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

Radiation Pressure: Problem Solving01:09

Radiation Pressure: Problem Solving

The radiation pressure applied by an electromagnetic wave on a perfectly absorbing surface equals the energy density of the wave. The wave's momentum also gets transferred to the surface when an electromagnetic wave is entirely absorbed by it. The rate at which momentum is transmitted to an absorbing surface perpendicular to the propagation direction equals the force on the surface.
The average value of the rate of momentum transfer divided by the absorbing area represents the average force per...
Schwarzschild Radius and Event Horizon01:21

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...
Surface Area Calculations01:22

Surface Area Calculations

Surface area calculations for a graph z = f(x, y) are fundamental in engineering applications involving curved structures such as satellite dishes. A parabolic dish reflects communication signals efficiently, but engineers must determine its exact curved surface area to estimate coating materials, fabrication costs, and structural requirements. Since the rim of the dish forms a circular boundary, the surface area is calculated over a circular domain in the xy-plane.Parametric Representation of...
Kepler's Third Law of Planetary Motion01:18

Kepler's Third Law of Planetary Motion

In the early 17th century, German astronomer and mathematician Johannes Kepler postulated three laws for the motion of planets in the solar system. In 1909, he formulated his first two laws based on the observations of his forebears, Nikolaus Copernicus and Tycho Brahe. However, in 1918, he published his third law of planetary motion, which gives a precise mathematical relationship between a planet's average distance from the Sun and the amount of time it takes to revolve around the Sun. It...
Kepler's Second Law of Planetary Motion01:29

Kepler's Second Law of Planetary Motion

In the early 17th century, German astronomer and mathematician Johannes Kepler postulated three laws for the motion of planets in the solar system. His first law states that all planets orbit the Sun in an elliptical orbit, with the Sun at one of the ellipse's foci. Therefore, the distance of a planet from the Sun varies throughout its revolution around the Sun.
While in an elliptical orbit, the total energy of the planet is conserved. Therefore, the planet slows down when it is at apogee and...
Kepler's First Law of Planetary Motion01:10

Kepler's First Law of Planetary Motion

In the early 17th century, German astronomer and mathematician Johannes Kepler postulated three laws for the motion of planets in the solar system. He formulated his first two laws based on the observations of his forebears, Nikolaus Copernicus and Tycho Brahe.
Polish astronomer Nikolaus Copernicus put forth a theory that stated a heliocentric model for the solar system. According to this heliocentric theory, all the planets, including Earth, orbit the Sun in circular orbits.
On the other hand,...

You might also read

Related Articles

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

Sort by
Same author

Definition of treatment-resistant late-life depression: Conclusions from a European Task Force Delphi process.

European psychiatry : the journal of the Association of European Psychiatrists·2026
Same author

Longitudinal associations of psychological distress with subsequent cognitive decline and dementia: a multi-cohort study.

medRxiv : the preprint server for health sciences·2025
Same author

LILAC - An Integrated Approach to Diagnosis and Intervention in Autism Spectrum Disorder.

Irish medical journal·2024
Same author

Cancer Decedents' Hospital End-of-Life Care Documentation: A Retrospective Review of Patient Records.

Journal of palliative care·2023
Same author

Antihypertensive Agents and Incident Alzheimer's Disease: A Systematic Review and Meta-Analysis of Observational Studies.

The journal of prevention of Alzheimer's disease·2022
Same author

Experimental verification of principal losses in a regulatory particulate matter emissions sampling system for aircraft turbine engines.

Aerosol science and technology : the journal of the American Association for Aerosol Research·2022

Related Experiment Video

Updated: Jul 12, 2026

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics
09:00

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics

Published on: October 27, 2017

Measurement of solar radius changes.

B J Labonte, R Howard

    Science (New York, N.Y.)
    |November 20, 1981
    PubMed
    Summary

    Solar radius measurements from 1974 show no significant change. The study establishes a precise limit on solar radius variation, constrained by systematic effects in photoelectric observations.

    Area of Science:

    • Solar physics
    • Stellar astronomy
    • Photometry

    Background:

    • The Sun's radius is a fundamental parameter in solar and stellar models.
    • Variations in solar radius could indicate changes in internal structure or magnetic activity.
    • Long-term, precise measurements are crucial for detecting subtle solar radius changes.

    Purpose of the Study:

    • To determine if the Sun's radius has changed since 1974.
    • To establish observational limits on solar radius variation.
    • To identify factors limiting measurement precision.

    Main Methods:

    • Utilizing photoelectric solar radius measurements from Mount Wilson Observatory.
    • Analyzing data collected over several decades.
    • Quantifying measurement uncertainties and systematic effects.

    More Related Videos

    Measurement of Aerosols Optical Thickness of the Atmosphere using the GLOBE Handheld Sun Photometer
    06:27

    Measurement of Aerosols Optical Thickness of the Atmosphere using the GLOBE Handheld Sun Photometer

    Published on: May 29, 2019

    X-ray Beam Induced Current Measurements for Multi-Modal X-ray Microscopy of Solar Cells
    10:16

    X-ray Beam Induced Current Measurements for Multi-Modal X-ray Microscopy of Solar Cells

    Published on: August 20, 2019

    Related Experiment Videos

    Last Updated: Jul 12, 2026

    Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics
    09:00

    Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics

    Published on: October 27, 2017

    Measurement of Aerosols Optical Thickness of the Atmosphere using the GLOBE Handheld Sun Photometer
    06:27

    Measurement of Aerosols Optical Thickness of the Atmosphere using the GLOBE Handheld Sun Photometer

    Published on: May 29, 2019

    X-ray Beam Induced Current Measurements for Multi-Modal X-ray Microscopy of Solar Cells
    10:16

    X-ray Beam Induced Current Measurements for Multi-Modal X-ray Microscopy of Solar Cells

    Published on: August 20, 2019

    Main Results:

    • Photoelectric solar radius measurements show no statistically significant change.
    • A precise upper limit of approximately 0.1 arc second (1 standard deviation) for solar radius variation was established.
    • Residual systematic effects were identified as the primary limitation on measurement accuracy.

    Conclusions:

    • The Sun's radius has remained remarkably stable over the observation period.
    • Future solar radius measurements require careful control of systematic effects.
    • The findings contribute to understanding solar stability and long-term solar evolution.