---
title: "Scientists Say the Sun Is Smaller Than We Thought"
description: "By using sound waves propagating through the Sun, researchers think our star's radius may be fractionally shorter than the traditional model."
date: "2023-11-11"
modified: "2023-11-11"
authors:
  - name: "Frank Landymore"
    job_title: "Contributing Writer"
    link: "https://futurism.com/authors/flandymore"
url: "https://futurism.com/the-byte/scientists-say-sun-smaller-than-thought"
categories:
  - "Off-World"
  - "Space"
tags:
  - "solar system"
  - "Sun"
  - "the digest"
  - "the sun"
---

# Scientists Say the Sun Is Smaller Than We Thought

![By using sound waves propagating through the Sun, researchers think our star's radius may be fractionally shorter than the traditional model.](<https://futurism.com/wp-content/uploads/2023/11/scientists-say-sun-smaller-than-thought.jpg>)
*Realistic 3D Star Surface \<em\>Image: DrPixel/Getty Images\</em\>*

## Coming Up Short

The Sun is just a tiny bit smaller than once believed, according to new research.

A [new study](<https://arxiv.org/abs/2310.11299>), available online as it undergoes peer review, backs up previous work that used sound waves in the Sun — essentially its seismic activity — to calculate its size, which also found a discrepancy in the star's radius compared to the traditional solar model.

Now, by using a different so-called "mode" of sound waves, the researchers found that the radius of the Sun is smaller by a few hundredths of a percent, or a difference of a few dozen miles, which could have bigger implications on how we understand the workings of its internal structure.

"Seismological inferences are saying things that relate to the nuclear reactions, the chemical composition and the basic structure of the sun," study co-lead author Douglas Gough at the University of Cambridge [told *New Scientist*](<https://www.newscientist.com/article/2401527-the-sun-is-smaller-than-we-thought-it-was/>).

## F-Mode Island

While scientists have traditionally estimated the Sun's size by measuring its luminous outer shell called the photosphere, more recent methods have turned to the star's oscillation modes.

As sound waves propagate through the Sun's interior, they bounce off the photosphere and cause patches of the surface to oscillate. Scientists divide these waves into different "modes" depending on what causes them.

F-mode waves have been used in the past to estimate the Sun's size, with the results suggesting the star was slightly smaller than the standard. But there was some uncertainty surrounding those estimates, because as the researchers explain, f-mode waves may not fully penetrate the photosphere and as such are less reliable for measurements.

For a firmer finding, the researchers instead used p-mode waves. These are caused by huge pressure fluctuations in the Sun's turbulent interior and are able to pass through the core with ease. That resulted in a radius "more or less consistent" with f-mode estimates, the researchers wrote, adding credence to the idea of a smaller Sun.

## Adding Up

However fractional the difference may be — just hundredths of a percent, to reiterate — it means a potentially huge difference in the Sun's structure and composition, where absolute precision is paramount.

"There's the potential to reach misleading conclusions about the subtle elements of the sun's internal structure," William Chaplin at the University of Birmingham, who was not involved in the study, told *New Scientist*.

**More on the Sun:** *[NASA's Solar Probe Survived Flying Right Through Massive Sun Explosion](<https://futurism.com/the-byte/nasa-solar-probe-sun-explosion>)*

## Author
At Futurism, my work has often centered on bringing a sense of clarity and insight to complex topics ranging from the regulation of emerging technologies to the esoteric ideologies of Silicon Valley executives, while striving not to lose the poetic sense of awe inspired by often-obscure fields like astrophysics and quantum computing. I broke the story of CNET using AI to produce articles that turned out to be riddled with factual errors and plagiarism — a dam-breaking inflection point, as I've reported, that's inspired copycats and endless discourse while beguiling stakeholders ranging from tech giants to purveyors of spam around the web. My work at Futurism has been cited by publications including CBS News, the Los Angeles Times, Vice, Gizmodo, Engadget, the Verge, and Vanity Fair. I grew up in locales ranging from India to China, and now live in the exotic suburbs of Virginia. In my free time, I'm an avid reader of weird sci-fi literature, an aficionado of East Asian cinema, and, regrettably, a relapsed gamer. Allegedly, I’m working on a debut novel, currently untitled.

### Author social links  
[Bluesky](<https://bsky.app/profile/f-w-l.bsky.social>)