An artist's impression of two black holes subject to each other's gravity. Researchers have identified a new speed limit for the universe’s most extreme collisions. According to a study published in ...

Driving a spacecraft around a planet isn’t anything like driving on a planet. A physicist explains orbital navigation.

The planets of our solar system move in ellipses. We've known this, so we are told, ever since Johannes Kepler devised his laws of planetary motion in the early 1600s. While it's true that orbits are ...

UCLA astrophysicists have now measured the shape of the orbits of exoplanets—from the size of Jupiter down to the size of ...

Cometary orbits exhibit a wide range of shapes and eccentricities, not all being highly elliptical. Comets originating from the Oort Cloud possess highly eccentric elliptical orbits, subject to ...

This week's question comes from Wilma David in Ottawa, Ontario. David asks: Given that the sun is almost perfectly spherical (not oblate), why do planets orbit the sun in an ellipse? I understand that ...

Quick: How many moons does the Earth have? You might be forgiven for saying “one,” but it turns out the question isn’t all that easy to answer … because it depends on what you mean by “moon.” Of ...

SEVERAL attempts have been made in recent years to establish whether models of the galactic mass distribution admit a third isolating integral of motion for stellar orbits in addition to the ...

Ever since the 16th century when Nicolaus Copernicus demonstrated that the Earth revolved around in the Sun, scientists have worked tirelessly to understand the relationship in mathematical terms. If ...