I know what time zones are😡. My question is: how is George S saying 8 am when it’s 9 am where he is? Does he record 4 intros one for each US time zone?

In order for most people in the world to experience daylight at the same hours on a clock, time zones were invented because the Earth is in different positions relative to the sun at the same actual time (when it's night in New York, it's daytime in Hong Kong, for example). Because people have a hard time accepting that 3pm can be in the middle of the night, we developed time zones. Each time zone is roughly 1/24 of the Earth's circumference wide (at the relevant latitude). So, when you compare noon in New York to noon in Western Indiana, you are both talking the time when the sun is highest in the sky, rather than one of you seeing it slightly lower.

12 o'clock Noon is when the sun is directly North/South/overhead, but not East or West any. But because it would be impossible to keep appointments if everywhere kept its own local time, we break geography into big chunks called "time zones." Everywhere in that zone agrees to use the same time, which is about correct for the middle of the zone, and is exactly one hour offset from the zones on either side.

Because the sun is over the east before it's over the west, the eastern zones experience things like sunrise, local noon, and sunset before zones to the west. So, if local noon is 12o'clock, then by the time it's 12 in the central zone, it's already 1 on the east where local noon happened an hour ago.

Before the invention of time zones, each locality decided what time it was by setting "noon" to the time of day when the sun rose to the highest point in the sky. That worked well enough when life moved more slowly.

After the railroads connected cities and it became important to know to the minute when something was scheduled to happen, a difference in "noon" between your town and mine made scheduling extremely difficult. Time zones were established so that people all over a region could agree that 8:00 is 8:00, even if that meant the sun reached the highest point in the sky at 12:04 in my town on the same day it reached the highest point at 11:44 in your town.

An agreement like that works well for people up to a few hundred miles apart. Much farther though, and you'll have to convince people in the far west portion of the continent that the sun rises at 3:00 a.m. on the same day that the people in the east say it rises at 6:00 a.m. So they divided the continent into "time zones", each 15 degrees of longitude wide (which is what you get when you divide the planet's 360° by its 24 hour rotation period) as a compromise between everyone-everywhere-agrees-to-use-the-same-clock and everyone-gets-to-use-whatever-clock-they-choose.

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New York City is in the eastern time zone, which is 1 hour ahead of Central time zone.

As such 8am in Chicago (central time) is the same time as 9am in New York City (eastern time)

The earth spins as it's rotating around the sun. That means if we drew a line from the sun through the center of the earth, that line would hit a different part of the planet every moment that passes.

It just so happens we've divided the day into 24 "hours", and the sun hits the same place twice if you wait that long. (Technically it's a tiny bit different from 24 hours but that's something that only matters once we get into higher-end calculations.)

So the "time zones" are made by borders that are ROUGHLY where that "direct" line from the sun hits an hour apart. I say "ROUGHLY" because these are also political boundaries so they're set by people who vote or own land etc.

This was done for our own timekeeping convenience, so that we could understand questions like, "When is it morning on the west coast?" easier. Imagine if we made everything use East Coast time. That would mean we'd have to remember that "morning" in California will be somewhere around "noon" in this time.

Is it really easier to remember, "California is 4 hours later than NY so at 8AM in NYC it is 4AM in California"? Well, that's subjective. But this is how we did it, and it'd be at least as complicated to do it the other way.

The main place where this makes the most sense is day boundaries. We understand when the time changes from 11:59 PM to 12:00 AM the date has changed. But if we didn't have time zones, some people's day would start at 1AM. Some would start at 2 AM. Everyone's day would roll over at a different time of day. They'd have to show up to work at a different hour, etc.

From that perspective, even if you travel to a far-away place, it's easier to remember, "I need to be at the office when all the clocks around me say 8AM" than it is to figure out, 'OK, here the workday starts at 7PM so that's when I need to be at the office.'

So, put short: it ties our time to roughly when we expect the sun to rise and set. If we didn't have time zones, in some places the sun would rise at midnight, and the name "midnight" wouldn't make a lot of sense if associated with 12 AM.

Edit

To answer your question: yes, they record multiple intros. Most of these shows are mixtures of live TV and pre-recorded cuts, and often they cut to other actors. So they might do the startup of the show with a pre-recorded introduction, then the title jingle, then move to live footage. Or, in the Eastern time zone, they might be running a commercial break while the host does a live introduction for the Western time zone. Then when that introduction is finished, the Western time zone gets commercials or another segment, and eventually everything syncs back up to live footage again. Sometimes "live" shows like this aren't actually "live" in all time zones because of these logistics.