How to see all the solar system’s planets in the night sky at once

All the planets in our solar system are lining up to parade through the night sky at the same time. This extraordinary celestial event will see the sky scattered with seven visible planets in what is known as a grand planetary alignment.

The eight planets in our solar system orbit the sun in roughly the same plane because they all formed from the same source. waste disk around the sun The line that the Sun traces across the daytime sky, called the ecliptic, lines up with this plane, so when the planets appear in the sky, they all appear roughly along the ecliptic. It’s not a perfect line for the planets because their orbits are slightly tilted, but it’s pretty close.

Never is this more evident than in a planetary alignment. An alignment involving all the planets except Mercury is taking place in mid-January. Uranus and Neptunebeing the most distant planets, it will only be visible through a telescope, but the others may be visible to the naked eye.

A major alignment, including Mercury, will only happen on a few evenings around February 28, depending on your location. All seven planets will be visible just after sunset, stretching out in an arc across the sky.

By the time the sky is completely dark, Mercury and Saturn it will sink below the horizon, followed shortly by Neptune and Venus. The best time to see the planets will be after sunset, when all but Mars, Jupiter and Uranus will be close to the horizon. Those three will hang around all night, but spotting three planets in the sky isn’t nearly as rare as finding seven.

The main thing that prevents these alignments from being visible all the time – apart from the weather – is the difference in orbital periods between the planets. Mercury, which is closest to the sun, takes about 88 Earth days to complete one orbit, while Neptune, which is farthest away, takes almost 165 Earth years.

A great alignment is possible when all the planets are far enough from the sun, so they are visible at night, and they can all be seen in roughly the same half of the sky, at the same time. Orbital coincidence is remarkable: sometimes there are multiple grand alignments in a year, and sometimes several years go by without a single one.

In some ways, a planetary alignment is just an optical illusion: the planets are still millions or billions of miles apart, and if you looked from outside our solar system, you’d never see them. gathered in a perfect line shining from the sun But for stargazers around the world, it’s a great opportunity to see all the planets at once, neatly arranged across the sky.