Night Skies of May 2011
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The whole world is abuzz at the unique gathering of planets occurring in the early morning night skies. May 11th witnessed the closest coming together of Jupiter, Venus, Mercury, and Mars; with the Moon joining them during its passage across the skies. This is the best time to see planets in their true colours showing off their name – planets, which means “wanderers”. Our ancestors had already seen the true nature of planets by following the changes in their positions across the fixed background of stars.
However, that is a difficult job for casual observers. For us, the ongoing spectacle in our morning skies provides a clear view of the movement of planets by watching their day-by-day shifts in the eastern skies just before dawn.
By 30th May, the Moon will have joined the gathering to show the four planets lined up like a string of pearls with bright Jupiter highest, followed by red Mars, below which will be the brightest Venus as a morning star and a faint Mercury at the lower end that will be rather difficult to see in the brightness of the rising sun. A thin crescent Moon will be slightly off the line of planets that day, and will be positioned between Jupiter and Mars. The previous day, 29th May, the Moon will be seen above Jupiter. Comparing the positions of the Moon in the sky on the two days, 29th and 30th May, you will be able to see how much the Moon moves across the sky every day, which is about 12 degrees per day which adds up to 360 degrees over the 30 day lunar month.
Such a string of planets also shows that they are all positioned in a flat plane in space moving around the Sun in circles that are all lie in one flat plane. When viewed from Earth, all planets, and the Moon and the Sun, can only be seen within a narrow path running from east to west in the sky. When these heavenly objects are close enough along our line of sight, they are seen to all lie in a line. If we look through a telescope, we would even see Uranus a little above Jupiter along the planetary line.
Further down the road, get prepared for an uncomfortably close flyby in November of an asteroid called 2005 YU55. It has a diameter of 400 metres and will approach us within nearly three quarters (0.85) of the distance to the Moon. This event is unique because object is very big and is coming uncomfortably close to us, making it a “potentially hazardous asteroid”, according to the Minor Planet Centre in the USA.
The object will not be visible to the naked eye but we can prepare to observe it through a telescope as it zips across our skies, hoping that its path is not bent towards us by the Earth’s gravitational pull. Scientists have calculated that the pull is not sufficient to bend the asteroid’s path enough for it to strike the Earth. Such asteroid strikes have occurred in the past. For example, an asteroid the size of a mountain struck Earth around 65 million years ago and caused devastation that led to the extinction of dinosaurs.
In the night skies this month during early evening, we continue to see Saturn occupy the skies. Though not very bright, it is easy to make out as a steadily shining star that does not twinkle like other stars. Take a telescope to it and enjoy its ever-widening set of rings that makes it look breathtaking, like a tiny head with a hat.
The most recognizable constellation, Orion, bids us farewell and sets by 8 p.m. Leo dominates the skies, though the full glory of this constellation with an inverted question mark forming the head of the lion, and its lounging body, can easily be obscured by city lights.
The Pointers, the Southern Cross in the southern sky and the Big Dipper in the northern sky, are well positioned from early evening and are high in the sky so they can be used to locate south and north (see map). Scorpio pops its front claws early in the evening and by 10 p.m. the sweeping, curving tail with the sting at its end formed by a close pair of stars is easily made out.
From our unique geographic position close to the equator, we can see 16 of the 21 brightest stars in the evening sky between 7 and 8 p.m. They are (in order of brightness, with their constellations in brackets) SIRIUS (the Dog), CANOPUS (Carina), ALPHA CENTAURI (Crux), ARCTURUS (Bootes), CAPELLA (in Auriga, just off the map, and sets at 7:30 in southeast), RIGEL (Orion), PROCYON (the Dog), BETELGEUSE (Orion), BETA CENTAURI (Crux), ALDEBARAN (in Taurus, just off the map, sets in the west at 7 p.m.), ACRUX (Southern Cross in Crux), ANTARES (Scorpius), SPICA (Virgo), POLLUX (Gemini), MIMOSA (Crux), and REGULUS (Leo). Identify the brightest stars using the map and you will understand better how to relate the sky to the star map, and the distortions of distances, especially close to the horizon.
The International Space Station is best seen this month on two days – on 15th and on 17th May, both times rising up from the northwest, and gliding towards the southeast horizon, except that on 15th May, it will not reach the southeast horizon, and instead will disappear suddenly as it enters the earth’s shadow region. On Sunday 15th the ISS will rise above the north western horizon around 7:05 pm and will rise more than 60 degrees in the sky, after which it will suddenly disappear in the southeast skies five minutes later.
On 17th, the ISS will rise again from the northwest skies but at around 6:20 pm. Again, it will glide up, heading southeast and will dip below that horizon seven minutes later.
Happy viewing.