Solar Facts

August 1, 2022

Limb Darkening is an Optical Effect on the Sun

[Alex on EARTHSKY.ORG] Limb darkening is an effect we can see on the sun where the edges of the sun are darker than the center, due to the amount of photosphere we're looking at.
May 3, 2022

Why are East & West on the Sun Reversed?

[Alex on EARTHSKY.ORG] East and west on the sun are opposite from what you might expect. On the sun, east is to the left and west is to the right. Learn why here. (Image: NASA/SDO)
May 1, 2022

What Does the Sun’s X-Ray Flux Tell Us?

[Alex on EARTHSKY.ORG] Solar physicists often speak of the sun's X-ray flux as being high, or low. Solar flares are like waves on the background ocean of the sun's X-ray flux.
March 26, 2022

Solar Filaments, aka Prominences, Arc Upwards

[Alex on EARTHSKY.ORG] Solar filaments (aka prominences, when viewed on the limb of the sun) are large, bright arcs of solar material and magnetic fields.
November 6, 2021

How Big is the Sun?

The Sun is really really big! It is difficult to get a true feel for how big it is because nothing in our daily life comes even close.
March 2, 2019

Layers of the Sun

The Sun, as shown by the illustration to the left, can be divided into six layers. From the center out, the layers of the Sun are as follows: the solar interior composed of the core (which occupies the innermost quarter […]
February 5, 2019

Our Star – An Introduction to the Sun

The Sun is 150 million kilometers (93 million miles) away from the Earth (this distance varies slightly throughout the year because the Earth's orbit is an ellipse and not a perfect circle).
October 5, 2018

Do Solar Flares Cause Earthquakes?

We have been getting a number of questions and comments lately regarding the possible relationship between solar activity and geological activity, such as earthquakes and volcanoes, so I have decided to look into the matter in more detail. First let […]
February 3, 2014

The Sun’s Magnetic Poles Have Flipped…Solar Max is Here!

Although this might sound alarming, there really is nothing to worry about! It’s a normal part of the solar cycle – it heralds the second half of the solar cycle. Learn about why this happens. At a Glance The sun’s […]
September 8, 2010

Solar Activity and the Solar Cycle

The Sun is not just a big bright ball. It has a complicated and changing magnetic field, which forms things like sunspots and active regions. The magnetic field sometimes changes explosively, spitting out clouds of plasma and energetic particles into […]