Follow your curiosity

What discovery has been shared with you?

FACTREE gives you something interesting to discover every day — and something worth talking about together.

Start with one fact. Explore it, go deeper, then follow whichever branch catches your imagination.

Choose subjects for a surprise

Exploring any topic

Begin your discovery

Your next discovery is one click away.

Choose one or more subjects above, or leave Any Topic selected and let curiosity decide.

Astronomy

The Orbital Mechanics Behind Interplanetary Travel

Quick fact

A Hohmann transfer orbit to Mars takes about 259 days with current propulsion, but a gravity assist from Venus can shorten the trip—though it may also extend it depending on the mission design.

Why this is interesting

Every rocket launch to another planet is a precise dance with gravity, not a straight-line chase. Why do spacecraft take looping paths across the solar system instead of aiming straight at Mars?