---
title: "How Do Astronomers Estimate the Mass of a Black Hole They Cannot See?"  
description: "How Do Astronomers Estimate the Mass of a Black Hole They Cannot See?"  
author: "María Fernanda Martínez"  
published: 2026-10-21  
canonical: https://answers.mindstick.com/qa/117993/how-do-astronomers-estimate-the-mass-of-a-black-hole-they-cannot-see  
category: "Mix Category"  
tags: ["Space", "astronomy", "black holes"]  
reading_time: 1 minute  

---

# How Do Astronomers Estimate the Mass of a Black Hole They Cannot See?

A black hole itself gives off no light, so I’m wondering how astronomers can put a number on its mass rather than just say that one is probably there. Do they infer it from stars orbiting nearby, from gas around it, or from gravitational waves?

Are the estimates equally reliable for a black hole at the centre of a galaxy and one detected through a binary-star system?


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Original Source: https://answers.mindstick.com/qa/117993/how-do-astronomers-estimate-the-mass-of-a-black-hole-they-cannot-see

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