Amateur astronomers may have already spotted six of the planets in January or early February, but on February 28, Mercury will join the parade, potentially allowing for viewing of seven planets at once. An alignment of six or more planets occurs every few decades.
This week, a seven-planet alignment will occur in the night sky. During the event, Mars, Jupiter, Mercury, Venus, Saturn, Uranus, and Neptune will line up in a line, with some of them visible to the naked eye. Ancient cultures identified these planets as moving points of light in the sky, in contrast to the background stars that remained stationary. In fact, the word “planet” is derived from the Greek word “πλανήτης” (planets) – “wanderer.”
Amateur astronomers may have already spotted six of the planets in January or early February, but on February 28, Mercury will also join the parade, potentially allowing viewing of seven planets at once, according to the Royal Observatory in Greenwich.
The planets in the solar system move in regular orbits around the sun, and sometimes they line up in the same region of space. NASA explains that the term "planetary alignment" refers to the visual arrangement of planets along with other celestial bodies, such as bright stars or the moon.
When this happens, the planets will always appear in an arc or a straight line in the sky, due to our vantage point from Earth within the solar system.
Mars, Jupiter, and Saturn are often observed in the night sky, but the combination of Venus and Hama adds to the uniqueness of the phenomenon.
How rare is the phenomenon?
"An alignment of several planets appearing close together in the sky happens from time to time, but it is considered relatively rare," explains Dr. Shyam Balaji, a researcher in cosmic particle physics at King's College London. He says an alignment of six or more planets occurs once every few decades, making Friday's upcoming event particularly rare.
Another advantage: New Moon on February 28th
That night, a new moon will occur, in which the moon is exactly between the sun and the Earth, so that its shadowed side is facing us.
This means that there will be no light pollution from the moon, planets will be easier to observe, and perhaps even more distant galaxies will be visible.
How and why do the planets line up in the sky?
On most nights, weather permitting, at least one bright planet can be seen in the night sky. While two or three planets are often visible in the hours around sunset, it is rare to see four or even five planets shining at the same time with the naked eye. These events, sometimes called "parades of the planets" or "planetary alignments," generate widespread public interest. While not particularly rare, they are worth observing because they do not occur every year.
The term "planetary alignment" is not a scientific term, but rather an observational one that can refer to a number of different phenomena. As the planets in the solar system orbit the sun, they sometimes line up in certain lines in events called oppositions and conjunctions. Planetary alignment can also refer to positions that appear to us to be aligned in the sky with other planets, the moon, or bright stars.
The planets in our solar system always appear along a line in the sky. This line, called the ecliptic, represents the plane in which the planets orbit the Sun, as seen from our perspective within that plane.
Before preparing to watch the planetary parade, you should consider their height above the horizon. In order for a planet to be visible to the naked eye, it must be at least a few degrees above the horizon, with 10 degrees or more being considered optimal. This is because Earth's atmosphere causes the light of celestial bodies to weaken when they are close to the horizon, making them difficult to see.
This challenge is especially significant after sunset and before sunrise, when the sky is still lit by twilight. If a planet appears too low in the sunset light, it will be very difficult to spot.
In addition to the five visible planets, the solar system includes Uranus (Uranus) and Neptune (Neptune), as well as dwarf planets such as Pluto. These planets are very distant and lie in the cold, dim region of the outer solar system. Neptune requires a telescope to be seen, while Uranus is bright enough to be visible to the naked eye under ideal conditions of very dark skies – but it is still difficult to spot without a telescope.
Because planetary alignments are most often observed during twilight, a time when the sky is not completely dark, Uranus and Neptune are rarely visible during these events. Therefore, claims of rare alignments involving six or seven planets must be understood in the context of the fact that not all of these planets can be seen with the naked eye.
Events where four or five planets are visible together to the naked eye usually occur every few years. Mars, Jupiter, and Saturn are often visible in the night sky, but the appearance of Venus and Mercury at the same time makes the alignment especially impressive.
These planets orbit the Sun in smaller, faster orbits than Earth. Venus is visible in the sky for only about two months, when it reaches its farthest point from the Sun (a state called "maximum longitude"). Mercury completes its orbit in only 88 days, so it is only visible for a few weeks at a time, either after sunset or before sunrise.
Contrary to popular belief, planetary alignments are not a one-night event. Because the planets move relatively slowly in their orbits, they can be observed together for weeks or even months. Even five-planet events can last for several days, until Mercury gradually disappears into the sunlight.
Although it is not an entirely rare event, a planetary alignment is a special opportunity to look up and marvel at our place in the solar system – with diverse worlds spread out before our eyes in the sky.
For explanation on the NASA website
More of the topic in Hayadan:
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Near sunset
Tomorrow is fine too.
What would be the best time to go see them?