Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Space-Time Curvature and the General Theory of Relativity01:17

Space-Time Curvature and the General Theory of Relativity

3.7K
In 1905, Albert Einstein published his special theory of relativity. According to this theory, no matter in the universe can attain a speed greater than the speed of light in a vacuum, which thus serves as the speed limit of the universe.
This has been verified in many experiments. However, space and time are no longer absolute. Two observers moving relative to one another do not agree on the length of objects or the passage of time. The mechanics of objects based on Newton's laws of...
3.7K
Atomic Nuclei: Larmor Precession Frequency01:11

Atomic Nuclei: Larmor Precession Frequency

2.2K
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession,...
2.2K
Motion Of A Charged Particle In A Magnetic Field01:22

Motion Of A Charged Particle In A Magnetic Field

6.0K
A charged particle experiences a force when moving through a magnetic field. Consider the field to be uniform and the charged particle to move perpendicular to it. If the field is in a vacuum, the magnetic field is the dominant factor determining the motion. Since the magnetic force is perpendicular to the direction of motion, a charged particle follows a curved path. The particle continues to follow this curved path until it forms a complete circle. Another way to look at this is that the...
6.0K
Schwarzschild Radius and Event Horizon01:21

Schwarzschild Radius and Event Horizon

2.4K
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...
2.4K
Speed of a Transverse Wave01:13

Speed of a Transverse Wave

2.2K
The speed of a wave depends on the characteristics of the medium. For example, in the case of a guitar, the strings vibrate to produce the sound. The speed of the waves on the strings and the wavelength determine the frequency of the sound produced. The strings on a guitar have different thicknesses but may be made of similar material. They have different linear densities, and the linear density is defined as the mass per length.
One of the key properties of any wave is the wave speed. Light...
2.2K
NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences01:17

NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences

1.3K
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
1.3K

You might also read

Related Articles

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

Sort by
Same author

Helium spin-echo as a surface-sensitive probe of vibrational energy dissipation.

Faraday discussions·2026
Same author

Constraints on Dark Matter Models from Supermassive Black Hole Evolution.

Physical review letters·2026
Same author

Editorial: Tips for early career researchers (ECRs) in searching the literature and in academic publishing.

Parasitology·2026
Same author

Towards a unified nomenclature for diseases associated with porcine circovirus infections.

The Veterinary record·2025
Same author

Methods of assessment of diabetic retinopathy in low- and middle-income countries: a protocol for scoping review.

BMJ open·2025
Same author

What's so special about special issues: Highlighting a central role of <i>parasitology</i> to support specific innovations and advance progress within our discipline.

Parasitology·2025

Related Experiment Video

Updated: Nov 17, 2025

Construction and Operation of a Light-driven Gold Nanorod Rotary Motor System
09:48

Construction and Operation of a Light-driven Gold Nanorod Rotary Motor System

Published on: June 30, 2018

9.1K

Cosmic String Interpretation of NANOGrav Pulsar Timing Data.

John Ellis1,2,3, Marek Lewicki1,4

  • 1Kings College London, Strand, London WC2R 2LS, United Kingdom.

Physical Review Letters
|February 12, 2021
PubMed
Summary

The NANOGrav Collaboration found evidence for a stochastic gravitational wave background, potentially from cosmic strings. This signal, if confirmed, differs from supermassive black hole mergers and could be detected by future observatories.

More Related Videos

Neutron Spin Echo Spectroscopy as a Unique Probe for Lipid Membrane Dynamics and Membrane-Protein Interactions
10:02

Neutron Spin Echo Spectroscopy as a Unique Probe for Lipid Membrane Dynamics and Membrane-Protein Interactions

Published on: May 27, 2021

4.3K
Generation and Coherent Control of Pulsed Quantum Frequency Combs
06:42

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Published on: June 8, 2018

9.4K

Related Experiment Videos

Last Updated: Nov 17, 2025

Construction and Operation of a Light-driven Gold Nanorod Rotary Motor System
09:48

Construction and Operation of a Light-driven Gold Nanorod Rotary Motor System

Published on: June 30, 2018

9.1K
Neutron Spin Echo Spectroscopy as a Unique Probe for Lipid Membrane Dynamics and Membrane-Protein Interactions
10:02

Neutron Spin Echo Spectroscopy as a Unique Probe for Lipid Membrane Dynamics and Membrane-Protein Interactions

Published on: May 27, 2021

4.3K
Generation and Coherent Control of Pulsed Quantum Frequency Combs
06:42

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Published on: June 8, 2018

9.4K

Area of Science:

  • Cosmology and astrophysics
  • Gravitational wave astronomy
  • Particle physics

Background:

  • Pulsar timing arrays have historically set upper limits on stochastic gravitational wave backgrounds (SGWB).
  • Recent NANOGrav Collaboration results suggest evidence for a common-spectrum process, challenging previous upper limits.

Purpose of the Study:

  • To interpret the NANOGrav signal within the framework of cosmic strings.
  • To determine the potential string tension (Gμ) associated with the observed signal.
  • To assess the detectability of such a cosmic string SGWB by current and future gravitational wave detectors.

Main Methods:

  • Analysis of pulsar timing data.
  • Interpretation of a stochastic common-spectrum process as a SGWB.
  • Comparison of the signal's frequency dependence with theoretical models of cosmic strings and supermassive black hole mergers.

Main Results:

  • The NANOGrav signal is consistent with a SGWB generated by cosmic strings.
  • The inferred string tension is Gμ∈(4×10^{-11},10^{-10}) at the 68% confidence level.
  • The signal's frequency dependence differs from that expected from supermassive black hole mergers.

Conclusions:

  • The NANOGrav detection provides compelling evidence for a cosmic string SGWB.
  • This SGWB would be detectable by next-generation observatories like SKA, LISA, and the Einstein Telescope.
  • Cosmic strings remain a viable candidate for generating the observed gravitational wave background.