The Solar System

The harvest moon is the full moon closest to the autumnal equinox, typically in late September or early October in the Northern Hemisphere.

By Nicole Antonio

Unlock the mysteries of Mercury Retrograde, its impact on astrology, and how to navigate its cosmic waves for personal growth.

By HowStuffWorks

Delve into the Earth's layers: crust, mantle, outer core, and inner core. Discover the secrets beneath our feet and the dynamic processes at play.

By HowStuffWorks

Explore the mysteries of the outer planets: Jupiter, Saturn, Uranus, and Neptune. Dive deep into their atmospheres, moons, and unique phenomena.

By HowStuffWorks

Nothing lasts forever. Does that include our home planet, too?

By Shichun Huang

Sometimes hundreds of people armed with high-tech cameras can make amazing scientific discoveries, as in the case of STEVE.

By Jesslyn Shields

March's full moon is called the worm moon for an unusual reason. What are some other names for the March moon and when can you see it?

By Valerie Stimac

Every 24 hours, Earth makes a full rotation on its axis. But why does Earth spin in the first place?

By Silas Laycock

Researchers at Australian National University studied 5,000 star-eating behemoths to find out.

By Christian Wolf

January's moon is called the wolf moon, but it's also known as the center moon and the freeze up moon (among other names). Here's why.

By Valerie Stimac

All of the planets in the solar system are named for Greek gods, except Earth. So where did the name come from?

By Mark Mancini

Why do planets in the solar system all seem to be round? Why not cylindrical? Or even cube-shaped?

By Mark Mancini

In the darkness of space, we're comforted by our moon, the circular inspirer of song lyrics, poetry, and wannabe astronauts. But what do you really know about the moon and its history? Take this quiz to find out.

By Nathan Chandler

Those stars twinkling in the nighttime sky may actually be crystal spheres. And our beloved star is headed in that direction, too. Eventually.

By Ian O'Neill, Ph.D.

A massive planet 10 times the size of Earth seems to have been lurking on the edge of our solar system for some time now. How come we never noticed it before?

By Patrick J. Kiger

Killer asteroids are all fun and games -- until they're headed for Earth. How do we stop cosmic hot potatoes from wiping out our planet?

By William Harris

It's not a pleasant thought, is it? But when you mix chaos theory with a few crazy cosmologists, those tidy, predictable orbits start getting lively.

By William Harris

Sunspots are peculiar dark areas that show up regularly on the surface of the sun -- and often for no reason. What causes them? What effect could these funny little spots have on the Earth?

By Patrick J. Kiger

Hundred of meteors fly across the sky every night, but only a few make it to Earth. Meteors are best known for the brilliant streaks of light they make as they burn up in the atmosphere. Learn about 10 memorable meteor crashes that left an impression.

By the Editors of Publications International, Ltd.

We know it's not made of green cheese, but what are the origins of the moon? Learn astronomers' theories about where the moon came from.

By Tracy V. Wilson

Why does the moon look so much bigger when it is near the horizon than when it is high up in the sky? This question has been pondered for hundreds if not thousands of years, and is commonly referred to as the moon illusion.

A magnetar is a neutron star with a super-strong magnetic field. Astronomers consider them among the scariest objects in the universe, but why?

By Valerie Stimac

Since the 1960s, we've been captivated by the planet Mars. How different is our neighbor, and what have we learned about the most explored planet?

By Craig Freudenrich, Ph.D., Nicholas Gerbis & Mark Mancini

A total solar eclipse is a rare event that can be an amazing thing to witness. Learn about solar eclipses and how to observe one safely.

By Craig Freudenrich, Ph.D.

If "nature abhors a vacuum," then why doesn't the vacuum of space suck away all of the Earth's atmosphere?