Are Uranus and Neptune rock giants and not ice giants?

Are Uranus and Neptune really ice giants as scientists have long thought? A new study suggests they might be much more rocky instead of icy on the inside.

Saturn at opposition – brightest for 2026 – on October 4

Don't miss Saturn at opposition on and around the night of October 4, 2026. That's when our planet Earth passes between the sun and Saturn.

Radiant point of meteor showers: All you need to know

Meteors enter Earth's atmosphere on parallel paths. So, you'll see meteors appear to come from a single point in the sky: the radiant point!

Dwarf planet Ceres discovered 225 years ago today

Dwarf planet Ceres was discovered by Giuseppe Piazzi on January 1, 1801. That was 225 years ago. It was 1st considered an asteroid.

Why is there no eclipse every full and new moon?

If the moon orbited Earth on the same plane that Earth circles the sun, we'd have an eclipse at every full and new moon. Here's why we don't.

Sun activity archive for January 2026

Sun activity archive for January 2026. A daily record of flaring, big filaments and prominences, and other sorts of activity, on our local star.

Greatest elongation, superior and inferior conjunction

When Mercury and Venus are as far from the sun as they get from our earthly point of view, they are at greatest elongation. It is the best time to observe them.

The moon illusion makes the moon look huge!

When you see a large-looking moon low in the sky, does the moon look bigger to you? That's the moon illusion that makes the moon look so big.

What is stellar magnitude?

The brightest stars to the eye are 1st magnitude, and dimmest stars to the eye are 6th magnitude. How does stellar magnitude work in astronomy?

Deep-sky objects: Small telescope and binocular targets

Deep-sky objects - including bright and dark nebulae, star clusters and distant galaxies - are favorite targets for amateur stargazers.