this post was submitted on 18 Aug 2023
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Giant black holes were supposed to be bit players in the early cosmic story. But recent James Webb Space Telescope observations are finding an unexpected abundance of the beasts.

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[โ€“] webghost0101@sopuli.xyz 7 points 1 year ago (1 children)

The things we see are from a millions years ago, who knows where or how big these are right now, might not even exist any more.

[โ€“] WhatAmLemmy@lemmy.world 10 points 1 year ago (1 children)

*Billions (13,000+ million). Based on our current understanding and their close proximity to each other in the early universe, most of them would have likely merged and many/most may be now at a size where it would take a google years to evaporate. The extremely small ones that did not merge may have already evaporated.

Source: Hawking radiation

[โ€“] chimerical@toast.ooo 3 points 1 year ago (1 children)

From my understanding they would still have a looong way to go before they would have evaporated.

[โ€“] WhatAmLemmy@lemmy.world 1 points 1 year ago* (last edited 1 year ago) (1 children)

I thought so too but apparently the length of time it takes a black hole to evaporate is based on mass and those with a low mass โ€” as in, the mass of the moon โ€” should have already evaporated. Only supermassive black holes are the ones likely to take a google years to evaporate.

Edit: none of the ones pictured are that small. We probably couldn't detect them for hundreds/thousands of years (e.g. until solar system sized telescopes).

[โ€“] chimerical@toast.ooo 1 points 1 year ago

According to this calculator a black hole the size of the moon would take 584,745,000,000,000,000,000,000,000,000,000,000,000,000,000 years. I'm always open to correction though. (5.84745E44)