The March Night Sky

Welcome to the March night sky. This is the month of the spring equinox when the sun passes the celestial equator travelling northwards. It marks the end of winter in the northern hemisphere and the beginning of spring.

This year it happens on the 20th and, on that day, the whole world has 12 hours daylight and 12 hours night. On the 27th we have the start of daylight saving time when the clocks go forward an hour over most of Europe.

On the 8th of this month we have the opposition of the gas giant planet Jupiter. This means that it will be at its brightest and at its closest to us. The term opposition simply means that a particular celestial object is opposite to the Sun and therefore will rise in the east at sunset, be due south at local midnight and will set in the west at sunrise.

Jupiter is at the moment in the constellation of Leo and, as its orbit around the sun is almost 12 years, it spends approximately one year in each of the Zodiac’s 12 constellations.

This planet in ancient times was always seen in a positive way as it was steady and reliable as it could be observed in the heavens for at least nine months of the year, unlike Mercury, Venus and Mars that have rather variable and somewhat irregular periods of visibility.

Also, Jupiter has a pleasant golden yellow colour and is always bright unlike Saturn that is considerably dimmer and variable in brightness due to its ever-changing ring angle relative to us. The name Jupiter is from the Roman God of the same name and was considered to be the Father of the Gods, much as Zeus was seen to be by the ancient Greeks.

On July 4 this year, a NASA probe called Juno (the mythological wife of Jupiter) will arrive at the planet and will go into a very eccentric polar orbit around the gas giant. This will keep the probe out of the powerful radiation belts that surround it.

These danger zones around Jupiter are caused by the strong magnetic field of the planet accelerating sub atomic particles and creating other potentially harmful effects that have to be understood if humans are to explore the Solar system in the hopefully near future.

There are no outstanding meteor showers in March but, oddly, around the middle of the month, there seems to be a higher-than-normal number of bright fireballs to be seen in the night sky, and why that is so nobody is quite sure, but possibly it may be down to the breakup of small comet or asteroid that crossed the orbit of the Earth many years ago and luckily did not collide with us, and we are now encountering the leftover fragments.

If that is the case, we really dodged the bullet in a manner of speaking as any impact of an object of more than 100 metres in diameter (as this hypothetical object must have been) is capable of destroying an entire city or worse.
The Moon is full on the 23rd, last quarter on the 31st, new on the 9th and first quarter on March 15.

By Clive Jackson
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Clive Jackson is the Director of the Camera Obscura (next to the Castle in Tavira), specialising in education and public outreach.
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