Discover WorldsFrom Mission Control
An observatory for exoplanets, stars, small bodies, and live space data from NASA and JPL.
New here? Compare two real planets and see what their measurements can tell you. No account needed.
Read the evidence
Start with a question.
How long is a year on another planet? How close is an asteroid flyby? What happens between a solar eruption and a geomagnetic storm? Choose a guide and work through the evidence.
Start with the TRAPPIST-1 comparison for a real example. You can change the time interval, compare the planets' sizes, and open the source records without creating an account.
Save a guide for later to build a reading list in this browser. Each guide ends with a question to investigate in the catalog.
Exoplanets
TRAPPIST-1 b and e: similar sizes, different years
Compare two real planets with a scale diagram, a month of orbital motion, and calculations you can reproduce from NASA data.
Exoplanets
Compare exoplanets without mistaking size for habitability
Work through radius, mass, and orbital period comparisons, then check what the measurements leave unanswered.
Space weather
Follow a space-weather event from the Sun to Earth
Connect solar events, upstream measurements, and geomagnetic activity without confusing an observation with a forecast.
Small bodies
Read an asteroid flyby without turning it into an impact warning
Put lunar distances, size estimates, and hazard labels in context with a worked encounter comparison.
Investigation / Small bodies
2023 BU: reconstruct a close-approach forecast
Convert a reported surface clearance into a geocentric distance, then see why the reference point and source date belong with the number.
Investigation / Space weather
May 2024: build a space-weather timeline
Separate a geomagnetic watch, an observed G5 storm, and a later solar flare by converting their timestamps to one time standard.
Daily Telescope Feed
Astronomy Picture of the Day
APOD feed in Cosmic Index style
Scan confirmed planets, filter by discovery method, and compare orbital properties.
Open ExoplanetsInspect host stars, stellar classes, and linked planetary systems.
Open StarsTrack asteroids and comets with close-approach context and orbit classes.
Open Small Bodies