View from Mars Hill: Planets on parade, with rare alignment
Published in Arizona Daily Sun – February 27, 2025
In her 2017 contemporary romance novel All the Lies We Tell—which I confess I have not read
completely, or even partially beyond the following quote—author Megan Hart muses, “If nine
planets in this universe can align, why can’t we?” It is the type of question many people ask
these days across our fractured country and beyond. But in purely astronomical terms, it begets a
follow-up question related to the frequency of planetary alignments, a timely topic due to the
current alignment of seven planets.
A planetary alignment, formally called a conjunction and often referred to as a planetary parade,
occurs when planets appear close together in the sky as seen from Earth. This definition is rather
restricted as it refers specifically to our solar system and not the myriad of other solar systems in
space. It is somewhat akin to the International Astronomical Union’s definition of a planet,
which limits the term to celestial bodies orbiting our Sun, even though scientists know of
thousands of planets around other stars. Nevertheless, this definition is useful for understanding
its concept, if not its inclusivity.
The proximity of planets during an alignment varies; sometimes they appear within a finger
width of each other, while other times they are spread across different parts of the sky but visible
at the same time. For the current seven-planet alignment, the latter is the case.
Alignments involving two or three planets occur frequently, typically multiple times per year.
However, as the number of planets in the alignment increases, these events become rarer.
Alignments of four or more planets happen every few years. Although not uncommon, they are
still a spectacular site, showcasing these worlds with their unique characteristics of moons,
atmospheres, and topographic features.
In the current alignment, five planets are visible to the naked eye, while the other two require
binoculars or a telescope to see. This alignment is short-lived, starting earlier this week and
lasting only a few days. Saturn and Mercury will soon become lost in the Sun’s glare, barely
visible on the western horizon at sunset. Above them shines Venus, the brightest planet in the
sky. Following an imaginary line from these three planets upward leads to Jupiter, nearly
overhead. Continuing eastward along this line leads to the reddish Mars.
To help identify these planets, various free astronomy apps, such as Star Walk 2, Sky Tonight,
and SkyView Lite may be used. These apps also provide the locations of Uranus and Neptune.
And what about Pluto? There is no need to debate its planetary status and decide whether to
include it in the current planetary alignment; it sets before the Sun, so it is not visible in the night
sky.