THE SOUTHWORTH PLANETARIUM

University of Southern Maine

96 Falmouth Street

Portland, Maine 04106

THE SOUTHWORTH ASTRONOMER

Sunday, March 24, 2024

What About the Lunar Eclipse?

If astronomers were more poetical than analytical, they might shyly ask, "If a solar eclipse has arrived, could a lunar eclipse be far behind?"   Of course, the problem with that phrasing is that a lunar eclipse could just as easily precede an eclipse as follow one.    The important point is that these eclipses do occur in pairs.     To understand why these two eclipses occur in pairs, we first look at nodes, the intersection points connecting Earth's orbital plane, or ecliptic, and the moon's orbit, which is inclined five degrees relative to the former.  

The two orbits intersect at two points, the descending node, which the moon crosses as it descends south of the ecliptic and the ascending node, which the moon crosses as it ascends north of the ecliptic.     The above graphic shows the two not-to-scale orbits and assumes that the Universe revolves around the type of Earth the gods would have produced had they been more into fungi ingestion.

Notice that the nodes are separated by 180 degrees.    The lunar conjunction point,or new moon is likewise 180 degrees away from the opposition point, or full moon.   Both a solar and a lunar eclipse can only occur when the moon is at or near a node.  Consequently, when the new moon is around a node during one orbit, the full moon will also be at or near the other node.    However, the nodes will generally shift enough to prevent the occurrence of an eclipse trio -solar-lunar-solar or lunar-solar-lunar.*

 

While humanity has lavishly showered a corrupt cult leader's amount of attention onto the April 8th eclipse, the preceding lunar eclipse, which, incidentally, happens tonight, has been, well, relegated to the shadows with nary a word in its favour.         

Wait!!   There is a lunar eclipse tonight and you are just NOW mentioning it?!  

Well, actually, yes, we're giving you very little notice because, honestly, there is very little to see.  Tonight's event will be a penumbral lunar eclipse, in which the full moon glides Quetzalcoatlus-like through the outer part of Earth's shadow. Consequently, the moon's brilliant facade will be slightly, but not immeasurably, darkened by Earth's penumbra. Think of it this way: if a blood-red total lunar eclipse is the empurpling of a furious man's countenance reacting to the annihilation of his home planet, a penumbral eclipse is the fleeting shadowing of a man's face who learns that Barbie and Ken have transmuted into penpals.        

It's just blah! 

However, as we are proud carriers of the Kepleran torch, we'll go through the elliptical motions.   

Time-table for Portland

Eclipse begins at 12:53 a.m.  Mon, March 25th
You'll notice absolutely nothing.

Maximum eclipse at 3:12 a.m. 

More than 93% of the Moon will be immersed in Earth's penumbra.     You'll likely notice nothing at all unless you're one of those bionic individuals whose eyes have been endowed with  time exposure capability

Eclipse ends at 5:32 a.m.

And you'll wonder where the night went.

Coincidentally, nautical twilight will begin precisely at 5:32 a.m. as well tomorrow morning.   

If you decide to wander wraith-like through the night world this evening, your senses will likely be bewitched by the glittering coruscations of moonlight along the ice-coated tree branches.    The penumbral lunar eclipse, however, will scarcely raise an eyebrow.

15 DAYS UNTIL THE APRIL 8TH ECLIPSE!

*Oh, if you ever find yourself muddling about the infinite kingdoms of astronomy or mathematics, be exceedingly careful when you attempt to make sweeping statements about anything.       For instance, you're standing on some corner platform and, to the astonishment of your rapt audience member, you proclaim  "According to the theoretical astrophysicists, no stable star can ever be more than 200 times as massive as the Sun."     Ha ha!    Tucked away in the 30 Doradus Nebula within the Large Magellanic Cloud is Bat99-98, which weighs in at the mat-bending weight of 228 solar masses.      Similarly, the statement that you generally can't have eclipse trios implies that once in a while an eclipse trio will happen.        Indeed, eclipse God Fred Espenak determined that three eclipses will occur within one month six times during the time period 1801-2300.  However, two of these eclipses will be partials.   Example:    July 1, 2000 - Partial solar eclipse; July 16, 2000 - Total lunar eclipse; July 31, 2000 - Partial solar eclipse.