back to article Boffins: Tireless star spurted deadly jets for half an hour at a time

Scientists studying one of the biggest cosmic explosions ever recorded have theorised that the enormous bang, from which super long-lasting gamma ray bursts were emitted, was caused by the death of a massive star up to 1,000 times bigger than the Sun. A team at the University of Warwick studied a mysterious explosion recorded on …

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Happy

"...a newly formed black hole in the heart of the star"

I suppose 7 billion years ago is 'newly', in the scheme of things...

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Trollface

Re: "...a newly formed black hole in the heart of the star"

Certainly from our perspective - and does any other perspecive matter?

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“The amazing thing is that nature seems to have found ways of blowing up a wide range of stars in the most dramatic and violent way.”

That has to be the quote of the day :)

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QoD

You beat me to it, so have an upvote.

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So, Mother Nature is actually a guy then ?

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Mushroom

Ah

Some pan-dimensional equivalent of Mythbusters at work, then.

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Unhappy

I wonder

how many local civilisations the explosion ended.

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Mushroom

Re: I wonder

All of them?

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Red Shift - red faces

The further away the object, the longer in earth perceived time an event of a particular duration wrt the frame of reference of the exploding object will appear, due to the relativistic doppler shift which gives us a red shift to lower frequencies of objects further away, due to the expanding universe. I wonder if they've taken this into consideration in relation to the longer than expected duration of this event ? It would be a simple but embarrassing mistake if this is the case.

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Holmes

Re: Red Shift - red faces

So, what do you think? Did they?

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Re: Red Shift - red faces

"So, what do you think? Did they?"

I'm far too inexpert to hold a strong view either way, but it's an interesting speculation. Highest observed redshifts suggest a z of around 8, and I guess (but am not sure this is what this means) this corresponds to the time multiple you would get in the duration of the burst. Gamma rays are such high frequency that a redshift reducing frequency by factor of 8 seems neither here nor there. Redshifts getting much closer to the start of the universe seem to multiply to much larger factors.

https://en.wikipedia.org/wiki/Redshift#Highest_redshifts

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Re: Red Shift - red faces

Yes, I think astrophysicists are aware of doppler shifting.

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Headmaster

Galactic Greenfagging

"Lethal gamma rays are produced during the deaths of massive stars"

That adjective "lethal", is pretty bizarre in this context.

Fleshbags worry about "lethal gamma rays" if the engineered fission reactor in the neighborhood has a little hiccup or if food is being sterilized by passing it along a fews of cobal 60 or some nasty job in a federal office warns darkly about "dirty bombs".

In this context, better replace "lethal" by "enormous amounts or" or maybe "planetbusting amounts of" or even "starbusting amounts of" or possibly "stargutbusting amounts of".

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Boffin

Re: Galactic Greenfagging

"Fleshbags worry about "lethal gamma rays" if the engineered fission reactor in the neighborhood has a little hiccup or if food is being sterilized by passing it along a fews of cobal 60 or some nasty job in a federal office warns darkly about "dirty bombs"."

Or when a Gamma powered scientist, in an agitated state, flings a Volvo through their high rise in the middle of the work day.

Boffin because you wouldn't like him when he's angry.

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Boffin

1 billion miles?

That's outside the orbit of Saturn, folks!

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Coat

1 billion miles?

Shouldn't that be one beeellion miles?

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Boffin

Re: 1 billion miles?

And what's a beeelion miles in a universe this size, anyway?

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Umm...

"In small stars, the gamma rays created in the explosion take a short time to reach the edge of the star, where they are propelled into space. With huge stars, the explosion takes much longer to travel through the star, meaning the gamma ray burst is longer."

Not quite right, I'm afraid.

It's correct that the larger the star, the longer it will take for the effects of an 'explosion' (not really the right word to use) at its center to propagate to the star's surface, but what we're talking about here is the duration of that 'explosion', or in other words, how long the 'explosion' went on for.

Whilst it's possible that the passage of the initial effects of the event changed the characteristics of the star as it passed through it, it's extremely difficult to imagine what sort of change could have occurred that would've slowed the effects from the final part of the event to the degree observed; in short, it would've taken roughly the same time for both the first effects and the final effects to make the journey.

To be sure though, a larger star will be required for a longer event; a smaller star would not have enough matter to sustain a longer event.

As no mention of the relative intensities of the gamma rays from this long burst, compared with a more typical short burst, adjusted for distance, of course, was made then assuming the intensities were similar it means that the rate of matter-energy conversion was about the same, which means that more matter had to be converted, over a longer period of time, which means a larger star. If, however, the intensity of the longer burst was relatively greater it means that a higher rate of matter-energy conversion was going on, and as the period of time remains unchanged it means that the star must have been even bigger.

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Anonymous Coward

7 billion light years is not (when I last looked) "half way to the edge of the observable universe" (a diameter of 93 beeellion light years)....so on our doorstep really.

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Where did you look that up?

The edge is still just ~15 x 10⁹ away.

Star Wars numbers about fantasy positions that are meant to "take into account expansion" by assuming some magic universal time don't count.

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Anonymous Coward

Talking about the 'edge' of the universe makes as much sense as talking about the 'edge' of the planet.

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Boffin

That is why they talk about the edge of the observable universe. One could also call this "edge" our event horizon. Just because crayons work in 2D does not mean 3-D (or for that matter n-D, for any positive integer n) objects cannot have an edge (or boundary if you like).

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Anonymous Coward

And what is 15 x 10⁹ in light years? Just google observerable universe......

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Meh

missing a big anomaly

Gentlepersons, gentlepersons and flamers, please, some gravitas.

How does a star get to 1000 solar masses ?

It should be blowing away any incoming matter when it gets to a theoretical 250 or so solar masses. That upper limit is being moved up in speculation, but 4 times the theoretical maximum is a stretch. Unless astrophyscists models are really incomplete ? Nice to imagine. How many layers of element burning would there be ? Inner core layers making iron and heavier stuff instead of needing colliding neutron stars to make gold. What would such a star radiate ? low energy gamma or just extreme UV ?

It does suggest a Mega-Mythbusters test sequence though :-)

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Re: missing a big anomaly

As I understand it, some theories hold that in the early universe stars were much more massive because they were formed entirely out of hydrogen. As time goes on there's less pure hydrogen available so stars can't be quite as big. The 1000+ solar mass stars are of the pure hydrogen variety (though 7 billion years ago seems a bit "late", I thought these were in the first few hundred million years after the big bang)

Inner core layers "should" never create anything heavier than iron, because it costs energy to do so. Some more recent theories believe that heavier elements are created inside stars despite this, because there's a LOT of energy inside a star and there's no law that prevents fusion that requires more energy input than is output. Either way, whether created inside a star or created as the result of a supernova, elements heavier than iron would be more rare as a result.

BTW, never heard this idea about gold being created by colliding neutron stars. This sounds like some crazy gold bug fable made to drive up the price by making it seem even more rare than it is. :)

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Re: missing a big anomaly

Rare? Imagine a cube 21m on each side. That's all of the gold we've dug out of the ground, ever. I call that rare.

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Re: missing a big anomaly

>a cube 21m on each sid... all of the gold we've dug out of the ground

IIRC, that's the low end of estimates (recently read somewhere on the BBC). But, either way, rarity's relative. So what are you relating it to?

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Re: missing a big anomaly

Relative to, for example, coal which is so common we scoop it out of the ground with machines like this one: Bagger 288

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Re: missing a big anomaly

Coal is not an element. If you calculated the same "cube x meters on side" for uranium and other heavier elements you'd come up with a far smaller amount. Not only is it rarer to start with, it decays over time and unlike gold actually has a use we can put it to, rather than most of it only being dug out of the ground so we can then store it back underground in vaults.

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Windows

Re: missing a big anomaly

Unfortunately uranium is not likely to be a fungible commodity and so is unlikely to become "money", like gold.

> so we can then store it back underground in vaults.

You now realize that there is value in having a commodity that takes the role of money and that cannot be debased by a ministerial stroke of genius whenever Klown Krugman writes another shitty column in the NYT.

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Re: missing a big anomaly

Coal is near-as-dammit an element: carbon (with a few impurities mixed in). And I stand by my point that we have easy access to LOTS of it, compared to only a tiny bit of gold.

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@Destroy All Monsters

Having a (mostly) useless commodity as money is rather silly when you think about it. Gold is money only due to history, and that's probably more due to its malleability, allowing it to be shaped before humans had the ability to work with other metals that had to be melted first.

In today's world energy is money in a much more real sense than gold. Look at the countries that dig up a lot of oil, gas, and coal from the ground, and compare them with countries that dig up a lot of gold. It's clear which you'd rather have a lot of.

Even at today's still bubblicious prices for gold, the value of the oil (just oil, not including gas and coal) produced in three years exceeds the value of all the gold that has ever been mined in the history of the world. Gold bugs would use this as an argument that the price deserves to much higher, but you can't run an industrial economy on gold.

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Anonymous Coward

Gosh Batman

Big stars go BANG much more than small stars go Bang.

Who'd a thunk it?

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Re: Gosh Batman

Big stars go BANG much moreso than small stars go BANG--but both really do go BANG.

FTFY.

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Anonymous Coward

I helped build the Gemini telescopes.

It is good to see some results from one.

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