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At a very steady rate, unstable carbon-14 gradually decays to carbon-12. The ratio of these carbon isotopes reveals the ages of some of Earth’s oldest inhabitants.
Some extremely large and hot stars blaze away with the luminosity of a million suns! But other stars look bright only because they’re near Earth.
During a penumbral eclipse, observant people in the right spot on Earth will look up and notice a dark shading on the moon’s face. Others look and notice nothing at all.
Nowadays, 4 totally eclipsed moons in a row are called Blood Moons. Why? We don’t know for sure, but the answer may lie in a 2013 book by 2 Christian pastors.
This year, in 2017, there are 12 full moons and 12 new moons, but only four eclipses – two lunar and two solar.
From Earth’s North and South Poles, all the stars appear as circumpolar. Meanwhile, at the equator, no star is circumpolar. And what about in between?
How big can stars get? And how do these monster stars get so big?
Uranus lies nearly sideways with respect to the plane of its orbit around the sun. That sideways tilt makes a huge difference between winter-summer on Uranus, and autumn-spring.
No matter where you are on Earth on December, January and February evenings, you’re looking toward bright stars in our local spiral arm.
By at least 1 definition, the year 2017 has 4 supermoons. Three are new moons and not visible in our sky. The only full moon supermoon of 2017 will come in December.
Happy birthday January babies! Your birthstone is the garnet.
Lucky New Year’s foods in the U.S. South and around the world. Happy 2017!
Before the dinosaurs, giant insects ruled the world more than 300 million years ago.
Year’s shortest day comes at winter solstice. But, for Northern Hemisphere, earliest sunsets happen around early December. Southern Hemisphere? Your earliest sunrises are around now.
One journey of our sun and planets around the center of our Milky Way galaxy is sometimes called a cosmic year. That’s approximately 225-250 million Earth-years.
A large ring or circle of light around the sun or moon is called a 22-degree halo by scientists.
The Brocken Spectre is your own shadow, cast on mists below you, when you are mountain climbing. The shadow may appear enormous and has a ring around it.
You can see it any clear evening …
Earth’s north star – Polaris – is located nearly directly above Earth’s north pole. There’s a star above Mars’ north pole, too, but it’s very faint.
Iridescent clouds – clouds with rainbow colors – happen when especially tiny water droplets or small ice crystals individually scatter light.
Arc to Arcturus, the springtime star
Cherry blossoms opening in Japan