Category Archives: The Solar System

According to official IAU figures, our Solar System contains one star, eight planets, over a hundred moons, a number of dwarf planets, countless asteroids and comets, and several tens of unmanned spacecraft.  If you want to know more about planets or other members of the Solar System, browse the articles listed below!

Podcast #5: Mercury

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Welcome to the 5th episode of the Urban Astronomer Podcast! We’re well on our way in the grand experiment of deciding how exactly to format the show, and today we’re trying yet another combination! We’ll start off by answering the question first asked in a classic Urban Astronomer article, one originally written back in 2010 and that’s been consistently popular with our readers:  Will an astronaut explode if they take off their helmet? Our feature item introduces my new co-host, and … Continue reading →

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Enceladus’s geysers caused by Saturn’s gravity

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In 2005, the Cassini spacecraft, which has been exploring the system of Saturn and its satellites since 2004, discovered enormous plumes of water spewing out into space from the satellite Enceladus.  These geysers are so powerful and pump out such enormous volumes of water that they are clearly visible from space.  But until recently, it wasn’t clear where all the water was coming from, or what force was propelling it upwards so violently.The water is expelled from a geographical feature … Continue reading →

The Sun

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Many, if not most, ancient and primitive societies worshipped the Sun as a god.  Sun worship continues to this day in various guises around the world.  This makes a lot of sense, because the Sun has a lot of the features in common with our various cultures’ gods. We are totally dependent on the Sun It is universally known, across all cultures from the most primitive to the most enlightened and sophisticated, that the Sun is the source of all … Continue reading →

Mercury

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Mercury is one of The five classical planets and an easy naked eye object.  The planets stood out from the other stars to our ancestors because of the way they all moved in regular patterns against the night sky, but Mercury was unique in its rapid motion and the way it never strayed far from the sun.  If the planets were to be named for gods, then it was only natural that the flighty mercurial one should be their messenger. … Continue reading →

The Five Planets

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  The ancients had beautifully dark skies, dusted with thousands of stars of varying brightness. At some point, they noticed that five of these stars were quite different from the rest.  Not only were they conspicuously bright, but they also moved against the background of the sky, while all the rest were fixed in place.  These movements weren’t all at the same speed, and varied over time, so these special stars became known as “Planets“, from the greek word for … Continue reading →