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"In fact, from the distant observer's point of view, nothing beyond the horizon really exists, and a physical black hole's mass could be said to consist of the

"In fact, from the distant observer's point of view, nothing beyond the horizon really exists, and a physical black hole's mass could be said to consist of the mass of the collapsing star, ever frozen in the last stages of its collapse." Mind blown. I remember reading that we cannot see a black hole with the naked eye, but never go an explanation as to why... This is a really good article.

gigatexal 8y ago
As a wannabe-black hole scientist I love pages like this!
AceJohnny2 8y ago
Brings back memories of Frederick Pohl's Gateway [1] book... (Spoiler) In the end, we learn that the main character (accidentally) abandoned his friends to a black hole. However (plot twist), it is discovered that because of gravitational time dilation (?), decades later from Earth time's perspective means that his friends are still falling towards the black hole. This always irked me, and this page explains why: the falling would have happened in a microsecond, it's just that the light from the falling ship will appear to slow down because of gravitational effect. [1] https://en.wikipedia.org/wiki/Gateway_(novel) https://en.wikipedia.org/wiki/Gateway_(novel)
- userulluipeste 8y ago
  I see that you are considering only the light, but there is more than that. Time dilatation around gravitational fields is real (we have it on Earth too). Given the extreme setting in this regard around a black hole, it may be possible that, even if the falling object has not yet arrived at the event horizon, there to be a significant and increasing time frame difference between that of a distant observer and that of the object moving closer to gravitational center, which lets the observer see a progressively slower fall. I find this to be more likely the reasoning behind the novel's depiction.
  - AceJohnny2 8y ago
    Yes, you are quite correct! Nevertheless, the nitpick applies: in the timeframe of the narrator outside the black hole, it's already way too late.
yesenadam 8y ago
Since, as the article explains, an outside observer would never see things falling towards the black hole actually reach the 'black' part - they'd just get slower and redder as they get close. So - wouldn't a black hole appear entirely surrounded by all the things that ever 'fell into it', still there outside it? I've never seen an 'artist's impression' of one that looks like that..a big ball of dust, rocks, ice etc. (Imagine if garbage bins looked like that..)
- userulluipeste 8y ago
  So... the black hole may look like a collapsing star but also like a planet? The only thing distinguishing it then would be its escorting (but not yet fallen) world around it?
deleted 8y ago
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gigatexal 8y ago

As a wannabe-black hole scientist I love pages like this!

AceJohnny2 8y ago

Brings back memories of Frederick Pohl's Gateway [1] book... (Spoiler) In the end, we learn that the main character (accidentally) abandoned his friends to a black hole. However (plot twist), it is discovered that because of gravitational time dilation (?), decades later from Earth time's perspective means that his friends are still falling towards the black hole. This always irked me, and this page explains why: the falling would have happened in a microsecond, it's just that the light from the falling ship will appear to slow down because of gravitational effect. [1] https://en.wikipedia.org/wiki/Gateway_(novel) https://en.wikipedia.org/wiki/Gateway_(novel)

userulluipeste 8y ago
I see that you are considering only the light, but there is more than that. Time dilatation around gravitational fields is real (we have it on Earth too). Given the extreme setting in this regard around a black hole, it may be possible that, even if the falling object has not yet arrived at the event horizon, there to be a significant and increasing time frame difference between that of a distant observer and that of the object moving closer to gravitational center, which lets the observer see a progressively slower fall. I find this to be more likely the reasoning behind the novel's depiction.
- AceJohnny2 8y ago
  Yes, you are quite correct! Nevertheless, the nitpick applies: in the timeframe of the narrator outside the black hole, it's already way too late.

yesenadam 8y ago

Since, as the article explains, an outside observer would never see things falling towards the black hole actually reach the 'black' part - they'd just get slower and redder as they get close. So - wouldn't a black hole appear entirely surrounded by all the things that ever 'fell into it', still there outside it? I've never seen an 'artist's impression' of one that looks like that..a big ball of dust, rocks, ice etc. (Imagine if garbage bins looked like that..)

userulluipeste 8y ago
So... the black hole may look like a collapsing star but also like a planet? The only thing distinguishing it then would be its escorting (but not yet fallen) world around it?

deleted 8y ago

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