Short · Astronomy
Does Earth really corkscrew through space?
Ride along with the Sun and the planets go round in circles. But the Sun orbits the Milky Way at about 230 km/s, so seen from the galaxy each orbit stretches into a coil, so long it’s nearly straight: in one year Earth goes round the Sun once, 940 million km, while the Sun carries it about 7.3 billion km. The orbits are tilted about 60° to the path, so Earth doesn’t trail behind the Sun in a vortex; half the year it’s out in front. One lap of the galaxy takes about 230 million years.
Opens Galactic Path Lab. Change the same thing yourself.
Transcript
Does Earth really corkscrew through space? Ride along with the Sun, and the planets just go round in circles. But the Sun races around the Milky Way at two hundred thirty kilometers a second. Now speed up the Sun. Seen from the galaxy, each orbit stretches into a coil, so long it's nearly straight. In one year, Earth loops the Sun once, while the Sun carries it over seven billion kilometers. And the orbits are tilted, so Earth doesn't trail behind the Sun. Half the year, it's out in front. One lap of the galaxy takes about two hundred thirty million years. Follow for more explainers like this.
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Learn more about Earth’s path through space
This model shows the coil at true scale. The guide adds where the vortex picture came from, what astronomers said about it, how fast we are really moving and where the model stops.
- Topic guideDoes Earth really corkscrew through space?Circles from the Sun, coils from the galaxy, the 60° tilt and the galactic year.
Interactive · Mars LoopWhy does Mars seem to move backward?The same idea closer to home: Mars seems to loop backward only because we watch it from a moving Earth.- Interactive demoEarth and SunSwitch between Earth-centred and Sun-centred views of the same motion.by Andrew Marsh · Opens on the creator’s site
JournalDoes Earth really corkscrew through space?Seen from the galaxy, Earth’s orbit is a coil, but stretched almost straight: 7.3 billion km long a year and 300 million km wide, tilted about 60°, not a vortex.