NGC 4395 size and scale context

The black hole in NGC 4395 powers an active galactic nucleus inside a small bulgeless galaxy. Its existence helped show that a galaxy does not need a large central bulge to host a feeding central black hole. Read its scale context, comparisons, and journey links on the canonical object page.

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Between the smallest and the largest, perspective is everything.

About

Scale of Space is a scroll-based journey through the universe, placing objects on a single logarithmic scale so you can compare size across an unbroken range.

Guides turn parts of that scale into curated essays, while focused views let you explore the same range through specific groups of objects.

Editorial

Solar System Planets From Electron to Atoms Stars To Scale Birth And Death Of Stars Black Holes To Scale

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Planets of the Solar System Stars of the Universe Black holes Subatomic scale

Return to Earth hello@scaleofspace.org

Between the smallest and the largest, perspective is everything.

About

Scale of Space is a scroll-based journey through the universe, placing objects on a single logarithmic scale so you can compare size across an unbroken range.

Guides turn parts of that scale into curated essays, while focused views let you explore the same range through specific groups of objects.

Editorial

Solar System Planets From Electron to Atoms Stars To Scale Birth And Death Of Stars Black Holes To Scale

Views

Planets of the Solar System Stars of the Universe Black holes Subatomic scale

Return to Earth hello@scaleofspace.org

Black holes

Cygnus X-1

Cygnus X-1 was the first cosmic object widely accepted as a black hole. It blazes in X-rays because the black hole is stripping hot gas from a massive blue supergiant companion and funneling it into a compact accretion flow.

Scale fact120 kmevent horizon diameter

Object class: Stellar black hole
Mass: ~21 solar masses
Estimated age: ~5 million years
Host: Cygnus X-1 binary system

Black holes

NGC 4395

Scale fact61,000 kmevent horizon diameter

Object class: Intermediate-mass black hole
Host: NGC 4395
Mass: ~10,000 solar masses

Black holes

HLX-1

HLX-1 is one of the strongest known candidates for an intermediate-mass black hole and lies off the plane of ESO 243-49. Hubble observations suggest it may be the stripped core of a cannibalized dwarf galaxy, leaving a midsize black hole with a small cluster of young stars around it.

Scale fact118,000 kmevent horizon diameter

Object class: Intermediate-mass black hole candidate
Host: ESO 243-49
Mass: ~20,000 solar masses