9.4.2019: First picture of a Black Hole (in M87)!

Black Holes [1] are singularities in space in time and must exist due to the General Relativity Theory (GRT) founded by Albert Einstein [2]. Astrophysicist have proposed that Black Holes are the building blocks of galaxies; and in particular are located in the center of active galaxies, usually knows as Quasars [3].

Black Holes are formed if a massive star is at their's end of nuclear fuel burning, probably exploding as a Supernova [4], while the remnant matter is to heavy to be stabilised as Neutron Star [5] and is undergoing a complete collapse. At a certain point in time given that collapse, the matter density in the core exceeds a point, where the escape velocity of particles is larger than the light of speed. On earth, given the earth mass, we have roughly an escape velocity of 10 km/s while for a Black hole it has to be about 300 000 km/s.

At that point, the Black Hole is detached from our universe and only can interact with it by means of its gravity (except for Hawking radiation): It becomes a singularity.

Now it has be claimed [6] to have 'pictured' a Black Hole in the 16 Mpc (55 million LJ) distant galaxy M87 (which is famous by its blue illuminated active kernel) [7]. The 'picture' was taken using Very Large Based Interferometry (VLBI) from Radio Telescopes [8] on the globe over several month.

While critics [9] were of course sceptical about those 'pictures', it hit the news rapidly. Not only, that the object is 16 Mpc way from us, but rather to take pictures of the core of a strong radiating galaxy like M87 - covered by billions of other suns, gas, and globular stellar clusters - seems to be more than challenging. We need to consider, that by virtue of the VLBI radio telescopes, the effective resolution is 40*10-3 arcsecs. 1 arcsec is the angle corresponding to 1 AU (Astronomical Unit = 150 000 km) as seen from a distance of 3.26 LYs (Lightyear) = 1 pc (parsec) [10]. Thus, with some math, it follows that two objects at M87 have to have minimal distance of 1/10 pc in order to be distinguishable.

Looking now at [11] (taken form [12]), the resolution is of 20*10-3 arcsecs is indicated, showing much more details below that level. However, we need to understand that this picture [11] is not a 'picture' but rather an extrapolated and interpreted piece of information joining the data of very many radio telescopes and transforming it to our conventional (visual) expectation: It matches actually our expectation; but could be far away from reality is well.

Anyway, probably the guess, that in this massive Black Hole about 6.5*109 solar masses are captured is very likely, though it is roughly 1/20 of the mass of our Milky Way. While the Event Horizon [13] of a star like our sun is a few km only, this gigantic massive Black Hole is larger than our Solar System; as depicted by [14], [15].


[1] en.wikipedia.org/wiki/Black_hole
[2] en.wikipedia.org/wiki/General_relativity
[3] en.wikipedia.org/wiki/Quasar
[4] en.wikipedia.org/wiki/Supernova
[5] en.wikipedia.org/wiki/Neutron_star
[6] www.eso.org/public/news/eso1907/
[7] en.wikipedia.org/wiki/Messier_87
[8] en.wikipedia.org/wiki/HALCA
[9] xkcd.com/2133/
[10] en.wikipedia.org/wiki/Parsec
[11] www.fehcom.net/diary/2019/apjlab1141f5_lr.jpg
[12] iopscience.iop.org/article/10.3847/2041-8213/ab1141/meta
[13] en.wikipedia.org/wiki/Event_horizon
[14] xkcd.com/2135/
[15] voyager.jpl.nasa.gov/mission/status/