It isn't called anything because it can never occur. It never has occurred in the past, and never will occur in the future. Even if all the planets were at the same heliocentric longitude relative to the Sun, the tilts of their orbits vary enough from the plane of the ecliptic that they still wouldn't be in line.
Another, more accurate, answer
Think of a very simple alignment of two planets, Earth and Venus. This only occurs a little more than once a century. To add a third planet to this alignment would take many millennia. To have all eight planets aligned would require an infinite amount of time.
Even so, the word for it is syzygy.
Chat with our AI personalities
Syzygy is a word used to describe three bodies in alignment. - this could be the sun, earth, moon or another planet. If its specifically for planets, the word conjunction is used as when viewed from the earth.
When all the planets are aligned, it is called a planetary alignment. This alignment is a rare event due to the different orbits and speeds of each planet around the sun.
Syzygy , when three or more planets are in alignment .
because its nice to make more room.
Planetary alignment, but this never has and never will happen. There is also another name for it I can't remember it, but it starts with an a and has three Y's in it.
A planetary alignment.
Conjunction is the term when they just appear to be aligned from an observer's point of view.
The 8 planets never have and never will all line up. But when two planets are aligned it is called a syzygy
There is no name for this because it's so statistically improbable that it'll likely never happen.
The last time all of the planets aligned in a straight line was 561 BC. This phenomenon is known as a grand conjunction, where all the visible planets appear to align along the zodiac during a short period.
The last time that all of the planets aligned in a straight line was in 561 BC. However, it's important to note that a perfect alignment of all the planets is a rare event due to their different orbital planes and speeds.
If you mean all our planets and comets, it's called the Sun. It is called "The Solar System".
It depends on what you mean by "alignment." There have been plenty of times that all the planets have been on more or less the same side of the Sun; there probably has never been a precise alignment (within, say, a few degrees) of all the planets simultaneously.
The planets do not align frequently. A perfect alignment of all planets in our solar system is very rare due to their different orbits and speeds of rotation. The last time all the planets aligned in a straight line was in 561 BC, and such a perfect alignment won't happen again for millions of years.