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How many supernova explode every year?

badastronomy.beehiiv.com

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Re: How many supernova explode every year?

#101

Post by marklar423 »

tialaramex wrote: post #9

That's one of my favourite hints in Outer Wilds. You will see a Supernova. Not with a fancy telescope, it's visible to the naked eye, and if you watch the sky you'll see another soon enough. You can see this right at the start, and unlike the random direction of the probe launch you don't need any game lore to, if you're smart enough, put two and two together.

It's funny, I noticed I happening and thought it was proof of the opposite - that there had to be some artificial cause for the supernovae (including the Sun), because a real supernova takes many years to progress, not 20 minutes.

Even after visiting the Sun Station I didn't believe it and thought it was a narrative red herring....so the ending was a surprise to me. Somehow.

Re: How many supernova explode every year?

#102

Post by Wobbles42 »

ur-whale wrote: post #85

Spoiler alert: > THIRTY SUPERNOVAE PER SECOND, over the entire observable Universe.

If we have events occuring at some rate in the entire observable universe, and that rate is one a human can easily visualize (e.g. "30"), then the answer to the question "how often do supernovas occur" is probably best summarized as "almost never".

Re: How many supernova explode every year?

#103

Post by belter »

The SuperNova Early Warning System (SNEWS): https://snews2.org/

brings together the fantastic [1] Super-Kamiokande, the [2] IceCube, and other global detectors, to provide early warning of Supernovas.

You can subscribe... https://snews2.org//alert-signup/

[1] https://en.wikipedia.org/wiki/Super-Kamiokande

[2] https://en.wikipedia.org/wiki/IceCube_Neutrino_Observatory

Re: How many supernova explode every year?

#104

Post by wruza »

ninkendo wrote: post #53
lifeisstillgood wrote: post #48

No wonder the Millennium Falcon takes so longer to calculate its jump to hyperspace. Tens of thousands a year is one an hour! There are so many supernovae you really could bounce too close to one and that would end your trip real quick

Star Wars takes place entirely within one galaxy, and the number of supernova per galaxy is something like 1 per century, so, nah, Han was just bullshitting to stall for time while his busted-ass computer cobbled together numbers.

Most movies don't even leave our stellar vicinity, because they want to use hyped star/constellation names and these are from the very local set of stars. Not only a naked eye sees only around a few thousands stars, but most of them are basically next door. The mean distance to the star that you can see is <1% of galaxy size. Almost everything you see is in a 10px circle on the 1080p fullscreen galaxy map.

Re: How many supernova explode every year?

#105

Post by Wobbles42 »

SwtCyber wrote: post #25

Absolutely mind-blowing how much our ability to observe the universe has exploded

Arguably, our ability to observe in any meaningful sense is still limited to light waves occuring inside a volume not much larger than the earth itself. I mean this in more than just a semantic sense surrounding the verb "observe" -- for all practical purposes everything outside of our solar system is indistinguishable from a preprogrammed light show being projected on a sphere centered on our sun with a diameter of less than a light year. There is a decent chance that will never change. The sheer size of the universe traps us in the ultimate version of Plato's cave.

Re: How many supernova explode every year?

#106

Post by throwawaymaths »

yzydserd wrote: post #37
herendin2 wrote: post #18

If I got the math right, then about 1 in every 32,000 stars in the universe goes supernova each year. That's scary. But I think I'm getting the math very wrong. edit: I guess my error might be related to confusing a probability factor with the number of incidents in a period. edit: The right answer is probably up to 1 in every 10bn stars go supernovae in the universe each year (or 1 in 10bn die and a fraction are sup…

A star "lasts" about 10 billion years, so you'd expect about 1 in 10 billion stars to 'die' each year, but only a tiny proportion (the very largest) go supernova. Numbers are huge. Even tiny ratios mean something like 10-100 stars go supernova every single second somewhere in the universe. Sounds a lot? Only about 1 star per galaxy goes supernova per century. A lot of galaxies. Mindblowing.

what's the rate of Type Ia supernovas? Higher I would guess? (n>=2-aries are common and medium mass main sequence stars are common, though it takes them a while to get to white dwarf)

Re: How many supernova explode every year?

#109

Post by Wobbles42 »

mrep wrote: post #35
roenxi wrote: post #4

We're dealing with the sum total of everything, if the true nature of things is that there are a finite number of supernovas I'd be surprised. The real shock is how small the number of supernovas is and how young everything seems to be in the known universe (the age of the observed universe is estimated at maybe double digit billion years). These are tiny numbers given that we're quite possibly dealing with infinity…

> 1 supernova a century A century being the amount of time it takes earth, one specific planet to orbit its star 100 times? What about all the other planets and stars?

A century is approximately three billion seconds, the second being variously defined across history as a multiple we find convenient of whatever universal natural constant we can most precisely measure -- most recently 10 billion or so of a specific type of vibration of cesium atoms.

All the other stars and planets would have the same experience, though their local orbital periods might result in different units of expression being more convenient.

Of course, as we leave our galaxy they would also be in significantly different reference frames and perhaps experience the rate differently as a result. We are assuming that, statistically, our relative velocity is not special and they see roughly the same relationship between red shift and distance that we do.

Re: How many supernova explode every year?

#110

Post by danso »

rookderby wrote: post #81

First off, dont look at the outer wilds discussion on here, just play the game. Second - they didnt say how many letters we need to encode all of the observable supernova in a given year! So 100 billion galaxies, 1 per year per galaxy, we have around 1 billion to encode. Sorry two edits this moring, first one was right. due to math without coffee. 1e9/26^6 is about 3, 1e9/26^7 is less than one. So we might see 'SN205…

LOL just started replaying OW for the first time in years, and my immediate reaction to seeing this headline was to go to the comments and make an OW reference
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