---
title: "Sagittarius A*: facts, distance and size – Krillion Space"
description: "Sagittarius A* is the supermassive black hole at the centre of our Milky Way galaxy, about four million times the mass of the Sun. With sourced facts."
url: https://krilion.app/atlas/sagittarius-a
language: en-US
---

# Sagittarius A*

Supermassive black hole. Depth 45 on the Krillion Space voyage, in the Galactic core and beyond.

Sagittarius A* is the supermassive black hole at the centre of our Milky Way galaxy, about four million times the mass of the Sun. Decades of tracking stars that orbit it earned a share of the 2020 Nobel Prize in Physics, and in 2022 the Event Horizon Telescope released the first image of its shadow.

![Sagittarius A* at depth 45 in Krillion Space, painted by the game (an illustration, not a photograph).](https://krilion.app/assets/atlas/sagittarius-a.webp)

## Fact sheet

- **Type:** Supermassive black hole
- **Distance:** About 26,700 light-years from Earth
- **Size:** About 4 million times the mass of the Sun; its shadow spans about half the width of Mercury's orbit
- **Constellation:** Sagittarius
- **Position in the sky:** Right ascension 17h 46m, declination −29° 01′
- **Seeing it from Earth:** It cannot be seen in visible light because thick dust blocks the view toward the galactic centre, but it is studied in radio waves, infrared and X-rays in the direction of the constellation Sagittarius.
- **On the voyage:** Depth 45, in the Galactic core and beyond section of the route, between Eta Carinae and the Large Magellanic Cloud

## Things to know

- On 12 May 2022 the Event Horizon Telescope team released the first image of Sagittarius A*, made by linking eight radio observatories around the world into one Earth-sized virtual telescope. ([ESO](https://www.eso.org/public/news/eso2208-eht-mw/))
- The image is based on observations from 2017 and took more than 300 researchers from 80 institutes about five years to produce. ([ESO](https://www.eso.org/public/news/eso2208-eht-mw/))
- Reinhard Genzel and Andrea Ghez shared half of the 2020 Nobel Prize in Physics for discovering a supermassive compact object at the centre of our galaxy, with the other half going to Roger Penrose. ([ESO](https://www.eso.org/public/news/eso2017/))
- The star S2 circles the black hole every 16 years, and at its closest pass in May 2018 it came within about 20 billion km while moving at almost 3% of the speed of light. ([ESO](https://www.eso.org/public/news/eso1825/))
- Tracking S2 with ESO's GRAVITY instrument pinned the distance to the black hole at about 8,180 parsecs, with an uncertainty of only about 0.3%. ([arXiv](https://arxiv.org/abs/1904.05721))

## Sources

- [ESO – Astronomers reveal first image of the black hole at the heart of our galaxy (eso2208)](https://www.eso.org/public/news/eso2208-eht-mw/)
- [ESO – 2020 Nobel Prize in Physics awarded for research with ESO telescopes (eso2017)](https://www.eso.org/public/news/eso2017/)
- [ESO – First successful test of Einstein's general relativity near supermassive black hole (eso1825)](https://www.eso.org/public/news/eso1825/)
- [GRAVITY Collaboration 2019, A&A 625, L10 – Geometric distance to the Galactic Center black hole (arXiv:1904.05721)](https://arxiv.org/abs/1904.05721)

## On the route

- Previous landmark: [Eta Carinae](https://krilion.app/atlas/eta-carinae)
- Next landmark: [Large Magellanic Cloud](https://krilion.app/atlas/lmc)
- [The whole Star Atlas](https://krilion.app/atlas)
- [Fly the voyage yourself](https://krilion.app/d/): every right answer warps your ship one stop deeper.