700 BC during humanity's Bronze Age. It is not known if the placement of the Callanish Stones has or had astronomical significance. The ultimate causes for the figure-8 shape of this and all analemmas are the tilt of the Earth axis and the ellipticity of the Earth's orbit around the Sun. At the solstices, the Sun will appear at the top or bottom of an analemma. The featured image was taken near the December solstice and so the Sun appears near the bottom. Equinoxes, however, correspond to analemma middle points -- not the intersection point. This coming Friday at 1:04 am (UT) -- Thursday in the Americas -- is the equinox ("equal night"), when day and night are equal over all of planet Earth. Many cultures celebrate a change of season at an equinox. Explore Your Universe: Random APOD Generator

Perseid Meteors from Durdle Door

What are those curved arcs in the sky? Meteors -- specifically, meteors from this year's Perseid meteor shower. Over the past few weeks, after the sky darkened, many images of Perseid meteors were captured separately and merged into a single frame, taken earlier. Although the meteors all traveled on straight paths, these paths appear slightly curved by the wide-angle lens of the capturing camera. The meteor streaks can all be traced back to a single point on the sky called the radiant, here just off the top of the frame in the constellation of Perseus. The same camera took a deep image of the background sky that brought up the central band of our Milky Way galaxy running nearly vertically through the featured image's center. The limestone arch in the foreground in Dorset, England is known as Durdle Door, a name thought to survive from a thousand years ago.



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