Stargazers had the chance to see a rare five planet alignment in the night sky this week, with the planets Mercury, Jupiter, Venus, Mars, and Uranus all set to align on the evening of Monday 27 March. A waxing crescent moon and the star cluster M35 were also set to be visible.
Of course, actually spotting the celestial bodies was all dependent on the weather - and a clear night free of cloud cover - as well as the equipment at your fingertips, as spotting all five of the planets proved a challenge.
Though many of the planets on display were visible with the naked eye, telescopes and binoculars were required to get the best view of what was described as a “planetary parade.”
In actuality, the planets in our solar system are separated by millions of miles of empty space. But since they orbit the Sun on roughly the same plane, at times their orbits can make it appear as if they are sitting “near” each other in the night sky.
Though the planets may not be aligning for quite as spectacular a display in the week ahead, they will still be visible from Earth if you know where to look. Here is everything you need to know about it.
What is a planetary alignment?
Planetary alignments occur when two or more planets in our solar system appear to align in a straight line as seen from Earth. While they can occur relatively frequently, the occurrence of planetary alignments can vary depending on a number of factors, such as the orbit of the planets involved and the observer’s location on Earth.
For example, alignments of two or more planets visible to the naked eye occur about once every one or two decades. However, alignments of all eight planets in our solar system are much rarer and only occur once every few centuries.
How to see the planets tonight
This week, Mercury and Jupiter will be visible around 20 to 25 minutes after the sun has set at approximately 7.25pm BST in the UK. The optimum conditions for spotting these planets are clear skies and a decent view of the horizon.
Venus, commonly referred to as the ‘evening star’, has been much easier to spot high up in the western evening sky for a number of weeks now, and should be the simplest of the planets to locate. Unlike stars, planets do not twinkle, so look for a static ‘star’ that is much brighter than all the others - that’ll be Venus.
Mars can be seen by locating the Moon first of all. To the upper left of the Moon, which will be a half-moon that evening, you should be able to see a yellow-orange ‘star’.
Just to the left of Mars you will catch sight of the M35 star cluster (with binoculars). Finally, Uranus can be located with the help of binoculars or a telescope to the upper left of Venus, giving off a pale green tint.
With the naked eye, it can sometimes be difficult to tell the difference between a star and a planet, but there are a few ways to distinguish between the two.
Planets often appear much brighter than stars, with the exception of only the brightest stars. They do not produce their own light, but rather reflect the light of the Sun, which makes them appear much brighter than stars.
They also move relative to the stars in the sky. While stars generally appear to stay in the same position, over the course of several nights, you can observe the planet’s motion relative to the stars.
Stars often also have a distinctive colour, ranging from blue-white to yellow, orange, or red. Planets, on the other hand, usually appear white or only slightly coloured. If you are still unsure what you are looking at, using a star chart or a mobile app can help you identify celestial objects in the night sky.