All things · Stars

Sagittarius A* (black hole): how big is it?

Sagittarius A* (black hole) is about 24 million km. In everyday terms, that is ≈ 17.2 Suns.

Size

24 million km

In metres

2.40 × 10¹⁰ m

Everyday comparison

≈ 17.2 Suns

Chapter

Stars

Did you know?

The supermassive black hole at the centre of our galaxy, with about 4 million times the Sun's mass.

How it compares

• About 10× bigger than Sirius (2.38 million km).
• About 1.5× smaller than Arcturus (35 million km).

Other things of a similar size

• Earth → Moon distance 384,000 km
• The Sun 1.39 million km
• Sirius 2.38 million km
• Arcturus 35 million km
• Earth → Sun distance 150 million km
• Betelgeuse 1.06 billion km

Sizes are rounded, typical values drawn from standard reference sources, including NIST/CODATA physical constants and NASA's planetary fact sheets. Real objects vary; see About for how sizes are chosen.