A spectacle of seven: Why planetary alignments matter to science
On the evening of February 28, stargazers will witness a rare celestial event: an alignment of seven planets visible in the night sky. Mercury will join Venus, Mars, Jupiter, Saturn, Uranus, and Neptune, creating a stunning planetary parade. While this spectacle is a treat for enthusiasts, it also holds scientific significance, offering insights into the mechanics of our Solar System and beyond.
The mechanics behind the alignment
The eight major planets of our Solar System orbit the Sun in a nearly flat plane, each moving at different speeds. Mercury, the innermost planet, completes an orbit in just 88 days, while Neptune, the farthest, takes a staggering 165 Earth years. Occasionally, several planets align on one side of the Sun, appearing as an arc in our night sky due to their shared orbital plane.
In January and February, six planets have been visible. On February 28, Mercury joins the line-up, completing a seven-planet parade. Bright planets like Mercury, Venus, Mars, Jupiter, and Saturn are easily visible to the naked eye, while Uranus and Neptune require telescopes or binoculars to spot.
“There’s something special about seeing the planets with your own eyes,” says Jenifer Millard, a science communicator and astronomer. “These are photons that have travelled millions or billions of miles to reach your retinas. It’s a direct connection to the universe.”
The scientific implications of alignments
While visually stunning, planetary alignments have sparked questions about their impact on Earth and the Solar System. Some have hypothesised that alignments might influence solar activity. In 2019, physicist Frank Stefani suggested that the combined tidal forces of Venus, Earth, and Jupiter during alignments might drive solar cycles by inducing small rotational waves, known as Rossby waves, within the Sun.
However, not all scientists agree. “The observational evidence suggests that planetary alignments directly causing the solar cycle just doesn’t happen,” says Robert Cameron, a solar scientist at the Max Planck Institute.
Unlocking the solar system
Beyond potential solar influences, planetary alignments have practical uses in space exploration. Alignments can reduce spacecraft travel time by utilizing a planet’s gravity to slingshot the craft further into space. This technique was famously employed during NASA’s Voyager missions.
In 1966, NASA scientist Gary Flandro identified an alignment of Jupiter, Saturn, Uranus, and Neptune that occurred in 1977, an event that happens once every 175 years. This alignment enabled Voyager 2 to visit all four planets in just 12 years. Without it, the journey would have taken decades longer.
Exploring exoplanets and distant halaxies
Alignments extend their utility beyond our Solar System. Astronomers use alignments to discover and study exoplanets—planets orbiting other stars—using the transit method. When an exoplanet passes in front of its star, it blocks some of the star’s light, revealing details about the planet’s size, orbit, and even atmosphere.
On a larger scale, alignments of galaxies enable gravitational lensing, a phenomenon where the gravity of a foreground galaxy magnifies the light of a more distant one. This has allowed telescopes like the James Webb Space Telescope to observe early galaxies and stars from the Universe’s first billion years.
The search for alien civilizations
Planetary alignments also provide unique opportunities to search for extra-terrestrial life. By observing planets as they align from our point of view, scientists can study their atmospheres or even look for potential communications between planets in alien systems.
Graduate student Nick Tusay used alignments in the Trappist-1 system to search for interplanetary signals, though the attempt was inconclusive. “Any time two planets align might be an interesting opportunity,” says Tusay.
A window to the universe
As we gaze at the seven planets aligning in February, we’re not just witnessing a rare celestial event; we’re connecting with the broader universe. From understanding solar activity to exploring distant worlds, these alignments are a reminder of how interconnected and dynamic our cosmos truly is.
Perhaps, somewhere else in the galaxy, another civilization is looking at their own planetary parade—and wondering about us.
Source: BBC
