Moons of Mars - Deimos
By the late 19th century we knew Jupiter, Saturn, Uranus and Neptune had moons. But it seemed that there were no Martian moons. Then in 1877 American astronomer Asaph Hall surprised the world with two Martian moons. Why did it take so long to find them? And why did Hall call them Fear and Terror?
Tarantula Nebula – Facts for Kids
Arachnophobes needn't worry about this tarantula. It's not a big spider, it's a big nebula that looks a bit like a spider in some photos. It's also so far away that its light takes 170,000 years to get here. Stars are born there, stars die there, and it's a spectacular object.
Spring Triangle – a Seasonal Asterism
There are 88 official constellations covering the sky with no gaps or overlaps. There are also lots of asterisms, recognizable patterns of stars that aren't constellations. They have no official standing, but they have the advantage over many constellations of resembling what they represent.
ABC of Astronomy – B Is for Bok Globule
B is for Bok globule, a kind of dark nebula studied by Bart Bok. B is for Bayer who invented a handy system of star designations beginning with a Greek letter. And B is for Baily's beads. You won't find them in a jewelry shop, but you might see them in a solar eclipse, as Francis Baily did.
Oort Cloud - Facts for Kids
Where do comets come from? The Oort Cloud is home to a trillion comets at the edge of the Solar System, nearly half way to the next star. Sometimes they get kicked out and sometimes they come to visit the inner Solar System.
Transit of Venus - Measuring the Solar System
On June 8, 2004 millions of people witnessed an event that no one still alive had ever seen: a transit of Venus. Another occurred in June 2012, but it was the last for over a hundred years. What is a transit of Venus? How did it help to work out out the size of the Solar System?
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