---
title: "SMSS J2157-3602"
url: "https://spacecatalog.org/object/smss-j2157-3602"
release: "DR1"
licence: "CC-BY-4.0"
citation: "SpaceCatalog. SMSS J2157-3602 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/smss-j2157-3602"
---

# SMSS J2157-3602

SMSS J2157-3602 is a quasar in the constellation [Piscis Austrinus](https://spacecatalog.org/constellation/piscis-austrinus), 138.0 Gly from Earth. Its mass is 3.4×10¹⁰ M☉. It was discovered in 2018.

The fastest-growing [black hole](https://spacecatalog.org/black-holes) known, taking in roughly the mass of the [Sun](https://spacecatalog.org/object/sun) every day. At 34 billion solar masses it is among the heaviest measured anywhere, and it is still eating.

## At a glance

- **WHAT IT IS:** Quasar
- **HOW FAR:** 138.0 Gly — A luminosity distance, from its redshift — how faint it looks. The light itself left 12.1 billion years ago.
- **WHERE TO LOOK:** [Piscis Austrinus](https://spacecatalog.org/constellation/piscis-austrinus) — The patch of sky it sits in, as seen from Earth.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | Quasar |
| MASS | 3.4×10¹⁰ M☉ |
| DISTANCE FROM EARTH | 138.0 Gly — by luminosity distance from a published redshift, flat ΛCDM with H0 = 70 km/s/Mpc |
| CONSTELLATION | Piscis Austrinus |
| RIGHT ASCENSION (J2000) | 21h 57m 28.2s |
| DECLINATION (J2000) | −36° 02′ 15.2″ |
| DISCOVERED | 2018 |

## Catalogue data

### WHAT KIND OF THING IT IS

What the object is in itself, rather than how it happens to look from here.

| Field | Value |
| --- | --- |
| Accretion state | quasar — a thin disc near its Eddington limit |
| Mass | 3.4×10¹⁰ M☉ |

### WHERE IT IS AND HOW IT MOVES

Position, motion across the sky and the size it covers on it. These are measurements of the object as seen from here, so every one of them depends on where here is.

| Field | Value |
| --- | --- |
| Redshift (z) | 4.665 |

## Also known as

- Common name: SMSS J2157-3602

## Source

[SpaceCatalog curated data](https://spacecatalog.org/releases) — CC-BY-4.0

How this was made: https://spacecatalog.org/methods#source-curated

## Cite this page

SpaceCatalog. SMSS J2157-3602 \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/smss-j2157-3602

```bibtex
@misc{spacecatalog_smss-j2157-3602,
  author       = {{SpaceCatalog}},
  title        = {{SMSS J2157-3602}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/smss-j2157-3602},
  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from SpaceCatalog curated data.}
}
```

SpaceCatalog curated data — CC-BY-4.0

The page itself, with its pictures, the sky map and the observing tools: https://spacecatalog.org/object/smss-j2157-3602