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 ...

Studying the orbits of thousands of exoplanets shows that large planets tend to have elliptical orbits, while smaller planets tend to have more circular orbits. This split coincides with several other ...

As planetary systems evolve, gravitational interactions between planets can fling some of them into eccentric elliptical orbits around the host star. Smaller planets should be more susceptible to this ...

When Johannes Kepler made the intuitive leap in the early 1600s to realize that planetary orbits were not circular, as they had been assumed to be for millennia, he stuck to the trusty ellipse. Indeed ...

How does a planet’s size influence its orbit around its parent star? This is what a recent study published in the Proceedings of the National Academy of Sciences hopes to address as a team of ...

A: When two spiral galaxies collide, gravity is the main force that comes into play. As the galaxies approach each other, gravitational forces start to pull the stars, gas, and dust of the spiral arms ...

Careful reanalysis of data from more than a decade ago indicates that Saturn's biggest moon, Titan, does not have a vast ocean beneath its icy surface, as suggested previously. Instead, a journey ...

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 ...