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Despite the common visual representations that depict all eight planets in perfect alignment, this isn't a frequent or realistic occurrence. alxpin/Getty ImagesYou may have come across a horoscope claiming that the planets are aligned — or perhaps the stars are in perfect position — and now’s the ideal moment to take a chance, like buying a lottery ticket! This makes one wonder: Can the planets really ever all line up in a neat row across the sky?
Can an alignment of all eight planets actually occur?
While there are occasional headlines about planetary alignment, the reality is that a complete alignment of all planets is nearly impossible. Even seeing all the planets on one side of the sun is a rare event. By the time another planetary alignment occurs, Earth's landscape will likely be very different, even if only five or six planets form a distant line in the night sky.
Planetary Orbits, Axial Tilts, and Alignment
The varying orbits of the planets in our solar system make it impossible for them to align from Earth's perspective. Although we're taught that the solar system operates on a flat plane where planets orbit on the same level, each planet follows a unique orbit within the ecliptic — the sun's imaginary path in the sky. Mercury deviates the most, by 7 degrees, while other planets vary around 3 degrees from being perfectly flat.
This doesn't even account for other bodies in the solar system. Pluto, once considered a planet, has a 17-degree deviation from the solar system’s orbital plane, and other dwarf planets are even more erratic compared to the eight main planets. Though these deviations may seem minor, they are enough to make any alignment practically impossible from Earth's point of view, the 'third rock from the sun.'
If you picture the eight major planets lined up in a row, stretching from the sun with just 1 degree of separation, this alignment is estimated to occur once every 13.4 trillion years. To put that into perspective, our solar system is 4.5 billion years old, and the universe is only 13.7 billion years old. This alignment has almost certainly never occurred and never will, as the sun is expected to become a red giant in about 5 billion years, destroying Mercury and Venus, and getting dangerously close to Earth.
Exploring the Planets in the Night Sky
This artwork depicts the arrangement of the inner planets of our solar system, showing their order from the sun. Aaron Rutten/ShutterstockIt's a rare event for all eight major planets to be visible in the same section of the sky. This phenomenon occurs only once every few thousand years, with the last occurrence recorded in 949 C.E. However, if you're satisfied with seeing just six planets simultaneously, you'll have the opportunity to witness this rare sight on June 3, 2024, August 28, 2024, and January 18, 2025.
When you narrow the focus to only the visible planets — Mercury, Venus, Mars, Jupiter, and Saturn — even this rare alignment isn't something you'll see every night in the same part of the sky.
Although we know gravity affects celestial bodies (and those of us living on Earth), there's no cause for concern during the rare moments when the planets align. There is no significant effect on Earth when planetary alignments take place — however, NASA has leveraged these alignments to its benefit, particularly when launching missions like the Voyager 2 "Grand Tour", which started in 1977 to explore various planets and solar system objects.
