[ExI] First Picture of a Black Hole!

Darin Sunley dsunley at gmail.com
Thu Apr 11 03:11:53 UTC 2019

Ask, and ye shall receive :


On Wed, Apr 10, 2019 at 8:59 PM Stuart LaForge <avant at sollegro.com> wrote:

> Tomaz Kristan wrote:
> >
> > Shouldn't it be the Sagittarius? Much smaller and much closer one?
> >
> > Why is that now?
> >
> > On Wed, Apr 10, 2019 at 3:38 PM John Clark <johnkclark at gmail.com> wrote:
> >
> >> https://www.nytimes.com/2019/04/10/science/black-hole-picture.html
> >>
> As John pointed out their angular widths should be about almost equal
> at 5:4 for SgrA* vs M-87*. While there is a lot of dust between us and
> SgrA*, that shouldn't affect meters-wide radiowaves. So my guess is
> that the paper published back in January that suggested that the radio
> jet of Sagittarius A* is pointed directly at us is actually correct.
> http://www.astronomy.com/news/2019/01/radio-jets-from-the-milky-ways-black-hole-could-be-pointing-right-at-earth
> The radio jet pointing directly at us would make the picture of SgrA*
> just look like a bright blotch of light with no dark "shadow" apparent
> so it would not look much like a "black" hole. Even in the picture
> M-87* they have, the shadow is not quite as dark as the peripheral
> space suggesting there is some radio emission occurring between it and
> us.
> And also, I know they billed it as a mere "picture" but would it have
> killed them to put in some form of scale or the galactic plane of M-87
> or something for reference? The shadow of the BH looks like an ellipse
> elongated in the NE to SW direction. That could be the equatorial
> plane of the black hole's rotation in which case it would be spinning
> pretty fast. But with no frame of reference it might as well be a
> photo of a UFO.
> Stuart LaForge
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