Category Archives: Astronomy

All about astronomy: What it is, how the Solar System works, famous astronomers and more

Lyrids

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The Lyrid meteor shower is one of the better known highlights of the meteor-watching calendar.  It usually peaks around three weeks into April, and while it doesn’t produce many meteors (5-10 per hour, although some years have unexpectedly surged to more than 100 per hour), they’re reasonably bright and hard to miss, with the occasional fireballs that cast shadows for a few fractions of a second.   As the name suggests, Lyrids have their radiant in the northern constellation Lyra … Continue reading →

What is an equinox?

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An equinox is a point in the Earth’s orbit when day and night are both exactly the same length.  There are two equinoxes (or equinoctes if you want to be excessively correct) each year, but they also mark the change of the seasons between warm and cold.  The Earth’s axis is tilted, so that for half of each year, one hemisphere is tilted towards the Sun, so that it gets more heat and light from the Sun that the other. … Continue reading →

What does Jupiter weigh?

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Jupiter has a mass of about 1.9 x 1027kg – 1900 trillion Trillion kilogrammes.  That’s more than double all the other planets, asteroids, comets and dust of the entire Solar System put together.  Jupiter is BIG, yet still manages to not weigh anything at all.  How?  Because it is in orbit around the Sun, just like an astronaut orbits the Earth, and so experiences zero gravity.  That’s not to say there is no gravity around Jupiter – it has plenty gravity … Continue reading →

Solar Flares

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As anybody with an internet connection has heard, on 21 December 2012 various events will coincide:  The appearance of the dread planet Nibiru, the alignment of the Solar System with the galactic core, the end date of the Mayan Long Count, which will cause (via various pseudo-scientific mechanisms) the Sun to go crazy, belching out Solar Flares which will strip the earth of its protective atmospheric layers and snuff out life on earth.  Gosh! Before we go on, I need … Continue reading →

What does Mars weigh?

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Mars does not have a weight, but does have a mass of about 6.4 x 1023 kilograms, which is a little more than a tenth that of Earth.  When astronauts or spacecraft orbit the Earth, we describe them as being weightless, because they are in freefall.  They are not resisting gravity (the way your body does when you stand on the ground) so “Weight” becomes a totally meaningless concept when you’re in space.    Written by Allen Versfeld Comments?  Questions? … Continue reading →