There are 2,299 exoplanets featured in the video up top, all of which have been discovered by NASA's Kepler spacecraft since 2009.
In reality, these planets — which all reside within the Milky Way, albeit well beyond the reaches of our own solar system — circle some 1,770 different stars, but thanks to some handy work by planetary scientist Alex Parker, we can see how all these planets stack up against one another by orbital distances, orbital periods and even accurate scale — ranging in size from 1/3 to 84 times the radius of Earth. You'll want to watch this in full screen, with HD, to make sure you can still spot the tiniest planets. Some headphones wouldn't hurt, either.
Writes Parker, a postdoc at the Harvard-Smithsonian Center for Astrophysics:
The animation is rendered with a time-step of 30 minutes, equal to the long-cadence time sample of the Kepler observatory. Three white rings illustrate the average orbital distances of Mercury, Venus, and Earth on the same scale.
When the system is animated edge-on, it is clear that there is no time during which the sample of stars the Kepler spacecraft is observing does not contain a planet transiting a star. In fact, on average there are dozens of transits occurring amongst the Kepler sample at any given instant.
The Kepler observatory has detected a multitude of planet candidates orbiting distant stars. The current list contains 2321 planet candidates, though some of these have already been flagged as likely false-positives or contamination from binary stars. This animation does not contain circumbinary planets or planet candidates where only a single transit has been observed, which is why "only" 2299 are shown.
One of the most remarkable things about this animation is its ability to highlight not only the power of the Kepler telescope, but its limitations. "Prior to the Kepler mission, we knew of perhaps 500 exoplanets across the whole sky," said Doug Hudgins, Kepler program scientist, in a statement back in January. "Now, in just two years staring at a patch of sky not much bigger than your fist, Kepler has discovered more than 60 planets and more than 2,300 planet candidates." At the same time, keep in mind that a planet needs to pass between the star it orbits and Kepler's field of view in order for the telescope to detect it, which strongly suggests that there are countless other stars our there hiding from Kepler's view, still waiting to be discovered — perhaps as many as 160-billion planets in our galaxy alone.