Epic black hole 64 EP

Holmberg 15A

RA 10.4602° · Dec -9.3032° · blackhole

Loading sky survey…

🌌 View in 3D star map

Tonight’s visibility

Computing the sky for your location…

Score breakdown

· 4 badges

64 pts · Epic

Epic 78 pts → Anomaly

Monster: over a billion Suns +28
Black hole +26
Outside our galaxy entirely +6
Dormant (nothing left to eat) +4

Total score 64

14 more points to reach Anomaly.

Badges

Black hole · +26
Outside our galaxy entirely · +6
Monster: over a billion Suns · +28
Dormant (nothing left to eat) · +4

Trivia

What makes it special

Dormant. Nothing is falling into it right now, so it gives off no light of its own at all. It was found purely by what its gravity does to everything nearby.

Hard to believe

Ultramassive. In the heaviest class of black hole known — a billion Suns or more in a single object.
Mass. It weighs about 40 billion times as much as the Sun, all of it crushed into a region with no surface and no size at all.

Handle with care

A gentle crossing. It is so vast that the stretching is mild at the horizon: you would cross the point of no return entirely intact, feeling nothing, with no way of knowing you had done it.
No way back. Cross the event horizon and every path you could possibly take leads inwards. It is not that you cannot go fast enough — it is that 'out' has stopped being a direction.

What it actually is

Where it lives. It sits at the very heart of Holmberg 15A (Abell 85 BCG).
What it is. A supermassive black hole. Practically every large galaxy has one, and how they grew so enormous so early in cosmic history is still an open question.

Sense of scale

In perspective. Deep in the extragalactic distance — further than the entire Virgo Cluster of galaxies.

Properties

accreting: no
bh class: supermassive
constellation: Cet
dist ly: 700000000
first imaged: no
gw detection: no
host galaxy: Holmberg 15A (Abell 85 BCG)
is sgr a: no
mass solar: 40000000000
name: Holmberg 15A
named: no
schwarzschild km: 118160309459.644

Nearby objects

About Holmberg 15A

Holmberg 15A is an epic black hole. It lies about 700,000,000 light-years from Earth and sits in the constellation Cet.

Nothing is falling into it right now, so it gives off no light of its own at all. It was found purely by what its gravity does to everything nearby.

How to see it

Look for Holmberg 15A in the constellation Cet.

Like any astronomical target, Holmberg 15A is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. The visibility panel above works out tonight's viewing window for your saved location.

Why Holmberg 15A is an epic black hole

Holmberg 15A scores 64 points on Spacedle's rarity scale, which places it in the epic tier. Another 14 points would lift it into a rarer tier.

That score comes from 4 science badges — Black hole, Outside our galaxy entirely, Monster: over a billion Suns and Dormant (nothing left to eat) — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.