Complex Numbers

Hot Shoulder

Posting early today because, like many people, I have stuff to do later. In my case, though, the stuff is completely unrelated to tomorrow's holiday.

I've written about Betelgeuse before, most recently here: "Betelgeuse 2" . This is, however, a different article, more recent, from Big Think.

    This is what we’ll see when Betelgeuse goes supernova  
The closest known star that will soon undergo a core-collapse supernova is Betelgeuse, just 640 light-years away. Here’s what we’ll observe.

And already I have Quibbles.

1: "what we'll see." It's extremely unlikely that anyone alive as I write this will see it happen. I'm a gambling man, and I wouldn't bet on it, not unless some bookie was offering billion-to-one odds and I could bet, like, a dollar. The headline uses the same value of "we" as people do when they talk about when "we" will colonize distant star systems (hopefully not Betelgeuse).

2. "will soon undergo." As with "we," they're using a variant value of "soon." Best estimate I've seen is within 100,000 years. That's soon in cosmic terms. It's not soon in human terms. Hell, 100,000 years ago, we'd (entirely different definition of "we" this time) barely started using fire.

3. "640 light-years away." Yeah... maybe. For whatever technical reason (it's been explained to me, but it's over my head), B's distance has been tricky to pin down. Wiki claims 400-600 light years, and that's a huge margin which doesn't even include 640.

I should reiterate here that even if it's at the low end of that scale, astronomers expect no ill effects for any life remaining on Earth when it happens. Of course, astronomers have been known to be wrong, from time to time.

But, okay. Issues with the headline don't always transfer to the actual text. It's just that it's the first thing we see, so getting it right is kinda a big deal. I'm not saying that it's clickbait, but it is a bit sensationalized.

The stars in the night sky, as we typically perceive them, are normally static and unchanging to our eyes. Sure, there are variable stars that brighten and fainten, but most of those do so periodically and regularly, with only a few exceptions. One of the most prominent exceptions is Betelgeuse, the red supergiant that makes up one of the “shoulders” of the constellation Orion.

Hence the title of today's entry.

Over the past five years, not only has it been fluctuating in brightness, but its dimming in late 2019 and early 2020, followed by a strange brightening in 2023, indicates variation in a fashion never before witnessed by living humans.

It is necessary for a human to be living in order to witness anything (metaphysics and religion aside), but I think they mean it's weirder than it's been for the past 100 years or so.

There’s no scientific reason to believe that Betelgeuse is in any more danger of going supernova today than at any random day over the next ~100,000 years or so, but many of us — including a great many professional and amateur astronomers — are hoping to witness the first naked-eye supernova in our galaxy since 1604.

As unlikely as it might be, I've said before that it would be very, very cool if I got to see it. I'm just not betting on it.

Located approximately 640 light-years away, it’s more than 2,000 °C cooler than our Sun, but also much larger, at approximately 900 times our Sun’s radius and occupying some 700,000,000 times our Sun’s volume. If you were to replace our Sun with Betelgeuse, it would engulf Mercury, Venus, Earth, Mars, the asteroid belt, and even Jupiter!

See, those numbers don't hit very well with people, including me. Even comparing the size to our solar system doesn't give us a visceral idea of just how fucking huge that star is (not to mention I'd question the Jupiter orbit thing, because red giants like that just don't have a well-defined surface in the way that we think of the Sun as having one).

This image   might help with the size comparison.

Even when it transitions to the more advanced stages of life within its core, from carbon-burning to then neon and oxygen and eventually silicon fusion, we won’t have any directly observable signatures of those events.

Dude, people are easily confused. I get that stars, like people or cats, have a birth, time of existence, and death. As far as we know, though, stars themselves don't harbor life. Yes, the universe is weird, and it's fun to speculate that maybe they do, but "life" in this case is a metaphor for how stars change over time. Calling it life just begs people to misunderstand, deliberately or not, what's meant.

The article goes on to describe what whoever's on Earth when it happens can expect to experience when the event finally occurs. Not going to quote more, but it's pretty interesting, in my opinion. Pay no mind to the "it really happened 640 [or whatever] years ago" thing, though; it's irrelevant except as a way to acknowledge that information has a maximum speed.

Naturally, being science, everything there is based on our best knowledge at this point in time. I'd also expect surprises. But those surprises will only serve to advance the science.

Unless, of course, they're wrong about the "it won't irradiate and sterilize the Earth" thing.

Sleep tight!