Astronomy 101

One of my main goals is to try and share a bit of knowledge and understanding about the incredible universe. I have been steadily writing and posting various articles to explain and educate the masses (that's you, dear reader!) a bit more about some of the science behind the hobby. An urban astronomer might never see most of the things we talk about here, but it's still good to know about them. Below, an index of all the articles so far:

Allen Versfeld's picture

Do all planets spin in the same direction?

This very detailed enhanced-colour image from ESO’s Very Large Telescope shows the dramatic effects of very young stars on the dust and gas from which they were born in the star-forming region NGC 6729.  Credit: ESO/Sergey StepanenkoDear Urban Astronomer

Do all planets spin the same way, or are there some planets where the sun rises in their equivalent of West? Does it depend on the particular solar system? What about the stars in a galaxy -- do they all spin in the same direction? Do all galaxies spin the same way, or do they even spin at all?


Amanda Dominy (extracted from facebook conversation)

Dear Amanda

First, the short answer: All rotations and revolutions in a planetary system are in the same direction, except for when they aren't.  These motions are not necessarily in the same direction between neighbouring stars, even stars born from the same gas cloud.  The stars themselves do move through a galaxy in the same direction in a roughly circular orbit, except for when they don't.

So that's all cleared up then.  But just in case you're still in the dark, here's a more detailed answer: Read more about Do all planets spin in the same direction?

Allen Versfeld's picture

What is a Blood Moon?

Lunar eclipse

A few days ago, I was asked on facebook to explain what a Blood Moon was.  I'd heard the term before, but never as an astronomical term so I went online and googled it.  It seems that they are supposed to be incredibly rare events, but that there will be four of them in 2014.  This is considered to be a hugely significant thing, and is being used to sell a lot of books making various prophecies about world changing events.  As usual, the authors variously reference Nostradamus, the biblical Revelation of St John, obscure writings by ancient civilizations and various aspects of both new age and pagan mysticism.  Which is all very interesting if you take that sort of thing seriously, but doesn't answer the question:  What is a Blood Moon? Read more about What is a Blood Moon?

Allen Versfeld's picture

How long is a year on Jupiter?


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