Astronomers observe for the first time the actual motion of spirals in a protoplanetary disk, revealing gravitational ...

When you look at the solar system, you might notice that the planets' orbits are tilted, and oddities in the protoplanetary ...

More planets are changing directions. First, Mercury circled retrograde. This week, Mars is reversing course and Neptune starts spinning forward again. Going retrograde and stationing direct are the ...

Credit: NASA/Sophia Roberts In the radial-velocity detection technique, with which 51 Pegasi b, the first planet known to orbit a sun-like star, was found, astronomers measure the Doppler shift of a ...

This wild but constrained motion implies predicting precise trajectories is difficult, but the planet’s mass and speed probably several hundred miles per hour relative to the Sun will decide whether ...

Shedding light on the gravity of the situation. Most people do not realize that many of the stars and heavenly bodies they see in the sky no longer exist. In fact, many have ceased to exist for ...

A planet's year length depends on its distance from the Sun. Planets closer to the Sun have shorter years. A planet's rotation speed is unrelated to its year length. Planets' orbital speeds vary ...

Nothing in the universe is truly standing still. Everything is in motion, from planets and stars to galaxies themselves. Hello, curious kids! Do you have a question you’d like an expert to answer? Ask ...

A planet's north pole is defined by its position relative to the solar system's invariable plane. The invariable plane is a fixed reference point perpendicular to the solar system's rotation. A planet ...