Happy perihelion!

[Jeremy McCreary]

Earth passed through perihelion this morning — January 4, 2025 — at 0528 Pacific Standard Time. It's closest to the sun at this point in its slightly elliptical orbit — about 2% closer than average. This annual solar system event always falls about 14 days after the December solstice.

I'm sure our northern high-latitude members enjoyed the extra warmth.
;^}

The Pagans celebrated the astronomical events they were aware of, and last night, we did the same with some neighbors. It's fun to be aware of events that play out at time and distance scales far larger than those of daily life but still affect us in ways we can actually observe.

So how exactly is perihelion observable? Well, ocean tides at the new and full moons closest to perihelion tend to be the biggest astronomical tides all year, and the observable tides here in SoCal lately have been no exception. We had one such new moon on December 30.

If the moon also happens to be at perigee at these times, you get the biggest astronomical tides of all. Storm surges can complicate these otherwise reliable patterns.

 

[Jeremy McCreary]

Oops, almost forgot — last sunset before perihelion:

 

[Stefan Mikes]

I'm sure our northern high-latitude members enjoyed the extra warmth.
;^}

Yea, right. It was -3 C instead of -6 C (the latter was measured just after the sunset)

 

[Chargeride]

Vans covered in snow, Sun is rubbish.

 

[herringbur]

Oops, almost forgot — last sunset before perihelion:

Stickman Hook​

View attachment 188075View attachment 188076

Looks nice, what was the temperature then?

 

[Jeremy McCreary]

Looks nice, what was the temperature then?

Don't recall, but guessing 55±5°F by that time of day in mid-winter with little cloud cover.

 

[AlariciManci]

Earth passed through perihelion this morning — January 4, 2025 — at 0528 Pacific Standard Time. It's closest to the sun at this point in its slightly elliptical orbit — about 2% closer than average. This annual solar system event always falls about 14 days after the December solstice.

I'm sure our northern high-latitude members enjoyed the extra warmth.
;^}

The Pagans celebrated the astronomical events they were aware of, and last night, we did the same with some neighbors. It's fun to be aware of events that play out at time and distance scales far larger than those of daily life but still affect us in ways we can actually observe.

So how exactly is perihelion observable? Well, ocean tides at the new and full moons closest to perihelion tend to be the biggest astronomical tides all year, and the observable tides here in SoCal lately have been no exception. We had one such new moon on December 30.
driving games
If the moon also happens to be at perigee at these times, you get the biggest astronomical tides of all. Storm surges can complicate these otherwise reliable patterns.

What tools or methods do you recommend for observing tides and other effects during perihelion?

 

[Jeremy McCreary]

One approach would be to look up the date and time of perihelion, the date and time of the closest perigees, then look over a local tide table with phases of the moon to see how the highest and lowest tides around these times correlate.

King (high) tides by definition occur annually at the full or new moons closest to perihelion. Here in coastal SW SoCal, the king tides are visibly the biggest all year.

If you're a regular beachgoer, you'll notice the difference. The low tides around king tides are also extreme.

King tides are a big deal here. They make the local TV news before and after, and people flock to the beaches to see them first-hand. If we happen to have big swell coming in at the time, the results can be pretty spectacular, as the biggest wave sets can then smash directly into our sea cliffs at full force.

Quite a show, but it also comes with a risk of wave flooding in low-lying areas at the shore.

 

[stompandgo]

Same deal here.