# Supermassive surprise: the biggest black holes EVER

Here’s a genuine record-breaker: a black hole with nearly ten billion times the mass of our Sun, an event horizon that would stretch five times further than the orbit of Pluto if we had the misfortune to have it drop in, and a gravitational sphere of 4,000 light-years. With such a huge mass and long reach, it’s no surprise that …

#### “These black holes may shed light..."

What? I had understood that black holes *absorbed* light! Oh, wait....

#### Correct

So "it" can't be a black hole.

But like with small children and Santa Claus, it is sometimes kinder not to tell people the truth. Chirgwin wants to believe, and NASA want to believe. Let's leave them to it.

#### Considered... done

Maybe Aliens have observed Hawking radiation? And isn't it supposed to be axial only?

#### Testify, brother!

This article contains material on gravity. Gravity is a theory, not a fact, regarding a force that cannot be directly seen. This material should be approached with an open mind, studied carefully and critically considered.

#### In a nearby Euro Galaxy

After a period of inflation ... supermassive paper money black holes formed everywhere.

This is their story...

Kudos to El Reg for the wording in the intro, " an event horizon that would stretch five times further than the orbit of Pluto" versus the wording in the Berkeley article linked to:

"within a region five times the size of our solar system."

Since Eris orbits the Sun at a distance 3 times greater than Pluto, and is still within the Solar System, there's a very big difference in size between the wording used by El Reg, and that used by Berkeley. A nice touch of care and attention to detail, well done!

A region is a area/volume, which is the unit used by Berkely but El Reg used a distance.

Pretty sure something needs to be divided by Pi at some point.

So, lots of mixed units and definitions.

You cannot really know who means what.

#### Actually El Reg is correct

So if someone says "a circle with the area of a pound coin" and someone else says "a circle with the radius of a pound coin", it's ambiguous how large the circle is? :p

It certainly isn't clear what Berkeley mean by "the solar system" though; El Reg is at least more precise.

Wolfram Alpha says the radius of the event horizon is 3x10^13 m (http://www.wolframalpha.com/input/?i=event+horizon+10000000000+solar+mass - isn't Alpha awesome?)

It says pluto's orbital radius is 6x10^12 m. So El Reg has got this EXACTLY CORRECT at five times the radius of pluto's orbit.

Incidentally, Wolfram also says that 10000000000 solar masses is the theoretical limit on the possible size of a black hole, which is interesting.

#### @Eddie Edwards

So if someone says "a circle with the area of a pound coin" and someone else says "a circle with the radius of a pound coin", it's ambiguous how large the circle is? :p

But your maths falls down when it comes to multiples, as in this occasion.

Area of 5 circles the size of pound coins = 5 * pi * r^2

Area of circle with 5 times the radius of a pound coin = pi * (5*r)^2

Not the same answer.

#### Big enough...

to have a survivable gravity gradient. Anyone what to have a look inside?

My guess is you'll find Heechee....

#### I've seen it. It's rubbish.

We may already be inside the event horizon of a really big (vastly hugely mind-bogglingly big) black hole that we choose to call The Universe.

http://gregegan.customer.netspace.net.au/PLANCK/Complete/Planck.html

“Yes! The centre of the hole lies in our future, now. We won't hit the singularity face-first, we'll hit it future-first — just like hitting the Big Crunch. And the direction on this platform that used to point towards the singularity is now facing ‘down’ on the map — into what seems from the outside to be the hole's past, but is really a vast stretch of space. There are billions of light years laid out in front of us — the entire history of the hole's interior, converted into space — and it's expanding as we approach the singularity. The only catch is, elbow room and head room are in short supply. Not to mention time.”

Hmmm....I'll bite.

Length of a double decker bus = 12 metres (newer models in the UK) - We'll call this "L"

Average distance from the Sun to Pluto = 5,906,376,272 km (the variance is between 4.44 billion km and 7.38 billion km based on it's elliptical orbit), in metres = 5,906,376,272,000 - We'll call this "D"

So... D divided by L = 492,198,022,667 Double Decker Buses.

I think...

#### times 10

remember they said 5 times the size of our solarsystem/plutos orbit. I assume this means a circle, so twice the distance to Pluto then times 5 or 4,921,980,226,670 DD buses.

#### If a black hole was a long way from a galaxy...

and moving directly towards it in the same orbital plane, would it hoover it up?

The reason I ask is that, everything would come from one direction, and the matter would perhaps funnel into towards it, as it approached. Is it only when there's a lateral movement do we see orbits and accretion discs?

This question I forward to the astrophysicist known as Dobbin.

#### Like water down a hole-

I imagine that it would start off going straight in, but the slightest unbalance to one side or the other (or the other...3 dimentions...) would impart a rotary or orbital component, which would lead to the usual spiral...

/IANAA

This object is still going to be an order of magnitude less massive than a galaxy (which may have 100 - 500 billion stars) but comparitively spatially tiny.

My estimation would be that the object would essentially punch right through mostly scattering stars, gas, dust, etc., around initially into chaos and then reassmble into a galaxy eventually with the hole at the centre (as is observed).

#### Finances

I thought this was about Guv'ment finances from the headline until I read the story.

they are of course a very sick joke

#### Only a trillion stars

around it? And I thought I was feeling insignificant enough *before* I read that.

#### Every knows black holes emit light...

.. in the form of x-rays.

I know you can't see it, but they're very good for checking broken bones....