A seismic shift occurred in astronomy during the Scientific Revolution, beginning with 16th-century polymath Copernicus and his proposal that the Earth revolved around the sun. By the 17th century, ...

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 ...

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 ...

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 ...

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 ...

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 ...