OK – this will take a while to explain, but I’ll try to be brief.

I wanted to do a Hanukkah post – especially because Hanukkah 2024 has the unusual aspect of starting on Christmas (Western Christmas, that is) this year. Yes – Hanukkah runs from sundown on December 25, 2024 until sundown on January 2, 2025.

Now, you may have noticed that I spelled Hanukkah “wrong” in the title. Well, the holiday turns out to have 24 different “wrong” spellings! I simply picked the one that celebrated “X” the most!

Lex Rofeberg
@Lexaphus

Since the time for this debate is nearing: The right way to spell Hanukkah is to change the spelling of Channuka each time that you mention Xanukah. Khannike is a delightful holiday (get it?) when one eats fried foods and remembers miracles. Mark your calendar, Janice is coming!

11:18 AM · Nov 9, 2021

WHAT THE HEXH???!!! LOL!!!

Here’s the article that tweet came from.

LINK: https://jewishunpacked.com/how-do-you-spell-hanukkah/

The replies on that tweet are hilarious, by the way!

LINK: https://x.com/Lexaphus/status/1458106787027197962

Anyway, back to X. And to this blog.

I wanted to do two posts – an extra Xanukah post, and a post about the Grok AI now being free. And then I needed to do the Christmas post, but thankfully Aubergine did that, so I only had to do those two posts. And THEN I got the idea to combine them!

As to the point about the Grok AI, I was seeing ads on X for Grok now being free. Like this one.

A few days ago, I decided to try it. I clicked on the ad when I saw it, and it took me right to Grok. So I asked Grok a question.

Grok – please tell me more about this image. I’m curious why the pictured object has the shape that it does, which is different from most ringed planets. https://ton.twitter.com/onboarding/subscriptions/free_grok_prompt_blackhole2_min.png

What follows is the answer that was returned in under 15 seconds.

15 web pages

The image you’re referring to likely depicts a black hole, specifically showcasing the visual phenomenon known as the “photon ring.” Here’s an explanation of why this object appears differently from most ringed planets:

Shape and Appearance: Unlike planetary rings which are composed of particles orbiting a planet in a relatively flat plane, the shape in your image is due to the unique gravitational effects of a black hole.

• Photon Ring: The bright ring you see is not a physical structure but an optical effect. It’s caused by photons (light particles) that orbit the black hole multiple times due to extreme gravitational lensing before escaping towards the observer. This results in a ring-like structure that appears around the black hole’s shadow. The light from the accretion disk or material around the black hole bends in the intense gravity, creating this luminous ring. The thickness and brightness of this ring can vary based on the black hole’s mass, spin, and the viewing angle.
• Black Hole’s Shadow: Inside this photon ring is the black hole’s shadow, which is essentially the silhouette of the event horizon—the point beyond which no light or matter can escape. This shadow appears dark because any light or matter that crosses the event horizon cannot be seen from outside. The size of the shadow is roughly twice the size of the event horizon, making it larger than what you might expect just by looking at the black hole itself.
• Difference from Planetary Rings: Planetary rings are made of ice, dust, and rock particles that orbit the planet due to its gravity but remain within a certain band due to stable orbits. A black hole’s photon ring, however, is an effect of spacetime curvature, where light paths are significantly altered around the black hole, creating an illusion of a ring. This is not due to physical material distribution but how light travels in the extreme gravity of a black hole.
• Scientific Significance: The imaging and study of such phenomena help in understanding general relativity, black hole physics, and the behavior of matter and light in extreme gravitational fields. The first direct image of a black hole, captured by the Event Horizon Telescope, was of M87’s black hole and showed this very ring, confirming theoretical predictions about how black holes should appear.

This visual representation is a testament to the bizarre effects predicted by Einstein’s theory of general relativity, where gravity can bend light to such an extent that we observe phenomena like the photon ring.

photon ring theory

gravitational lensing

OK – that was cool. So I decided to ask it another question that’s relevant today, and would take me a while to search.

Grok – please explain why Hanukkah normally happens before Christmas (December 25), but it happening after Christmas this year.

25 web pages

10 posts

Hanukkah normally occurs before Christmas because it follows the Hebrew calendar, which is lunisolar. Here’s how it works:

• Hebrew Calendar: Hanukkah begins on the 25th day of the Hebrew month of Kislev. The Hebrew calendar is based on both lunar and solar cycles, with months starting with the new moon. Because lunar months are about 29.5 days long, there are roughly 12 lunar months in a solar year, but this cycle is shorter than the solar year, causing a drift. To realign the calendar with the solar year, an extra month (a second Adar) is added approximately every three years in a 19-year cycle. This adjustment ensures that holidays like Hanukkah maintain their seasonal timing.
• Gregorian Calendar: In contrast, the Gregorian calendar, which is solar-based, has a fixed date for Christmas on December 25. Since the Hebrew and Gregorian calendars do not align perfectly, the date of Hanukkah on the Gregorian calendar varies from year to year, typically falling between late November and late December.

This year, in 2024, Hanukkah starts at sundown on December 25 and continues until January 2, 2025, due to the specific alignment of the lunar and solar calendars. It’s a rare occurrence for Hanukkah to begin on or after Christmas Day:

• Rare Coincidence: The last time Hanukkah started on Christmas Day was in 2005, and it won’t happen again until 2035. This is because the Hebrew calendar’s leap year system occasionally pushes Hanukkah later into December, sometimes even into January, but rarely this close to or after Christmas.
• Leap Year Influence: The Jewish calendar’s leap year, where an extra month is inserted, can shift Hanukkah’s timing on the Gregorian calendar. In a year like 2024, the leap year effect has resulted in Hanukkah starting later than usual, thus coinciding with or following Christmas.

In summary, the variable nature of the Hebrew calendar’s lunisolar system causes Hanukkah’s date to shift relative to the fixed solar-based Gregorian calendar, leading to this rare occurrence where Hanukkah begins after Christmas.

Hebrew calendar leap years

Other lunisolar calendars

WELL – that was excellent. Grok really gives nice answers – and FAST.

So – if you’re ready – give Grok a try.

https://x.com/i/grok

And have a Mherry Xhristmas and a Xhappy Xhanukkah!

W