Planet parade: is there one tonight, and when is the next?

What a planet parade really is

"Planet parade" is not an astronomical term. It is a popular name for a stretch of nights when several planets are above the horizon at the same time, after sunset or before sunrise. They do not form a straight line and they are not close together: they are scattered along a great arc across the sky, sometimes more than 100 degrees long, from low on one horizon to high in the south. What makes the sight special is seeing several worlds at once and realising they all sit on the same path.

Because there is no official definition, news stories count planets in different ways. Some count Uranus and Neptune, which you cannot see without a telescope. Some count planets that are technically above the horizon but lost in the twilight glare. The table on this page uses a clear rule: each planet must be at least 5 degrees above the horizon at the same moment, with the Sun at least 6 degrees below it. We also say how many of the planets are bright enough to see with the eye alone, which is the number that matters if you are going outside to look.

Why the planets lie along one line

The solar system is flat. The Sun and planets formed 4.6 billion years ago from a spinning disc of gas and dust, and the planets still orbit within a few degrees of that disc's plane. Mercury's orbit is the most tilted, at 7 degrees; the rest are within about 3.5 degrees of the Earth's.

We see that plane edge-on, because we are inside it. Projected on the sky, it becomes a great circle called the ecliptic, the path the Sun appears to follow through the year and the line through the middle of the zodiac constellations. So whenever several planets are up at once, they always fall along the same arc, with the Moon somewhere near it too. The orange dashed line in the diagram above is the ecliptic for that moment, and the live sky view draws it as well.

The arc rarely looks like a neat line over the horizon. On spring evenings and autumn mornings in the Northern Hemisphere the ecliptic stands steeply up from the horizon, so the planets climb high. On autumn evenings and spring mornings it lies low, and a parade hugs the horizon. That is one reason the same parade looks quite different from New York and from Sydney.

What "alignment" means to an astronomer

Conjunctions

Astronomers talk about conjunctions: two objects sharing the same right ascension or ecliptic longitude, which usually means they look close together. A conjunction of two bright planets, such as Venus and Jupiter less than a degree apart, is far more striking than a spread-out parade, and happens most years. The Moon has a conjunction with every planet each month; see what planet is next to the Moon tonight.

Oppositions and great conjunctions

A planet at opposition is lined up with the Earth and Sun, on the far side of us from the Sun. It is then at its closest and brightest and up all night. A great conjunction is a meeting of Jupiter and Saturn, which happens every 20 years; the last, on 21 December 2020, brought them within a tenth of a degree.

Heliocentric alignment

Seen from above the Sun, the planets never line up. They move at very different speeds, from Mercury's 88-day orbit to Neptune's 165 years, so they are always spread around the circle. Today the smallest slice of the circle that contains all eight planets is about 195 degrees, and the tightest grouping at any time from 2026 to 2028 is about 131 degrees, on October 30, 2026. A true line of all the planets on one side of the Sun does not happen in any human lifetime.

No, an alignment cannot hurt the Earth

Every few years a "planetary alignment" is blamed in advance for earthquakes, floods, power cuts or bad luck. It is worth knowing why that cannot happen. The only way the planets could act on the Earth is through gravity, and what matters for tides and stresses is not the pull itself but how much it changes across the Earth's width. That tidal effect falls with the cube of the distance, which makes distant planets almost irrelevant.

• Venus at its closest: a tide about 15,000 times weaker than the Moon's.
• Jupiter at its closest: a tide about 140,000 times weaker than the Moon's.
• Mars at its closest: a tide about 330,000 times weaker than the Moon's.
• Mercury at its closest: a tide about 1,800,000 times weaker than the Moon's.
• Saturn at its closest: a tide about 3,900,000 times weaker than the Moon's.

Add all five together, as if every one were at its closest at the same time, which is impossible, and they still reach only about 1/13,000 of the Moon's tide. The Moon's own pull changes by much more than that every month as its distance varies. Studies of earthquake records have found no link to planetary positions. A parade is a sight to enjoy, nothing more.

How to see a planet parade

• Time it right. For an evening parade, go out about 45 minutes after sunset. Mercury and Venus are low in the west and set soon after; the outer planets are higher. For a morning parade, start about 90 minutes before sunrise.
• Find a low horizon. The planets nearest the Sun are always the lowest. A beach, a hill or an open field beats a street.
• Work along the line. Start with the brightest planet, then follow an imaginary arc through it (the ecliptic) to find the others. The diagram above shows the order and spacing.
• Use binoculars for the faint ones. Uranus looks like a faint blue-green star in binoculars; Neptune needs a telescope and a chart.
• Check the Moon. A bright Moon near the line makes a lovely photo but washes out Uranus and Neptune.

For tonight's planets one by one, with rise and set times, see planets visible tonight. Related: what planet is next to the Moon · meteor shower tonight · Moon phase today