7 replies to this topic

[PhotonJohn]

Is tonight's planetary alignment considered to be Syzygy?

[KBHornblower]

No.

[azure1961p]

No.

[Dave Mitsky]

Syzygy can refer to more situations than is commonly thought.
 

https://sentinelmiss...ssary/syzygy-2/

 

https://everything.e...gy_(astronomy)/
 

https://sciencenotes...ation-examples/

[MrSyzygy]

As I research this, I'm seeing references to a "grand syzygy", however, the definition of this terminology is not clear. So I would still lean toward this event not being a syzygy, though some definitions claim it is.

[Dave Mitsky]

Grand Syzygy or Great Arc: All of the planets in the solar system lie within a few degrees of the ecliptic. Sometimes three or more bodies appear to align, even though the line is really an arc.

 

https://sciencenotes...ation-examples/

 

[N-1]

Aren't all planets in the solar system within a few degrees of the ecliptic all of the time?

[Dave Mitsky]

But an alignment doesn’t have to be perfectly straight to be called a syzygy, especially when we’re dealing with more than three objects.  According to this article from The New York Times, a syzygy of the Sun, Venus, Earth, Mars, Jupiter, and Saturn occured between March 25 and April 7, 1981.  The Sun and five planets came “within 2 degree of arc from a perfect straight line.”  Apparently that’s close enough.

 

But while that 1981 syzygy was pretty grand, it was not the grandest of grand syzygies.  The planets Mercury, Uranus, and Neptune were left out.  According to another article from The News York Times, a truly grand syzygy will happen on May 19, 2161, “[…] when eight planets (excluding Pluto) will be found within 69 degrees of each other […].”

 

https://planetpailly...words-syzygy-2/