APOD: Betelgeuse Imagined (2020 Jan 01)

[APOD Robot]

Betelgeuse Imagined

Explanation: Why is Betelgeuse fading? No one knows. Betelgeuse, one of the brightest and most recognized stars in the night sky, is only half as bright as it used to be only five months ago. Such variability is likely just normal behavior for this famously variable supergiant, but the recent dimming has rekindled discussion on how long it may be before Betelgeuse does go supernova. Known for its red color, Betelgeuse is one of the few stars to be resolved by modern telescopes, although only barely. The featured artist's illustration imagines how Betelgeuse might look up close. Betelgeuse is thought to have a complex and tumultuous surface that frequently throws impressive flares. Were it to replace the Sun (not recommended), its surface would extend out near the orbit of Jupiter, while gas plumes would bubble out past Neptune. Since Betelgeuse is about 700 light years away, its eventual supernova will not endanger life on Earth even though its brightness may rival that of a full Moon. Astronomers -- both amateur and professional -- will surely continue to monitor Betelgeuse as this new decade unfolds.

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[LarryF]

This decade is a year from being over.

[bystander]

This decade is a year from being over.

People seem to find it hard to understand the decade starts with year one not year zero, yet nobody I know starts counting at zero.

[Antony Rawlinson]

Much as I agree that the "new decade" stuff is misplaced, let's get back to the astrophysics. The main page says that the Betelgeuse supernova won't be a danger to us, but will "rival the full moon" in brightness. What it doesn't say is how long it will last.

Wanting to know about this, I found the page I've linked below. It says "So, how long does a supernova take to explode? ... a few months to brighten, and then just few years to fade away." Are scientists able to be more precise than this about a specific star, knowing its characteristics?

https://www.universetoday.com/119733/ho ... va-happen/

[Astronymus]

Damn, and I was thinking Orion looked odd this year... or the last. Something felt "wrong" in the constellation.

[neufer]

Click to play embedded YouTube video.

This decade is a year from being over.

People seem to find it hard to understand the decade starts with year one not year zero, yet nobody I know starts counting at zero.

The 20th Century officially ended 1/1/2001
but the 1900's ended 1/1/2000.

A decade can refer to any consecutive ten year period.

[orin stepanek]

Just got to musing;how far out would
be the habitable zone of this Star! Then
do we even know if it has any planets?
By the way; Nicely done artist image:
Kudos to EsoCalcada

[AlanNY]

Click to play embedded YouTube video.

This decade is a year from being over.

People seem to find it hard to understand the decade starts with year one not year zero, yet nobody I know starts counting at zero.

The 20th Century officially ended 1/1/2001
but the 1900's ended 1/1/2000.

A decade can refer to any consecutive ten year period.

While technically true, people don't start each year claiming "It's a new decade." No one talked about beginning a new decade as January 1, 2019, approached. It only comes up in years ending in 0 and 1. Once we get past January 1, 2021 we won't hear about it again until 2030 approaches.

[orin stepanek]

This decade is a year from being over.

People seem to find it hard to understand the decade starts with year one not year zero, yet nobody I know starts counting at zero.

+1 I heartily agree

[sillyworm 2]

Interesting to note that 2 suns have been found to orbit BETELGEUSE.Thank you links!

[Chris Peterson]

This decade is a year from being over.

People seem to find it hard to understand the decade starts with year one not year zero, yet nobody I know starts counting at zero.

It depends what you're counting. If you're counting things, you start at one. If you're counting quantities (like time) you start at zero.

[Chris Peterson]

A decade can refer to any consecutive ten year period.

So can a century. Just not conventionally named centuries. In common usage, decades are named by their tens. We've just entered the 20's. So by convention, today is the first day of a new, named decade.

[neufer]

This decade is a year from being over.

People seem to find it hard to understand the decade starts with year one not year zero, yet nobody I know starts counting at zero.

+1 I heartily agree

Happy 203^rd Decade!

203 is the seventh Bell number, giving the number of partitions of a set of size.

The Bell triangle is a triangle of numbers analogous to Pascal's triangle, whose values count partitions of a set in which a given element is the largest singleton. It is named for its close connection to the Bell numbers, which may be found on both sides of the triangle, and which are in turn named after Eric Temple Bell.

Code: Select all

                    1
                 1     2
              2     3     5
           5     7    10    15
       15    20    27    37    52
    52    67    87   114   151   203
203   255   322   409   523   674   877

[heehaw]

Decadent discussion!

[Antony Rawlinson]

It depends what you're counting. If you're counting things, you start at one. If you're counting quantities (like time) you start at zero.

Not in this case. The Christian Era (or "Common Era") started with the year 1, not the year 0 - which was not designated.

This means that centuries - when stated as divisions of time - run from the year ending "01" to the year ending "00". Similarly decades (as divisions of time) run from the year ending "1" to the year ending "0".

[Chris Peterson]

It depends what you're counting. If you're counting things, you start at one. If you're counting quantities (like time) you start at zero.

Not in this case. The Christian Era (or "Common Era") started with the year 1, not the year 0 - which was not designated.

This means that centuries - when stated as divisions of time - run from the year ending "01" to the year ending "00". Similarly decades (as divisions of time) run from the year ending "1" to the year ending "0".

Astronomically, however, we use Julian days for our counting of time... and they begin with zero. Centuries, like decades, can start anywhere. You're only considering one convention... which I already excluded in the case of decades.

The 20s began with 1 Jan 2020, just like the 2000s began with 1 Jan 2000. And we can only accurately count time starting at zero. You're talking about a naming convention only.

[SeedsofEarfth]

Further to the discussion concerning the 3rd decade of the 21st century: We have just completed 20 years in the 21st century. We are now in the 21st year, thus, we are in the 20's (3rd decade), not the teens. When you complete your 20th year of life, we say you are 20 years old, and that holds for 365 days. However, all 365 of those days make up your 21st year, because you have already comppleted your 20th year.

[AlanNY]

This decade is a year from being over.

People seem to find it hard to understand the decade starts with year one not year zero, yet nobody I know starts counting at zero.

It depends what you're counting. If you're counting things, you start at one. If you're counting quantities (like time) you start at zero.

The current calendar did not start with 0. It started with the year 1. It would be odd to say the first decade of our calendar was 9 years and first century 99 years.

[E Fish]

Regardless of whether or not this is a new decade (and since humans named the years, decades, centuries, etc, and there are multiple calendars in use even now, is anyone surprised at the inconsistency?), I love this artist's conception of Betelgeuse. I tell my students about how big Betelgeuse is, how much energy is pouring off it at all times, and I may just snag this pictures to show them and help them understand it better.

I've never seen a supernova myself (I was only six when the one in the Large Magellanic Cloud occurred), and I'd love to see something as impressive as a supernova as bright as the full Moon.

[Ann]

Click to view full size image

Betelgeuse is a fat man with indigestion.

Ann

[neufer]

Regardless of whether or not this is a new decade (and since humans named the years, decades, centuries, etc, and there are multiple calendars in use even now, is anyone surprised at the inconsistency?), I love this artist's conception of Betelgeuse. I tell my students about how big Betelgeuse is, how much energy is pouring off it at all times, and I may just snag this pictures to show them and help them understand it better. I've never seen a supernova myself (I was only six when the one in the Large Magellanic Cloud occurred), and I'd love to see something as impressive as a supernova as bright as the full Moon.

One of the very few extragalactic supernovae visible in 50mm binoculars

---

• You could have seen one with a small telescope
  (in the current 202^nd decade) if you had wished:

<<SN 2011fe was a Type Ia supernova discovered by the Palomar Transient Factory (PTF) survey on 24 August 2011 during an automated review of images of the Messier 101 from the nights of 22 and 23 August 2011. It was located in Messier 101, the Pinwheel Galaxy, 21 million light years from Earth. It was observed by the PTF survey very near the beginning of its supernova event, when it was approximately 1 million times too dim to be visible to the naked eye. It is the youngest type Ia ever discovered. About 13 September 2011, it reached its maximum brightness of apparent magnitude +9.9 which equals an absolute magnitude of about -19, equal to 2.5 billion Suns. At +10 apparent magnitude around 5 September, SN 2011fe was visible in small telescopes. As of 30 September the supernova was at +11 apparent magnitude in the early evening sky after sunset above the northwest horizon. It had dropped to +13.7 as of 26 November 2011.>>

[Antony Rawlinson]

I've never seen a supernova myself (I was only six when the one in the Large Magellanic Cloud occurred), and I'd love to see something as impressive as a supernova as bright as the full Moon.

It might put a handicap on other astronomical observations for the duration of the phenomenon. Can anyone say how long the Betelgeuse supernova is expected to last, or is there no way of estimating it until it happens?

[Ann]

People seem to find it hard to understand the decade starts with year one not year zero, yet nobody I know starts counting at zero.

+1 I heartily agree

Happy 203^rd Decade!

203 is the seventh Bell number, giving the number of partitions of a set of size.

The Bell triangle is a triangle of numbers analogous to Pascal's triangle, whose values count partitions of a set in which a given element is the largest singleton. It is named for its close connection to the Bell numbers, which may be found on both sides of the triangle, and which are in turn named after Eric Temple Bell.

Code: Select all

                    1
                 1     2
              2     3     5
           5     7    10    15
       15    20    27    37    52
    52    67    87   114   151   203
203   255   322   409   523   674   877

This is what I love about you, Art. Not that I understand a thing of what you are saying.

But even I can see that that Bell triangle sure is elegant. Then again, "Happy 203^rd Decade!"? You lost me there, I'm afraid.

On the other hand, so what if I don't understand? It's not necessary for me to understand everything I see or hear to get a glimpse of the amazing worlds that bright and thoughtful people construct inside their heads.

So thanks again, Art.

Ann

[Chris Peterson]

People seem to find it hard to understand the decade starts with year one not year zero, yet nobody I know starts counting at zero.

It depends what you're counting. If you're counting things, you start at one. If you're counting quantities (like time) you start at zero.

The current calendar did not start with 0. It started with the year 1. It would be odd to say the first decade of our calendar was 9 years and first century 99 years.

Already addressed. Twice.

[neufer]

"Happy 203^rd Decade!"?

You lost me there, I'm afraid.

I misspoke: the 203^rd Decade doesn't actually begin for another year.

Or, if you prefer you can refer to it as:

• the 3^rd Decade of the 21^st Century or
  
  the 3^rd Decade of the 1^st Century of the 3^rd Millennium.