Venus - the third brightest object in the sky and often mistakenly identified as a UFO - is at its best right now, writes Suffolk astronomer Neil Norman.
Have you seen the star Betelgeuse in Orion yet? Last month I wrote about its possible demise in a supernova explosion at some point in the near future, well, since then it has dimmed further and is now the dimmest it has been in 150 years.
Will it go boom? It will one day, but we are still awaiting the tell-tale signs of neutrinos being detected coming from the area of the sky that Betelgeuse is located. If we detect a rush of these, then we can safely say the party has really started.
This month I thought the main topic of conversation should be the exceptionally bright planet Venus that can be seen fairly high up after sunset in the south-western sky. You cannot fail to miss it as it is really rather dazzling
And the way to tell if you are seeing a planet and not a star? Planets do not 'twinkle' because they shine from reflected light from the sun unlike stars that shine through light they have made through fusion within their cores.
Venus is incredibly bright for three main reasons:
1. It is currently close to Earth (currently around 1 astronomical unit, or 93,000,000 miles)
2. It is a fairly large planet. The diameter of Venus is 6,052km, Earth comes in at 6,371 km
3. The planet is enveloped in a dense atmosphere that reflects virtually all the light it receives from the Sun back out into space.
But this beautiful planet hides a very dark and bizarre side too. The clouds in the atmosphere do not break - ever. No observation can be made of the surface of the planet.
The atmosphere is made of almost entirely carbon dioxide and the clouds are 96% sulfur dioxide and reflect 75% of the light that falls onto them. These clouds do actually produce precipitation but instead of water they produce a rain of sulphuric acid.
The surface temperature of the planet is the hottest in the solar system despite the fact that Venus is not the closest planet to the sun. The average temperature is 470C and that is mainly due to the fact that the planet cannot release the heat trapped within the atmosphere. Think of a cloudy summer's day here; it becomes very hot and uncomfortable but as soon as the clouds dissipate that 'muggy' feeling goes away as the heat from the day is released back into space.
On Venus the atmosphere blankets the planet and the heat is so intense at the surface that the rocks actually glow orange and the heat can melt lead. The atmosphere also has a pressure at the surface some 90 times greater than at the surface of Earth (a pressure equal to about 1km below the surface of an ocean) and can crush spacecraft easily. The surface of Venus is 90% basalt and around 65% of the planet is covered in volcanic plains.
Now, all this sounds quite horrendous but now onto the oddities.
How about the fact that Venus has a day longer than its year? The planet rotates on its axis in 243 Earth days and orbits the Sun once every 224.7 Earth days. This is due to the fact that the planet must have been hit by another planet-sized object in the early formation of the solar system. This statement is supported by the fact that the planet is upside down! Yes, you read that right, Venus is the wrong way up.
This means that the sun rises in the west and sets in the east (hypothetically, if one could stand on the planet and see the sun in a clear sky); again this could only be caused by a major impacting body colliding with Venus.
Uranus also suffered a similar fate and actually 'rolls' around its orbit about the sun.
Whilst looking at Venus, remember that it is the third brightest object in the sky, with only the sun and moon being brighter. It is so bright that it has been reported by the public to the authorities as a UFO.
Obviously its brightness and slow sinking motion towards the horizon as it sets alarms people and they believe this is not a natural sight, but of course the people don't take into account the Earth's rotation sadly.
So ,tonight as you look at Venus - so named because of its beauty - remember that this creation of the Roman pantheon in all its angelic guise is in fact the literal closest thing to Hell one could ever imagine. Venus at its best.
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