
Betelgeuse Fades More - Amorymeltzer
https://astroblogger.blogspot.com/2019/12/betelgeuse-fades-more.html
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jameshart
Confused me to read "Betelgeuse is the bright red star below the "saucepan" of
Orion." \- Orion doesn't have a 'saucepan', he has a sword, and Betelgeuse is
at the _top_ of.. oh, wait a minute...

Went back to check. Yup, this blogger is in Australia.

Just something to keep in mind if you're following his observation tips :)

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WizardAustralis
I will consider this pay back for all the astronomy information I read through
only to realize they are talking North Hemisphere.

When I got my telescope (Equatorial Reflector) the first thing the manual
talks about is "Find the North Star" \- Good luck doing that at 47 degrees
South Latitude.

Will have to take a gander tonight and see what Betelgeuse is up to.

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dr_zoidberg
As another southern hemisphere dweller, I feel you. It's incredible what an
impressive amount of astronomical information is only availabe with a northern
hemisphere point of view, and it's down on us to take care of "translating" it
to our location. Even more so when you consider the huge telescopes that have
been/are being built in Chile by Europe.

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WizardAustralis
I chose to think we have the exclusive view of the south that the north misses
out on. ;)

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tyfon
I always look at Betelgeuse when I am out walking an it's a clear sky. It's
very easy to spot and you can pick out the colour difference with the naked
eye.

I hope it will go supernova in my lifetime, it will be spectacular. This
dimming might be a sign of that.

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0xFFFE
May be it's gone supernova already.

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perl4ever
Some say it's better to regard anything with a lightlike separation as being
simultaneous and that things with a spacelike separation essentially don't
exist for practical purposes. So when the light reaches us is when it happens,
because not even gravity can affect us beforehand.

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0xFFFE
Convenient perhaps, but the engineer in me doesn't want to accept that. Light
is the fastest thing in the universe and it takes 642 years to reach us from
this particular star. So we are lagging by 642 years. Those are the facts.

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zaroth
Except that those photons haven’t aged a single day, right?

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0xFFFE
Genuinely curious as to why you think they haven't aged a single day. Doesn't
it depend on the point of reference? Earth is 500 light seconds from the Sun.
So any photon hitting the eye is at least 500 seconds old. Hypothetically
speaking, if a human were to be born on the Sun's surface and reach earth at
the speed of light, he/she is at least 500 seconds old on Earth's clock?

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pacificmint
Sure, but from the frame of reference of the human it’s not. If the human
would travel at 99% of the speed of light, then time dilation would make it a
lot less than 500 seconds.

If an object moves at the speed of light, Mathematically no time is passing.

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mathieuh
It's also why we can detect muons on Earth, a particle that would have decayed
by the time it reaches us if its age depended on our frame of reference.

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0xFFFE
I looked up after your reply, they decay by losing energy based on the matter
they interact with. So in the vacuum of space they can travel great distances
as long as they don't interact with the matter.

Source:
[https://cosmic.lbl.gov/SKliewer/Cosmic_Rays/Muons.htm](https://cosmic.lbl.gov/SKliewer/Cosmic_Rays/Muons.htm)

~~~
lokedhs
You are misreading the document. The muons are created in the top of the
atmosphere and decays after a very short amount of time. The point is that
they decay so fast that they shouldn't be able to reach the ground. They
manage to do that because time passes much slower for the muon. Or to put it
differently, from the point of view of the muon the thickness of the
atmosphere has been compressed to become much smaller than from the point of
view of an observer on Earth.

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0xFFFE
You are right, I misread the document. I stand corrected.

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pvg
Some historical context and interesting references, including a recent
estimate on the supernova timeframe:

[https://twitter.com/EricMamajek/status/1208176941502590976](https://twitter.com/EricMamajek/status/1208176941502590976)

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rwmj
Fascinating, but I think the most interesting thing was:

> _" Centuries later [than the original text from 964AD] in Europe, a scribe
> mistransliterated Arabic Y in Yad al-Jauza' to B & rest is history"._

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JulianMorrison
So wait, you're telling me it's actually Yeetlejuice?

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anonymfus
TIL that in English Betelgeuse is pronounced like Beetlejuice. In Russian for
example it's more like Be-tel-geyser (like British geyser).

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pvg
I'm not so sure British geyser is really pronounced with a гей.

[https://dictionary.cambridge.org/us/pronunciation/english/ge...](https://dictionary.cambridge.org/us/pronunciation/english/geyser)

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Filligree
I've heard of a lot more variable stars over the last few years, all of them
having unusually low dips.

The explanation is simple--I'm noticing now, and I didn't before--but it's
amusing to imagine there's some other reasons. Aliens building Dyson swarms,
whatever. Never mind that the timeline doesn't work out...

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downrightmike
More likely better telescopes

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mihaaly
Any recent change in the method of measurements?

