Posts by 

C. Alex Young


Sun activity: Seeing a solar eclipse from space

Sun activity for March 22, 2023: GOES-16 captured a partial solar eclipse from space earlier today. We might have a moderate geomagnetic storm on March 24.

Sun activity archive for February 2023

Sun activity archive for February 2023. A daily record of our local star, as it edges toward the peak of Solar Cycle 25, expected in mid-decade.

Sun activity archive for January 2023

Sun activity archive for January 2023. A daily record of flaring, big filaments and prominences, and other sorts of activity, on our local star.

What makes a giant sunspot?

A giant sunspot - AR 3190 - is crossing the face of the sun this week. It'lll soon disappear, but is still visible as of January 21, 2023. What makes it?

Aurora season: Why more auroras at equinoxes?

An aurora season occurs in October and March each year, due to the way the magnetic fields of the sun and the Earth work in conjunction with sun-Earth geometry.

Limb darkening is an optical effect on the sun

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.

Why are east and west on the sun reversed?

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.

A Grand Solar Minimum? Or a normal sun?

A Grand Solar Minimum happens when the peaks of several solar cycles in a row show less than average intensity. Are we in one?

What does the sun’s X-ray flux tell us?

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.

Solar filaments, aka prominences, arc upwards

Solar filaments (aka prominences, when viewed on the limb of the sun) are large, bright arcs of solar material and magnetic fields.