Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Globular and Fibrous Proteins

Globular and Fibrous Proteins

Many proteins can be classified into two distinct subtypes - globular or fibrous. These two types differ in their shapes and solubilities.
Globular proteins are also known as spheroproteins and typically are approximately round in shape. They contain a mix of amino acid types and contain differing sequences in their primary structures. Globular proteins have many different functions, such as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be...

Globular and Fibrous Proteins

Globular and Fibrous Proteins

Many proteins can be classified into two distinct subtypes - globular or fibrous. These two types differ in their shapes and solubilities.
Globular proteins are also known as spheroproteins and typically are approximately round in shape. They contain a mix of amino acid types and contain differing sequences in their primary structures. Globular proteins have many different functions, such as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be...

Schwarzschild Radius and Event Horizon

Schwarzschild Radius and Event Horizon

No object with a finite mass can travel faster than the speed of light in a vacuum. This fact has an interesting consequence in the domain of extremely high gravitational fields.
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape velocity with the...

Detection of Black Holes

Detection of Black Holes

Although black holes were theoretically postulated in the 1920s, they remained outside the domain of observational astronomy until the 1970s.
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...

Globular Proteins

Globular Proteins

In organisms, proteins are the most abundant macromolecules. They act as the building blocks of life and play various crucial roles in the body. Proteins can be broadly classified into two distinct subtypes based on their shape and solubilities: globular proteins and fibrous proteins.
Globular proteins serve many important physiological functions, such as acting as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be soluble in the aqueous...

Gravitation Between Spherically Symmetric Masses

Gravitation Between Spherically Symmetric Masses

The gravitational potential energy between two spherically symmetric bodies can be calculated from the masses and the distance between the bodies, assuming that the center of mass is concentrated at the respective centers of the bodies.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Atacama Large Aperture Submillimeter Telescope (AtLAST) science: Resolving the hot and ionized Universe through the Sunyaev-Zeldovich effect.

Open research Europe·2025

Same author

Atacama Large Aperture Submillimeter Telescope (AtLAST) science: Surveying the distant Universe.

Open research Europe·2024

Same author

Cygnus X-1 contains a 21-solar mass black hole-Implications for massive star winds.

Science (New York, N.Y.)·2021

Same author

Accretion-induced variability links young stellar objects, white dwarfs, and black holes.

Science advances·2015

Same author

Inference for the physical sciences.

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences·2013

Same author

Two stellar-mass black holes in the globular cluster M22.

Nature·2012

Search research articles

Related Experiment Video

Updated: Jun 1, 2026

Studying Organelle Dynamics in B Cells During Immune Synapse Formation

Studying Organelle Dynamics in B Cells During Immune Synapse Formation

Published on: June 1, 2019

A black hole in a globular cluster.

Thomas J Maccarone¹, Arunav Kundu, Stephen E Zepf

¹School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK. tjm@phys.soton.ac.uk

|January 5, 2007

Summary

Astronomers detected an accreting black hole in a globular cluster within galaxy NGC 4472. This finding provides evidence for black hole formation and survival in dense stellar environments.

Area of Science:

Astrophysics
Stellar Dynamics
X-ray Astronomy

Background:

Globular clusters are dense collections of old stars.
High stellar densities suggest frequent stellar interactions and collisions.
The existence of black holes within globular clusters is debated due to theoretical predictions of their formation and ejection.

Purpose of the Study:

To investigate the presence of black holes in globular clusters.
To provide observational evidence for black hole formation and survival in these dense stellar systems.

Main Methods:

X-ray observations of a globular cluster in the giant elliptical galaxy NGC 4472.
Analysis of X-ray luminosity and variability to identify the nature of the compact object.

More Related Videos

Full-Circle Cauterization of Limbal Vascular Plexus for Surgically Induced Glaucoma in Rodents

Full-Circle Cauterization of Limbal Vascular Plexus for Surgically Induced Glaucoma in Rodents

Published on: February 15, 2022

Grossing of Non-neoplastic Globes, Including Fetal Eyes

Grossing of Non-neoplastic Globes, Including Fetal Eyes

Published on: May 30, 2025

Related Experiment Videos

Last Updated: Jun 1, 2026

Studying Organelle Dynamics in B Cells During Immune Synapse Formation

Studying Organelle Dynamics in B Cells During Immune Synapse Formation

Published on: June 1, 2019

Full-Circle Cauterization of Limbal Vascular Plexus for Surgically Induced Glaucoma in Rodents

Full-Circle Cauterization of Limbal Vascular Plexus for Surgically Induced Glaucoma in Rodents

Published on: February 15, 2022

Grossing of Non-neoplastic Globes, Including Fetal Eyes

Grossing of Non-neoplastic Globes, Including Fetal Eyes

Published on: May 30, 2025

Main Results:

Detection of an accreting object with an X-ray luminosity of approximately 4 x 10^39 erg s^-1.
The object's luminosity is consistent with a black hole in an old stellar population.
Rapid X-ray luminosity variations (factor of seven in a few hours) rule out superposition of neutron stars.

Conclusions:

The observed X-ray signature strongly indicates the presence of an accreting black hole within the globular cluster.
This discovery supports theories suggesting black holes can form and persist in the dense environments of globular clusters.
The findings contribute to understanding the end-states of stellar evolution and compact object populations in dense stellar systems.