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[Music]

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nasa's fermi gamma-ray space telescope

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has spotted the shortest burst of gamma

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rays ever seen from a collapsing star

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it challenges the traditional

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classification of gamma-ray bursts also

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called

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grbs grbs those lasting less than two

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seconds are thought to occur when

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orbiting objects like neutron stars

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spiral together and merge

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longer bursts come from massive stars at

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the ends of their lives a black hole

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forms at the center of the collapsing

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star it drives long-lasting jets that

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drill through the star producing gamma

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rays when they emerge

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the star then transforms into a

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supernova

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on august 26 2020 fermi detected a grb

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lasting about one second

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instruments on other spacecraft saw it

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too including nasa's wind and mars

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odyssey missions

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they helped narrow down the location to

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a patch of sky in the constellation

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andromeda

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less than a day after the grb

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astronomers identified a fading source

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of visible light using the zwicky

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transient facility at palomar

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observatory

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this was the bursts afterglow

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nasa's swift satellite soon recorded

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x-rays from it and within days

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ground-based radio telescopes observed

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it too

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after a few weeks when the afterglow had

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decayed ground-based observatories

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confirmed the presence of a brightening

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supernova

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this means the grb must have come from a

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massive collapsing star not a merger

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astronomers think this burst called grb

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2008 2008-26a was on the verge of not

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occurring at all

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about 6.6 billion years ago a massive

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star in a distant galaxy reached the end

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of its life

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its core collapsed and formed a black

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hole which launched near-light speed

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particle jets through the star

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just as they breached the surface the

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jets shut down producing a surprisingly

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brief grb

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astronomers think it's likely some short

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grbs they've detected are misclassified

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as mergers when instead they're really

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bursts from jets that nearly failed to

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drill through collapsing stars

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we only detect grbs when the jets aim in

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our direction

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even accounting for this

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long grbs still occur at a lower rate

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than the supernova type associated with

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them

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this means most collapsing massive stars

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likely fail to produce long-lived jets

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dying

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at least from the gamma-ray perspective

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with a whimper