When the planets align

Elvira Hattingh
The “wandering planets” – the seven celestial bodies visible without a telescope – will appear in a straight line in the night sky this month – a rare event that occurs only once in about every 20 years.
Mercury, Venus, Jupiter, Mars and Saturn will appear in a line in the night sky and in order according to their distance from the sun, about half an hour to an hour before sunrise from 23 to 25 June. The fact that they appear in this exact order makes the event even more exceptional.
The 24th will be the best opportunity to witness the so-called "big planet parade". The sun and moon will be the sixth and seventh celestial bodies roughly in line with these five planets.
The sun itself will still be just below the horizon during the event and will drown out the other wandering planets as it rises.
Nasa explains that although the planets Saturn, Mars, Jupiter and Venus have already been visible in the morning sky in recent months, Mercury has only recently joined them as from about 3 June. The small planet, which mostly moves close to the sun and is therefore only slight visible, is currently making a brief appearance above the horizon at dawn, before being “erased” by the rising sun.
The big parade on June 24th is special because the last time five planets appeared together in our night sky and still formed a straight line, was in December 2004. This kind of event will only occur again in 2040.
There is great excitement around the world about the celestial event and the non-profit organisation Astronomers Without Borders considers it one of their top night sky events for 2022.
While it is not uncommon to see a “mini planet parade” (when three planets are visible in our night sky), this “small parade” requires the alignment of at least four planets, while a “large parade” that involves five to six planets, is far more rare.
A parade of six planets only happens every 100 years or so. The closest that all eight planets in our solar system will come into alignment is on 6 May 2492. However, the planets will not form a straight line, but rather appear together in the night sky.
A "full parade", which involves all the planets in our solar system, is extremely rare and takes billions of years to occur.
However, June's "planet parade" can be seen in most places around the world - except for the North and South Pole areas.
A planetary parade is also called an appulse.
TimeAndDate explains that the word planet is originally derived from Greek and actually means "wanderer", which was formerly used to distinguish celestial bodies in our night sky from stars that are apparently stationary.
It is also explained that although it may seem from the earth that the wanderers form an almost perfect straight line, it is actually just an illusion because depth perception is lacking.
Seen from space, the celestial bodies will never be able to really form a straight line, because each one moves in its own orbit and their axis tilt differs too much.
If you could see the solar system from above, it would appear that the planets were randomly scattered on one side of the sun, livescience.com explains.
In addition, the influence of the alignment of the planets on the earth is extremely small - even less than the effect of the moon's gravity on the earth.